Telomerase comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-05-31. Where a claim depends on a specific study, the study is described rather than over-claimed.
The published literature is dominated by a small number of research groups, much of it in Russian-language journals, and independent replication outside those groups is limited. Studies are typically small, use cultured cells or rodent models, and report endpoints that differ between papers, which makes comparison difficult. Large randomised human trials have not appeared in the indexed literature. Questions about absorption, distribution and clearance are therefore still treated as open in reviews that mention the compound.
Epitalon is a synthetic tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. Its design traces to epithalamin, a peptide fraction prepared from bovine pineal gland extracts that researchers in Saint Petersburg began investigating in the 1970s. The compound has a molecular formula of C14H22N4O9 and a nominal molecular mass near 390 daltons. It holds no approved drug status in the United States or the European Union, and material sold under this name is generally offered as a research chemical rather than a finished pharmaceutical product.
Proposed mechanisms centre on cell-culture observations rather than a defined receptor interaction. Several reports describe increased expression of the telomerase catalytic subunit after exposure of cultured human cells, and the authors attributed the effect to short peptide fragments entering the nucleus and influencing gene transcription. No receptor for the tetrapeptide has been identified, and the free peptide is expected to be degraded rapidly by plasma peptidases. Whether any measurable fraction reaches intact tissues after administration remains an unresolved question rather than an established finding.
The molecule is a short, linear, hydrophilic peptide that dissolves readily in water or aqueous buffer. Its principal chemical liabilities are hydrolytic rather than oxidative, since it contains no cysteine, methionine, or tryptophan residues. The aspartate–glycine step is a recognised site for aspartimide formation under mildly acidic or basic conditions, generating isoaspartate and succinimide-related products over time. Desiccated lyophilised powder held at −20 °C is comparatively stable, whereas dilute solutions degrade faster and are best frozen as single-use aliquots rather than thawed repeatedly.
No pharmacopoeial monograph exists for this peptide, so quality rests on the supplier's internal specifications and on whatever independent testing a purchaser arranges. Certificates of analysis differ widely in which tests they report and in the limits applied. The counter-ion introduced during purification, commonly acetate or trifluoroacetate, changes the net peptide content of a given mass of powder, so two samples of equal weight may not contain equal amounts of the active sequence. Third-party laboratories can verify purity, identity, residual solvents, and counter-ion content for a fee, which makes documentation more informative than labelling.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Synthetic tetrapeptide, four residues |
| Nominal mass | Approximately 390 Da | Free peptide; salt forms differ |
| Appearance | White to off-white powder | Commonly supplied lyophilised |
| Solubility class | Freely soluble in water | Also dissolves in aqueous buffer |
| Typical storage | −20 °C, desiccated | Cold packs used during transport |
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
Human data are limited to small studies, often without the randomization, blinding, or control groups expected in contemporary clinical research. Reported outcomes have included changes in melatonin levels, immune markers, and subjective measures, but sample sizes were generally too small to support firm conclusions. Some reviews treat the peptide as promising while noting methodological weaknesses; others question whether the observed effects are specific. The compound is frequently discussed in longevity-focused communities, where enthusiasm often outpaces the published evidence. Separating established findings from speculation is therefore important when reading summaries of this research.
Epitalon emerged from research conducted in Saint Petersburg by Vladimir Khavinson and colleagues, who studied short peptides as potential regulators of aging. The work built on epithalamin, a pineal gland extract reported to influence neuroendocrine function. Epitalon was designed as a synthetic counterpart with a defined sequence, allowing reproducible experiments that extracts could not support. Early publications described effects on melatonin rhythms and lifespan in animal models. These findings circulated mainly in Russian-language journals during the 1990s, which limited their visibility among English-speaking researchers.
Atenolol is a beta blocker medication primarily used to treat high blood pressure and heart-associated chest pain. Although used to treat high blood pressure, it does not seem to improve mortality in those with the condition. Other uses include the prevention of migraines and treatment of certain irregular heart beats. It is taken orally (by mouth) or by intravenous injection (injection into a vein). It can also be used with other blood pressure medications. Common side effects include feeling tired, heart failure, dizziness, depression, and shortness of breath. Other serious side effects include bronchial spasm. Use is not recommended during pregnancy and alternative drugs are preferred when breastfeeding. It works by blocking β1-adrenergic receptors in the heart, thus decreasing heart rate, force of heart beats, and blood pressure. Atenolol was patented in 1969 and approved for medical use in 1975. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication. In 2023, it was the 75th most commonly prescribed medication in the United States, with more than 9 million prescriptions.
However, a June 2017 study found that (2R,6R)-HNK does in fact block the NMDA receptor, similarly to ketamine. These findings suggest that the antidepressant-like effects of (2R,6R)-HNK may not actually be NMDA receptor-independent and that it may act in a similar manner to ketamine. Ketamine, (2R,6R)-HNK, and (2S,6S)-HNK have been found to be possible ligands of the estrogen receptor ERα (IC50 = 2.31, 3.40, and 3.53 μM, respectively). In 2024, HNK was found to act as a highly potent positive allosteric modulator of the opioid receptors, including of the μ-opioid receptor (MOR). It shares this action with ketamine and norketamine. They are all active in this action at very low concentrations, for instance 1 nM. Ketamine, norketamine, and HNK can potentiate the effects of endogenous opioids like met-enkephalin and exogenous opioids like morphine. Opioid receptor positive allosteric modulation by these agents may be involved in their therapeutic effects, for instance their antidepressant and analgesic effects.
Congenital abnormalities: Atrial septal defect Aortopulmonary window Ebstein's Anomaly Patent Ductus Arteriosus (PDA) Surgical intervention: Transcatheter closure of a PDA Incidence: due to the close proximity of the LRLN to the aortic arch, transient paralysis can occur in 10% of cases while permanent effects can occur in 1% of cases. This can further be attributed to using metal clips (used to control bleeding) during the surgical procedure and is more common in premature infants. Cardiac disease: Left atrial enlargement due to valvular heart disease Notable case: A middle-aged male had ongoing cough, hoarseness of voice, and shortness of breath for two years without a history of smoking was found to have mitral valve stenosis due to calcification. This led to left atrial enlargement, elevated pulmonary artery pressure, pulmonary artery hypertension, and right ventricular enlargement. This cardiomegaly, or enlargement of the heart, led to compression of the LRLN. Atrial Myxoma Aorta: Traumatic injury Incidence: Although injury to the thoracic aorta is often fatal, in 10% of cases that take longer to present, hoarseness may be the first symptom. Aortic dissection More commonly affects the right recurrent laryngeal nerve as the most common type of aortic dissection is type A (Figure 2). Pseudoaneurysm Notable case: A male with long-standing uncontrolled hypertension and hoarseness of voice attributed to life-long smoking was found to have a pseudoaneurysm of the aortic arch which was compressing the LRLN.
==== Variable phenomena – dependently arisen processes ==== The principle of conditionality, which is real and stable, is contrasted with the "dependently arisen processes", which are described as "impermanent, conditioned, dependently arisen, of a nature to be destroyed, of a nature to vanish, of a nature to fade away, of a nature to cease." SA 296 describes them simply as "arising thus according to causal condition, these are called dharmas arisen by causal condition."
Sources: en.wikipedia.org
=== Persons with disabilities === During 2025, the Karnataka Labour Department worked on a proposed legislative framework for reservations for persons with disabilities in education and private-sector employment. The draft framework proposed up to 10 percent reservation in educational institutions and 5 percent in private-sector employment, subject to legislative and policy processes.
== Early life == Princess Zita of Bourbon-Parma was born at the Villa Pianore in the Italian Province of Lucca, 9 May 1892. The unusual name Zita was given to her after Zita, a popular Italian saint who had lived in Tuscany in the 13th century. She was the third daughter and fifth child of the deposed Robert I, Duke of Parma, and his second wife, Infanta Maria Antonia of Portugal, a daughter of King Miguel of Portugal and his wife Adelaide of Löwenstein-Wertheim-Rosenberg. Zita's father had lost his throne as a result of the movement for Italian unification in 1859 when he was still a child. He fathered twelve children during his first marriage to Princess Maria Pia of the Two Sicilies (six of whom were mentally disabled, and three of whom died young). Duke Robert became a widower in 1882, and two years later he married Infanta Maria Antonia of Portugal. The second marriage produced a further twelve children. Zita was the 17th among Duke Robert's 24 children. Robert moved his large family between Villa Pianore (a large property located between Pietrasanta and Viareggio) and his Schwarzau Castle in Lower Austria. It was mainly in these two residences that Zita spent her formative years. The family spent most of the year in Austria, moving to Pianore in the winter and returning in the summer. To move between them, they took a special train with sixteen coaches to accommodate the family and their belongings.
=== Cinematography === Ricoh GR digital cameras, a series of digital cameras manufactured by Ricoh Ricoh GR (large sensor compact camera), the current line of cameras in the GR series Golmaal Returns, a Hindi comedy film Generator Rex, an animated sci-fi series Guilty Remnant, a fictional cult in The Leftovers (TV series)
Levamisole is one of the most common cutting agents used to lace illicit cocaine, with studies showing that between 2009 and 2016, 50–70% of all cocaine specimens worldwide contained levamisole, reflecting similar high rates of contamination across North America and Europe. Before trafficking to the United States, the cocaine is frequently adulterated with levamisole. By October 2017, this figure had risen further, with the US Drug Enforcement Administration (DEA) reporting that 87% of seized and analyzed cocaine bricks in the United States contained levamisole, making it the most common adulterant in cocaine at that time. In the body, levamisole is converted into aminorex, a substance with amphetamine-like stimulant effects and a long duration of action. Levamisole-adulterated cocaine is associated with cocaine/levamisole-associated autoimmune syndrome (CLAAS) and cocaine- and levamisole-induced vasculitis (CLIV). Reagent testing kits can be used to detect the presence of cocaine and levamisole.
== Bibliography == Catinon, M., Ayrault, S., Boudouma, O., Bordier, L., Agnello, G., Reynaud, S., & Tissut, M. (2014). Isolation of technogenic magnetic particles. Science of the Total Environment, 475, 39-47 (abstract).
Sources: en.wikipedia.org
Caffeine from coffee or other beverages is absorbed by the small intestine within 45 minutes of ingestion and distributed throughout all bodily tissues. Peak blood concentration is reached within 1–2 hours. It is eliminated by first-order kinetics. Caffeine can also be absorbed rectally, evidenced by suppositories of ergotamine tartrate and caffeine (for the relief of migraine) and of chlorobutanol and caffeine (for the treatment of hyperemesis). However, rectal absorption is less efficient than oral: the maximum concentration (Cmax) and total amount absorbed (AUC) are both about 30% (i.e., 1/3.5) of the oral amounts. Caffeine's biological half-life – the time required for the body to eliminate one-half of a dose – varies widely among individuals according to factors such as pregnancy, other drugs, liver enzyme function level (needed for caffeine metabolism) and age. In healthy adults, caffeine's half-life is between 3 and 7 hours. The half-life is decreased by 30–50% in adult male smokers, approximately doubled in women taking oral contraceptives, and prolonged in the last trimester of pregnancy. In newborns the half-life can be 80 hours or more, dropping rapidly with age, possibly to less than the adult value by age 6 months. The antidepressant fluvoxamine (Luvox) reduces the clearance of caffeine by more than 90%, and increases its elimination half-life more than tenfold, from 4.9 hours to 56 hours.
== Role in hydrocarbon generation == When animal or plant matter is buried during sedimentation, the constituent organic molecules (lipids, proteins, carbohydrates and lignin-humic compounds) break down due to the increase in temperature and pressure. This transformation occurs in the first few hundred meters of burial and results in the creation of two primary products: kerogens and bitumens. It is generally accepted that hydrocarbons are formed by the thermal alteration of these kerogens (the biogenic theory). In this way, given certain conditions (which are largely temperature-dependent) kerogens will break down to form hydrocarbons through a chemical process known as cracking, or catagenesis. A kinetic model based on experimental data can capture most of the essential transformation in diagenesis, and a mathematical model in a compacting porous medium to model the dissolution-precipitation mechanism. These models have been intensively studied and applied in real geological applications. Diagenesis has been divided, based on hydrocarbon and coal genesis into: eodiagenesis (early), mesodiagenesis (middle) and telodiagenesis (late). During the early or eodiagenesis stage shales lose pore water, little to no hydrocarbons are formed and coal varies between lignite and sub-bituminous. During mesodiagenesis, dehydration of clay minerals occurs, the main development of oil genesis occurs and high to low volatile bituminous coals are formed. During telodiagenesis, organic matter undergoes cracking and dry gas is produced; semi-anthracite coals develop.
=== Allotropes === At ambient conditions, berkelium assumes its most stable α form which has a hexagonal symmetry, space group P63/mmc, lattice parameters of 341 pm and 1107 pm. The crystal has a double-hexagonal close packing structure with the layer sequence ABAC and so is isotypic (having a similar structure) with α-lanthanum and α-forms of actinides beyond curium. This crystal structure changes with pressure and temperature. When compressed at room temperature to 7 GPa, α-berkelium transforms to the β modification, which has a face-centered cubic (fcc) symmetry and space group Fm3m. This transition occurs without change in volume, but the enthalpy increases by 3.66 kJ/mol. Upon further compression to 25 GPa, berkelium transforms to an orthorhombic γ-berkelium structure similar to that of α-uranium. This transition is accompanied by a 12% volume decrease and delocalization of the electrons at the 5f electron shell. No further phase transitions are observed up to 57 GPa. Upon heating, α-berkelium transforms into another phase with an fcc lattice (but slightly different from β-berkelium), space group Fm3m and the lattice constant of 500 pm; this fcc structure is equivalent to the closest packing with the sequence ABC. This phase is metastable and will gradually revert to the original α-berkelium phase at room temperature. The temperature of the phase transition is believed to be quite close to the melting point.
Pantoprazole was the third PPI and was introduced to the German market in 1994. It has a difluoroalkoxy sidegroup on the benzimidazole part and two methoxy groups in position 3 and 4 on the pyridine. Pantoprazole was first prepared in April 1985 by a small group of scale-up chemists. It is a dimethoxy-substituted pyridine bound to a fluoroalkoxy substituted benzimidazole. Pantoprazole sodium is available as gastroresistant or delayed release tablets and as lyophilized powder for intravenous use.
28 October 2014: Wilkinson A/L Primus, a Malaysian convicted of trafficking heroin in 2008 and sentenced to death in 2009. When changes to the law took effect in 2013, he applied for re-sentencing and was re-sentenced to life imprisonment in 2014 on the grounds that he was intellectually challenged and suffering from depression at the time of the crime. 20 April 2015: Cheong Chun Yin, a Malaysian convicted of trafficking heroin in 2008 and sentenced to death in 2010. He lost his appeal to the Court of Appeal in 2010. When changes to the law took effect in 2013, he applied for re-sentencing and was re-sentenced in 2015 to life imprisonment and 15 strokes of the cane. His boss and accomplice, Pang Siew Fum, was also re-sentenced to life imprisonment on the same day, due to Pang suffering from depression at the time of the crime. 1 July 2015: Kester Ng Wei Ren, a 47-year-old Singaporean caught trafficking in 23.38g of heroin on 12 August 2008. He tried to argue that he only meant to import only 9.92g of heroin while the rest of his drug supply was only meant for his own consumption. Ng was given the mandatory death penalty in 2010 and he also lost his appeal in the same year. After changes to the law took effect in 2013, Ng applied for re-sentencing but he did not meet the criteria to be re-sentenced to life imprisonment. Hence he lost his appeal to be re-sentenced on 1 July 2015 since he was not certified as a courier. He was presumably executed sometime following the loss of his re-sentencing application.
Sources: en.wikipedia.org
No. Epithalamin is a heterogeneous peptide fraction obtained from pineal gland extract and contains many components. Epitalon is a single synthetic tetrapeptide with the sequence Ala-Glu-Asp-Gly. Researchers synthesised the shorter peptide while attempting to identify active sequences within the extract.
No endogenous peptide with this exact sequence has been described as a circulating hormone or signalling molecule. The tetrapeptide was designed as a synthetic analogue based on fragments observed in pineal preparations. Any activity discussed in the literature therefore refers to administered material rather than to a natural pool of the compound.
It is not an approved medicine in major jurisdictions and does not appear in the major pharmacopoeias. Material is usually distributed as a research chemical or laboratory reagent. Such labelling places handling responsibility on the purchaser and does not indicate that a regulatory body has reviewed the substance.
Mass spectrometry provides the identity check, because the observed mass is compared with the theoretical mass of the AEDG sequence. Chromatography separates and quantifies impurities but does not by itself prove which peptide is present. The two techniques are normally used together.