The short version of thiol group fits in a sentence. The long version — which is the one that helps — is below.
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Interpreting glutathione measurements requires attention to pre-analytical variables. The GSSG concentration in a sample can rise artificially during storage or processing, making the GSH/GSSG ratio unreliable if not controlled. Reference ranges vary by specimen type, assay, and population, so comparisons across studies are difficult. Plasma glutathione is low and sensitive to hemolysis, while whole blood reflects primarily erythrocyte content. Many studies measure total glutathione rather than the reduced and oxidized forms separately, which limits conclusions about redox status.
Accurate measurement of glutathione begins with careful sample handling. Because GSH oxidizes rapidly to GSSG, samples must be processed quickly or frozen immediately. Acid precipitation with metaphosphoric acid or perchloric acid is common; it lowers pH, precipitates proteins, and helps preserve the reduced form. Chelating agents such as EDTA can limit metal-catalyzed oxidation. For whole blood, hemolysis releases glutathione from erythrocytes, so plasma and serum values differ substantially from whole blood values.
Several analytical methods can quantify glutathione, including high-performance liquid chromatography (HPLC) with UV or fluorescence detection for separating GSH and GSSG. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) offers higher specificity and sensitivity, often detecting nanomolar concentrations. The enzymatic recycling assay, often called the Tietze method, measures total glutathione by coupling reduction of GSSG to a colorimetric or fluorometric readout. Capillary electrophoresis and electrochemical detection are also used in specialized laboratories. Each method has distinct advantages and limitations regarding throughput, cost, and susceptibility to interference.
Glutathione reference materials are sensitive to oxygen, light, and elevated temperature. Solid material is typically stored desiccated at -20 °C or below, while solutions require tighter control because thiol oxidation proceeds faster in liquid form. Aqueous solutions are often prepared fresh, kept cold, and protected from air; some protocols add acid or chelating agents to slow metal-catalyzed oxidation. Repeated freeze-thaw cycles can accelerate degradation and should be avoided. Stability data vary by matrix, so laboratories usually verify performance with their own storage conditions.
Quality control for glutathione measurements includes calibration with authenticated standards, internal standards where available, blank correction, and spike recovery checks. Because glutathione can form during sample processing or degrade before analysis, pre-analytical handling is a major source of variability. Interlaboratory comparisons often show differences in reported values due to method-specific calibration and detection principles. Interpretive thresholds are context-dependent, and no single reference range applies across all tissues or matrices. Researchers generally report both reduced and oxidized forms, along with the method and sample handling details.
Quantification of glutathione in biological or food samples commonly uses liquid chromatography coupled to ultraviolet, fluorescence, electrochemical, or mass spectrometric detection. Because the thiol group oxidizes readily, samples are often acidified or derivatized immediately after collection to stabilize reduced glutathione. Enzymatic recycling assays and colorimetric kits offer higher throughput but generally lower specificity than chromatographic methods. Mass spectrometry can distinguish glutathione from related thiols and allow simultaneous measurement of oxidized forms. Reported concentrations depend strongly on sample type, extraction procedure, and analytical platform.
| Property | Value | Notes |
|---|---|---|
| Common analytical method | LC-MS/MS or HPLC | Separation of GSH and GSSG |
| Limit of detection | Nanomolar range | Method dependent |
| Typical sample storage | -80 °C | For biological matrices |
| Common reducing agent | TCEP or DTT | Prevents oxidation during processing |
| Common synonym | Gamma-glutamylcysteinylglycine | Systematic name |
Glutathione functions in redox balance, detoxification, and sulfur amino acid storage. It participates in reactions that help maintain ascorbate and protein thiol status. The molecule serves as a cofactor for several enzymes, including glutathione peroxidases and glutathione S-transferases. These enzymes reduce peroxides and conjugate electrophiles, respectively. Glutathione also contributes to the metabolism of xenobiotics and to the transport of cysteine between tissues. How interorgan transport and tissue-specific regulation shape whole-body pools remains an active area of study.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. Its cysteine residue carries a thiol group, which allows the molecule to participate in reduction and oxidation reactions. The compound exists in most living cells, where the reduced form, often abbreviated GSH, is usually more abundant than the oxidized disulfide form, GSSG. Intracellular concentrations are commonly in the millimolar range, while extracellular concentrations are much lower. This uneven distribution supports its role as a major cellular redox buffer.
Common analytical approaches include enzymatic recycling assays, high-performance liquid chromatography, and mass spectrometry. Enzymatic recycling measures total glutathione after converting GSSG back to GSH, while separation methods can quantify GSH and GSSG separately. Derivatization may be used to improve detection or stability during analysis. LC-MS/MS offers high specificity and can distinguish glutathione from related thiols and adducts. Each method has different sensitivity, throughput, and susceptibility to interference, so method selection depends on the study question and sample matrix.
For solid glutathione reagents, storage at low temperature and protection from moisture and light are typical precautions. Aqueous solutions can oxidize over time, and pH affects stability; alkaline conditions generally promote thiol oxidation. Some protocols prepare fresh solutions, while others use antioxidants or chelators to limit metal-catalyzed oxidation. Purity and counterion content can vary among commercial preparations, affecting concentration calculations. Certificates of analysis and validated assays help verify identity and purity.
The discovery of nuclear fission occurred in 1938 in the buildings of the Kaiser Wilhelm Society for Chemistry, today part of the Free University of Berlin, following over four decades of work on the science of radioactivity and the elaboration of new nuclear physics that described the components of atoms. In 1911, Ernest Rutherford proposed a model of the atom in which a very small, dense and positively charged nucleus of protons was surrounded by orbiting, negatively charged electrons (the Rutherford model). Niels Bohr improved upon this in 1913 by reconciling the quantum behavior of electrons (the Bohr model). In 1928, George Gamow proposed the liquid-drop model, which became essential to understanding the physics of fission. In 1896, Henri Becquerel had found, and Marie Curie named, radioactivity. In 1900, Rutherford and Frederick Soddy, investigating the radioactive gas emanating from thorium, "conveyed the tremendous and inevitable conclusion that the element thorium was slowly and spontaneously transmuting itself into argon gas!" In 1919, following up on an earlier anomaly Ernest Marsden noted in 1915, Rutherford attempted to "break up the atom." Rutherford was able to accomplish the first artificial transmutation of nitrogen into oxygen, using alpha particles directed at nitrogen 14N + α → 17O + p. Rutherford stated, "...we must conclude that the nitrogen atom is disintegrated," while the newspapers stated he had split the atom.
Although no approved therapeutics are based on ricin, it does have the potential to be used in the treatment of tumors to destroy targeted cells. Because ricin is a protein, it can be linked to a monoclonal antibody to target cancerous cells recognized by the antibody. The major problem with ricin is that its native internalization sequences are distributed throughout the protein. If any of these native internalization sequences are present in a therapeutic agent, the drug will be internalized by, and kill, untargeted non-tumorous cells as well as targeted cancerous cells. Modifying ricin may sufficiently lessen the likelihood that the ricin component of these immunotoxins will cause the wrong cells to internalize it, while still retaining its cell-killing activity when it is internalized by the targeted cells. However, bacterial toxins, such as diphtheria toxin, which is used in denileukin diftitox, an FDA-approved treatment for leukemia and lymphoma, have proven to be more practical. A promising approach for ricin is to use the non-toxic B subunit (a lectin) as a vehicle for delivering antigens into cells, thus greatly increasing their immunogenicity. Use of ricin as an adjuvant has potential implications for developing mucosal vaccines.
Chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) is an organic compound mainly used as a broad spectrum, nonsystemic fungicide, with other uses as a wood protectant, pesticide, acaricide, and to control mold, mildew, bacteria, algae. Chlorothalonil-containing products are sold under the names Bravo, Echo, and Daconil. It was first registered for use in the US in 1966. In 1997, it was the third most used fungicide in the US, behind only sulfur and copper, with 12 million pounds (5.4 million kilograms) used in agriculture that year. Including nonagricultural uses, the United States Environmental Protection Agency (EPA) estimates, on average, almost 15 million lb (6.8 million kg) were used annually from 1990 to 1996.
When her husband died in 1882 she told the Boston Globe that malicious animal magnetism had killed him. While Eddy argued that reality was entirely spiritual (and therefore entirely good), it remained true that human beings were affected by their belief in evil, which meant it had power, even if the power was an illusion. Evil was "like a bankrupt to whom credit is still granted", writes Wilson. To defend herself against it, Eddy organized "watches", during which students (known as mental or metaphysical workers) would give "adverse treatment" to her enemies. This was called "taking up the enemy in thought". According to former students, Eddy would tell them to say (often with Richard Kennedy in mind): "You are affected as you wish to affect me. Your evil thought reacts upon you," then to call Kennedy bilious, consumptive or poisoned by arsenic. Eddy set up what she called a secret society of her students (known as the P. M., or private meeting) to deal with malicious animal magnetism, but she said that the group only met twice. In her later years, Wilson writes, Eddy came to see animal magnetism as an impersonal force and concluded that individuals ought not to be "taken up in thought". From 1890 she felt that her students were focusing on it too much, and thereafter public discussion of malicious animal magnetism declined, although Gottschalk adds that it continued to play an important role in the teaching of Christian Science. Adam H.
Sources: en.wikipedia.org
=== Phase 1 === AZD-4041 – orexin OX1 receptor antagonist – opioid-related disorders BI-1356225 – ghrelin O-acyltransferase (GOAT) inhibitor – opioid-related disorders Cebranopadol (GRT-6005; PRK-101; TRN-228) – μ-opioid receptor agonist, nociceptin receptor agonist – substance-related disorders CSX-1004 – monoclonal antibody against fentanyl – opioid-related disorders Dimethyltryptamine/harmine (DMT/harmine; RE-01) – combination of dimethyltryptamine (DMT) (serotonin 5-HT2A receptor agonist and serotonergic psychedelic) and harmine (monoamine oxidase inhibitor (MAOI) and other actions) – cocaine-related disorders DPI-125 (MCP-201) – μ-opioid receptor agonist, δ-opioid receptor agonist, κ-opioid receptor agonist – opioid-related disorders Ibuprofen/ketotifen (SJP-005) – combination of ibuprofen (cyclooxygenase (COX) inhibitor/NSAID) and ketotifen (histamine H1 receptor antagonist, other actions) – opioid-related disorders Icalcaprant (ABBV-1354; CVL-354) – κ-opioid receptor antagonist – opioid-related disorders KNX-100 (SOC-1) – oxytocin-like drug / indirect oxytocin receptor modulator – opioid-related disorders, substance-related disorders Mavoglurant (AFQ-056; STP-7) – metabotropic glutamate mGlu5 receptor antagonist – cocaine-related disorders MEB-1170 – μ-opioid receptor biased agonist – opioid-related disorders Mebufotenin (5-MeO-DMT) – non-selective serotonin receptor agonist, serotonin 5-HT1A and 5-HT2A receptor agonist, and serotonergic psychedelic – substance use disorders MST-01 – undefined mechanism of action – smoking withdrawal Nalmefene (AV-104; TH-104) – μ-opioid receptor antagonist, κ-opioid receptor weak partial agonist – opioid-related disorders Naltrexone implantable pellets (BICX-102, BICX-104) – opioid receptor antagonist – alcoholism, opioid-related disorders, substance-related disorders Nezavist (DCUK-OEt) – peripherally selective GABAA receptor positive allosteric modulator (etomidate site) – alcoholism Noribogaine (DMX-1001) – various actions – alcoholism NRS-033 (nalmefene prodrug) – μ-opioid receptor antagonist, κ-opioid receptor weak partial agonist – opioid-related disorders OMS-527 (OMS-182399; OMS527) – phosphodiesterase PDE7 inhibitor – cocaine-related disorders Psilocybin (MLS-101/MLS101) – non-selective serotonin receptor agonist, serotonin 5-HT2A receptor agonist, serotonergic psychedelic – opioid-related disorders Smoking cessation therapeutics - Astraea Therapeutics – nicotinic acetylcholine receptor antagonists – smoking withdrawal SXC-2023 – cystine/glutamate transporter (SLC7A11) – cocaine-related disorders Tezampanel (LY-293558; NGX-424; PRN-001-01) – ionotropic glutamate AMPA and kainate receptor antagonist – opioid-related disorders Zabaglurant (Heptares 25; HTL-0014242; HTL14242; TMP-301) – metabotropic glutamate mGlu5 receptor negative allosteric modulator – cocaine-related disorders, substance-related disorders
== See also == History of atomic theory History of molecular theory History of crystallography before X-rays Geometrical crystallography before X-rays Physical crystallography before X-rays Timeline of chemistry Timeline of crystallography
=== 16 March === Poland announced that it will provide four MiG-29s to Ukraine with in the next few days. The rest of Poland's MiG-29 fleet is being serviced to also be ready for transfer at a later time. The total number to be sent is unclear with different sources speculating from 11 to 19.
== Aging == With age, tissue homeostasis declines partly because stem/progenitor cells fail to self-renew or differentiate. DNA damage caused by exposure of stem/progenitor cells to reactive oxygen species (ROS) may play a key role in epidermal stem cell aging. Mitochondrial superoxide dismutase (SOD2) ordinarily protects against ROS. Loss of SOD2 in mouse epidermal cells was observed to cause cellular senescence that irreversibly arrested proliferation in a fraction of keratinocytes. In older mice, SOD2 deficiency delayed wound closure and reduced epidermal thickness.
In the case of chain-end scission, monomers are released and this process is referred to as unzipping or depolymerization. Which mechanism dominates will depend on the type of polymer and temperature; in general, polymers with no or a single small substituent in the repeat unit will decompose via random-chain scission. The sorting of polymer waste for recycling purposes may be facilitated by the use of the resin identification codes developed by the Society of the Plastics Industry to identify the type of plastic.
Sources: en.wikipedia.org
Belize has a high prevalence of communicable diseases such as respiratory diseases and intestinal illnesses. Under the second term of the Briceño administration, the long-awaited free health care for all Belizeans was launched. The programme is the National Health Insurance Belize and it has been implemented by region until 100% of the population is covered. Health care is practically free and fees if any, are charged from 10% to as low as .5% of total cost on treatments and medications.
=== Encounters with humans === Attacks on humans are rare, but Komodo dragons have been responsible for several human fatalities, both in the wild and in captivity. According to data from Komodo National Park spanning a 38-year period between 1974 and 2012, there were 24 reported attacks on humans, five of them fatal. Most of the victims were local villagers living around the national park. Komodo dragons generally avoid encounters with humans. Juveniles are very shy and will flee quickly into a hideout if a human comes closer than about 100 metres (330 ft). Older animals will also retreat from humans from a shorter distance away. If cornered, they may react aggressively by gaping their mouth, hissing, and swinging their tail. If they are disturbed further, they may attack and bite. Although there are anecdotes of unprovoked Komodo dragons attacking or preying on humans, most of these reports are either not reputable or have subsequently been interpreted as defensive bites. Only very few cases are truly the result of unprovoked attacks by atypical individuals who lost their fear of humans.
== IUBMB classification == Oxidoreductases, enzymes that catalyze oxidation-reduction reactions, constitute Class EC 1 of the IUBMB classification of enzyme-catalyzed reactions. Any of these may be called dehydrogenases, especially those in which NAD+ is the electron acceptor (oxidant), but reductase is also used when the physiological emphasis on reduction of the substrate, and oxidase is used only when O2 is the electron acceptor. The systematic name of an oxidoreductase is "donor:acceptor oxidoreductase", but, when possible, it is more conveniently named as "donor dehydrogenase".
==== Acupuncture and other interventions ==== While acupuncture leads to improvements in pain relief, this improvement is small and may be of questionable importance. Waiting list–controlled trials for peripheral joint osteoarthritis do show clinically relevant benefits, but these may be due to placebo effects. Acupuncture does not seem to produce long-term benefits. Electrostimulation techniques such as TENS have been used to treat osteoarthritis in the knee. However, there is no conclusive evidence to show that it reduces pain or disability. A Cochrane review of low-level laser therapy found unclear evidence of benefit, whereas another review found short-term pain relief for osteoarthritic knees. Further research is needed to determine if balneotherapy for osteoarthritis (mineral baths or spa treatments) improves a person's quality of life or ability to function. There is low-quality evidence that therapeutic ultrasound may be beneficial for people with osteoarthritis of the knee; however, further research is needed to confirm and determine the degree and significance of this potential benefit. Therapeutic ultrasound is safe and reduces pain and improves physical function in knee osteoarthritis. While phonophoresis does not improve functions, it may offer greater pain relief than standard non-drug ultrasound. There is weak evidence suggesting that electromagnetic field treatment may result in moderate pain relief; however, further research is necessary, and it is not known if electromagnetic field treatment can improve quality of life or function.
Sources: en.wikipedia.org
Glutathione oxidizes quickly when cells are disrupted or when samples sit at room temperature. Rapid processing or immediate freezing minimizes the conversion of GSH to GSSG. This step helps ensure that the measured ratio reflects the original biological state.
The Tietze assay is an enzymatic recycling method that measures total glutathione. It uses glutathione reductase to reduce GSSG back to GSH, which then reacts with a chromogen or fluorophore. The reaction cycles repeatedly, amplifying the signal for detection.
Yes, but the choice of blood fraction matters. Plasma or serum contains low glutathione levels and is easily affected by hemolysis. Whole blood mainly reflects the high glutathione content of erythrocytes, so results from different fractions are not directly comparable.
Acidification lowers pH and helps prevent oxidation of the thiol group during extraction and storage. It can also precipitate proteins and stabilize the reduced form before analysis.