The short version of 冻干粉 fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-11-29 and is reviewed periodically as new material appears.
Clinical interest in tesamorelin arose from the need to address visceral adiposity in people living with HIV. Antiretroviral therapy improved survival but was associated in some patients with central fat accumulation, altered lipid profiles, and metabolic complications. This condition, often called HIV-associated lipodystrophy, involves excess visceral adipose tissue that is difficult to manage through diet and exercise alone. Investigators evaluated tesamorelin because GHRH analogs can stimulate growth hormone secretion and influence fat distribution without direct liposuction or invasive procedures.
A Phase 3 program led to regulatory approval in the United States in 2010 for reduction of excess visceral abdominal fat in adults with HIV and lipodystrophy. Subsequent studies examined effects on liver fat, muscle area, and metabolic markers, with mixed findings for some endpoints. Long-term cardiovascular outcomes and effects on mortality remain uncertain because most trials were relatively short and focused on imaging-based fat measurements. Use in populations without HIV has been studied experimentally but is not part of the approved indication.
特沙莫瑞林的检测通常依赖反相高效液相色谱和质谱联用。反相色谱可分离肽主峰与缺失序列、氧化产物等杂质，质谱则提供精确质量以确认身份。对于复杂基质中的定量，常采用液相色谱-串联质谱，并配合固相萃取或蛋白沉淀。生物样品中的肽易降解，因此采集和处理条件会影响结果。
稳定性研究通常考察温度、光照、湿度和 pH 对肽链的影响。冻干粉在低温避光条件下较为稳定，复溶后则需控制保存时间并避免反复冻融。肽类可能发生氧化、脱酰胺、水解和聚集，这些变化会改变色谱纯度。强制降解实验用于识别主要降解途径并验证分析方法的专属性。
| Property | Value | Notes |
|---|---|---|
| Molecular weight | Approximately 5,136 Da | Based on the 44-amino-acid peptide backbone and N-terminal modification. |
| Appearance | White to off-white lyophilized powder | Usually supplied in single-use vials for reconstitution. |
| Solubility | Freely soluble in water; slightly soluble in some organic solvents | Peptide nature supports aqueous reconstitution. |
| Typical storage | 2–8 °C, protected from light | Refrigeration reduces degradation; avoid freezing unless specified. |
| Common analytical method | Reverse-phase high-performance liquid chromatography | Used for identity, purity, and quantification. |
| Synonyms | Tesamorelin, TH9507, GHRH(1-44) analog | Generic descriptors; avoid proprietary names. |
The native hormone is produced in the hypothalamus and acts on the anterior pituitary. Binding of GHRH to its receptor stimulates synthesis and release of growth hormone into circulation. Because the analogue retains the receptor-binding region of the parent sequence, it engages the same receptor and triggers the same downstream signaling. The result is increased growth hormone secretion from pituitary cells, which in turn influences hepatic production of insulin-like growth factor 1. This axis is the basis for the compound's measured biological effects.
Interest in this peptide developed because native GHRH has a short circulating lifetime. The N-terminal modification slows cleavage by dipeptidyl peptidase IV, an enzyme that removes the first two residues of many peptides and terminates their activity. Slower degradation means a longer window of receptor stimulation per administration. This design logic parallels other modified peptide hormones, where a small chemical change at a vulnerable site yields a more durable molecule without altering the core mechanism of action.
The peptide is synthesized chemically rather than extracted from biological sources. Solid-phase synthesis builds the chain from the C-terminus toward the N-terminus, after which the hexenoyl group is attached. Purity is typically assessed by high-performance liquid chromatography, and identity is confirmed by mass spectrometry. Regulatory review of the finished product focuses on these analytical controls, since small deviations in sequence or modification can change biological activity. Questions about long-term effects on the pituitary axis remain areas of continued investigation.
冻干粉末一般在 -20°C 或更低温度、干燥避光条件下保存，可维持较长时间的稳定。复溶后稳定性明显下降，溶液中的肽链易发生水解、氧化与聚集，通常需冷藏并在短期内用完。反复冻融会加速聚集与降解，建议分装后单次使用。缓冲体系的 pH 与离子强度同样影响聚集速率，需要按具体实验条件验证。
研究用与临床用材料的标准并不相同。质量控制通常覆盖纯度、残留溶剂、反离子含量、微生物限度与内毒素水平，各项均有对应检测方法。随货文件应包含批号、检测项目、方法与结果，使数据可以追溯。核验时应关注纯度是否按主峰面积计算、杂质是否已定性、方法是否经过验证，这些信息决定结果能否被外部重复。
Physicochemical behavior is dominated by the peptide backbone. The molecule is hydrophilic and carries a net positive charge near neutral pH, owing to several arginine and lysine residues. In solution it adopts a largely unstructured conformation, and aggregation is a known concern for peptide products of this size. Oxidation of methionine and deamidation of asparagine or glutamine residues are the principal chemical degradation routes. These liabilities shape how the material is formulated, handled, and analyzed, and they explain why lyophilized presentations are common in research settings.
Tesamorelin is a synthetic peptide analog of growth hormone-releasing hormone, built from 44 amino acids. Its sequence follows the natural human GHRH(1-44) backbone, with a trans-3-hexenoyl group attached to the N-terminal tyrosine. This modification blocks recognition by dipeptidyl peptidase IV, the enzyme that rapidly truncates the native hormone in circulation. The result is a molecule with a substantially longer plasma residence time than unmodified GHRH, which makes it practical for clinical and laboratory study.
Receptor-level activity begins when the peptide binds the GHRH receptor, a class B G-protein-coupled receptor found on pituitary somatotroph cells. Occupancy triggers Gs-mediated activation of adenylyl cyclase and a rise in intracellular cyclic AMP, which in turn promotes synthesis and pulsatile release of growth hormone. Because the compound acts upstream of the growth hormone axis rather than supplying hormone directly, its effect depends on intact pituitary function. Binding studies in cell culture and animal models have established this pathway; the detailed kinetics of receptor recycling in humans remain less well characterized.
== Research == Sinclair has expressed the view that there is no limit to human lifespan, and that there is a backup copy of the genetic and epigenetic information in us. While Sinclair was in Guarente's lab, he discovered that sirtuin 1 (called sir2 in yeast) slows aging in yeast by reducing the accumulation of extrachromosomal rDNA circles. Others working in the lab at the time identified NAD as an essential cofactor for sirtuin function. In 2002, after he had left for Harvard, he clashed with Guarente at a scientific meeting at Cold Spring Harbor Laboratory, challenging Guarente's description of how sir2 might be involved in aging; this set off a scientific rivalry. In 2003, Sinclair learned that scientists at a Pennsylvania biotech company called Biomol Research Laboratories had developed a biochemical assays in which they thought that polyphenols including resveratrol activated SIR2. This led to publications authored in part by Sinclair in both Nature and Science in 2003. However, by 2005, it became clear that the biochemical assay consists of a fluorescent probe that interacts nonspecifically with resveratrol and that resveratrol is not a SIR2 activator Despite the scientific debunking of resveratrol, Sinclair maintains an outspoken advocacy for resveratrol as an anti-aging drug and supplement. High-profile papers claiming age reversal of mice have also come under intense scrutiny. Sinclair's lab has continued to work on resveratrol and analogues of it as part of their research program in anti-aging.
totipotency A state of cell potency in which a cell or nucleus fully retains the ability to differentiate into all of the cell types represented in the adult organism, or to give rise to all of these cell types upon transplantation into an appropriate cytoplasm (as in nuclear transfer). Such cells or nuclei are said to be totipotent. The zygote that serves as the progenitor cell for sexually reproducing multicellular organisms is the archetypal totipotent cell; almost all of the cells into which it ultimately differentiates are not totipotent, though some cells such as stem cells remain totipotent or pluripotent throughout the organism's life.
A substrate (quartz, silicon, stainless steel, carbon fibers, etc.) is coated with a catalytic metal (Fe, Co, Ni) layer. Typically that layer is iron and is deposited via sputtering to a thickness of 1–5 nm. A 10–50 nm underlayer of alumina is often also put down on the substrate first. This imparts controllable wetting and good interfacial properties. When the substrate is heated to the growth temperature (~600 to 850 °C), the continuous iron film breaks up into small islands with each island then nucleating a carbon nanotube. The sputtered thickness controls the island size and this in turn determines the nanotube diameter. Thinner iron layers drive down the diameter of the islands and drive down the diameter of the nanotubes grown. The amount of time the metal island can sit at the growth temperature is limited as they are mobile and can merge into larger (but fewer) islands. Annealing at the growth temperature reduces the site density (number of CNT/mm2) while increasing the catalyst diameter. The as-prepared carbon nanotubes always have impurities such as other forms of carbon (amorphous carbon, fullerene, etc.) and non-carbonaceous impurities (metal used for catalyst). These impurities need to be removed to make use of the carbon nanotubes in applications.
Sources: en.wikipedia.org
Two days after the execution, then-Governor Jeb Bush suspended all executions in the state and appointed a commission "to consider the humanity and constitutionality of lethal injections." The ban was lifted by Governor Charlie Crist when he signed the death warrant for Mark Dean Schwab on July 18, 2007. On November 1, 2007, the Florida Supreme Court unanimously upheld the state's lethal-injection procedures. A study published in 2007 in PLOS Medicine suggested that "the conventional view of lethal injection leading to an invariably peaceful and painless death is questionable." The execution of Romell Broom was abandoned in Ohio on September 15, 2009, after prison officials failed to find a vein after two hours of trying on his arms, legs, hands, and ankle. This stirred up more intense debate in the United States about lethal injection. Broom's execution was later rescheduled for March 2022, but he died in 2020 before the sentence could be carried out. Dennis McGuire was executed in Lucasville, Ohio, on January 17, 2014. According to reporters, McGuire's execution took more than 20 minutes, and he was gasping for air for 10–13 minutes after the drugs had been administered. It was the first use of a new drug combination, which was introduced in Ohio after the European Union banned sodium thiopental exports. This reignited criticism of the conventional three-drug method. Clayton Lockett died of a heart attack during a failed execution attempt on April 29, 2014, at Oklahoma State Penitentiary in McAlester, Oklahoma.
You can't field the ball deep. You have to get out in front of it." Remarked Bagwell, "I was basically being given a lesson from Ozzie Smith at first base during a pitching change. It's pretty cool." The next year, Bagwell hit .273, driving in 96 runs with 18 home runs. In 1993, the Astros improved to a third-place finish in the National League West division, and in mid-September, Bagwell was batting .320 with 20 home runs and 88 RBI. However, a pitch from the Philadelphia Phillies' Ben Rivera broke the fourth metacarpal bone in Bagwell's left hand, ending his season prematurely. It was the first of three successive seasons that ended early or was interrupted due to an incoming pitch breaking the same bone in that hand. His tendency to dip just before starting to swing made his hand more vulnerable to being hit by inside pitches. His .320 average was sixth in the NL. In February 1994, Bagwell and the Astros agreed to a one-year contract with a $2.4 million base salary (USD, $5.3 million today).
They concluded more experimental research is needed to investigate the toxicity of mephedrone. Doctors who treated a 15-year-old female suffering from mephedrone intoxication suggested in The Lancet that, like MDMA, mephedrone may promote serotonin-mediated release of antidiuretic hormone, resulting in hyponatraemia and an altered mental state. In another case, a 19-year-old male was admitted to hospital suffering from inflammation of the heart, 20 hours after taking one gram of mephedrone. The doctors treating the patient stated it was caused by either a direct toxic effect of mephedrone on the heart muscle, or by an immune response. One case of acquired methaemoglobinaemia, where a patient had "bluish lips and fingers", has also been reported, after the user snorted one gram of mephedrone. The patient started to recover after arriving at the hospital and it was not necessary to administer any medication.
Sources: en.wikipedia.org
7-Chlorokynurenic acid (7-CKA) is a tool compound that acts as a potent and selective competitive antagonist of the glycine site of the NMDA receptor. It produces ketamine-like rapid antidepressant effects in animal models of depression. However, 7-CKA is unable to cross the blood-brain-barrier, and for this reason, is unsuitable for clinical use. As a result, a centrally-penetrant prodrug of 7-CKA, 4-chlorokynurenine (AV-101), has been developed for use in humans, and is being studied in clinical trials as a potential treatment for major depressive disorder, and anti-nociception. In addition to antagonizing the NMDA receptor, 7-CKA also acts as a potent inhibitor of the reuptake of glutamate into synaptic vesicles (or as a vesicular glutamate reuptake inhibitor), an action that it mediates via competitive blockade of vesicular glutamate transporters (Ki = 0.59 mM). 5,7-Dichlorokynurenic acid Evans blue Kynurenic acid Xanthurenic acid
=== Atomic === A nobelium atom has 102 electrons. They are expected to be arranged in the configuration [Rn]5f147s2 (ground state term symbol 1S0), although experimental verification of this electron configuration had not yet been made as of 2006. The sixteen electrons in the 5f and 7s subshells are valence electrons. In forming compounds, three valence electrons may be lost, leaving behind a [Rn]5f13 core: this conforms to the trend set by the other actinides with their [Rn]5fn electron configurations in the tripositive state. Nevertheless, it is more likely that only two valence electrons are lost, leaving behind a stable [Rn]5f14 core with a filled 5f14 shell. The first ionization potential of nobelium was measured to be at most (6.65 ± 0.07) eV in 1974, based on the assumption that the 7s electrons would ionize before the 5f ones; this value was later refined to be 6.62621 eV (639.33 kJ/mol). The ionic radius of hexacoordinate and octacoordinate No3+ had been preliminarily estimated in 1978 to be around 90 and 102 pm respectively; the ionic radius of No2+ has been experimentally found to be 100 pm to two significant figures. The enthalpy of hydration of No2+ has been calculated as 1486 kJ/mol.
Rosiglitazone (Avandia): the European Medicines Agency recommended in September 2010 that it be suspended from the EU market due to elevated cardiovascular risks. Pioglitazone (Actos): remains on the market but has also been associated with increased cardiovascular risks. Troglitazone (Rezulin): used in 1990s, withdrawn due to hepatitis and liver damage risk. Multiple retrospective studies have resulted in a concern about rosiglitazone's safety, although it is established that the group, as a whole, has beneficial effects on diabetes. The greatest concern is an increase in the number of severe cardiac events in patients taking it. The ADOPT study showed that initial therapy with drugs of this type may prevent the progression of disease, as did the DREAM trial. The American Association of Clinical Endocrinologists (AACE), which provides clinical practice guidelines for management of diabetes, retains thiazolidinediones as recommended first, second, or third line agents for type 2 diabetes mellitus, as of their 2019 executive summary, over sulfonylureas and α-glucosidase inhibitors. However, they are less preferred than GLP-1 agonists or SGLT2 inhibitors, especially in patients with cardiovascular disease (which liraglutide, empagliflozin, and canagliflozin are all FDA approved to treat). Concerns about the safety of rosiglitazone arose when a retrospective meta-analysis was published in the New England Journal of Medicine.
The pools of A, B, and C have delta values defined as δA, δB, and δC respectively. These values are related to the ratio of heavy to light isotopes in each pool, and are the conventional means by which scientists express the isotopic composition of materials. Importantly, δB is distinct from δb listed on the diagram, as δb is the isotopic composition of B produced from A before it mixes with the pool of B. The isotopic compositions of the pools and products are related through fractionation factors that reflect the kinetic isotope effects (KIEs) associated with each reaction. For A → B,
Sources: en.wikipedia.org
It is a synthetic peptide analog of human growth hormone-releasing hormone. It is used clinically to reduce excess visceral abdominal fat in adults with HIV-associated lipodystrophy. It works by stimulating pituitary growth hormone release.
Pivotal trials enrolled adults with HIV and excess visceral abdominal fat, often in the context of antiretroviral therapy. Participants were assessed mainly by computed tomography for visceral adipose tissue. The approved indication remains specific to that population.
Long-term effects on cardiovascular events, mortality, and sustained fat distribution are not well established. Most trials measured changes over months rather than years. Open questions also include whether benefits persist after treatment stops.
反相高效液相色谱用于分离和纯度评估，质谱用于分子量确认。肽图谱或串联质谱可进一步验证序列。具体方法需根据样品基质和监管要求选择。