A practical reference on lyophilization: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
Tesamorelin occupies a narrow position among agents that act on the growth hormone axis. Unlike growth hormone itself, which is given as replacement, it stimulates the pituitary to release the hormone in pulses, so the downstream increase in insulin-like growth factor 1 depends on intact somatotroph function. Other peptides in the same family include shorter GHRH fragments and synthetic secretagogues with different stability profiles. Several points remain unresolved, including whether the reduction in visceral fat translates into fewer cardiovascular events, what happens to metabolic markers after long-term use, and how the drug compares with lifestyle or surgical approaches.
Tesamorelin is a synthetic peptide that belongs to the growth hormone-releasing hormone family and contains the same forty-four amino acid sequence as endogenous GHRH, extended at the amino terminus by a trans-3-hexenoyl group. That small fatty acid modification protects the peptide from rapid cleavage by dipeptidyl peptidase-4, the enzyme that shortens the half-life of native GHRH to only a few minutes. Chemically the compound is produced by solid-phase peptide synthesis, purified by chromatography, and supplied as a sterile lyophilized powder for reconstitution.
Regulatory approval in the United States came in 2010, when the Food and Drug Administration cleared the peptide for the reduction of excess abdominal fat in adults with HIV infection and associated lipodystrophy. The decision rested mainly on two randomized phase 3 trials that enrolled roughly eight hundred patients and ran for twenty-six weeks. Participants receiving active drug showed substantially greater declines in visceral adipose tissue than those receiving placebo, while total body weight changed comparatively little. A reformulated presentation was later approved, and the product has remained a niche therapy rather than a general weight-loss agent.
Growth hormone released from the pituitary stimulates the liver and other tissues to produce insulin-like growth factor 1, a stable circulating protein that serves as a practical marker of activity. Clinical studies therefore track IGF-1 concentrations alongside the hormone itself, and they commonly measure body composition with imaging rather than relying on body weight alone. Visceral adipose tissue, the fat surrounding abdominal organs, is quantified by computed tomography in the studies that supported approval. Adverse effects reported in trials include injection-site reactions, joint pain, and increases in blood glucose, which is why monitoring accompanies use.
Questions remain about how much of the observed fat reduction reflects direct GHRH-receptor signaling versus the downstream growth hormone and IGF-1 surge. It is also unclear whether the compound produces meaningful benefit in populations without lipodystrophy, since trials in cognitive impairment did not reach their stated goals. Long-term effects on glucose metabolism and on cardiovascular outcomes are not fully characterized. Published work generally describes effects on surrogate markers rather than on hard clinical endpoints, and independent replication of some findings is limited.
Tesamorelin acts on the growth hormone-releasing hormone receptor, a G-protein-coupled receptor found on somatotroph cells in the anterior pituitary. Binding triggers a rise in intracellular cyclic AMP, which in turn opens ion channels and raises calcium concentrations, leading to release of stored growth hormone into the bloodstream. Because the peptide works through the same receptor as the body's own GHRH, the resulting secretion follows a pulsatile pattern rather than a continuous elevation. The N-terminal modification slows enzymatic breakdown, so the signal persists longer than it would with the unmodified hormone.
| Property | Value | Notes |
|---|---|---|
| Peptide class | Synthetic GHRH analogue | 44 residues; N-terminal trans-3-hexenoyl group |
| First approval year | 2010 | United States; HIV-associated abdominal fat accumulation |
| Administration route | Subcutaneous injection | Abdominal site; clinician-administered or self-injected |
| Common synonyms | TH9507; tesamorelin acetate | Development code and acetate salt form |
| Originator | Canadian biotechnology firm | Original developer and regulatory sponsor |
Several related peptides act on the same receptor, including sermorelin, a shorter GHRH fragment, and modified analogs such as CJC-1295 and modified GRF(1-29) that are common in research settings rather than approved products. Tesamorelin differs from growth hormone itself in that it acts upstream, prompting the pituitary to release the hormone through physiological signaling rather than supplying it directly. Terminology in the literature distinguishes GHRH analogs, growth hormone secretagogues, and recombinant growth hormone, although popular discussion often blurs these categories together. Precise naming matters when comparing study results.
Tesamorelin is a synthetic peptide of 44 amino acids that reproduces the sequence of human growth hormone-releasing hormone (GHRH) and carries a trans-3-hexenoyl group on its N-terminal tyrosine. That small fatty-acid modification blocks cleavage by dipeptidyl peptidase-4, the enzyme that rapidly degrades native GHRH in plasma. The result is a molecule with a longer circulating half-life than the natural hormone while retaining the same receptor target. It is supplied as a lyophilized powder for reconstitution and belongs to the broader class of GHRH analogs studied for effects on pituitary growth hormone secretion.
Once reconstituted, the peptide is handled as a solution and is less stable than the lyophilized powder. Aqueous solutions are commonly kept cold and used within a defined period. Buffer composition and pH influence degradation rates, with extremes of acidity or alkalinity accelerating hydrolysis. Preservatives may be added in multi-dose formats to limit microbial growth. Freezing and thawing of solutions is generally avoided because it can cause precipitation or loss of activity.
Identity and purity are assessed by reversed-phase high-performance liquid chromatography, which separates the peptide from related impurities. Mass spectrometry, often coupled to liquid chromatography, confirms molecular mass and detects chemical modifications. Peptide mapping and amino acid analysis can verify sequence integrity. Water content is measured by Karl Fischer titration, and residual solvents may be checked by gas chromatography. These methods together support batch-to-batch consistency and routine quality control.
Clinical investigation has focused on HIV-associated lipodystrophy, a condition in which antiretroviral therapy contributes to abnormal fat distribution. Excess visceral adipose tissue accumulates in the abdomen while peripheral fat may be lost. Tesamorelin was evaluated for reducing this visceral fat depot, with trials measuring changes in abdominal fat by imaging rather than by body weight alone. The rationale rests on the known lipolytic effects of growth hormone. Effects on visceral fat are documented, while long-term outcomes regarding cardiovascular risk remain less clearly established.
Tesamorelin is a synthetic peptide analog of growth hormone-releasing hormone, composed of 44 amino acids. It was designed to retain the biological activity of the native hormone while resisting rapid enzymatic degradation. The compound is classified as a growth hormone secretagogue and belongs to the broader family of hypothalamic releasing factors. In research and clinical settings, it is studied for its ability to stimulate pituitary growth hormone release. Its structure includes a modification at the N-terminus that contributes to an extended half-life relative to native growth hormone-releasing hormone.
Identity and purity are assessed with reversed-phase high-performance liquid chromatography, which separates the peptide from truncated or oxidized forms. Mass spectrometry confirms the expected molecular weight, and peptide mapping after enzymatic digestion verifies the amino acid sequence. Water content is measured because residual moisture affects stability, and tests for aggregates or particulates are standard for injectable peptides. Circular dichroism can indicate whether the molecule has adopted an unexpected secondary structure in solution.
Research supply is often accompanied by a certificate of analysis listing chromatographic purity, mass confirmation, and storage conditions. Laboratories compare that document with an independent test when material is intended for bench work, since certificates describe a batch rather than an individual vial. Published studies usually state the source and purity of the peptide because small differences in purity can shift measured activity. Full analytical validation is rarely reported, which leaves batch-to-batch comparability an open question.
=== North Africa === The Medical Research Council decided that the time had come for field trials of penicillin. The location of centres to receive the drug was kept secret so as to not provoke demand for the drug when it was still in short supply. Florey was asked to go to North Africa, where the North African campaign was ongoing. He travelled to Algiers on the hospital ship HMHS Newfoundland in May 1943. On 29 June he was joined by Hugh Cairns, another Rhodes Scholar from Adelaide, who now held the rank of brigadier in the British Army, and was in charge of St Hugh's Military Hospital (Head Injuries) in Oxford, who brought with him a stockpile of 40 million Oxford units of penicillin. Florey resisted well-intentioned efforts by the War Office to grant him military rank. Over the next two months Florey and Cairns flew back and forth between Algiers, Sousse and Tripoli, with a week in Cairo. They treated over one hundred cases and compiled a report that ran to over one hundred pages. He gave lectures on penicillin, and his report contained recommendations for training of medical officers in its use. The fighting in North Africa ended in May 1943, so most of the cases Florey saw were not recently wounded soldiers, but ones with old wounds that had not healed; battle casualties began arriving again after the Allied invasion of Sicily in July. He considered that the source of infection in many cases was from the hospital rather than the battlefield, and advocated changes to the way that patients were treated to take advantage of the properties of penicillin.
Another use for affinity chromatography is the purification of specific proteins using a gel matrix that is unique to a specific protein. For example, the purification of E. coli β-galactosidase is accomplished by affinity chromatography using p-aminobenyl-1-thio-β-D-galactopyranosyl agarose as the affinity matrix. p-aminobenyl-1-thio-β-D-galactopyranosyl agarose is used as the affinity matrix because it contains a galactopyranosyl group, which serves as a good substrate analog for E. coli β-Galactosidase. This property allows the enzyme to bind to the stationary phase of the affinity matrix and β-Galactosidase is eluted by adding increasing concentrations of salt to the column. Alkaline phosphatase from E. coli can be purified using a DEAE-Cellulose matrix. A. phosphatase has a slight negative charge, allowing it to weakly bind to the positively charged amine groups in the matrix. The enzyme can then be eluted out by adding buffer with higher salt concentrations.
Phytoestrogens exert their effects primarily through binding to estrogen receptors (ER). There are two variants of the estrogen receptor, alpha (ER-α) and beta (ER-β) and many phytoestrogens display somewhat higher affinity for ER-β compared to ER-α. The key structural elements that enable phytoestrogens to bind with high affinity to estrogen receptors and display estradiol-like effects are:
If recovery of usable ruthenium is a goal, an extremely pure technetium target is needed; if small traces of the minor actinides such as americium and curium are present in the target, they are likely to undergo fission and form more fission products which increase the radioactivity of the irradiated target. The formation of ruthenium-106 (half-life 374 days) from the 'fresh fission' is likely to increase the activity of the final ruthenium metal, which will then require a longer cooling time after irradiation before the ruthenium can be used. The actual separation of technetium-99 from spent nuclear fuel is a long process. During fuel reprocessing, it comes out as a component of the highly radioactive waste liquid. After sitting for several years, the radioactivity reduces to a level where extraction of the long-lived isotopes, including technetium-99, becomes feasible. A series of chemical processes yields technetium-99 metal of high purity.
Sources: en.wikipedia.org
Colombia withdrew from the 1946 South American Championship but won their first international title later that year at the football tournament of the 1946 Central American and Caribbean Games, staged in Barranquilla in December. After Cuba and Mexico withdrew, judging that the strength of the remaining entrants did not justify the cost of sending teams, the competition was played as a single round-robin; Colombia won all six matches, scoring 20 goals and conceding seven, defeating Curaçao, Venezuela, Guatemala, Puerto Rico, Costa Rica and Panama. The team was coached by Peruvian manager José Arana Cruz, one of the first foreign coaches in the Colombia setup, whose tenure coincided with the country's first major international success.
=== Radio wave absorption === Stacked graphene layers on a quartz substrate increased the absorption of millimeter (radio) waves by 90 per cent over 125–165 GHz bandwidth, extensible to microwave and low-terahertz frequencies, while remaining transparent to visible light. For example, graphene could be used as a coating for buildings or windows to block radio waves. Absorption is a result of mutually coupled Fabry–Perot resonators represented by each graphene-quartz substrate. A repeated transfer-and-etch process was used to control surface resistivity.
{\displaystyle {\begin{aligned}{\frac {\partial f(t,j)}{\partial t}}&=2k_{+}m(t)f(t,j-1)-2k_{+}m(t)f(t,j)\\&+2k_{\rm {off}}f(t,j+1)-2k_{\rm {off}}f(t,j)\\&+k_{-}\sum _{i=j+1}^{\infty }f(t,i)-k_{-}(j-1)f(t,j)\\&+k_{1}m(t)^{n_{1}}\delta _{j,n_{1}}+k_{2}m(t)^{n_{2}}M(t)\delta _{j,n_{2}}\\\\\end{aligned}}}
By 2015, even at 90 years old, Mahathir remained sharp and combative. He repeatedly called for prime minister Najib Razak to resign over the 1Malaysia Development Berhad scandal (1MDB). On 30 August 2015, he and Siti Hasmah attended the Bersih 4 rally, a mass protest organised in response to the scandal. In 2016, Mahathir chaired the Malaysian Citizens' Declaration, which brought together several political figures and non-governmental organisations in calling for Najib's resignation. In this declaration, Mahathir listed 37 points. Later, the Citizens' Declaration reached one million signatures in May of the same year. In the 2016 Sungai Besar by-election, he supported Amanah and other Pakatan Harapan leaders, lending his influence to the opposition coalition. Mahathir left UMNO in 2016, and formed Parti Pribumi Bersatu Malaysia (BERSATU). The new party was officially registered on 9 September 2016, and Mahathir became its chairman. By 2017, he had officially joined the opposition coalition Pakatan Harapan. Negotiations then took place between different factions of the coalition for Mahathir to become the chairman and prime ministerial candidate. He assumed the position of chairman on 14 July 2017, despite reservations from supporters of Anwar Ibrahim, who could not contest in polls himself while imprisoned. In 2016, Mahathir had his police outriders withdrawn after his privileges were revoked due to his participation in anti-government events.
== History == The detection of nitrates and nitrites for GSR has been around since the early 1900s. The first recorded use of paraffin wax as a lifting medium was done by Dr. Iturrioz in 1914 and was popularized in 1933 by Teodoro Gonzalez of the Mexico City Police Laboratory. The aptly named paraffin test is also referred to as the diphenylamine test, dermal nitrate test and the Gonzalez test. This test consisted of coating a suspect's hands with paraffin wax, allowing it to solidify and peeling it away before adding a diphenylamine/sulfuric acid reagent. The presence of dark blue spots is said to indicate a positive result. This is no longer used in casework due to the high number of false positives caused by the commonality of nitrates and nitrites in a variety of mundane products such as fertilisers. In 1971 John Boehm presented some micrographs of gunshot residue particles found during the examination of bullet entrance holes using a scanning electron microscope. If the scanning electron microscope is equipped with an energy-dispersive X-ray spectroscopy detector, the chemical elements present in such particles, mainly lead, antimony and barium, can be identified. In 1979 Wolten et al. proposed a classification of gunshot residue based on composition, morphology, and size. Four compositions were considered characteristic:
Sources: en.wikipedia.org
gametogenesis The process by which eukaryotic precursor germ cells divide and differentiate into haploid gametes. Depending on the organism, gametes may be generated from haploid germ cells by mitosis or diploid germ cells by meiosis.
The seven-year market exclusivity period differs from traditional patent law in that it does not begin until the drug is granted FDA approval and is independent of the drug's current patent status. Furthermore, if a market competitor wishes to introduce a drug for the same indication, the onus is on the competitor to prove that their drug is therapeutically superior (e.g. increased efficacy, less toxicity, etc.) when compared to the present drug indicated for the rare disease of interest. This incentive creates an attractive monopolistic market for companies interested in developing a product for any given rare disease. Television historian and Allmovie contributor Hal Erickson credits two episodes of the television series Quincy, M.E. for helping the ODA pass in the USA: "Seldom Silent, Never Heard" (1981) and "Give Me Your Weak" (1982). The show's star, Jack Klugman, even testified before Congress concerning the orphan drug issue.
=== Animal === Microchimerism occurs in most pairs of twins in cattle. In cattle (and other bovines), the placentas of fraternal twins usually fuse and the twins share blood circulation, resulting in exchange of cell lines. If the twins are a male–female pair, then XX/XY microchimerism results, and male hormones partially masculinize the heifer (female), creating a martin heifer or freemartin. Freemartins appear female, but are infertile and so cannot be used for breeding or dairy production. Microchimerism provides a method of diagnosing the condition, because male genetic material can be detected in a blood sample.
==== Crystallinity ==== When applied to polymers, the term crystalline has a somewhat ambiguous usage. In some cases, the term crystalline finds identical usage to that used in conventional crystallography. For example, the structure of a crystalline protein or polynucleotide, such as a sample prepared for x-ray crystallography, may be defined in terms of a conventional unit cell composed of one or more polymer molecules with cell dimensions of hundreds of angstroms or more. A synthetic polymer may be loosely described as crystalline if it contains regions of three-dimensional ordering on atomic (rather than macromolecular) length scales, usually arising from intramolecular folding or stacking of adjacent chains. Synthetic polymers may consist of both crystalline and amorphous regions; the degree of crystallinity may be expressed in terms of a weight fraction or volume fraction of crystalline material. Few synthetic polymers are entirely crystalline. The crystallinity of polymers is characterized by their degree of crystallinity, ranging from zero for a completely non-crystalline polymer to one for a theoretical completely crystalline polymer. Polymers with microcrystalline regions are generally tougher (can be bent more without breaking) and more impact-resistant than totally amorphous polymers. Polymers with a degree of crystallinity approaching zero or one will tend to be transparent, while polymers with intermediate degrees of crystallinity will tend to be opaque due to light scattering by crystalline or glassy regions.
Sources: en.wikipedia.org
It is a laboratory-made peptide of forty-four amino acids whose sequence matches human growth hormone-releasing hormone, with a modified amino terminus. The modification is a short unsaturated fatty acid chain attached to the first residue. This change slows enzymatic breakdown and lengthens the time the peptide stays active in circulation.
The clinical program was designed around HIV-associated lipodystrophy, a condition in which fat accumulates abnormally around the internal organs. Trials enrolled that specific population, so the evidence base covers it rather than the general population. Regulators approved the drug for the studied indication only, and promotion outside it is not permitted.
Growth hormone therapy supplies the finished hormone directly, while this peptide acts upstream and asks the pituitary to secrete its own. That difference means the response depends on a functioning pituitary and on the body's normal feedback loops. It also means the circulating hormone profile is pulsatile rather than a flat, injected level.
It acts upstream at the pituitary receptor and depends on functioning somatotroph cells to produce any effect. Growth hormone injections bypass that step and deliver the hormone directly. The pharmacokinetic profiles and the resulting feedback on the body's own secretion therefore differ.