Neuroprotective effect of dipeptide AVP(4-5)-NH<Subscript>2</Subscript> is associated with nerve growth factor and heat shock protein HSP70

In vitro experiments demonstrated the neuroprotective effect of dipeptide pGlu-Asn-NH₂, which corresponded to the N-terminal fragment of the major vasopressin metabolite AVP(4-9). The dipeptide in concentrations of 10⁻⁵–10⁻⁷ M prevented death of HT-22 immortalized hippocampal neurons under conditions of oxidative stress and protected PC-12 rat pheochromocytoma cells from neurotoxic compound 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. pGlu-Asn-NH₂ in a concentration of 10⁻⁶ M increased the content of endogenous neuroprotective substances, neurotrophin NGF and heat shock protein HSP70 in HT-22 cells. Our results indicate that this dipeptide can be used for the therapy of Parkinson’s disease. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 10, pp. 424–426, October, 2007     

Effect of a synthetic leu-enkephalin analog on the intensity of DNA synthesis in insects

The hexapeptide dalargin (a synthetic analog of leu-enkephalin) injected in the hemolymph of bee moth (Galleria mellonella) and of mealworm (Tenebrio molitor) causes a dose-dependent increase in the DNA content and an increase in the³H-thymidine incorporation in DNA. In bee moth, the maximum (43–68%) increase in radioactivity is observed after injection of 10⁻⁸ to 10⁻¹⁰ M of dalargin per insect, in mealworm, the highest radioactivity of DNA (73 and 162% increase) is recorded after 10⁻¹¹ and 10⁻⁹ M dalargin per insect. Dalargin modifies the nucleic acid metabolism in the insects, which manifests itself as accumulation of extra DNA and enhanced DNA biosynthesis. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 123, No. 4, pp. 417–419, April, 1997     

Mechanisms for the effect of arginine-containing dermorphin analogue on proliferative processes in the gastric mucosa of albino rats

Treatment with synthetic arginine-containing dermorphin analogue sedatin (100 mg/kg, 5 intraperitoneal injections) stimulated DNA synthesis in the gastric mucosa and decreased spontaneous and induced chemiluminescence in homogenates of the stomach from albino rats. Non-arginine sedatin analogue in the same dose had little effect on DNA synthesis and free radical oxidation. Fivefold treatment with NO synthase inhibitor L-NAME (9.3×10⁻⁵ mol/kg) suppressed DNA synthesis in the gastric mucosa. Sedatin did not modulate DNA synthesis against the background of L-NAME administration. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 9, pp. 282–284, September, 2007     

Biological activity of FGF-23 fragments

The phosphaturic activity of intact, full-length, fibroblast growth factor-23 (FGF-23) is well documented. FGF-23 circulates as the intact protein and as fragments generated as the result of proteolysis of the full-length protein. To assess whether short fragments of FGF-23 are phosphaturic, we compared the effect of acute, equimolar infusions of full-length FGF-23 and various FGF-23 fragments carboxyl-terminal to amino acid 176. In rats, intravenous infusions of full-length FGF-23 and FGF-23 176–251 significantly and equivalently increased fractional phosphate excretion (FE Pi) from 14 ± 3 to 32 ± 5% and 15 ± 2 to 33 ± 2% (p < 0.001), respectively. Chronic administration of FGF-23 176–251 reduced serum Pi and serum concentrations of 1α,25-dihydroxyvitamin D. Shorter forms of FGF-23 (FGF-23 180–251 and FGF-23 184–251) retained phosphaturic activity. Further shortening of the FGF-23 carboxyl-terminal domain, however, abolished phosphaturic activity, as infusion of FGF-23 206–251 did not increase urinary phosphate excretion. Infusion of a short fragment of the FGF-23 molecule, FGF-23 180–205, significantly increased FE Pi in rats and reduced serum Pi in hyperphosphatemic Fgf-23 ^−/− knockout mice. The activity of FGF-23 180–251 was confirmed in opossum kidney cells in which the peptide reduced Na⁺-dependent Pi uptake and enhanced internalization of the Na⁺-Pi IIa co-transporter. We conclude that carboxyl terminal fragments of FGF-23 are phosphaturic and that a short, 26-amino acid fragment of FGF-23 retains significant phosphaturic activity.     

<Emphasis Type="Italic">In vitro</Emphasis> effects of thyroliberin on structural state of plasma membranes in mouse brain and liver

The spin probe method was employed to study in vitro the effect of regulatory peptide thyroliberin on structural state of surface (0.8 nm) and deep (2 nm) lipid layers of the plasma membranes in mouse liver and brain. Thyroliberin in a concentration range of 10⁻³–10⁻¹⁸ M enhanced structural order of surface lipids, the maximum effect was observed at 10⁻⁹–10⁻¹⁰ M. The dose-effect dependencies for microviscosity of deep lipids were nonlinear and had 3 extrema at 10⁻⁴–10⁻⁷ M, 10⁻⁹ M, and 10⁻¹⁴–10⁻¹⁶ M. The greatest changes in lipid microviscosity produced by 10⁻⁹ M thyroliberin are explained by lipid-receptor interaction. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 8, pp. 151–154, August, 2007     

Correction effect of ATP on platelet aggregation and blood coagulation <Emphasis Type="Italic">In Vitro</Emphasis> and in the presence of circulating thrombin in rats

ATP added to plasma samples in concentrations of 5×10⁻³−5×10⁻⁵ M in vitro decreased ADP-induced platelet aggregation. Platelet aggregation stimulated with thrombin under similar experimental in vitro conditions significantly decreased in the presence of 5×10⁻⁶ M ATP and tended to decrease under the influence of ATP in concentrations of 5×10⁻³ and 5×10⁻⁷−5×10⁻⁹ M ATP. When endogenous thrombin in the circulation was stimulated by intravenous infusion of tissue thromboplastin, pretreatment with ATP (4 intramuscular injections, 0.75 mg/kg) produced a correction effect and normalized disturbed anticoagulant activity and platelet aggregation. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 4, pp. 364–366, April, 2007     

Isolation and Characterization of Human Monoclonal Autoantibodies to Glutamic Acid Decarboxylase

Production of human monoclonal autoantibodies to glutamic acid decarboxylase M_r 65,000 (GAD₆₅), characterization of their isotype, binding affinity, V region sequences and competition with autoantibodies in patients' sera is described. Lymphocytes from a patient with Addison's disease who had GAD₆₅ autoantibodies without diabetes were immortalised and fused to a mouse/human hybridoma. In addition, mouse monoclonal antibodies to GAD₆₅ were produced using standard techniques. F(ab')₂s from our monoclonals and the GAD6 mouse monoclonal were used in competition with intact monoclonals and sera from diabetic patients for binding to ¹²⁵I-labelled GAD₆₅ (amino acids 46-586). Reactivities of the human monoclonals with GAD 65,000/67,000 M_r chimeras were also studied. Variable region genes of human monoclonals were sequenced and analysed. The human monoclonals (n = 3) had affinity constants for GAD₆₅ of 2.2 &#50 10⁹, 5.8 &#50 10⁹, 1.3 &#50 10¹⁰ mol/l^{&#109 1}; affinities of the mouse monoclonals (n = 5) ranged from 1.1 &#50 10⁸ to 5.4 &#50 10¹⁰ mol/l^{&#109 1}. The binding of each of the human monoclonals was inhibited by GAD6 F(ab')₂ and the binding of GAD6 antibody was inhibited by the human monoclonal F(ab')₂s suggesting that the epitopes for these antibodies were overlapping. Studies with GAD₆₅/GAD₆₇ chimeras indicated that the human monoclonals reacted with C-terminal epitopes. The human monoclonals, GAD6 and 3/5 mouse monoclonals inhibited serum autoantibody binding to ¹²⁵I-labelled GAD₆₅. Overall, the human monoclonals were of high affinity, reacted with C-terminal epitopes and showed evidence of antigen driven maturation; they represented only a proportion of the repertoire of autoantibodies to GAD₆₅ in the donor's serum and in the sera of patients with type-1 diabetes.     

Effect of <Emphasis Type="Italic">n</Emphasis>-tyrosol on blood viscosity and platelet aggregation

Experiments on rats showed that n-tyrosol limited the increase in blood viscosity during thermal exposure at a shear rate of 5–300 sec⁻¹ and inhibited ADP-induced platelet aggregation. The effects of n-tyrosol are comparable to that of pentoxyphylline. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 1, pp. 67–69, January, 2007     

Cl<Superscript>−</Superscript> conduction of GABA<Subscript>A</Subscript>-receptor complex of synaptic membranes of rat brain cortex after development of chronic epileptization of the brain (pharmacological kindling)

Experiments on Wistar rats showed that basal and muscimol-induced ³⁶Cl⁻ entry into synaptoneurosomes isolated from the brain cortex decreased after kindling (30 mg/kg pentylenetetrazole intraperitoneally for 30 days) in animals with seizure severity score 4–5. Changes in Cl⁻ conduction during kindling are discussed. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 3, pp. 255–258, March, 2008     

Choline transport and its osmotic regulation in renal cells derived from the rabbit outer medullary thick ascending limb of Henle

 Organic osmolytes such as betaine and glycerophosphorylcholine (GPC) are of major importance concerning volume regulation of inner and outer medullary epithelial cells. Recently we demonstrated that the intracellular betaine content in rabbit kidney cells derived from the outer medullary thick ascending limb of Henle’s loop (TALH) is osmotically regulated by betaine synthesis. In this context it was our purpose to characterize the uptake of choline, a precursor of betaine and GPC. We found TALH cells to possess a specific choline transport system with a maximum velocity (V _max) of 71 ± 12 pmol ·μl^–1 cell water · min^–1 and an apparent affinity (K _m) of 155 ± 19 μmol · l^–1. The uptake of choline was sodium independent and not electrogenic, but it was significantly reduced by the removement of chloride from the incubation medium. After long-term adaptation of TALH cells to a hyperosmotic medium (600 mosmol · l^–1, osmolarity adjusted with NaCl or urea) a significant higher choline uptake rate was observed (V _max: 166 ± 9 (NaCl), 96 ± 12 (urea) pmol ·μl^–1 cell water · min^–1). Our results suggest that the uptake of choline is due to higher intracellular requirements of choline under hypertonic conditions. Finally, an increase in the V _max of the choline transport system may enable sufficient synthesis of betaine and GPC. Received: 7 April 1997 / Received after revision: 2 June 1997 / Accepted: 3 June 1997     

Detection and characterization of DNA polymerase activity in Entamoeba histolytica

 DNA polymerase activity was detected and characterized in nuclear extracts from trophozoites of Entamoeba histolytica. The activity was high at pH 2 to pH 6, but at pH 8 and 10 the activity was very low. The presence of K⁺ was inhibitory for the activity and a higher concentration of K⁺ markedly inhibited the activity. Magnesium ions (Mg²⁺) were absolutely required for activity and its optimal concentration was 6 to 8 mM. The activity was markedly inhibited by aphidicolin which is an inhibitor of mammalian DNA polymerases α, δ, and ɛand also by N-ethylmaleimide which is an inhibitor of DNA polymerases, α, γ, δand ɛ. However, inhibition of the activity by 2’, 3’-dideoxythymidine-5’-triphosphate which is an inhibitor of DNA polymerases βand γwas relatively weak. Thus sensitivity of the E. histolytica enzyme to these inhibitors was similar to that of mammalian DNA polymerases (α, δand ɛ) of the αfamily. Monoclonal antibodies against human DNA polymerase αdid not bind to DNA polymerase of E. histolytica. Received: 19 April 1995 / Accepted: 16 June 1995     

Effect of Antibodies to Glutamate and GABA on the Stress Response in C57Bl/6 Mice

We studied the effect of antibodies to glutamate and GABA (active immunization with conjugates of glutamate—bovine serum albumin and GABA—bovine serum albumin) on the course of combined water-immersion stress in C57Bl/6 mice. Preimmunization of animals with the conjugate of glutamate—bovine serum albumin was accompanied by strong production of antibodies to glutamate, which reduced the majority of signs of the stress response. Antibodies to GABA had no effect on the development of stress. Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 147, No. 3, pp. 272–275, March, 2009     

Protective effect of low-doses of antibodies to S-100 protein on the formation of long-term sensitization in <Emphasis Type="Italic">Helix lucorum</Emphasis>

Injection of antibodies to Ca-binding protein S-100 in a dilution of 10⁻¹² before the formation of long-term sensitization in Helix lucorum (10 min before the first electric shock) prevented the increase in defense reactions of pneumostome closure and ommatophore withdrawal. Thus, we demonstrated a protective effect of low-dose antibodies to S-100 on the formation of long-term sensitization as a neurobiological model of anxiety and depression. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 5, pp. 490–493, May, 2007     

Characterization of a Plasmodium chabaudi gene encoding a protein with glutamate-rich tandem repeats

Several highly antigenic proteins containing tandem repeats rich in glutamic acid residues have been described in Plasmodium falciparum. However, relatively little information is available about analogous genes in rodent parasites. This report describes a 4.2-kb genomic DNA fragment from P. chabaudi with a deduced amino acid sequence that is predominantly glutamate-rich tandem repeats. Several different monoclonal antibodies raised against a 93-kDa P. chabaudi protein, which does not correspond to the cloned DNA fragment, recognize a recombinant protein expressed from the 4.2-kb DNA fragment. The only sequence similarities between these two genes are tandem repeats with a predominance of glutamate pairs followed by a hydrophobic residue. This repetitious-sequence motif may be the basis for the observed cross-reactivity. A similar motif has been demonstrated to be the basis for antibody cross-reactivity between glutamate-rich proteins of P. falciparum. The expression of multiple glutamate-rich proteins with cross-reacting epitopes may be a general phenomenon in Plasmodium species. Received: 3 March 1998 / Accepted: 7 July 1998     

The results of Mancini’s test depend on the presence bound metal cations in the test protein

Samples of human serum γ-globulin with specifically bound copper or zinc cations were studied in Mancini’s radial immunodiffusion test with human antibodies to IgG (H+L). The intensity of antibody binding to zinc-modified protein was 10–20% higher in comparison with the reference sample, while detection of γ-globulin with bound copper by antibodies was 20–30% lower than in the corresponding reference sample. Comparison with the results of native γ-globulin testing indicates limitations of Mancini’s method as the quantitative assay for practical diagnosis, because under certain clinical conditions the traditional method can give over-and underestimated results. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 4, pp. 437–440, April, 2008     

Interactions and possible functional characteristics of Tag7-S100A4 protein complex

Peptidoglycane-recognizing protein Tag7 formed a complex with S100A4 (a representative of S100 protein family), the apparent dissociation constants in the absence and presence of Ca²⁺ were 2×10⁻⁸ M and 10⁻⁹ M, respectively. Analysis of fluorescence spectra of hydrophobic fluorescent probe 2-toluidinyl naphthalene-6-sulfonate in the presence of S100A4 and Tag7 proteins showed that extensive area or several sites are involved into the complex formation between these proteins. The formation of Tag7-S100A4 complex had virtually no effect on the role of S100A4 in the regulation of intracellular Ca²⁺ metabolism. Removal of not only Tag7, but also S100A4 from neutrophil conditioned medium reduced lysis of E. coli cell, while addition of the Tag7-S100A4 complex to the medium restored antibacterial activity. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 2, pp. 151–153, February, 2008     

Cross-reactive and major virus-specific epitopes are located at the N-terminal halves of the cylindrical inclusion proteins of turnip mosaic and zucchini yellow mosaic potyviruses

Summary.  To investigate the antigenic nature of cylindrical inclusion proteins (CIPs) of the potyviruses Turnip mosaic virus (TuMV) and Zucchini yellow mosaic virus (ZYMV), monoclonal antibodies (MAbs) against the two CIPs were produced and epitopes on the CIPs were localized using Escherichia coli-expressed CIP fragments in Western blot analysis. All 23 MAbs against ZYMV CIP reacted only with ZYMV CIP. In contrast out of the 18 MAbs produced against TuMV CIP, 14 MAbs were TuMV CIP-specific while the remaining four MAbs cross-reacted with both CIPs. The four cross-reactive MAbs recognized two distinct epitopes in the N-terminal half of TuMV CIP corresponding to amino acid residues 103–119 and 224–237. Thirteen out of 14 TuMV CIP-specific MAbs recognized two distinct epitopes within residues 1–102 and 120–214, while the other one recognized an epitope within residues 301–644. On the other hand, 21 out of 23 ZYMV CIP-specific MAbs recognized epitopes within residues 1–118, while the remaining two recognized epitopes within residues 301–522. These results suggest that cross-reactive and major virus-specific epitopes are located at the N-terminal half of the respective CIPs. Received August 10, 1999 Accepted March 2, 2000     

Immunochemical analysis of common antigenic determinants in insulin and apoprotein B Molecules

A study is performed of the mechanism underlying stress diabetes, which develops in human beings and animals under stress. Dot-immunoanalysis shows the presence of common antigenic determinants in insulin, apoprotein B, and apoprotein B-containing low density and very low density lipoproteins isolated from human and rat serum. Electrophoresis, immunoelectroblotting, and immunoenzyme analysis reveal 5–6 peptides belonging to apoB, which specifically react with anti-insulin and anti-very low density lipoprotein antibodies. Insulinlike immunoreactivity is also identified in human serum supernatant obtained after precipitation of the total low density and very low density lipoprotein fraction and after removal all lipoproteins from it. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 9, pp. 258–261, September, 1994     

Blood serum DNA in patients with rheumatoid arthritis is considerably enriched with fragments of ribosomal repeats containing immunostimulatory CpG-motifs

We previously hypothesized that the sequence of transcribed region of human ribosomal repeats is selectively accumulated in circulating extracellular DNA due to its increased resistance to double-strand breaks caused by accumulation of single-chain breaks produced by nucleases. The contents of rDNA in blood serum DNA and in DNA from leukocytic nuclei both in healthy donors and in patients with rheumatoid arthritis were compared using dot hybridization method. By the content of non-methylated CpG-repeats, transcribed region of rDNA is identical to bacterial DNA, which is characterized by potent immunostimulatory effect. The transcribed region of rDNA (13.3 kb) contains more than 200 CpG-motifs capable of interacting with TLR9 receptors, which are the mediators of the cell immune response to the action of CpG-rich DNA fragments. The data suggest that DNA from dead cells circulating in the peripheral blood is enriched with sequences possessing potent immunostimulatory properties. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 142, No. 9, pp. 282–285, September, 2006     

Correlation between the content of albumin and carotenoids in human vitreous body during prenatal development

The dynamics of the content albumin and carotenoids in human fetal vitreous body during weeks 16–31 of gestation was studied. The maximum values of total albumin (1.42 mg) and carotenoids (276 ng) during the studied period were recorded on weeks 20–22. Albumin concentration peaked during week 17 (2.11×10⁻⁴ mol/liter) and carotenoids during weeks 16–17 (about 0.045×10⁻⁴ mol/liter) of prenatal development. By week 31, the concentrations and total content of albumin and carotenoids in the vitreous body decreased. The physiological role of the studied components of the vitreous body for prenatal development of human eye is discussed. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 11, pp. 522–525, November, 2007