This is a working overview of 反相色谱, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-09-01. Anything still debated is marked as such rather than presented as settled.
Development work on the compound, originally designated TH9507, focused on conditions in which reduced growth hormone signaling is thought to contribute to altered body composition. The United States Food and Drug Administration approved it in 2010 for the treatment of excess visceral abdominal fat in adults with human immunodeficiency virus infection and lipodystrophy. Later research examined other populations, including adults with mild cognitive impairment, where a large trial did not meet its primary endpoints. This mixed record illustrates how a single mechanism can produce clear effects in one setting and inconclusive results in another.
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.
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。
纯度与身份确认依赖色谱与质谱的组合。反相高效液相色谱在 214 nm 紫外检测下分离主峰与相关杂质，给出纯度百分比与保留时间；电喷雾或基质辅助激光解吸电离质谱提供分子量，用于确认 N 端修饰是否完整。序列层面可通过肽图或氨基酸分析验证。含量测定常用紫外吸收法或氮元素分析，不同方法之间需要做交叉校验。
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。
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic 44-residue GHRH analog | Sequence matches human GHRH(1-44); differs only at the N-terminus |
| Nominal molecular mass | Approximately 5,136 Da (free base) | Small variation arises from counterion and salt form |
| Appearance | White to off-white lyophilized powder | Supplied in single-use vials intended for reconstitution |
| Solubility class | Freely soluble in water | Practically insoluble in nonpolar organic solvents |
| Typical storage | 2 to 8 degrees Celsius, protected from light | Reconstituted material is handled according to label instructions |
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.
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 binds the growth hormone–releasing hormone receptor on pituitary somatotroph cells. The receptor signals through the Gs protein, raising intracellular cAMP and activating protein kinase A. That cascade triggers release of stored growth hormone in pulses rather than a steady stream. Because the drug acts at the receptor that normally controls this process, its effect depends on the body's own signaling architecture rather than on a synthetic pathway. The resulting hormone profile reflects the timing of each pulse, not only its size.
Measured responses usually involve growth hormone and insulin-like growth factor 1, known as IGF-1. Growth hormone rises in bursts and is difficult to sample reliably, while IGF-1 shifts more slowly and can be assessed from a single blood draw. Studies therefore treat IGF-1 as the more practical pharmacodynamic marker. Both are indirect, showing that the receptor was engaged rather than that the peptide reached a particular concentration. Direct exposure measurement requires an assay aimed at the molecule itself.
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.
Tesamorelin is a synthetic analog of growth hormone-releasing hormone, a peptide hormone produced by the hypothalamus. The molecule retains the 44-amino-acid sequence of human GHRH and carries a trans-3-hexenoyl modification at its N-terminus. This modification increases resistance to enzymatic degradation and extends the peptide's functional stability relative to native GHRH. The compound is supplied as a lyophilized powder for reconstitution and subcutaneous administration in clinical settings. Its development code was TH9507, and it belongs to the GHRH analog class. It is not a growth hormone product; instead, it acts upstream to stimulate endogenous growth hormone release.
The concept of yin and yang is also applicable to the human body; for example, the upper part of the body and the back are assigned to yang, while the lower part of the body is believed to have the yin character. Yin and yang characterization also extends to the various body functions, and – more importantly – to disease symptoms (e.g., cold and heat sensations are assumed to be yin and yang symptoms, respectively). Thus, yin and yang of the body are seen as phenomena whose lack (or over-abundance) comes with characteristic symptom combinations:
To Lore Alford Rogers In recognition of his quarter-century service in the advancement of knowledge, embracing important contributions in pure science as well as its applications to industry; and because he embodies in the highest degree their ideal of unselfish devotion and untiring loyalty, alike to his work and to his fellow workers--this volume is dedicated, with admiration and affection, by those who have been privileged to serve under his leadership. In the early 1930s Rogers was involved in research on cheese, including Swiss, cheddar, and Roquefort. He set off for the International Dairy Congress in Italy. In 1936 the Borden Company announced that it would provide cash awards and gold medals for "meritorious work in science as it is related to the dairy industry." Two recipients were selected for the first prizes: Lore A. Rogers of the USDA and Carl F. Huffman of Michigan State University. Rogers was praised for his numerous contributions to the field, noting "there is not a branch in our industry that has not felt the helping hand of his genius." In his casual, almost self-effacing style, but with serious reflection upon receiving the prize, Rogers took the opportunity to educate the next generation of researchers.
Mahathir was born at his parents' home in a poor neighbourhood at Lorong Kilang Ais, Alor Setar, in the capital of the Malay sultanate of Kedah under a British protectorate, on 10 July 1925. He was the first prime minister who was not born into the aristocracy or a prominent religious or political family. Mahathir's mother, Wan Tempawan Wan Hanapi, was a Malay from Kedah. His father, Mohamad Iskandar, was from Penang of Malay and Indian descent. Mahathir's paternal grandfather had come from Kerala, British India. Some claim that Mahathir's facial features resemble those of Kerala Chief Minister Pinarayi Vijayan, although they are not related. Mohamad Iskandar was the principal of an English-medium secondary school, whose lower-middle-class status meant his daughters were unable to enrol in a secondary school. Wan Tempawan Wan Hanapi had only distant relations to members of Kedah's royalty. Both had been married previously. Mahathir was born with six half-siblings and two full-siblings. His childhood home, with a single shared bedroom and no electricity supply, was later converted to a tourist attraction and opened to the public. During his childhood, Mahathir enjoyed playing snakes and ladders and demonstrated multiple creative talents, including playing the trumpet, interior decorating, and engaging in crafts and carpentry work. He once shared that he was bullied in his youth, recalling how he sold balloons for a small profit but was forced by a stronger peer to use his earnings to buy food for him.
Urine analysis is primarily used because of its low cost. Urine drug testing is one of the most common testing methods used. The enzyme-multiplied immune test is the most frequently used urinalysis. Complaints have been made about the relatively high rates of false positives using this test. Urine drug tests screen the urine for the presence of a parent drug or its metabolites. The level of drug or its metabolites is not predictive of when the drug was taken or how much the patient used. Urine drug testing is an immunoassay based on the principle of competitive binding. Drugs which may be present in the urine specimen compete against their respective drug conjugate for binding sites on their specific antibody. During testing, a urine specimen migrates upward by capillary action. A drug, if present in the urine specimen below its cut-off concentration, will not saturate the binding sites of its specific antibody. The antibody will then react with the drug-protein conjugate and a visible colored line will show up in the test line region of the specific drug strip. A common misconception is that a drug test that is testing for a class of drugs, for example, opioids, will detect all drugs of that class. However, most opioid tests will not reliably detect oxycodone, oxymorphone, meperidine, or fentanyl. Likewise, most benzodiazepine drug tests will not reliably detect lorazepam. However, urine drug screens that test for a specific drug, rather than an entire class, are often available.
Axatilimab, sold under the brand name Niktimvo, is a monoclonal antibody used for the treatment of chronic graft-versus-host disease. It is a blocker of the colony stimulating factor-1 receptor. It is given by injection into a vein. The most common side effects include infections; increased blood level of liver enzymes; decreased blood level of phosphate; low red blood cell count (anemia); muscle, bone, or joint pain; increased blood level of pancreatic enzymes; low energy; increased blood level of calcium; increased blood level of a muscle enzyme; increased blood level of a bone enzyme; nausea; headache; diarrhea; cough; fever; shortness of breath; and infusion related reactions. Infusion-related reactions are common and can be serious. Axatilimab was approved for medical use in the United States in August 2024. The US Food and Drug Administration (FDA) considers it to be a first-in-class medication.
Sources: en.wikipedia.org
The American Journal of Respiratory Cell and Molecular Biology is a monthly peer-reviewed medical journal and an official publication of the American Thoracic Society. It covers research on the structure and function of the respiratory system under physiologic and pathophysiologic conditions. It was established in July 1989. The founding editors-in-chief were Jerome S. Brody, Robert M. Senior, and Mary C. Williams. John A. Mcdonald served as editor from 1993 to 1998. Kenneth B. Adler (North Carolina State University) served as editor from 2009 to 2016. Paul Schumacker (Northwestern University) served as editor from October 1, 2016, to October 21, 2023. Andrew Halayko (University of Manitoba) assumed the editorship on November 1, 2023. The journal is abstracted and indexed in BIOSIS Previews, Current Contents/Life Sciences, Current Contents/Critical Care Medicine, Embase, Index Medicus/MEDLINE/PubMed, Science Citation Index Expanded, and Scopus. According to the Journal Citation Reports, the journal has a 2024 impact factor of 5.3. Official website
The iodine pit, also called the iodine hole or xenon pit, is a temporary disabling of a nuclear reactor due to the buildup of short-lived neutron poisons in the reactor core. The main isotope responsible is 135Xe, mainly produced by beta decay of 135I. 135I is a weak neutron absorber, while 135Xe is the strongest known neutron absorber. When 135Xe builds up in the fuel rods of a reactor, it significantly lowers their reactivity, by absorbing a significant amount of the neutrons that provide the nuclear reaction. The presence of 135I and 135Xe in the reactor is one of the main reasons for its power fluctuations in reaction to change of control rod positions. The buildup of short-lived fission products acting as nuclear poisons is called reactor poisoning, or xenon poisoning. The buildup of stable or long-lived neutron poisons is called reactor slagging.
In May 2016 by a vote of 12–2, with several members of the committee expressing reservations about Sanofi's plans to offer two pens with different ratios of insulin glargine and lixisenatide - one for people who had never taken insulin before and one for people who had; there was also concern about how to handle dosing when switching people from a single drug regimen to the combination drug. In August 2016 the FDA told Sanofi that it was delaying a final decision for three months, and asked Sanofi for more data on how people used the delivery devices. Patent protection for lixisenatide expired in 2020.
=== From vitamers === Animals are auxotroph for this enzyme co-factor and require it or an intermediate to be supplemented, hence its classification as a vitamin, unlike MoCo or CoQ10 for example. PLP is synthesized from pyridoxal by the enzyme pyridoxal kinase (gene PDXK), requiring one ATP molecule. PDXK can also produce 5'-phosphates of the other vitamers (pyridoxine and pyridoxamine), with pyridoxine 5′-phosphate oxidase converting these alternative 5'-phosphates into PLP. PLP is made and metabolized in the liver. PLP and other vitamin B6 phosphates can be broken down by pyridoxal phosphatase, which removes the phosphate group.
Sources: en.wikipedia.org
It is a synthetic peptide built from 44 amino acids arranged in the same order as human growth hormone-releasing hormone. A short fatty-acid chain, described as a trans-3-hexenoyl group, is attached to the first amino acid. The finished molecule is formulated as a sterile powder that is dissolved before use.
No. It is a releasing-factor analog that signals the pituitary gland to secrete growth hormone, whereas recombinant growth hormone is the hormone itself administered directly. The two are chemically distinct and act at different points in the same endocrine pathway. This distinction is often lost in informal discussion.
Native growth hormone-releasing hormone is broken down within minutes by dipeptidyl peptidase-4 in the bloodstream. Adding the hexenoyl group at the N-terminus shields the peptide from that enzyme. The modification does not change the receptor it targets, only how long the peptide survives in circulation.
多肽在反相柱上按疏水性差异分离，能有效区分主峰、缺失序列片段与氧化产物。配合紫外检测可获得可量化的纯度百分比，是肽类分析的常规手段。