immune modulation raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2025-08-16 and is reviewed periodically as new material appears.
市售的胸腺素α1通常以冻干粉形式提供，溶解后用于注射。其氨基酸组成包括多个酸性残基，因此在中性pH下带负电荷。该肽可溶于水和生理盐水，但在有机溶剂中溶解度有限。储存条件通常为冻干状态下负20摄氏度，溶解后需冷藏并避免反复冻融。常见的同义词包括胸腺肽α1、thymalfasin和Tα1。
胸腺素α1（thymosin alpha 1，Tα1）是一种由28个氨基酸组成的酸性肽，N端被乙酰化，分子量约为3108道尔顿。该肽最早从牛胸腺组织提取物中分离，属于胸腺素组分5的一个成分。其序列在不同哺乳动物中高度保守，提示其具有基本的生物学功能。名称中的“α1”指其在电泳中的迁移位置，并非表示亚型编号。它既存在于胸腺，也存在于脾脏和淋巴结等免疫组织。
Immunological studies connect the peptide to multiple parts of the immune response. It has been reported to engage Toll-like receptor signaling, to promote dendritic cell maturation, and to influence the balance of T helper cell subsets. Changes in natural killer cell activity and in cytokine release appear in cell culture and animal models. These observations describe broad immunomodulatory behavior rather than a single defined receptor target, and the primary molecular interaction has not been settled.
Thymosin alpha-1 is a synthetic 28-amino-acid peptide whose sequence was first identified in extracts of bovine thymus tissue during the 1970s. The chain carries an acetyl group on its N-terminal serine. Its acidic residue content is high, which produces strong water solubility and an isoelectric point well below neutrality. Material supplied for laboratory and clinical use is manufactured by solid-phase peptide synthesis rather than purified from animal tissue. Different salt forms, such as the acetate, alter the counter-ion content without changing the peptide backbone.
| Property | Value | Notes |
|---|---|---|
| 化学分类 | 线性肽 | 由28个氨基酸组成 |
| 分子量 | 约3108 Da | 合成版本一致 |
| 外观 | 白色至类白色粉末 | 冻干品 |
| 溶解度 | 易溶于水 | 微溶于有机溶剂 |
| 储存温度 | -20°C（冻干） | 溶解后2-8°C |
Within the immune system, the peptide acts on several cell types rather than a single target. Reported activities include promotion of T-cell maturation, enhancement of natural killer cell activity, and modulation of cytokine production by dendritic cells and macrophages. Some of these effects appear to operate through toll-like receptor signaling, though the precise receptor-level mechanism remains debated. Whether the observed immune changes translate into clinical benefit is a separate question and depends on the indication studied.
The peptide was described in the 1970s as a component of thymic extracts, and early research focused on restoring immune function in immunodeficiency states. A synthetic version entered clinical development in the 1980s and is approved as a drug in several countries for conditions such as chronic hepatitis B and certain immunodeficiencies. Approval status varies widely by jurisdiction, and in the United States it is not an approved therapeutic. Regulatory and clinical positions differ, so statements about efficacy should be tied to specific indications and studies.
Thymosin alpha-1 is a synthetic peptide of 28 amino acids, corresponding to the N-terminal fragment of prothymosin alpha. Its sequence begins with acetylation at the N-terminus, a modification that affects stability and receptor interaction. The peptide is acidic, with a calculated isoelectric point near 4.2, and carries no disulfide bonds, so its secondary structure is largely flexible in solution. Molecular mass is approximately 3108 daltons. The native form was first isolated from bovine thymus tissue, while pharmaceutical material is produced by solid-phase peptide synthesis.
Thymosin alpha-1 is a synthetic peptide of 28 amino acid residues that corresponds to a naturally occurring fragment first isolated from thymus tissue. Its chain is acetylated at the amino terminus, a modification that shields the peptide from rapid cleavage by aminopeptidases. The molecule carries a net negative charge at physiological pH and dissolves freely in water. Researchers classify it as an immune-modulating agent rather than a classical hormone, because it acts on several cell types of both the innate and the adaptive immune system.
The peptide was identified during work in the 1970s on thymosin fraction 5, a partially purified extract of calf thymus. Investigators separated that mixture and characterized individual components, one of which they named thymosin alpha-1. The same compound later received the international nonproprietary name thymalfasin. Commercial material is produced by solid-phase peptide synthesis rather than by extraction, so synthetic and natural forms share an identical sequence. Naming conventions vary across the literature, and readers should distinguish the alpha-1 peptide from other thymosins that have unrelated sequences and functions.
Stability depends on temperature, pH, and the number of freeze-thaw events the sample has experienced. Freeze-dried material is commonly held at -20 °C or colder, while reconstituted liquid is kept cold and used within a short window. Extreme pH and prolonged light exposure can promote deamidation, oxidation, or aggregation, particularly at asparagine and methionine positions. Adsorption to container walls can lower the measured concentration of a dilute solution even when the peptide molecules themselves remain intact.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or chemically modified byproducts. Mass spectrometry confirms the expected molecular mass and can indicate acetylation state or sequence errors. Amino acid analysis and peptide mapping supply complementary sequence-level information, while endotoxin testing is relevant for preparations intended for cell or animal work. Purity figures reported by suppliers refer to the method used and are not directly comparable across laboratories unless conditions are stated.
Lyophilized material is typically treated as a hygroscopic solid that should be brought to room temperature before the container is opened, which limits condensation on the powder. Reconstitution is commonly done with sterile water or a buffered diluent, and gentle mixing is preferred over vigorous agitation to reduce foaming and surface adsorption. Because peptides can bind to plastic and glass, diluents containing a small amount of carrier protein are sometimes used in laboratory work. Working solutions are generally aliquoted and prepared fresh rather than subjected to repeated freezing and thawing.
Thymosin alpha-1 is a 28-residue peptide first isolated from thymus tissue in the 1970s. It corresponds to the N-terminal portion of thymosin beta-4, from which it is cleaved in vivo. The peptide carries an acetyl group at its N-terminus, a modification that affects its charge and stability. Synthetic material produced by solid-phase peptide synthesis is chemically identical to the natural fragment and is the form used in research and clinical studies.
Laboratory work indicates that the peptide acts on cells of both the innate and adaptive immune systems. Reported effects include signalling through Toll-like receptors on dendritic cells, enhanced T-cell maturation, and increased natural killer cell activity. These actions are described largely from cell-culture and animal experiments, and the precise receptor-level events remain incompletely defined. Studies in humans have generally measured immune markers rather than a single defined molecular target. The resulting picture remains partly descriptive.
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Results across trials have been mixed, and several studies were small or conducted under differing protocols. Regulatory status varies by country, and the compound is not approved in every jurisdiction where it is studied. Evidence for any single indication should be read with attention to sample size and endpoint choice.
The isotope pattern in the spectrum, which is unique for elements that have many natural isotopes, can also be used to identify the various elements present. Once a chemical formula has been matched to the spectrum, the molecular structure and bonding can be identified, and must be consistent with the characteristics recorded by GC–MS. Typically, this identification is done automatically by programs which come with the instrument, given a list of the elements which could be present in the sample. A "full spectrum" analysis considers all the "peaks" within a spectrum. Conversely, selective ion monitoring (SIM) only monitors selected ions associated with a specific substance. This is done on the assumption that at a given retention time, a set of ions is characteristic of a certain compound. This is a fast and efficient analysis, especially if the analyst has previous information about a sample or is only looking for a few specific substances. When the amount of information collected about the ions in a given gas chromatographic peak decreases, the sensitivity of the analysis increases. So, SIM analysis allows for a smaller quantity of a compound to be detected and measured, but the degree of certainty about the identity of that compound is reduced.
These genes can be placed in three categories: genes that increase the risk of migraine in general, those that specifically increase risk for migraine with aura, and those that specifically increase risk for migraine without aura. Three of these genes, CALCA, CALCB, and HTR1F, are already targets for migraine specific treatments. Five genes are specific to risk of migraine with aura, PALMD, ABO, LRRK2, CACNA1A and PRRT2, and 13 genes are specific to risk of migraine without aura. Using the accumulated genetic risk of common variations to calculate a so-called polygenetic risk score, it is possible to assess, for example, the treatment response to triptans.
Emus forage in a diurnal pattern and eat a variety of native and introduced plant species. The diet depends on seasonal availability with such plants as Acacia, Casuarina and grasses being favoured. They also eat insects and other arthropods, including grasshoppers and crickets, beetles, cockroaches, ladybirds, bogong and cotton-boll moth larvae, ants, spiders and millipedes. This provides a large part of their protein requirements. In Western Australia, food preferences have been observed in travelling emus; they eat seeds from Acacia aneura until the rains arrive, after which they move on to fresh grass shoots and caterpillars; in winter they feed on the leaves and pods of Cassia and in spring, they consume grasshoppers and the fruit of Santalum acuminatum, a sort of quandong. They are also known to feed on wheat, and any fruit or other crops that they can access, easily climbing over high fences if necessary. Emus serve as an important agent for the dispersal of large viable seeds, which contributes to floral biodiversity. One undesirable effect of this occurred in Queensland in the early twentieth century when emus fed on the fruit of prickly pears in the outback. They defecated the seeds in various places as they moved around, and this led to a series of campaigns to hunt emus and prevent the seeds of the invasive cactus being spread. The cacti were eventually controlled by an introduced moth (Cactoblastis cactorum) whose larvae fed on the plant, one of the earliest examples of biological control.
The two substrates of this enzyme are androsterone and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are 5α-androstane-3,17-dione, reduced NADH, and a proton. The alternative cofactor nicotinamide adenine dinucleotide phosphate is also used by this enzyme. The enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor, more specifically it is part of the group of hydroxysteroid dehydrogenases. The systematic name of this enzyme class is 3alpha-hydroxysteroid:NAD(P)+ oxidoreductase (B-specific). Other names in common use include hydroxyprostaglandin dehydrogenase, 3alpha-hydroxysteroid oxidoreductase, and sterognost 3alpha. This enzyme participates in 3 metabolic pathways: bile acid biosynthesis, c21-steroid hormone metabolism, and androgen and estrogen metabolism.
Encouraged by women in the community, it is primarily intended to protect chastity, deter promiscuity, and offer protection from assault. By 2013, UNICEF in conjunction with the Somali authorities reported that the prevalence rate among 1- to 14-year-old girls in the autonomous northern Puntland and Somaliland regions had dropped to 25% following a social and religious awareness campaign. About 93% of Somalia's male population is also reportedly circumcised. Somalia has one of the lowest HIV infection rates on the continent. This is attributed to the Muslim nature of Somali society and adherence of Somalis to Islamic morals. While the estimated HIV prevalence rate in Somalia in 1987 (the first case report year) was 1% of adults, a 2012 report from UNAIDS says that since 2004, estimates from 0.7% to 1.0% have been assumed. Although healthcare is now largely concentrated in the private sector, the country's public healthcare system is in the process of being rebuilt, and is overseen by the Ministry of Health. The Minister of Health is Qamar Adan Ali. The autonomous Puntland region maintains its own Ministry of Health, as does the Somaliland region in northwestern Somalia.
Sources: en.wikipedia.org
== Further reading == Tropane Alkaloid Poisoning on eMedicine Krenzelok, Edward P. (February 2010). "Aspects of poisoning and treatment". Clinical Toxicology. 48 (2): 104–110. doi:10.3109/15563651003630672. PMID 20229618. S2CID 28433567. Rätsch, C. (2005) [1998]. The Encyclopedia of Psychoactive Plants. Rochester, VT: Park Street Press. ISBN 978-0-89281-978-2. Archived from the original on 22 August 2013. Retrieved 9 September 2017. Roblot, F; Montaz, L; Delcoustal, M; Gaboriau, E; Chavagnat, JJ; Morichaud, G; Pourrat, O; Scepi, M; Patte, D (1995). "Intoxication par Datura stramonium: Le diagnostic est clinique, le traitement est symptomatique" [Datura stramonium poisoning: the diagnosis is clinical, treatment is symptomatic]. La Revue de Médecine Interne (in French). 16 (3): 187–90. doi:10.1016/0248-8663(96)80689-8. PMID 7740228.
== Overall survival == For incident dialysis patients (mean age ~65 years), median survival is about 3 years, with adjusted mortality rates of 187.7 per 1,000 patient-years. 1-year survival: 80–85% overall; 60–70% for patients ≥65 years. 3-year survival: ~57% for HD, ~68% for peritoneal dialysis (PD). 5-year survival: 35–42% for HD; PD outcomes converge long-term.
== Signs and symptoms == The typical symptoms of UIP are progressive shortness of breath and cough for a period of months. In some patients, UIP is diagnosed only when a more acute disease supervenes and brings the patient to medical attention.
The parietal serous pericardium, which lines the interior side of the superficial portion of the pericardial sac, is fused to and inseparable from the fibrous pericardium The visceral serous pericardium, also known as the epicardium, covers the myocardium of the heart and can be considered its serosa. It is largely made of a mesothelium overlying some elastin-rich loose connective tissue. During ventricular contraction, the wave of depolarization moves from the endocardial to the epicardial surface. Both of these layers function in lubricating the heart to prevent friction during heart activity. The visceral serous pericardium extends to the root of the great vessels and joins the parietal serous pericardium at the anatomical base of the heart. This junction occurs at two areas: the ventricular outflow tracts where the aorta and pulmonary trunk leave the heart, and the inflow tracts where the superior/inferior vena cava and pulmonary veins enter the heart. The root of the great vessels and the associated reflections of the serous pericardium creates various smaller sacs and tunnels known as pericardial sinuses, as well as radiographically significant pericardial recesses, where pericardial fluid can pool and mimic mediastinal lymphadenopathy.
Sources: en.wikipedia.org
=== Nanoparticle drug delivery === Delivering medications to the brain has long been a significant challenge in treating neurological diseases. The main reason lies in the blood-brain barrier (BBB), a highly selective, protective layer that shields the brain from toxins and pathogens in the bloodstream. While the BBB is crucial for maintaining brain health, it also makes it difficult for most therapeutic drugs to reach their target, especially in conditions like Alzheimer's and Parkinson's disease. As a result, conventional drug delivery methods often fall short, either causing unwanted side effects or failing to deliver a high enough concentration to be effective. To address this, researchers have turned to nanoparticles, tiny engineered carriers designed to sneak past the BBB and deliver drugs directly to the brain tissue These particles can be tailored to take advantage of the body's own transport systems. For example, by attaching certain molecules to their surfaces, nanoparticles can trigger receptor-mediated transcytosis, a natural process that allows them to pass through cells lining the BBB and enter the brain. This kind of targeted delivery helps reduce the drug's exposure to the rest of the body, lowering the risk of side effects and increasing concentration where it matters most. So far, this strategy has shown promise in delivering treatments to the brain for conditions like Alzheimer's and Parkinson's disease. Several types of nanoparticles are being studied for this purpose.
Holders of more than 99% of the shares elected to participate. Holmes contributed shares to the company and gave up equity to offset potential dilution to non-participating shareholders. In May 2018, John Carreyrou reported that American business and government leaders lost more than $600 million by privately investing in Theranos. Major investments had been made by the Walton family ($150 million), Rupert Murdoch ($121 million), Betsy DeVos ($100 million), the Cox family (of Cox Media Group) ($100 million) and Larry Ellison. The final liquidation of the company in September 2018 rendered these investments worthless.
During translation, ribosomes synthesize polypeptide chains from mRNA template molecules. In eukaryotes, translation occurs in the cytoplasm of the cell, where the ribosomes are located either free floating or attached to the rough endoplasmic reticulum. In prokaryotes, which lack a nucleus, the processes of both transcription and translation occur in the cytoplasm. Ribosomes are complex molecular machines, made of a mixture of protein and ribosomal RNA, arranged into two subunits (a large and a small subunit), which surround the mRNA molecule. The ribosome reads the mRNA molecule in a 5'-3' direction and uses it as a template to determine the order of amino acids in the polypeptide chain. To translate the mRNA molecule, the ribosome uses small molecules, known as transfer RNAs (tRNA), to deliver the correct amino acids to the ribosome. Each tRNA is composed of 70–80 nucleotides and adopts a characteristic cloverleaf structure due to the formation of hydrogen bonds between the nucleotides within the molecule. There are around 60 different types of tRNAs, each tRNA binds to a specific sequence of three nucleotides (triplets known as codons) within the mRNA molecule and delivers a specific amino acid. The ribosome initially attaches to the mRNA at the start codon (AUG) and begins to translate the molecule. The mRNA nucleotide sequence is read in codons (three adjacent nucleotides in the mRNA molecule correspond to a single codon).
Sources: en.wikipedia.org
它不是经典的内分泌激素，而是一种免疫调节肽。其作用主要通过局部免疫细胞间的信号传递实现，而非经血液循环作用于远隔器官。
天然胸腺素α1主要从胸腺组织提取，也可在脾脏和淋巴结中检出。目前研究和临床使用的多为化学合成版本，不再依赖动物组织。
胸腺素组分5是牛胸腺提取物的粗组分，包含多种肽。胸腺素α1是其中一种被纯化和表征的单一肽，具有明确的28个氨基酸序列。
It is usually described as an immunomodulatory peptide rather than a classic circulating hormone. No endocrine gland is known to release it as a primary secretory product, and its measured presence in blood is not firmly established.