A practical reference on Neurotrophic factor: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-08-28. Anything still debated is marked as such rather than presented as settled.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
| Property | Value | Notes |
|---|---|---|
| Typical purity report | 95% or higher by HPLC | Area percentage at 214 nm |
| Identity confirmation | Mass spectrometry | Electrospray or MALDI |
| Powder storage | -20 C, desiccated | Protect from light |
| Solution storage | 2-8 C short term | Freeze aliquots for longer |
| Quality document | Certificate of analysis | States method and value |
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
=== Other vertebrates === There is no credible evidence that the candiru, a South American parasitic catfish, can swim up a human urethra if one urinates in the water in which it lives. The sole documented case of such an incident, written in 1997, has been heavily criticized upon peer review, and this phenomenon is now largely considered a myth. The skin of a chameleon is not adapted solely for camouflage purposes, nor can a chameleon change its skin color to match any background. Chameleons usually change color for social signaling, based on their mood, and for heat regulation. The use in social signaling may be to display bright colors for only brief periods of time to avoid increased visibility to predators. Contrary to the allegorical story about the boiling frog, frogs die immediately when cast into boiling water, rather than leaping out; furthermore, frogs will attempt to escape cold water that is slowly heated before reaching their critical thermal maximum. The Pacific tree frog and the Baja California chorus frog are some of the only frog species that make a "ribbit" sound. The misconception that all frogs, or at least all those found in North America, make this sound comes from its extensive use in Hollywood films. The memory span of goldfish is much longer than just a few seconds. It is up to a few months long. Pacus, South American fish related to piranhas, do not attack or feed on human testicles.
A special form of clubbing is hypertrophic pulmonary osteoarthropathy (HPOA), known in continental Europe as Pierre Marie-Bamberger syndrome. This is the combination of clubbing and thickening of periosteum (connective tissue lining of the bones) and synovium (lining of joints), and is often initially diagnosed as arthritis. It is commonly associated with lung cancer.
The Mali cobra (Naja katiensis) is a venomous species of spitting cobra native to western Africa. The venom of this species consists of postsynaptic neurotoxins and cardiotoxins with cytotoxic (necrotizing) activity. An average wet venom yield of 100 mg has been reported for this species. The average murine LD50 value of this species is 1.15 mg/kg IV, but there is an IV LD50 range of 0.97 mg/kg-1.45 mg/kg. The West African spitting cobra is one of the most common causes of snakebite in Senegal. Over 24 years, from 1976 to 1999, a prospective study was conducted of overall and cause-specific mortality among the population of 42 villages of southeastern Senegal. Of 4228 deaths registered during this period, 26 were caused by snakebite, four by invertebrate stings and eight by other wild or domestic animals. The average annual mortality rate from snakebite was 14 deaths per 100,000 population. Among persons aged one year or over, 0.9% (26/2880) of deaths were caused by snakebite and this cause represented 28% (26/94) of total deaths by accidents. Of 1280 snakes belonging to 34 species collected, one-third were dangerous, and the proportions of Viperidae, Elapidae and Atractaspidae were 23%, 11% and 0.6%, respectively. This species was third, responsible for 5.5% of the snakebites.
Smith, a farmer from the Midlands town of Selukwe who had been seriously wounded while serving in the British Royal Air Force during the Second World War, was Southern Rhodesia's first native-born Prime Minister. Regarded in British political circles as a "raw colonial"—when he took over, Smith's personal experience of the UK comprised four brief visits—he promised a harder line than Field in independence talks. The RF's replacement of Field drew criticism from the British Labour Party, whose leader Harold Wilson called it "brutal", while Nkomo described the new Smith Cabinet as "a suicide squad ... not interested in the welfare of all the people but only in their own". Smith said he was pursuing a middle course between black Rhodesian rule and apartheid so that there would still be "a place for the white man" in Southern Rhodesia; this would benefit the blacks too, he claimed. He held that the government should be based "on merit, not on colour or nationalism", and insisted that there would be "no African nationalist government here in my lifetime". Salisbury's blunt refusal to be part of the Wind of Change caused the Southern Rhodesian military's traditional British and American suppliers to impose an informal embargo, and prompted Whitehall and Washington to stop sending Southern Rhodesia financial aid around the same time.
Interaction with cell membrane receptors (extrinsic pathway) Interaction with mitochondria (intrinsic pathway) The first of these pathways involves the binding of a ligand to a receptor located on the surface of the cell membrane. The interaction of these two entities leads to the activation of various genes and releases a cascade of proteins characteristic of the apoptosis process. Arsenic trioxide also interacts with mitochondria. One of the initial changes in their structure induced by the drug is the opening of megachannels and the release of so-called "death proteins", primarily cytochrome c, APAF-1 (apoptotic peptidase activating factor 1), AIF (apoptosis-inducing factor), Smac/DIABLO protein, and endonucleases from the intermembrane space of mitochondria into the cytosol. In the cytoplasm, a protein complex known as the apoptosome forms, which activates further processes leading to apoptosis. Regardless of whether apoptosis is induced externally or internally, it always involves caspases, whose activation irreversibly leads the cell down the path of programmed cell death. Additionally, apoptosis is regulated by proteins from the Bcl-2 family, which can act as either pro-apoptotic or anti-apoptotic factors. The cause of acute promyelocytic leukemia is the translocation of the gene encoding the retinoic acid receptor (RARα) from chromosome 17 to a location near the PML gene on chromosome 15. This leads to the fusion of genes and the production of the PML/RARα protein. This protein inhibits differentiation and the death of the cells in which it is present.
Sources: en.wikipedia.org
The Kizil Caves (also romanized as Qizil or Qyzyl; Uyghur: قىزىل مىڭ ئۆي, lit. 'The Thousand Red Houses'; Chinese: 克孜尔千佛洞; lit. 'Kizil Caves of the Thousand Buddhas') are a set of Buddhist rock-cut caves located near Kizil Township (克孜尔乡; Kèzī'ěr Xiāng) in Baicheng County, Aksu Prefecture, Xinjiang, China. The site is located on the northern bank of the Muzat River 65 kilometres (40 miles) (75 km; 50 miles by road) west of Kucha. This area was a commercial hub of the Silk Road. The caves have an important role in Central Asian art and in the Silk Road transmission of Buddhism, and are said to be the earliest major Buddhist cave complex in China, with development occurring between the 3rd and 8th centuries CE. The caves of Kizil are the earlier of their type in China, and their model was later adopted in the construction of Buddhist caves further east. Another name for the site has been Ming-oi (明屋), although this term is now mainly used for the site of Shorchuk to the east. The Kizil Caves were inscribed in 2014 on the UNESCO World Heritage List as part of the Silk Roads: the Routes Network of Chang'an-Tianshan Corridor World Heritage Site.
5-Hydroxyeicosanoid dehydrogenase (5-HEDH) or more formally, nicotinamide adenine dinucleotide phosphate (NADP+)-dependent dehydrogenase, is an enzyme that metabolizes between two eicosanoid metabolites of arachidonate 5-lipoxygenase (5-LOX): 5-hydroxyeicosatetraenoic acid (5-(S)-HETE), and its 5-keto analog 5-oxo-eicosatetraenoic acid (5-oxo-ETE). It also acts in the reverse direction, metabolizing 5-oxo-ETE to 5(S)-HETE. Since 5-oxo-ETE is 30–100-fold more potent than 5(S)-HETE in stimulating various cell types, 5-HEDH is regarded as a regulator and promoter of the influence that 5-LOX and its metabolites have on cell function. Although 5-HEDH has been evaluated in a wide range of intact cells and in crude microsome preparations, it has not yet been evaluated for its structure or gene, and most studies on it have been limited to human tissues.
A laboratory study on rats produced by the Armed Forces Radiobiology Research Institute showed that, after a study period of 6 months, rats treated with depleted uranium coming from implanted pellets, comparable to the average levels in the urine of Desert Storm veterans with retained DU fragments, had developed a significant tendency to lose weight with respect to the control group. Substantial amounts of uranium were accumulating in their brains and central nervous systems, and showed a significant reduction of neuronal activity in the hippocampus in response to external stimuli. The conclusions of the study show that brain damage from chronic uranium intoxication is possible at lower doses than previously thought. Results from computer-based neurocognitive tests performed in 1997 showed an association between uranium in the urine and "problematic performance on automated tests assessing performance efficiency and accuracy." A 2021 report concluded that uranium from exploding munitions did not lead to Gulf War illness (GWI) in veterans deployed in the 1991 Persian Gulf War. The study found no differences in secretion of uranium isotopic ratios from those meeting the standard-case definitions of GWI and control veterans without GWI. The researchers say that the most likely remaining causes for GWI are widespread low-level exposure to sarin nerve gas released by the destruction of Iraqi chemical weapons storage facilities in January 1991.
== Adverse effects == In individuals already taking sulphonylureas, use of DPP-4-class medications concurrently increases their risk for low blood sugar events relative to those on sulphonylureas alone. Adverse effects include nasopharyngitis, headache, nausea, heart failure, hypersensitivity, and skin reactions. In late August 2015, the US FDA issued a warning that drugs like sitagliptin, saxagliptin, linagliptin, alogliptin, and other DPP-4 inhibitors could cause joint pain that can be severe and disabling. However, studies assessing risk of rheumatoid arthritis among DPP-4 inhibitor users have been inconclusive. A 2014 review found that the use of saxagliptin and alogliptin increased individuals' risk of developing heart failure, leading the FDA to add warnings to the labels of these drugs in 2016. A 2018 meta-analysis indicated that the use of DPP-4 inhibitors was associated with a 58% increased risk of developing acute pancreatitis compared to placebo or no treatment. Additionally, a 2018 observational study suggested an elevated risk of developing inflammatory bowel disease, specifically ulcerative colitis, which peaked after three to four years of use and decreased after more than four years. Finally, a 2020 Cochrane systematic review found insufficient evidence to suggest that metformin monotherapy reduced all-cause mortality, serious adverse events, cardiovascular mortality, non-fatal myocardial infarction, non-fatal stroke, or end-stage renal disease when compared to DPP-4 inhibitors for the treatment of type 2 diabetes.
==== October-November 2008 ==== In October 2008, Duel reported that soldier Maksim Pasko, who died near Gori on 12 August, had sent several SMSes. One SMS was sent on 3 August 2008 and said: "Don't worry too much, the Georgian militants are battering Tskhinvali. We were given orders to go there." Another SMS, sent on 5 August 2008, said: "Yesterday, our artillerists were messing with Georgia. 22 were killed and 150 injured." It was also reported that Russian military transport aircraft and attack helicopters began flying in the airspace of Abkhazia since 5 August 2008. Maksim Pasko had served in the 693rd Regiment. In October 2008, Russian military officer told Zavtra that at about 03:00 AM on 8 August, his division commander called him. He also said, "We took prisoners and they told us that after our break and the battle at a military base, a rumor spread that two Russian divisions had invaded Georgia and were sweeping everything in their path, and were slaughtering everyone without mercy." In October 2008, Sovershenno Sekretno newspaper reported that the 135th Motorized Rifle Regiment of the 58th Army received the order to move towards Tskhinvali a few hours before the Georgian attack.
Sources: en.wikipedia.org
== Prevention == The first control method is preventive and aims to eradicate the adult flies before they can cause any damage. The second control method is treatment once the infestation is present, and concerns the infected animals (including humans). The principal control method of adult populations of myiasis-inducing flies involves insecticide applications in the environment where the target livestock is kept. Organophosphorus or organochlorine compounds may be used, usually in a spraying formulation. One alternative prevention method is the sterile insect technique (SIT) where a significant number of artificially reared sterilized (usually through irradiation) male flies are introduced. The male flies compete with wild breed males for females to copulate and thus cause females to lay batches of unfertilized eggs that cannot develop into the larval stage. One prevention method involves removing the environment most favourable to the flies, such as by removal of the tail. Another example is the crutching of sheep, which involves the removal of wool from around the tail and between the rear legs, which is a favourable environment for the larvae. Another, more permanent, practice that is used in some countries is mulesing, where the skin is removed from young animals to tighten remaining skin – leaving it less prone to fly attack. To prevent myiasis in humans, there is a need for general improvement of sanitation, personal hygiene, and extermination of the flies by insecticides.
=== Reversibility === Minimal intervention, reversibility, and future treatability are core principles of contemporary conservation. Adhesive treatments that have failed or exceeded their lifespan may need to be removed, which may compromise or further damage delicate textiles. Because affixed supports can affect a fabric's drape or hand, and reversibility is not assured, conservators should evaluate alternative methods before proceeding with treatment. Despite these factors, adhesive consolidation is often the only option for severely damaged textiles. As with all types of treatment, conservators need to find a balance between intervention and potential loss of the artifact, a decision that requires a thoughtful weighing of risks and assessment of the post-treatment consequences. Some alternatives to adhesive consolidation include crepeline encapsulation, pressure mounts, and customized non-vertical display systems.
=== Cardiovascular system === Meta-analyses have reported a reduced risk of death from ischemic heart disease and from cerebrovascular disease among vegetarians. A 2023 systematic review and meta-analysis of prospective cohort studies found that vegetarian diets were associated with a reduced risk of cardiovascular disease overall and of ischemic heart disease in particular, while evidence for stroke was less clear.
Most organisms synthesize NAD+ from simple components. The specific set of reactions differs among organisms, but a common feature is the generation of quinolinic acid (QA) from an amino acid – either tryptophan (Trp) in animals and some bacteria, or aspartic acid (Asp) in some bacteria and plants. The quinolinic acid is converted to nicotinic acid mononucleotide (NaMN) by transfer of a phosphoribose moiety. An adenylate moiety is then transferred to form nicotinic acid adenine dinucleotide (NaAD). Finally, the nicotinic acid moiety in NaAD is amidated to a nicotinamide (Nam) moiety, forming nicotinamide adenine dinucleotide. In a further step, some NAD+ is converted into NADP+ by NAD+ kinase, which phosphorylates NAD+. In most organisms, this enzyme uses adenosine triphosphate (ATP) as the source of the phosphate group, although several bacteria such as Mycobacterium tuberculosis and a hyperthermophilic archaeon Pyrococcus horikoshii, use inorganic polyphosphate as an alternative phosphoryl donor.
Sources: en.wikipedia.org
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.
Dry powder is kept frozen, desiccated, and shielded from light. Dissolved material is aliquoted and frozen to limit freeze-thaw cycles. Short-term refrigerated storage is common for working solutions.
Russia registers it as a prescription nasal product. Most other markets classify it as a research chemical with no approved medical use. Oversight of purity and labeling is consequently minimal in those markets.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.