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At least 199 records · Page 11Linked to original sources
PubMed1991

Competition between tuftsin and HIV-1, HIV-2 envelope protein sequences.

Syntheses of tuftsin-like partial sequences of HIV-1 and HIV-2 gp-120 proteins: Thr-Lys-Ala-Lys (I), Thr-Lys-Ala-Lys-Arg (II), Pro-Thr-Lys-Ala-Lys-Arg (III), Thr-Lys-Glu-Lys (IV), Thr-Lys-Glu-Lys-Arg (V), and Pro-Thr-Lys-Glu-Lys-Arg (VI) are described. From HIV-1 partial sequences peptide I inhibited the phagocytosis stimulating activity of tuftsin. The inhibitory potency diminished progressively for peptides II and III, in parallel to the increase of their slight phagocytosis stimulating activity. Similar results were obtained also for the fragments of the HIV-2 gp120 protein. The inhibitory activity, clearly visible for IV, diminished with peptide chain elongation. Peptides IV and VI were devoided of the phagocytosis stimulating activity while peptide V was slightly active.

Amino Acid Sequence↗
PubMed1990

[A comparative analysis of the morphochemical changes in the neurons of the visual and sensorimotor cortices and the nucleus accumbens of rats administered tuftsin].

White rats were treated with a single administration of tetrapeptide tuftsin (Thr-Lys-Pro-Arg) in the dose 300 mcg/kg (b.w). Using interferometry, the protein content and concentration were assessed 15, 30 and 60 minutes after injection. The area of the neuron cytoplasm and nucleus were measured too. The nucleoplasmic balance and dispersion were calculated. Significant alterations in the protein contents and cellular area, nucleoplasmic balance and dispersion were detected in neurons of visual, sensomotor cortex and of n. accumbens. A possible interrelation is discussed between tuftsin action and the functional activity of neurons, between the level of their protein metabolism and establishment of emotional and motor response.

Animals↗
PubMed1989

[Post-stress correlation of the functional activity of macrophages by tuftsin and its derivatives].

The effect of 15 day programmed neurotization on the functional activity of the peritoneal macrophages has been studied. The NBT-test and the adhesion measurements were used. The experimental neurosis resulted in the decrease of the macrophage functional activity and in leukopenia. Tuftsin did not restore the stress induced depression of macrophage activity but led to additional rise of the adrenal glands weight and to pronounced granulocyte-monocytosis. Pentapeptide analog of tuftsin gave the additional inhibition of NBT-activity of the macrophage. Heptapeptide analog favoured the restoration of the macrophage activity after neurotization and stimulated lymphopoiesis.

Adrenal Glands↗
PubMed1989

[Effect of tuftsin on the leucyl aminopeptidase activity of the subcellular components in cerebral cortical formations].

The administration of a tetrapeptide tuftsin in a dose of 300 mkg/kg body weight for 15, 75 minutes leads to the change in specific activity of leucyl-arylamidase in subcellular component and their membrane which has been isolated from the rabbit sensomotor cortex and visual cortex. Reaction of a tetrapeptide depends on time. It is strongly pronounced in sensomotor cortex and has an advantage in synaptosomes and their membrane. Possibility of tuftsin in protein exchange of cellular and subcellular component is discussed.

Animals↗
PubMedDate not supplied

[Effect of the neuropeptide tuftsin and its derivatives on metabolism in various structures of the brain].

A study was made of the effect of the neuropeptide tuftsin and its derivatives on some indicators of the metabolism in limbic structures and cortex of the brain in 200 rats. It was shown that tuftsin and its derivatives raise the content of nicotinamide coenzymes at the expense of the oxidized forms of NAD, activate cytochrome-c-oxidase and dehydrogenases largely in the limbic structures. Thus the peptides under study were found to increase the intensity of cell respiration and to enhance intracellular redox processes, i. e. to largely activate the vital activity of the cells of the brain emotiogenous structures.

Animals↗
PubMedDate not supplied

[Effect of tuftsin, a neuropeptide and its derivatives on the content of nicotinamide coenzymes and the activity of cytochrome- c-oxidase of brain tissue].

Tuftsin, a neuropeptide, and its derivatives are studied for their influence on the content of oxidized and reduced forms of nicotinamide enzymes as well as on the activity of cytochrome-c-oxidase of the cortex and limbic system. Peptides under study are shown to increase the content of nicotinamide coenzymes, mainly due to the oxidized forms of NAD and enhance the activity of cytochrome-c-oxidase as well mainly in the emotiogenic brain structures. Under these conditions tuftsin and its derivatives intensify cellular respiration of the neurons.

Animals↗
PubMed1988

Influence of tuftsin-like synthetic peptides derived from C-reactive protein (CRP) on platelet behaviour.

C-reactive protein (CRP) is an acute-phase reactant that modifies platelet function differently, depending upon its physiochemical state. Aggregated and ligand-complexed forms of CRP initiate the activation of platelets, whereas naturally occurring CRP peptides inhibit platelet activation. The present study documents neutral proteases of the polymorphonuclear leucocyte (PMN) to cleave CRP into reaction products with the potential to inhibit platelet activation, and explore the structure-function relationships involved in the regulation of platelet activation by CRP using synthetic CRP peptides. Evidence was obtained that (i) a minimum of two linear functional domains exist within CRP that influence platelet activation; (ii) they reside in the mid-portion and at the C-terminus of the CRP molecule; (iii) the mid-portion domain inhibits platelet activation stimulated by adenosine diphosphate (ADP) or acid-soluble collagen, whereas the C-terminal domain initiates platelet activation; (iv) the functional expression of the C-terminal domain is maximized when the linear peptide is immobilized on latex; and (v) both CRP domains contain a homologue of the immunoregulatory signal peptide, tuftsin. These data suggest that the molecular mechanisms by which platelet processes are modulated by CRP may be related to the presence of tuftsin homologues in CRP.

Amino Acid Sequence↗
PubMedDate not supplied

[Effect of tuftsin and its analog on learning, memory and exploratory behavior in rats].

On Wistar male rats the influence of tetrapeptide tuftsin and its analogue TP-1 (300 mkg/kg, i/p) on animals behaviour was studied. It is shown that administration of peptides increases the rat's exploratory activity. Activating influence of TP-1 was continued for 6 h. Daily multiple administration of tuftsin or TP-1, 15 min prior to the beginning of experiments facilitates the learning and stability of conditioned reaction with food reinforcement. Experimental animals react significantly weaker than the control ones to emotionally negative influence, produced by a sharp reduction of the amount of alimentary reinforcement control.

Animals↗
PubMed1987

The influence of synthetic tuftsin and its analogs on the function of granulocytes of children with acute lymphoblastic leukemia.

The effect of tuftsin, its synthetic analogs and arginine on phagocytosis of Staphylococcus aureus by granulocytes from leukemic children was investigated in vitro. The high stimulatory effect of tuftsin and arginine was shown. The decrease of phagocytosis of PMN from healthy subjects after preincubation with its analogs and arginine was observed, suggesting the regulatory effect of these peptides.

Adolescent↗
PubMed1986

[Various neurochemical aspects of the action of the tetrapeptide tuftsin on limbic system structures (histochemical and biochemical study)].

Tetrapeptide tuftsin action on the activity of succinate dehydrogenase (SDG), malate dehydrogenase (MDG) and monoamine-oxidase (MAO) in microstructures of the neocortex, hippocampus and hypothalamus (supraoptic and paraventricular nuclei, retrochiasmic zone) has been investigated by means of histochemical methods. Simultaneously, pyruvate-, malate-, glutamate-, alfaketoglutamate-, succinate- and lactate-dehydrogenase activity in the neocortex and in the structures of the limbic system has been studied biochemically. SDG and MDG activity increases in neurons and glycocytes of all the hypothalamic formations mentioned. Changes in the activity of dehydrogenases in the hippocampus and neocortex under the same stimulation are less pronounced. MAO activity also increases in the nerve terminals converging on the bodies and dendrites of hypothalamic neurons and in the preterminal fibers of the neocortex, Tuftsin increases oxidative-reducing processes in various structures of the brain, but at the same time it possesses a predominant influence on the limbic system structures.

Animals↗
PubMed1986

[Effect ot tuftsin on cerebral monoamine oxidase and acetylcholinesterase activity].

The administration of a tetrapeptide tuftsin at a dose of 300 mkg/kg body weight for 30, 75 min or 3 days leads to the changes in specific activity of monoamine oxidase, forms A and B, and acetylcholinesterase in synaptosomal and cellular mitochondrial subfractions from the rabbit sensorimotor cortex and nucleus caudatus. The reciprocity of neuro-transmitter systems and specific peptide effects on the brain structures have been demonstrated. The results suggest that tuftsin has an activating effect on dopamine metabolism.

Acetylcholinesterase↗
PubMed1993

[Stimulation of oxygen metabolism in human blood phagocytes as affected by tuftsin-like peptides derived from the C-reactive protein molecule].

Effects of synthetic peptides analogous to those cleaved by proteolysis from human C-reactive protein (CRP) molecule on the level of oxygen metabolism of blood neutrophils and monocytes were studied. The effects of the peptides were compared with the effect of tetrapeptide Thr-Lys-Pro-Arg (tuftsin). CRP-derived peptides stimulated phagocyte oxygen metabolism as effectively as tuftsin. Their effect did not depend on the presence of a second stimulus (E. Coli LPS) in the medium. Neutrophils and monocytes responded to CRP-derived peptides differently.

Amino Acid Sequence↗
PubMedDate not supplied

[Effect of the tetrapeptide tuftsin on activity of the monoaminergic system of the brain in experimental pathology].

Single administration of the regulating peptide tuftsin Thr- Lys-Pro-Arg (300 micrograms/kg) was shown to affect the state of the transmitter systems in the brain of rats treated with the sedative drug haloperidol in a total dosage of 15 mg/kg within 30 days. Haloperidol therapy caused reciprocal alterations in the activity of monoamine oxidases A and B, in the levels of dopamine, noradrenaline, serotonin, and 5-hydroxyindolyl acetic acid, as well as a decrease in the rate of depolarization-dependent Ca(2+)-capture in the synaptosomes of the rat brain cortex and neostriatum (N. caudatus); under these conditions tuftsin normalized the parameters studied to a certain extent, which was more pronounced in N. caudatus. The peptide appeared to activate synaptic transfer in the dopaminergic nerve endings and to contribute to balance restoration in the neurotransmitter systems (particularly in the neostriatum) impaired by abnormalities.

Amino Acid Sequence↗
PubMedDate not supplied

[Use of the computer simulation method of complementary amino acids base on a genetic code algorithm for the search for new peptide compounds belonging to tuftsin-like activity].

Methods of k-neighbours and neural networks were used for prediction of pharmacological effects of new compounds wits tuftsin-like activities. The tested compounds were constructed by the complementarity rule of genetic code algorithm. Five of seven substitutions with stereocomplement amino acids in the tuftsin sequence lead to new active compounds. Thus, the use of amino acid complementary code can be a helpful tool for the construction of a new immunomodulating peptide.

Algorithms↗
PubMed2003

Protective role of tuftsin fragment 1-3 in an animal model of intracerebral hemorrhage.

Intracerebral hemorrhage (ICH) causes morbidity and mortality and commonly follows the reperfusion after an ischemic event. Tissue plasminogen activator (tPA), a fibrinolytic serine protease, is routinely given for the treatment of stroke. However, tPA also can promote neuronal death, suggesting that caution should be exercised when using it. Furthermore, tPA upon brain injury mediates microglial activation and modulates neuronal survival. To investigate the role of tPA and microglia during brain hemorrhage, we induced experimentally ICH by intracerebral injection of collagenase. Seven days after the introduction of ICH, it persisted in tPA-deficient (tPA(-/-)) mice but is drastically reduced in size in wild-type mice. Three weeks after ICH, there are still red blood cells in tPA(-/-) but not in wild-type animals. Activated microglia persist around the injury site. When microglial activation is inhibited by tuftsin fragment 1-3 macrophage/microglial inhibitory factor (MIF), the stroke injury volume is significantly reduced, and the neurobehavioral deficits exhibited by the mice are improved. Our results suggest that endogenous tPA assists in the clearance of intracerebral hemorrhage, presumably by affecting microglial activation, and MIF could be a valuable neuroprotective agent for the treatment of ICH.

Animals↗
PubMed1989

Nonimmune-mediated phagocytosis by "premedullary" lung macrophages: effects of concanavalin A, tuftsin, and macrophage-inhibitory peptide.

Free cells arising in organ-cultured embryonic rat and hamster lungs share ultrastructural, lysosomal enzyme, and cell membrane properties with typical alveolar macrophages, expressing the developmental potential of the earliest-macrophage precursors resident in the lungs. In the lung culture environment cell proliferation is supported and macrophage attributes are developed despite absence of lymphocytes from the system. We have shown previously that among these attributes, the cells respond with increased phagocytosis of erythrocytes if these are opsonized with immunoglobulin G. Attention has now been turned to the question of nonimmune-mediated phagocytosis by the same population. Living macrophages that emerged from lung cultures bound rhodamine-coupled soybean and wheat germ agglutinins to a greater degree than concanavalin A (Con A), which nevertheless promoted lateral translocation of occupied receptors in the cell membrane. Emerged cells also phagocytosed living bacteria and native yeast cells (Y). The percentage of macrophages ingesting 3 or more yeast cells increased 400 (hamsters) to 500% (rats) when yeast was preincubated with Con A (200 micrograms/ml). Pretreatment of macrophages with Tuftsin (100 microM) enhanced uptake of Y by 100 (hamster) to 200% (rat). Pretreatment of macrophages with macrophage-inhibitory peptide (500 microM) appeared to inhibit phagocytosis of Y by 60% in hamsters but had no significant effect on cells from rat lung cultures.

Animals↗
PubMed1994

Analysis of a bioactive synthetic analogue of tuftsin by tandem mass spectrometry: anomalous fast atom bombardment activated processes.

Fast atom bombardment (FAB) tandem mass spectrometry has been used to analyse the biologically potent, partially modified retro-inverso (PMRI) synthetic isomer of tuftsin: this compound represents the active peptide of the fraction of gamma-globulin (leukokinin) which binds specifically to blood neutrophilic leukocytes and monocytes. Protonated molecules and fragment ions were collisionally dissociated at low energies in a triple-quadrupole mass spectrometer to yield a complete picture of the reactions that occur in the condensed and in the gas phase. The study shows that, when retro-inversion is within the N-terminal amino acid, charge localization at the basic sites (possibly at the N-terminus) induces a marked decomposition of the molecule, the loss of ammonia being the most favourable fragmentation process. Also, artifacts are formed in the liquid phase via bimolecular reactions promoted by the high-energy beam. The findings indicate that despite the fact that PMRI isomers of this type are stable against exo-peptidases and also stable under acidic conditions, they appear to be labile under conditions where the energy deposition, due to FAB is necessarily high.

Amino Acid Sequence↗