This is a working overview of ESI-MS, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-08-13 and is reviewed periodically as new material appears.
现有文献多来自小规模、短期的研究，涉及生长激素缺乏、术后肠麻痹等方向。长期使用是否导致受体脱敏，以及重复给药后效应是否衰减，仍属开放问题。不同研究之间的剂量、给药途径和受试者特征差异较大，因此结论外推需谨慎。关于临床获益的确切证据尚不充分，需要更大规模的对照试验来澄清。
Ipamorelin 是一种合成五肽，在 20 世纪 90 年代被报道为生长激素促分泌剂。其结构基于胃饥饿素受体激动剂的设计思路，但并非天然激素。早期药理学研究显示，它可刺激垂体释放生长激素，而对应激激素轴的影响相对较小。该化合物常被用作研究生长激素调节通路的工具分子。
Long-term storage of the dry powder is typically at minus twenty degrees Celsius or lower, protected from light and moisture. Solutions are commonly kept frozen and thawed only once, because repeated freeze-thaw cycles can promote aggregation and loss of measurable peptide content. Buffers near neutral pH are preferred over strongly acidic or strongly basic conditions. Shipping at ambient temperature is acceptable for short periods when the powder remains sealed and desiccated.
Identity and purity are assessed by complementary methods rather than a single test. Reversed-phase high-performance liquid chromatography separates the peptide from related impurities and reports a percentage purity. Mass spectrometry, most often with electrospray ionization, confirms the expected molecular mass and detects sequence-related variants. Amino acid analysis can verify composition, while water content and residual counterion measurements support the mass balance of a batch. Stability studies under accelerated conditions are used to estimate shelf life, though such estimates carry uncertainty for long-term storage.
| Property | Value | Notes |
|---|---|---|
| 分子式 | C38H49N9O5 | 五肽，含非天然氨基酸残基 |
| 分子量 | 711.85 g/mol | 理论值，盐形式可能略有差异 |
| 外观 | 白色至类白色粉末 | 冻干粉常见 |
| 溶解性 | 易溶于水 | 也可溶于部分极性有机溶剂 |
| 储存条件 | -20°C，干燥避光 | 长期保存通常推荐 |
Verification of identity and purity relies on analytical methods used across peptide chemistry. Reverse-phase high-performance liquid chromatography separates components by hydrophobicity and provides a purity estimate. Mass spectrometry confirms molecular mass and helps detect modifications. Together these techniques give complementary information about whether a sample matches its expected structure. Results depend on method parameters and reference standards, so reported purity values are meaningful only when the analytical conditions are stated. Consistency between laboratories requires comparable protocols and well-characterized reference materials.
Peptides such as ipamorelin are subject to chemical and physical degradation. Hydrolysis of peptide bonds, oxidation of susceptible residues, and aggregation are common pathways that reduce purity over time. The rate of these processes depends on temperature, moisture, pH, and the number of freeze-thaw cycles a sample undergoes. Because the compound is typically handled as a lyophilized powder, controlling moisture during storage is a central concern. Degradation products can be detected with separation techniques that resolve the parent peptide from related impurities.
In the scientific literature, ipamorelin appears mainly in preclinical studies, receptor binding assays, and reviews of growth hormone secretagogues. Authors often discuss its selectivity profile alongside limitations such as small sample sizes, short study durations, and differences between species. Some papers examine pharmacokinetics and clearance, but human data are limited and not sufficient to define general clinical effects. Regulatory discussion treats the compound as an investigational or research substance rather than an approved therapy in most jurisdictions. Open questions include oral bioavailability, long-term endocrine effects, and whether selectivity observed in animals persists in humans.
Research peptides such as ipamorelin are commonly supplied as lyophilized powder and characterized by analytical certificates. Reversed-phase high-performance liquid chromatography is used to estimate purity by ultraviolet absorbance, while mass spectrometry confirms molecular identity and detects sequence-related impurities. Counterion content, water content, and residual synthesis reagents can affect the reported mass balance. A certificate of analysis may list a purity percentage, but that number depends on the analytical method and the definition of impurity peaks. Independent verification is often recommended because research supply chains vary in quality control practices.
The molecule contains five residues, including alpha-aminoisobutyric acid, D-2-naphthylalanine, and D-phenylalanine, and it ends in a lysine amide. Non-natural and D-configured residues make the chain less susceptible to common peptidases, which helps explain its resistance to rapid breakdown. Its molecular formula is C38H49N9O5, corresponding to a free-base mass near 711.9 daltons. The C-terminal amide removes a negative charge and is a recurring feature in receptor-active peptides of this family. These structural choices are usually discussed as the basis for its selectivity profile.
Published animal and early human work describes growth hormone release that is separated from comparable rises in adrenocorticotropic hormone and cortisol. Prolactin changes are reported as small in the same studies. Selectivity is attributed to binding at the ghrelin receptor and to the downstream signaling that follows, rather than to differences in how quickly the peptide is cleared. Authors commonly label the compound selective rather than potent, because the same mass produces a smaller growth hormone response than some older secretagogues tested in parallel. Whether that profile holds across species and routes of administration remains an open question.
Human data remain limited and come mainly from small, short-term studies conducted decades ago. The peptide has not received approval as a medicine from major regulators, so current availability is largely as a research chemical. Reported effects on growth hormone pulsatility, appetite, and body composition should be read as preliminary, since few independent groups have replicated the original findings. Analytical characterization of research-grade material varies between suppliers, which complicates comparison across studies. Regulatory status also differs by country, and some jurisdictions classify it as a prescription-only or otherwise restricted item.
Ipamorelin is a synthetic pentapeptide classified as a growth hormone secretagogue. Its sequence, Aib-His-D-2-Nal-D-Phe-Lys-NH2, combines three non-proteinogenic residues with a C-terminal amide. The N-terminal aminoisobutyric acid unit and the two aromatic D-amino acids distinguish it from peptides assembled only from standard L-amino acids. Its formula is C38H49N9O5, corresponding to an average mass near 711.9 Da. At neutral pH the molecule carries a net positive charge, a property that shapes its behaviour in chromatographic and electrophoretic systems.
The compound was developed at Novo Nordisk during the 1990s as part of a programme seeking secretagogues with improved selectivity. It was described in the peer-reviewed literature in 1998 alongside related pentapeptides from the same series. Investigators advanced it because it raised growth hormone output in animal models while leaving other pituitary hormones comparatively unaffected. The development code NNC 26-0161 appears in earlier reports, and ipamorelin later became the common designation in published work.
===== Process ===== A large fraction of human tumor mutations are effectively patient-specific. Therefore, neoantigens may also be based on individual tumor genomes. Deep-sequencing technologies can identify mutations within the protein-coding part of the genome (the exome) and predict potential neoantigens. In mice models, for all novel protein sequences, potential MHC-binding peptides were predicted. The resulting set of potential neoantigens was used to assess T cell reactivity. Exome–based analyses were exploited in a clinical setting, to assess reactivity in patients treated by either tumor-infiltrating lymphocyte (TIL) cell therapy or checkpoint blockade. Neoantigen identification was successful for multiple experimental model systems and human malignancies. The false-negative rate of cancer exome sequencing is low—i.e.: the majority of neoantigens occur within exonic sequence with sufficient coverage. However, the vast majority of mutations within expressed genes do not produce neoantigens that are recognized by autologous T cells. As of 2015 mass spectrometry resolution is insufficient to exclude many false positives from the pool of peptides that may be presented by MHC molecules. Instead, algorithms are used to identify the most likely candidates. These algorithms consider factors such as the likelihood of proteasomal processing, transport into the endoplasmic reticulum, affinity for the relevant MHC class I alleles and gene expression or protein translation levels.
Mammals are a diverse class of animals, mostly terrestrial but some are aquatic and others have evolved flapping or gliding flight. They mostly have four limbs, but some aquatic mammals have no limbs or limbs modified into fins, and the forelimbs of bats are modified into wings. The legs of most mammals are situated below the trunk, which is held well clear of the ground. The bones of mammals are well ossified and their teeth, which are usually differentiated, are coated in a layer of prismatic enamel. The teeth are shed once (milk teeth) during the animal's lifetime or not at all, as is the case in cetaceans. Mammals have three bones in the middle ear and a cochlea in the inner ear. They are clothed in hair and their skin contains glands which secrete sweat. Some of these glands are specialized as mammary glands, producing milk to feed the young. Mammals breathe with lungs and have a muscular diaphragm separating the thorax from the abdomen which helps them draw air into the lungs. The mammalian heart has four chambers, and oxygenated and deoxygenated blood are kept entirely separate. Nitrogenous waste is excreted primarily as urea. Mammals are amniotes, and most are viviparous, giving birth to live young. Exceptions to this are the egg-laying monotremes, the platypus and the echidnas of Australia. Most other mammals have a placenta through which the developing foetus obtains nourishment, but in marsupials, the foetal stage is very short and the immature young is born and finds its way to its mother's pouch where it latches on to a teat and completes its development.
== Overdose == MDMA overdose symptoms vary widely due to the involvement of multiple organ systems. Some of the more overt overdose symptoms are listed in the table below. The number of instances of fatal MDMA intoxication is low relative to its usage rates. In most fatalities, MDMA was not the only drug involved. Acute toxicity is mainly caused by serotonin syndrome and sympathomimetic effects. MDMA's toxicity in overdose may be exacerbated by caffeine, with which it is frequently cut in order to increase volume. The estimated fatal dose of MDMA in humans is around 15 or 16 times a typical recreational dose. Sympathomimetic side effects can be managed with carvedilol. A scheme for management of acute MDMA toxicity has been published focusing on treatment of hyperthermia, hyponatraemia, serotonin syndrome, and multiple organ failure.
=== Der Schrecken Gottes: Attar, Hiob und die metaphysische Revolte (postdoctoral thesis 2005) === It is precisely this question that Kermani addresses in his postdoctoral thesis Der Schrecken Gottes: Attar, Hiob und die metaphysische Revolte (The Terror of God: Attar, Job and the Metaphysical Revolt). In this book, Kermani takes up the basic idea of practical-authentic theodicy, which consists in demanding God's justice against the injustice of the world, that is, in Kantian terms, postulating the reality of God and thus God's authentic self-justification without attributing to God the wish to achieve this doctrinally himself. This postulate necessarily includes protest against suffering, which is expressed in quarreling with God and accusing God. Even though wrestling with God is largely frowned upon in Islamic orthodoxy, as it is in Christian orthodoxy, the Islamic mystical literature cited by Kermani, as well as the Book of Job, reveal ways of wrestling with God that are nourished by devotion to God and can accompany the indispensable, postulative discourse on God. For Kermani, the most significant testimony to this wrestling is The Book of Suffering by the Persian mystical poet Attar (1145–1221), a text that shows how in the Islamic tradition it is possible to argue and quarrel with God. From the perspective of the fools whom Attar references, God appears both as the persecutor and tormentor of humankind and yet also as its last hope.
Sources: en.wikipedia.org
Kief is a powder, rich in trichomes, that can be sifted from the leaves, flowers and fruits of cannabis plants and either consumed in powder form or compressed to produce cakes of hashish. The term derives from colloquial Arabic كيف kēf/kīf, meaning pleasure.
Physical activity can be related to a person's professional activities, non-work related daily activities like walking or cycling, or it can be in the form of activities such as recreation or team sports. The specific type of activity can be tailored to populations such as children, pregnant women, and elderly adults. Tailored activity to one's fitness level also encourages the body to heal properly and prevent any injuries as a result of exercise. Physical inactivity leads to less energy expenditure and is a factor that impacts obesity rates in both children and adults. Physical inactivity has become a worldwide concern since inactivity also elevates the risk of heart disease. With a regular active lifestyle it can reduce the risk for noncommunicable diseases like diabetes, heart disease, and dyslipidemia (high cholesterol). Physical activity not only reduces the risk of noncommunicable diseases, but it also can benefit the body such as improving sleep patterns, reducing both anxiety and depression, and of course, helps weight loss and weight management.
1967: Sue Arnold became the first female British Geological Survey person to go to sea on a research vessel. 1967: South African radiobiologist Tikvah Alper discovered that scrapie, an infectious brain disease affecting sheep, did not spread via DNA or RNA like a viral or bacterial disease. The discovery enabled scientists to better understand diseases caused by prions. 1967: Yvonne Brill, a Canadian-American rocket and jet propulsion engineer, invented the hydrazine resistojet propulsion system. 1968: Japanese pioneer of molecular biology Tsuneko Okazaki studied DNA replication and discovered Okazaki fragments. 1969: British biostratigrapher Beris Cox became the first female paleontologist in the British Geological Survey. 1969: British botanist Irene Manton became the first woman president of the British Pteridological Society. 1969: Ukrainian-born astronomer Svetlana Gerasimenko co-discovered the 67P/Churyumov–Gerasimenko comet. 1969: A group of women scientists from the United States (Lois Jones, Terry Tickhill, Kay Lindsay, Eileen McSaveney, and Jean Pearson) and New Zealand (Pamela Young) become the first women to visit and work at the South Pole.
== Current events and advocacy == The management of CEC has gained increasing attention in recent years due to their potential impact on public health and the environment. In response to these concerns, various governmental and international organizations have initiated efforts to address CEC through research, regulation, and public outreach. In January 2024, the White House Office of Science and Technology Policy announced a coordinated federal research initiative to address CEC in surface waters. The initiative aims to enhance understanding of the sources, occurrence, and effects of CEC, as well as to develop effective strategies for their removal and management. Furthermore, the Organization for Economic Co-operation and Development (OECD) has been actively involved in addressing CEC. The OECD Workshop on Managing Contaminants of Emerging Concern in Surface Waters brought together experts from various countries to discuss challenges and solutions related to CEC, emphasizing the importance of international collaboration in tackling this global issue. These recent developments underscore the growing recognition of the need for concerted efforts to address the challenges posed by CEC to protect public health and the environment. Advocacy efforts for the regulation of CEC are important to push for legislation and regulatory action. Environmental advocacy groups raise awareness about the potential risks associated with CEC and urge for the advancement of environmental protection policies.
An aortogram involves injection of contrast material while taking X-rays of the aorta. Once commonly used, its use has since been supplanted by less invasive and more sensitive imaging modalities. The American Heart Association does not recommend the use of aortograms as a first line imaging modality in the diagnoses of aortic dissections. They note that aortograms have limited sensitivity and are more invasive than other tests.
Sources: en.wikipedia.org
Several types of cells support an action potential, such as plant cells, muscle cells, and the specialized cells of the heart (in which occurs the cardiac action potential). However, the main excitable cell is the neuron, which also has the simplest mechanism for the action potential. Neurons are electrically excitable cells composed, in general, of one or more dendrites, a single soma, a single axon and one or more axon terminals. Dendrites are cellular projections whose primary function is to receive synaptic signals. Their protrusions, known as dendritic spines, are designed to capture the neurotransmitters released by the presynaptic neuron. They have a high concentration of ligand-gated ion channels. These spines have a thin neck connecting a bulbous protrusion to the dendrite. This ensures that changes occurring inside the spine are less likely to affect the neighboring spines. The dendritic spine can, with rare exception (see LTP), act as an independent unit. The dendrites extend from the soma, which houses the nucleus, and many of the "normal" eukaryotic organelles. Unlike the spines, the surface of the soma is populated by voltage activated ion channels. These channels help transmit the signals generated by the dendrites. Emerging out from the soma is the axon hillock. This region is characterized by having a very high concentration of voltage-activated sodium channels. In general, it is considered to be the spike initiation zone for action potentials, i.e. the trigger zone. Multiple signals generated at the spines, and transmitted by the soma all converge here.
=== Microfractures of the fetal membranes === Throughout gestation the fetal membranes undergo remodeling to allow for the increase in size of the uterus. The remodeling of the fetal membranes occurs at both the level of the cells and the extracellular matrix (ECM). Structural abnormalities such as areas of where collagen has degraded, known as microfractures, have been observed in the amniotic membrane layer. Microfractures are characterised by:
== Engineering == In biochemical engineering, sparging can remove low-boiling liquids from a solution. The low-boiling components evaporate more rapidly, so the gas bubbles remove more of them from the bulk solution containing higher-boiling components. It is an alternative to distillation, and it does not require heat.
== Structure == The typical size of the nanocapsule used for various applications ranges from 10-1000 nm. However, depending on the preparation and use of the nanocapsule, the size will be more specific. Nanocapsule structure consists of nanovesicular system that is formed in a core-shell arrangement. The shell of a typical nanocapsule is made of a polymeric membrane or coating. The type of polymers used is of biodegradable polyester, as nanocapsules are often used in biological systems. Poly-e-caprolactone (PCL), poly(lactide) (PLA), and poly(lactide-co-glicolide) (PLGA) are typical polymers used in nanocapsule formation. Other polymers include thiolated poly(methacrylic acid) and poly(N-vinyl Pyrrolidone). As synthetic polymers have proven to be more pure and reproducible when compared naturally occurring polymers, they are often preferred for the construction nanocapsules. However, some natural occurring polymers such as chitosan, gelatin, sodium alginate, and albumin are used in some drug delivering nanocapsules. Other nanocapsule shells include liposomes, along with polysaccharides and saccharides. Polysaccharides and saccharides are used due to their non-toxicity and biodegradability. They are attractive to use as they resemble biological membranes. The core of a nanocapsule is composed of an oil surfactant that is specifically selected to coordinate with the selected drug within the polymeric membrane. The specific oil used must be highly soluble with the drug, and non-toxic when used in a biological environment.
== Interactions == GLUT4 has been shown to interact with death-associated protein 6, also known as Daxx. Daxx, which is used to regulate apoptosis, has been shown to associate with GLUT4 in the cytoplasm. UBX-domains, such as the one found in GLUT4, have been shown to associate with apoptotic signaling. So this interaction aids in the translocation of Daxx within the cell. In addition, recent reports demonstrated the presence of GLUT4 gene in central nervous system such as the hippocampus. Moreover, impairment in insulin-stimulated trafficking of GLUT4 in the hippocampus result in decreased metabolic activities and plasticity of hippocampal neurons, which leads to depressive like behaviour and cognitive dysfunction.
Sources: en.wikipedia.org
不是。它属于人工合成的五肽，设计上模拟胃饥饿素受体的部分作用，但不存在于人体天然激素谱中。
生长激素释放激素通过其专用受体起作用，而 ipamorelin 主要作用于胃饥饿素受体。两者可影响生长激素释放，但信号通路和下游效应并不相同。
研究多集中在生长激素释放的急性调节、受体选择性以及不同给药方式下的药代动力学。临床终点研究数量有限，长期结局尚不明确。
Dry powder is held at minus twenty degrees Celsius or colder, away from light and moisture. Sealed vials under inert gas limit degradation during storage.