This is a working overview of counterion, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-10-18. Anything still debated is marked as such rather than presented as settled.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
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.
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.
Verification of a sample usually begins with reversed-phase high-performance liquid chromatography, which resolves the peptide from truncated sequences and other impurities and expresses purity as a percentage of total peak area. Mass spectrometry by electrospray ionisation or matrix-assisted laser desorption supplies an independent check, because the measured mass can be compared against the theoretical value for AEDG. Amino acid analysis or tandem mass spectrometry sequencing can confirm residue order. Each of these methods answers a different question: a purity figure does not establish identity, and an identity match does not establish how much of the material is intact peptide.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic tetrapeptide | Four residues, linear chain |
| Residue sequence | Ala-Glu-Asp-Gly | Single-letter form AEDG |
| Calculated mass | 390.3 daltons | Value for the free, uncharged form |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility | Freely soluble in water | Often handled as a salt form |
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 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.
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.
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.
Reversed-phase high-performance liquid chromatography is the standard approach for assessing purity, usually with ultraviolet detection near 214 nm, where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the molecular mass and helps reveal truncation or deletion byproducts. Amino acid analysis can verify composition, and counterion content is sometimes measured because peptides purified with trifluoroacetic acid retain variable amounts of that salt. Purity figures reported without a stated method and detection wavelength are difficult to interpret.
Material sold for research use varies widely in documented quality. A useful verification package includes a certificate of analysis that states peptide content rather than only net weight, the chromatographic method and column used, and a mass spectrum consistent with the expected mass. Independent testing by a third-party laboratory is occasionally reported. Statements of identity resting only on a supplier label provide little assurance, and the gap between nominal mass and actual peptide content can be substantial once counterions and residual water are counted.
After a diplomatic crisis started between Venezuela and Guyana (both Brazilian neighbours) in October 2023, President Lula tried to mediate a de-escalation while stating that "we do not want and we do not need a war in South America". Officials from Brazil, along with those from the CARICOM, Colombia, the United Nations and the CELAC attended a meeting between Venezuelan and Guyanese presidents in December 2023 to ease tensions between the nations. Brazil offered to host further talks to promote peace in the region, which was agreed by the two countries, and a meeting between Venezuelan and Guyanese Foreign Ministers took place on 25 January 2024, with both parties pledging to keep the peace and hold further talks.
PyMOL – introduce a set of common PTM's into protein models AWESOME – Interactive tool to see the role of single nucleotide polymorphisms to PTM's Chimera – Interactive Database to visualize molecules
Nicolas Steno rejected Paracelsus's proposed organic origin for crystals. Steno first observed the law of constancy of interfacial angles when studying quartz crystals (De solido intra solidum naturaliter contento, Florence, 1669), and noted that, although the crystals of a substance differed in appearance from one to another, the angles between corresponding faces were always the same. Steno's work can be considered as the beginning of crystallography as an independent discipline. In 1678 Christiaan Huygens proposed a structural explanation of the double refraction of calcite based on ellipsoidal atoms. Huygens discovered the polarization of light by Iceland spar, a transparent form of calcite, and published his results in his Traité de la Lumière. Domenico Guglielmini's publications of 1688 (Riflessioni filosofiche dedotte dalle figure de Sali) and 1705 (De salibus dissertatio epistolaris physico-medico-mechanica) concluded that the earliest forms (he noted cube, rhombohedral parallelepiped, hexagonal prism, and octahedron) of various salt crystals are characteristic of each substance, are identical in form, indivisible, and have faces with identical inclinations to each other.
=== 24 January === Several senior and junior ministers resigned from positions in the Ukrainian government, including the deputy head of the President's Office, a deputy Defence Minister, the Deputy Prosecutor-General and the deputy infrastructure minister. German Chancellor Olaf Scholz agreed to provide Leopard 2 tanks and allowed other countries to do the same. Ukraine senior officials stated that around 100 Leopard 2 tanks from twelve countries were ready to be transferred to Ukraine. A missile hit a Turkish-owned cargo ship Tuzla and started a fire while at the Port of Kherson. There were no reported casualties.
Some of a patient's single nucleotide polymorphisms—slight differences in their DNA—can help predict how quickly they will metabolise particular drugs; this is called pharmacogenomics. For example, the enzyme CYP2C19 metabolises several drugs, such as the anti-clotting agent Clopidogrel, into their active forms. Some patients possess polymorphisms in specific places on the 2C19 gene that make poor metabolisers of those drugs; physicians can test for these polymorphisms and find out whether the drugs will be fully effective for that patient. Advances in molecular biology have helped show that some syndromes that were previously classed as a single disease are actually multiple subtypes with entirely different causes and treatments. Molecular diagnostics can help diagnose the subtype—for example of infections and cancers—or the genetic analysis of a disease with an inherited component, such as Silver-Russell syndrome.
Sources: en.wikipedia.org
Diphenoxylate (Lomotil, R-1132) is a centrally active opioid drug of the phenylpiperidine series that is used as a combination drug, prescribed in the United States under the trade name Lomotil, with atropine for the treatment of diarrhea. Diphenoxylate is an opioid and acts by slowing intestinal contractions; the atropine is present to prevent drug abuse and overdose. It should not be given to children due to the risk that they will stop breathing and should not be used in people with Clostridioides difficile infection.
=== Crash === Soon after the big boom, the first problems started to appear. There were problems getting products approved by the FDA and if they got approved there were often difficulties in getting insurance providers to pay for the products and getting it accepted by health care providers. For example, organogenesis ran into problems marketing its product and integrating its product in the health system. This partially due to the difficulties of handling living cells and the increased difficulties faced by physicians in using these products over conventional methods. Another example would be Advanced Tissue Sciences Dermagraft skin product which could not create a high enough demand without reimbursements from insurance providers. Reasons for this were $4000 price-tag and the circumstance that Additionally Advanced Tissue Sciences struggled to get their product known by physicians. The above examples demonstrate how companies struggled to make profit. This, in turn, lead investors to lose patience and stopping further funding. In consequence, several Tissue Engineering companies such as Organogenesis and Advanced Tissue Sciences filed for bankruptcy in the early 2000s. At this time, these were the only ones having commercial skin products on the market.
In size drones vary substantially: the oldest still alive (eight or nine thousand years old) tend to be around the size of humans, whereas later technology allows drones to be small enough to lie in a human's cupped palm; modern drones may be any size between these extremes according to fashion and personal preference. Some drones are also designed as utility equipment with its own sentience, such as the gelfield protective suit described in Excession.
By creating surveillance groups within hospitals, everyone would be held accountable for misconduct and improper disposal of waste. Consequences could be implemented where individuals would be required to pay a fine, or face unpaid suspension from work. Companies and governmental organization should also initiate non-routine checkups and searches, this would place pressure on hospitals to ensure that waste is properly disposed all year round. Voluntary clean-ups would involve hospital staff in assuring that medical waste is not littered around the hospital or thrown into regular garbage bins. Because hospitals, specifically ORs, generate the most medical waste in the healthcare industry, it is crucial for ORs to work towards developing sustainable initiatives. Items used in the operating room that cannot be reused in subsequent surgeries can be repurposed through donations to the community. For example, plastic trays and surgical gowns can be given to art classes, towels to cleaning initiatives, and foam packing to moving companies. Repurposing was taken to the next level by a warehouse called Donations In Kind, run by the Rotary Club, as it takes in repurposed medical supplies from ORs to provide support for hospitals and communities in developing nations. This warehouse is just one of 24 taking on this initiative.
Sources: en.wikipedia.org
Before 1830, few Americans used ice to refrigerate foods due to a lack of ice-storehouses and iceboxes. As these two things became more widely available, individuals used axes and saws to harvest ice for their storehouses. This method proved to be difficult, dangerous, and certainly did not resemble anything that could be duplicated on a commercial scale. Despite the difficulties of harvesting ice, Frederic Tudor thought that he could capitalize on this new commodity by harvesting ice in New England and shipping it to the Caribbean islands as well as the southern states. In the beginning, Tudor lost thousands of dollars, but eventually turned a profit as he constructed icehouses in Charleston, Virginia and in the Cuban port town of Havana. These icehouses as well as better insulated ships helped reduce ice wastage from 66% to 8%. This efficiency gain influenced Tudor to expand his ice market to other towns with icehouses such as New Orleans and Savannah. This ice market further expanded as harvesting ice became faster and cheaper after one of Tudor's suppliers, Nathaniel Wyeth, invented a horse-drawn ice cutter in 1825. This invention as well as Tudor's success inspired others to get involved in the ice trade and the ice industry grew. Ice became a mass-market commodity by the early 1830s with the price of ice dropping from six cents per pound to a half cent per pound. In New York City, ice consumption increased from 12,000 tons in 1843 to 100,000 tons in 1856. Boston's consumption leapt from 6,000 tons to 85,000 tons during that same period.
==== G ==== Genoa salami – an American variety of salami commonly believed to have originated in the area of Genoa. It is normally made from pork, but may also contain beef or be all beef. It is seasoned with garlic, salt, black and white peppercorns, fennel seeds, and red or white wine.
Tulips are mainly distributed along a band corresponding to latitude 40° north, from southeast of Europe (Greece, Albania, North Macedonia, Kosovo, Southern Serbia, Bulgaria, most part of Romania, Ukraine, Russia) and Turkey in the west, through the Levant (Syria, Israel, Palestinian Territories, Lebanon and Jordan) and the Sinai Peninsula. From there it extends eastwards through Jerevan (Armenia), and Baku (Azerbaijan) and on the eastern shore of the Caspian Sea through Turkmenistan, Bukhara, Samarkand and Tashkent (Uzbekistan), to the eastern end of the range in the Pamir-Alai and Tien-Shan mountains in Central Asia, which form the centre of diversity. Further to the east, Tulipa is found in the western Himalayas, southern Siberia, Inner Mongolia, and as far as the northwest of China. While authorities have stated that no tulips west of the Balkans are native, subsequent identification of Tulipa sylvestris subsp. australis as a native of the Iberian Peninsula and adjacent North Africa shows that this may be a simplification. In addition to these regions in the west tulips have been identified in Greece, Cyprus and the Balkans. In the south, Iran marks its furthest extent, while the northern limit is Ukraine. Although tulips are also found throughout most of the Mediterranean and Europe, these regions do not form part of the natural distribution. Tulips were brought to Europe by travellers and merchants from Anatolia and Central Asia for cultivation, from where they escaped and naturalised (see map).
===== Conservation burial ===== Conservation burial is a type of burial where burial fees fund the acquisition and management of new land to benefit native habitat, ecosystems and species. This usually involves a legal document such as a conservation easement. Such burials go beyond other forms of natural burial, which aim to prevent environmental damage caused by conventional burial techniques, by actually increasing benefits for the environment. The idea is for the burial process to be a net positive for the earth rather than just neutral. Scientists have argued that such burials could potentially generate enough funds to save every endangered species on the planet. The Green Burial Council certifies natural and conservation burial grounds in the U.S. and Canada.
==== Electronic Health Records ==== Sharing their electronic health records with people who have T2D helps them to reduce their blood sugar levels. It is a way of helping people understand their own health condition and involving them actively in its management.
Sources: en.wikipedia.org
The peptide contains four residues in the order alanine, glutamate, aspartate and glycine, abbreviated AEDG. The chain is linear and held together by three peptide bonds. Its calculated mass for the uncharged free form is about 390.3 daltons.
Epithalamin refers to a crude preparation derived from bovine pineal tissue, which contains many components. Epitalon is a single synthetic tetrapeptide identified from that material and produced by chemical synthesis. The two names are sometimes confused because early reports treated the synthetic peptide as an active fragment of the extract.
It has been registered for clinical use in Russia, where it is associated with a small family of short peptides. In most other jurisdictions it is not an approved medicine and is traded as a research chemical. Regulatory status varies by country and changes over time.
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.