A practical reference on tuftsin: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
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.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
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.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
| Property | Value | Notes |
|---|---|---|
| Route studied | Intranasal | Predominant route in published reports |
| Circulation stability | Short, minutes scale | Peptidases cleave it; the tail slows the process |
| Analytical method | RP-HPLC with mass spectrometry | Used for identity and purity assessment |
| Reported outcome domains | Anxiety and cognitive measures | Derived from small, mostly regional trials |
| Regulatory status | Marketed in Russia | Availability outside that market is limited |
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
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.
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.
Also, the Export-Import Bank's lending limit was raised in 1958 from $5 billion to $7 billion, and the administration advocated in January 1959 an expanded "food for peace" program. The overall trend in U.S. government development-assistance activity in the 1950s is indicated by the change in the number of U.S. staff in field missions, which during Eisenhower's years in office from 1953 to 1961 rose from 2,839 to 6,387.
This approach attempts to use as close to the exact IP conditions and components as the actual immunoprecipitation to remove any non-specific cell constituent without capturing the target protein (unless, of course, the target protein non-specifically binds to some other IP component, which should be properly controlled for by analyzing the discarded beads used to preclear the lysate). The target protein can then be immunoprecipitated with the reduced risk of non-specific binding interfering with data interpretation.
Hyperandrogenism is a medical condition characterized by high levels of androgens. It is more common in women than men. Symptoms of hyperandrogenism may include acne, seborrhea, hair loss on the scalp, increased body or facial hair, and infrequent or absent menstruation. Complications may include high blood cholesterol and diabetes. It occurs in approximately 5% of women of reproductive age. Polyendocrine metabolic ovarian syndrome accounts for about 70% of hyperandrogenism cases. Other causes include Congenital adrenal hyperplasia, insulin resistance, hyperprolactinemia, Cushing's disease, certain types of cancers, and certain medications. Diagnosis often involves blood tests for testosterone, 17-hydroxyprogesterone, and prolactin, as well as a pelvic ultrasound. Treatment depends on the underlying cause. Symptoms of hyperandrogenism can be treated with birth control pills or antiandrogens, such as cyproterone acetate or spironolactone. Other measures may include hair removal techniques. The earliest known description of the condition is attributed to Hippocrates. In 2011, the International Association of Athletics Federations (now World Athletics) and IOC (International Olympic Committee) released statements restricting the eligibility of female athletes with high testosterone, whether through hyperandrogenism or as a result of a difference in sex development (DSD). These regulations were referred to by both bodies as hyperandrogenism regulations and have led to athletes with DSDs being described as having hyperandrogenism.
== Biography == Yourcenar was born in Brussels, Belgium, as Marguerite Antoinette Jeanne Marie Ghislaine Cleenewerck de Crayencour, to Michel Cleenewerck de Crayencour and Fernande de Cartier de Marchienne. Her father was of French bourgeois descent, originating from French Flanders, and a wealthy landowner. Her mother, of Belgian nobility, died ten days after Marguerite's birth. She grew up in the home of her paternal grandmother, and adopted the surname Yourcenar as a pen name; in 1947, she also took it as her legal surname. Yourcenar's first novel, Alexis, was published in 1929. She translated Virginia Woolf's The Waves over a ten-month period in 1937. In 1939, her partner at the time, the literary scholar and Kansas City native Grace Frick, invited Yourcenar to the United States to escape the outbreak of World War II in Europe. She lectured in comparative literature in New York City and Sarah Lawrence College. Yourcenar and Frick became lovers in 1937 and remained together until Frick's death in 1979. After ten years spent in Hartford, Connecticut, they bought a house in Northeast Harbor, Maine, on Mount Desert Island, where they lived for decades. They are buried next to each other at Brookside Cemetery, Somesville, Mount Desert, Maine. Yourcenar's last companion was Jerry Wilson, with whom she had a tormented relationship; he died of AIDS in 1986. In 1951, Yourcenar published, in France, the novel Memoirs of Hadrian, which she had been writing on and off for a decade. The novel was an immediate success and met with critical acclaim.
Sources: en.wikipedia.org
In vitro studies indicate gepotidacin can inhibit specific drug transporters, but the clinical significance of these findings requires further evaluation. Excretion is mainly fecal (~52%, 30% unchanged) and urinary (~31%, 20% unchanged), with the latter being the major route for absorbed drug. Renal impairment leads to elevated gepotidacin exposure, with the degree of increase directly linked to the severity of kidney dysfunction. This effect is particularly pronounced in patients with end-stage renal disease undergoing hemodialysis. Additionally, impaired kidney function decreases urinary excretion of the drug, which may necessitate dosage adjustments in severe cases to ensure safe and effective treatment. Severe hepatic impairment also elevates gepotidacin exposure, while moderate hepatic impairment did not show a clinically relevant effect during clinical trials.
=== Awards received in the 1990s === Keene P. Dimick Award in Chromatography, Third International Symposium on Supercritical Fluid Chromatography Award for Pioneering Work in the Development of SFC; Marcel J.E. Golay Award and Medal, International Symposium on Capillary Chromatography; American Chemical Society Award in Separation Science and Technology; American Chemical Society Exceptional Achievement Award as a Capillary Gas Chromatography Short Course Instructor; R&D 100 Award for technologically significant new product: -PAGE Polyacrylamide Gel-filled Capillaries for Capillary Electrophoresis”; Jan E. Purkynje Memorial Medal of the Czech Academy of Sciences; R&D Magazine Scientist of the Year Award; M.S. Tswett Memorial Medal of the Russian Academy of Sciences; A.J.P. Martin Gold Medal of the Chromatographic Society of Great Britain; Theophilus Redwood Award, The Royal Society of Chemistry, Great Britain; Distinguished Teaching and Mentoring Award of the University Graduate School, Indiana University; Elected as a Foreign Member of the Royal Society of Sciences (Sweden); College of Arts & Sciences Distinguished Faculty Award, Indiana University.
Each e-cigarette company's designs generate different amounts of heating power. The evidence indicates that larger capacity tanks, increasing the coil temperature, and dripping configurations seem to be end-user-modified designs adopted by e-cigarette companies. Variable voltage e-cigarettes can raise the temperature within the device to allow users to adjust the e-cigarette vapor. No firm information is available on the temperature differences in variable voltage devices. The length of time that the e-cigarette vapor is being heated within the device also affects the e-cigarette vapor properties. When the temperature of the heating element rises, the temperature of the e-cigarette vapor in the air rises. The hotter air can support more e-liquid air density. E-cigarettes have a wide array of engineering designs. The differences in e-cigarette manufacturing materials are broad and often unknown. Concern exists over lack of quality control. E-cigarette companies often lack manufacturing standards or are non-existent. Some e-cigarettes are designed and manufactured to a high standard. The manufactured standards of e-cigarettes are not equivalent to pharmaceutical products. Improved manufacturing standards could reduce the levels of metals and other chemicals found in e-cigarette vapor. Quality control is influenced by market forces. The engineering designs typically affect the nature, number, and size of particles generated.
Sources: en.wikipedia.org
The flow is steady ( ∂.../∂t = 0 ). The radial and azimuthal components of the fluid velocity are zero ( ur = uθ = 0 ). The flow is axisymmetric ( ∂.../∂θ = 0 ). The flow is fully developed ( ∂ux/∂x = 0 ). Here however, this can be proved via mass conservation, and the above assumptions. Then the angular equation in the momentum equations and the continuity equation are identically satisfied. The radial momentum equation reduces to ∂p/∂r = 0, i.e., the pressure p is a function of the axial coordinate x only. For brevity, use u instead of
Even within the plant kingdom, Selaginella (sometimes called the resurrection plant), which grows in desert and mountainous areas, may be cracked and dried out, but will turn green again and revive after rain because of the function of trehalose. The two prevalent theories as to how trehalose works within the organism in the state of cryptobiosis are the vitrification theory, a state that prevents ice formation, or the water displacement theory, whereby water is replaced by trehalose. In bacterial cell wall, trehalose has a structural role in adaptive responses to stress such as osmotic differences and extreme temperature. Yeast uses trehalose as a carbon source in response to abiotic stresses. In humans, trehalose is thought to act as a neuroprotective by inducing autophagy and thereby clearing protein aggregates. Trehalose has also been reported for anti-bacterial, anti-biofilm, and anti-inflammatory (in vitro and in vivo) activities, upon its esterification with fatty acids of varying chain lengths.
== Other uses == Kombucha culture, when dried, becomes a leather-like textile known as a microbial cellulose that can be molded onto forms to create seamless clothing. Using different broth media such as coffee, black tea, and green tea to grow the kombucha culture results in different textile colors, although the textile can also be dyed using other plant-based dyes. Different growth media and dyes also change the textile's feel and texture. Dried and processed SCOBY has been investigated as a leather substitute. Additionally, the SCOBY itself can be dried and eaten as a sweet or savory snack. Kombucha can be further used for bioleaching of yttrium oxide from waste fluorescent lamp phosphors.
Soybeans suffer from the fungus Pythium spinosum in Arkansas and Indiana (United States), and China. In Japan and the United States, the Soybean dwarf virus (SbDV) causes a disease in soybeans and is transmitted by aphids.
Sources: en.wikipedia.org
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.
Intranasal delivery is the route described in most published work. It is used because the peptide is degraded quickly once it reaches circulation. Direct evidence of brain penetration in humans is lacking.
Most trials are small, regionally concentrated, and often lack rigorous blinding or placebo control. Independent replication is limited. Reviews in English generally rate the evidence as preliminary.
Reverse-phase HPLC is the usual method and gives a percentage purity value. Mass spectrometry then confirms the molecular mass. Together they provide a basic identity and purity profile for a lot.