If you have been reading about mass spectrometry and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-12-11. Where a claim depends on a specific study, the study is described rather than over-claimed.
Pharmacokinetic behaviour differs sharply between the two forms. The DAC-bearing peptide shows an extended circulation time measured in days, whereas the version without the complex is cleared within roughly half an hour. This gap shapes how researchers design dosing schedules in animal models. Whether the prolonged presence of the DAC form produces effects meaningfully different from the short-acting variant remains an open question, since comparative human data are scarce.
CJC-1295 is a synthetic peptide designed to mimic growth hormone-releasing hormone (GHRH), the endogenous signal that prompts the pituitary gland to release growth hormone. The compound is a modified fragment of the natural hormone, spanning the first twenty-nine amino acids of GHRH with several substitutions that slow enzymatic breakdown. Two variants circulate in research settings: one carrying a drug affinity complex (DAC) and one without it. The DAC-free form is frequently labelled Mod GRF(1-29) in catalogs and discussion forums.
The peptide binds GHRH receptors on somatotroph cells within the anterior pituitary, triggering a signalling cascade that increases growth hormone secretion. Its improved resistance to dipeptidyl peptidase IV degradation distinguishes it from the parent hormone. In the DAC-bearing version, a maleimide group reacts with a cysteine residue on serum albumin, forming a covalent bond that keeps the peptide in circulation far longer. That albumin attachment is the central design feature separating the two research variants.
The core sequence keeps the receptor-binding region of GHRH while replacing four positions that are vulnerable to dipeptidyl peptidase-4 and other proteases. Substitutions at positions 2, 8, 15, and 27 raise metabolic stability relative to the natural hormone. The N-terminal residues remain essential for activity, so changes there generally lower potency. Molecular weight sits near 3368 daltons for the tetrasubstituted analog without the linker, while the albumin-binding form is heavier because of the added maleimide group.
CJC-1295 is a synthetic peptide modeled on growth hormone-releasing hormone, the hypothalamic signal that prompts the pituitary to release growth hormone. Its sequence corresponds to the first twenty-nine residues of human GHRH, with four substitutions that slow enzymatic breakdown. Early descriptions placed the compound in research on growth hormone deficiency and related conditions, and later literature groups it with the long-acting GHRH analogs. The name appears in both laboratory and popular fitness writing, where it sometimes labels chemically different peptides.
| Property | Value | Notes |
|---|---|---|
| Molecular weight (with DAC) | ~3647 Da | Calculated from the full amino acid sequence |
| Molecular weight (without DAC) | ~3368 Da | Mod GRF(1-29) variant |
| Appearance | White lyophilized powder | Typical form supplied for research |
| Solubility | Soluble in water | Dissolves in aqueous buffers |
| Receptor target | GHRH receptor | Expressed on pituitary somatotroph cells |
Two forms circulate in research settings and are frequently confused. One carries the drug affinity complex and is often written as CJC-1295 with DAC; the other lacks that group and is usually called modified GRF(1-29). The two share the same core sequence but differ sharply in how long they persist in blood. Products labelled only as CJC-1295 normally refer to the version carrying the complex. Documentation that omits the distinction leaves the intended molecule ambiguous.
CJC-1295 is a synthetic peptide built as a long-acting analogue of growth hormone-releasing hormone. Its backbone matches the first twenty-nine residues of the natural human hormone, with four amino acid substitutions added to slow enzymatic breakdown. A reactive maleimide group, commonly termed the drug affinity complex, allows the peptide to attach to circulating albumin after administration. That albumin attachment keeps the molecule in the bloodstream for an extended period instead of being cleared within minutes.
The compound emerged from work at a Canadian biotechnology firm in the early 2000s. Early human studies examined its effect on growth hormone and insulin-like growth factor 1 in healthy volunteers and in people with HIV-associated fat redistribution. Reports described sustained increases in both markers after a single injection. Development did not advance to regulatory approval, and the clinical programme was later discontinued. The molecule is now encountered mainly as a research chemical rather than a marketed medicine.
Batch-to-batch consistency depends on solid-phase peptide synthesis and subsequent purification. Coupling efficiency, resin choice, and cleavage conditions all affect the final profile. Counter-ion content and moisture can shift the apparent mass of a batch. Documentation typically includes a certificate of analysis with chromatograms and spectra. Independent verification by a second laboratory is sometimes requested. Whether a given certificate reflects the actual vial contents depends on chain of custody. Analytical methods themselves carry uncertainty that should be stated alongside results.
Lyophilized material is typically stored at minus twenty degrees Celsius or lower. Keeping the vial dry and protected from light preserves peptide integrity. Repeated freeze-thaw cycles can cause aggregation or loss of activity. Once dissolved, solutions are generally kept at two to eight degrees Celsius. Stability data for reconstituted solutions vary, and long-term behavior is not fully established. Working aliquots reduce the number of times a stock container is opened.
Reverse-phase high-performance liquid chromatography is the standard tool for purity assessment. The technique separates the target peptide from truncated or modified byproducts. Mass spectrometry confirms molecular weight and supports sequence verification. Electrospray ionization and matrix-assisted laser desorption are both used. Amino acid analysis provides an independent check on composition. Purity values are commonly reported as area percentage from the chromatogram. Residual trifluoroacetate and water content are also measured in many quality programs.
The climate of mainland Portugal and Madeira, together with their surrounding waters, is Mediterranean, whereas the Azores and its adjacent waters mainly have a temperate oceanic climate. Portugal's terrain has a diverse variety of regional climates for its size. The average temperature in Portugal varies from 4–20 °C (39.2–68.0 °F) in the mainland, around 18 °C (64.4 °F) in the Azores, and 9–19 °C (48.2–66.2 °F) in Madeira. The Iberian Peninsula is located at the southern margin of the temperate zone and at the northern margin of the subtropical high-pressure zone. Additionally, Portugal's climate is influenced by the seasonal latitudinal shift of the jet stream, which directly impacts the trajectory of the polar front. Typically in the winter, the jet stream moves southwards and Portugal comes under the influence of the polar front, producing colder temperatures. When the polar front moves northward, Portugal comes under the influence of the Azores High bringing atmospheric stability during the summer. Upwelling occurs at the coast creating the Nortada, a summer wind along the coast. Wildfires are a serious challenge in Portugal, with nearly 30% of those recorded in 2024 having an undetermined origin and arson accounting for almost five-sixths of the total burned area. Between 2014 and 2024, Portugal recorded an annual average of 12,496 fires and 112,455 ha (434 sq mi) burned, making it the European Union country with both the highest average number of wildfires and the greatest average burned area over that period.
Illicium comes from the Latin illicio meaning "entice" or "seduce". Verum means "true" or "genuine". The name "badian" appears to derive, via French badiane, from the apparently descriptive Chinese name for it, 八角, pinyin: bājiǎo, lit. "eight horns". However, a derivation from the Persian بادیان bādiyān, "fennel", exists, with the Oxford English Dictionary indicating that its origin before that is unknown.
=== Approval history === On 22 December 2009, a New Drug Application (NDA) was submitted to the Food and Drug Administration (FDA) in the United States. On 16 September 2010, an FDA advisory panel voted 9–5 against approval of the drug based on concerns over both efficacy and safety, particularly the findings of mammary gland tumors of female rats. On 23 October 2010, the FDA decided not to approve the drug based on the available data. This was not only because cancer promoting properties could not be ruled out, but also because the weight loss efficacy was considered "marginal". On 10 May 2012, after a new round of studies submitted by Arena, an FDA panel voted to recommend lorcaserin with certain restrictions and patient monitoring. The restrictions include patients with a BMI of over 30, or with a BMI over 27 and a comorbidity such as high blood pressure or type 2 diabetes. On 27 June 2012, the FDA approved lorcaserin for use in adults with a body mass index (BMI) of 30 or greater (obese), or adults with a BMI of 27 or greater (overweight) and who had at least one weight-related condition such as high blood pressure (hypertension), type 2 diabetes, or high cholesterol (dyslipidemia). On 15 July 2016, the FDA approved the extended release version of lorcaserin for weight management with once-daily dosing instead of twice daily dosing. On 17 September 2020, the FDA withdrew approval for lorcaserin and for extended-release lorcaserin tablets.
Because primordial chemical elements often consist of more than one primordial isotope, there are only 83 distinct primordial chemical elements. Of these, 80 have at least one observationally stable isotope and three additional primordial elements have only radioactive isotopes (bismuth, thorium, and uranium).
== Urocortin affinity to receptors == Compared to UCN II or UCN III, UCN I has a greater binding affinity for the CRHR1 receptor. Urocortin III is extremely selective for the CRF2 receptor, in contrast to Urocortin I and comparable to Urocortin II. Of the two closely related CRF receptors (CRFR1 and CRFR2) that are members of the class B family of G protein-coupled receptors, each peptide activates at least one of them. CRFR2 can be effectively activated by UCN II and UCN III. By attaching itself to CRHR2 with a strong affinity, this peptide (UCNIII) helps regulate a number of bodily processes. All things considered, UCNs have approximately ten times more affinity for CRHR2 than CRH.
Sources: en.wikipedia.org
Kallistatin is a protein that in humans is encoded by the SERPINA4 gene. Kallistatin consists of three folded ß segments and eight helical structures and contains two functional domains, an active site and a heparin-binding site. Kallistatin signals through several receptors, including integrin ß3, lipoprotein receptor-related protein 6 (LRP6), nucleolin, and Krüppel-like factor 4 (KLF4).
Dashi is a family of stocks in Japanese cooking, typically made by briefly simmering a variety of kelp called kombu in nearly boiling water, often with other ingredients such as katsuobushi or shiitake. Myeolchi yuksu is a stock in Korean cooking made by briefly cooking dried anchovies with kelp in nearly boiling water. Glace de viande is stock, usually made from veal, that is highly concentrated by reduction. Ham stock, common in Cajun cooking, is made from ham hocks. Master stock is a Chinese stock used primarily for poaching meats, flavored with soy sauce, sugar, ginger, garlic, and other aromatics. Prawn stock is made from boiling prawn shells. It is used in Southeast Asian dishes such as laksa. Remouillage is a second stock made from the same set of bones. Bran stock is bran boiled in water. It can be used to thicken meat soups, used as a stock for vegetable soups or made into soup itself with onions, vegetables and molasses.
=== Endocrine === Dexamethasone is the treatment for the very rare disorder of glucocorticoid resistance. In adrenal insufficiency and Addison's disease, dexamethasone is prescribed when the patient does not respond well to prednisone or methylprednisolone. It can be used in congenital adrenal hyperplasia in older adolescents and adults to suppress adrenocorticotropic hormone (ACTH) production. It is typically given at night.
Pesce (1983), co-creator of The Adventures of Chico and Guapo, director of From Dusk Till Dawn 3: The Hangman's Daughter Lodge Kerrigan (1985), motion picture screenwriter and director of Rebecca H. Scott McGehee (1985), director of Uncertainty Katharina Otto-Bernstein (1986), Emmy Award-nominated filmmaker, producer, screenwriter daughter of German industrialist Werner Otto, billionaire heiress to the Otto GmbH fortune Cecily Rhett (1987), film editor, Stranger Inside Garth Stein (1987), Academy Award-winning producer, The Lunch Date Dan Futterman (1989), two-time Academy Award nominee for writing Capote and Foxcatcher Jessica Bendinger (1988), writer of Bring it On and for Sex and the City Andrew W.
Upgrading an existing 35-kilowatt generator to a brand new 200-kilowatt unit. Completely gutting and refinishing three laboratory spaces, which included: Removal of original built-in casework and replacement with modular units that can be moved to fit changing workflows. Replacement of fluorescent lighting with high-efficiency LED panels. Replacement of flaking epoxy floors with brand-new laboratory-grade finish. Addition of auxiliary cooling units for each space to provide the humidity and temperature control required to perform high complexity assays. Installation of new dedicated circuits tied into backup power via a new generator. Restoration and upgrade of the existing HVAC system The new lab was completed on August 1 and became operational on August 24.
Sources: en.wikipedia.org
=== Functional selectivity === Some nonbenzodiazepines can be subtype-selective, possibly providing anxiolytic effects with little to no hypnotic or amnesic effects or providing hypnotic effects with little or no anxiolytic effect. Non-sedating anxiolytic drugs derived from the same structural families as the Z-drugs have been developed, such as alpidem, indiplon, pagoclone and suriclone. A number of non-sedating benzodiazepine anxiolytics such as imidazenil and clobazam also exist, with the caveat that neither is a traditional 1,4-benzodiazepine. The functional selectivity is not unique to the nonbenzodiazepine structural class and has more to do with selectivity among different types of GABAA receptors or partial agonism, though this structural class does have more drug candidates.
In humans, maintenance from sexual maturity on (–)-deprenyl (1mg daily) is, for the time being, the most promising prophylactic treatment to fight against the age related decay of behavioral performances, prolonging life, and preventing or delaying the onset of age-related neurodegenerative diseases such as Parkinson's and Alzheimer's. The mechanism of selegiline's longevity-promoting effect has been researched by several groups, including Knoll and his associates at Semmelweis University, Budapest. The drug has been determined to be a catecholaminergic activity enhancer when present in minuscule concentrations far below those at which monoamine oxidase inhibitory activity can be observed, thereby potentiating the release of catecholamine neurotransmitters in response to stimuli. Knoll maintains that micro-doses of selegiline act as a synthetic analogue to a known or unknown trace amine in order to preserve the brain catecholaminergic system, which he perceives as integral to the organism's ability to function in an adaptive, goal-directed and motivated manner during advancing physical age:
== Amphoteric substances == An amphoteric substance is one that can act as an acid or as a base, depending on pH. Water (below) is amphoteric. Another example of an amphoteric molecule is the bicarbonate ion HCO−3 that is the conjugate base of the carbonic acid molecule H2CO3 in the equilibrium
=== eHealth and mobile Health (mHealth) interventions === A new emerging area of support for disease management is through digital technology using eHealth and mobile health (mHealth) interventions. These interventions have to potential to support the development of self-management skills, or assist the healthcare team to monitor symptoms. For JIA, current studies have focused on the health issues pain, health related quality of life, physical activity and disease management. Children and adolescents have used these interventions through a range of devices including computers, laptops, personal digital assistants, multimedia-players, and wearable accelerometers synchronised to smart phone. This allows access to these interventions from home. Early usability studies have been gaining positive feedback by children and adolescents. They are familiar with this type of technology and report liking these interventions. However further research is still needed to understand their full potential in supporting children and adolescents living with complex needs.
As nitrogen is an asphyxiant gas in itself, some jurisdictions have considered asphyxiation by inhalation of pure nitrogen as a means of capital punishment (as a substitute for lethal injection). In January 2024, Kenneth Eugene Smith became the first person executed by nitrogen asphyxiation.
Sources: en.wikipedia.org
The synthetic peptide keeps the receptor-binding region of GHRH but carries substitutions that resist enzymatic cleavage. In the DAC version, an added group also anchors the molecule to albumin, extending its presence in the bloodstream.
The maleimide group forms a covalent link with albumin, an abundant blood protein. This attachment slows clearance, so a single administration persists much longer than the unmodified peptide. The feature is the main reason the two variants are handled differently in study design.
It is not an approved therapeutic product in major regulatory jurisdictions. It appears in research chemical catalogs and scientific literature rather than pharmacy shelves. Clinical development was limited and did not reach approval.
Natural GHRH is degraded quickly by dipeptidyl peptidase-4 and related enzymes, giving it a half-life measured in minutes. CJC-1295 carries substitutions that slow that breakdown, so it stays intact longer. Both act at the same pituitary receptor and produce the same class of signal.