Effects Of Activities Research Articles

Phoenix dactylifera L. Fruit induces cell proliferation of A2780, A172 and HFFF2 cell lines

Dates fruit has been used as staple food in the Middle East for thousands of years and various types of dates are found worldwide. Dates and their constituents show various roles in diseases prevention and treatment through anti-oxidant, anti-inflammatory, anti-bacterial activity. In the present study we investigated the activity of aqueous and n-hexane extracts of Phoenix dactylifera L. fruit at various concentrations on A2780, A172 and HFFF2 cell lines proliferation by means of MTT (3-4, 5-dimethylthiazol-2-yl-2, 5 diphenyl tetrazolium bromide) assay. Aqueous and n-hexane extracts of date showed activatory effects on the cell lines and increased cell proliferation in a dose dependent manner. It has been previously reported that dates fruit possesses anticancer and antimutagenic effects. These disagreements can be explained by differences in cell line properties, type of date fruits and different solvents in the extracts. However, further investigation is needed to clarify the exact role of date in cell proliferation and cancer. In addition, n-hexane extract acted more powerful than the aqueous extract in increasing the cell lines proliferation. Therefore, it can be concluded that the active components that are responsible for the activatory effects are present in the n-hexane extract.

Effect of Th1/Th2 cytokine administration on proinflammatory SKOV-3 cell activation.

IntroductionInterleukin(IL)-1β, IL-6 and IL-12 might associate with inflammatory processes in a tumor progression and create a specific microenvironment for tumor growth. The aim of the study was to assess whether the Th1 and Th2 type cytokines, such as IL-2 and IL-10, affect ovarian carcinoma continuous cell line (SKOV-3) pro-inflammatory activation.Material and methodsSKOV-3 ovarian cells and peripheral blood mononuclear cells (PBMCs) were stimulated by IL-2 and IL-10. Additionally, SKOV-3 ovarian cells and PBMCs were co-cultured together. Proinflammatory activation of cancer cells was evaluated by measurement of IL-1β and IL-6 levels in culture fluid after 72 h of incubation.ResultsSKOV-3 cells and PBMCs secreted IL-1β and IL-6. After stimulation by IL-2 and IL-10, secretion of studied parameters was changed in a dose-dependent manner. The addition of a higher IL-2 level gave rise to an increase of IL-1β, IL-6 and IL-12 secretion in SKOV-3 cells. Stimulation by IL-10 increased only IL-1β secretion in SKOV-3 cells. However, IL-6 secretion decreased after stimulation with 25 ng/ml IL-10. Activatory effects of IL-2 and inhibitory effects of IL-10 in co-culture of SKOV-3 and PBMCs were observed.ConclusionsOur results suggested that Th1/Th2 type of cytokines might influence pro-inflammatory activation of SKOV-3 ovarian cells. Co-cultures of SKOV-3 and PBMCs showed significant changes in cross-talk between cancer and immune cells.

The Functional Property Changes of Muscular Na(v)1.4 and Cardiac Na(v)1.5 Induced by Scorpion Toxin BmK AGP-SYPU1 Mutants Y42F and Y5F.

Scorpion toxins are invaluable therapeutic leads and pharmacological tools which influence the voltage-gated sodium channels. However, the details were still unclear about the structure-function relationship of scorpion toxins on VGSC subtypes. In the previous study, we reported one α-type scorpion toxin Bmk AGP-SYPU1 and its two mutants (Y5F and Y42F) which had been demonstrated to ease pain in mice acetic acid writhing test. However, the function of Bmk AGP-SYPU1 on VGSCs is still unknown. In this study, we examined the effects of BmK AGP-SYPU1 and its two mutants (Y5F and Y42F) on hNa(v)1.4 and hNa(v)1.5 heterologously expressed CHO cell lines by using Na⁺-specialized fluorescent dye and whole-cell patch clamp. The data showed that BmK AGP-SYPU1 displayed as an activator of hNa(v)1.4 and hNa(v)1.5, which might indeed contribute to its biotoxicity to muscular and cardiac system and exhibited the functional properties of both the α-type and β-type scorpion toxin. Notably, Y5F mutant exhibited lower activatory effects on hNa(v)1.4 and hNa(v)1.5 compared with BmK AGP-SYPU1. Y42F was an enhanced activator and confirmed that the conserved Tyr42 was the key amino acid involved in bioactivity or biotoxicity. These data provided a deep insight into the structure-function relationship of BmK AGP-SYPU1, which may be the guidance for engineering α-toxin with high selectivity on VGSC subtypes.

Biphasic Influence of Bulk Anionic Phospholipids for PIP2 Gating of Kir2.1 Channels through Binding to Two Distinct Sites

Inwardly rectifying potassium (Kir) channels regulate cell excitability and potassium homeostasis. Our recent analyses show that Kir2.1 channels have a distinct (‘Secondary’) anionic phospholipid (PL(-)) binding site, in addition to the crystallographically determined (‘Primary’) PIP2 activating site. Docking results suggest that PL(-)s can bind to either site and therefore might compete with PIP2 at the ‘Primary’ site and inhibit. To test this prediction we performed the following assays with purified human Kir2.1 channels reconstituted in liposomes. First, Kir2.1 activity was measured with a fixed PIP2 content and with increasing content of various PL(-)s. At higher PL(-) levels, inhibition was observed that correlated well with predicted affinity at the ‘Primary’ site. The ‘Secondary’ site is generated by residues K64 and K219. K64C mutant channels are insensitive to PL(-) and only weakly PIP2-activated, but high PIP2 sensitivity is regenerated by tethering of K64C to the membrane by decyl-MTS modification. Inhibition by PL(-)s was more potent in decyl modified ‘Secondary’ site single (K64C) and double (k64C/K219A) mutant channels. It's likely that PL(-) binding at the ‘Primary’ site is augmented in these mutants as a consequence of increased effective PL(-) in the membrane as well as reduced electrostatic repulsion from the PL(-) at the ‘Secondary’ site. Finally PIP2 sensitivity was measured in the presence of increasing PL(-)s. The apparent PIP2 Kd was left-shifted at low PL(-) (as expected for the activatory effect at the ‘Secondary’ site), but shifted back to the right at higher PL(-)s, consistent with an inhibitory effect of bulk PL(-) at the ‘Primary’ site, if present at high enough levels in the membrane. Such interplay between PIP2 and other PL(-)s on Kir2.1 channel gating can be predicted by a mechanistic two-site binding model.

Comparative studies on analytical, antioxidant, and antimicrobial activities of a series of vegetal extracts prepared from eight plant species growing in Romania

Given the large applicability in both pharmaceutical and cosmetic field, this work was aimed at analytical (high-performance thin-layer chromatography [HPTLC] method), antioxidant (2,2-diphenyl-1-picrylhydrazyl [DPPH] method), and antimicrobial (diffusion method on Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 8739, and Candida albicans ATCC 10231) studies on a series of whole vegetal extracts and corresponding aqueous, ethyl acetate and chloroform fractions (selective extracts) prepared from eight plant species growing in Romania. Briefly, it was revealed moderate to certain activity against S. aureus ATCC 6538 and E. coli ATCC 8739 in the case of greater burdock leaves (Arctium lappa), beech leaves (Fagus sylvatica) and great willowherb aerial part (Epilobium hirsutum) whole extracts. Purple loosestrife aerial part (Lythrum salicaria) and sea-buckthorn leaves (Hippophae rhamnoides) whole extracts showed only weak activity against these bacteria, while tarragon aerial part (Artemisia dracunculoides), chokeberries leaves (Aronia melanocarpa) and quince fruit (Cydonia oblonga) whole extracts have not shown activity. Subsequently studies on the selective extracts have revealed that combinations of glycosides of the same aglycones lead to very different antimicrobial properties indicating synergistic effects between polyphenols (demonstrated in the case of Fagus sylvatica extracts) or the contribution of other phytocompounds to the final effect (demonstrated in the case of Arctium lappa extracts) and, secondly, that the glycosyl chain in which they occur may also contribute to the final antimicrobial effect (demonstrated by the fact that the most active vegetal extracts emphasized the dominance of flavonoid monoglycosides). Moreover, inhibitory antimicrobial effects were revealed (Arctium lappa extracts). Finally, none of the studied extracts acted against C. albicans ATCC 10231. Concerning antioxidant activity, DPPH tests indicated high potency of all tested extracts (IC50 measuring from 2.66 to 4.80). Further studies on the most active vegetal extracts which aim to reveal MICs values and potential inhibitory or activatory effects in combination with chemical antibiotics are ongoing.

Effects of the Olfactory Bulbs on the Activity of Reticular Neurons of the Bulbar Respiratory Center in Hypoxia

The study reported here seeks to explain the roles of different limbic system formations in controlling respiration in conditions of oxygen insufficiency. The effects of stimulation of the olfactory bulbs (OB) on medulla oblongata respiratory center (RC) neurons during exposure to hypoxia were studied in a laboratory barochamber. Stimulation of the OB in normoxia had a predominantly activatory influence on the baseline activity of neurons. During hypoxia, the responses of medulla oblongata respiratory center neurons to stimulation of the OB were phasic in nature. At the first stage of hypoxia (at an altitude of 4000–5000 m), on the background of hypoxic activation of neurons, the activatory influence of this formation on the spike activity of neurons persisted, albeit weakly. At an altitude of 7500–8000 m, (severe hypoxia phase), on the background of hypoxic suppression of medulla oblongata neuron activity and respiration overall, the activatory effect of stimulation of the OB on the spiked activity of neurons in the bulbar respiratory center was more marked than in the first stage. The results of these experiments provide grounds for the suggestion that the OB is among the limbic system formations with predominantly activatory influences on RC neurons. After lowering the animals to normal atmospheric pressure, there was gradual restoration of initial values for both baseline neuron activity and their responses to stimulation.

Control of KirBac3.1 Potassium Channel Gating at the Interface between Cytoplasmic Domains

KirBac channels are prokaryotic homologs of mammalian inwardly rectifying potassium (Kir) channels, and recent structures of KirBac3.1 have provided important insights into the structural basis of gating in Kir channels. In this study, we demonstrate that KirBac3.1 channel activity is strongly pH-dependent, and we used x-ray crystallography to determine the structural changes that arise from an activatory mutation (S205L) located in the cytoplasmic domain (CTD). This mutation stabilizes a novel energetically favorable open conformation in which changes at the intersubunit interface in the CTD also alter the electrostatic potential of the inner cytoplasmic cavity. These results provide a structural explanation for the activatory effect of this mutation and provide a greater insight into the role of the CTD in Kir channel gating.

Activation of transsulfuration pathway by salvianolic acid a treatment: a homocysteine-lowering approach with beneficial effects on redox homeostasis in high-fat diet-induced hyperlipidemic rats

BackgroundElevated homocysteine is a cardiovascular risk factor in hyperlipidemia. Transsulfuration pathway provides an endogenous pathway for homocysteine conversion to antioxidant glutathione (GSH). Salvianolic acid A (Sal A) contains two molecules of caffeic acid and one molecule of danshensu that is capable of enhancing homocysteine transsulfuration, which led to the hypothesis that Sal A has activatory effect on transsulfuration pathway and this effect may have beneficial effects on both homocysteine and redox status in hyperlipidemia.Methods and resultsTo test this hypothesis, we developed a rat model of hyperlipidemia induced by high-fat diet for 16 weeks, during which rats were treated with 1 mg/kg salvianolic acid A (Sal A) for the final 4 weeks. Activities of key enzymes and metabolite profiling in the transsulfuration pathway revealed that hyperlipidemia led to elevated plasma homocysteine levels after 16-week dietary treatment, which was associated with reduced activities of homocysteine transsulfuration enzymes, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE). The impaired transsulfuration pathway prevented homocysteine transsulfuration to cysteine, resulting in cysteine deficiency and subsequent reduction in GSH pool size. The redox status was altered in the setting of hyperlipidemia as indicated by GSH/GSSG ratio. Sal A treatment increased hepatic CBS and CSE activities, which was associated with reduced accumulation in circulating homocysteine levels and attenuated decline in hepatic cysteine content in hyperlipidemic rats. Sal A also led to an increase in GSH pool size, which subsequently caused a restored GSH/GSSG ratio. The activatory effect of Sal A on CBS was also observed in normal rats and in in vitro experiment.ConclusionOur results suggest that activation of transsulfuration pathway by Sal A is a promising homocysteine-lowering approach that has beneficial effects on redox homeostasis in hyperlipidemic settings.

Activatory Effect of Germination on Catalytic Capacity of Urease Extracted from Beans Samples (Effect of Germination on the Kinetics of Urease from Beans)

Activatory Effect of Germination on Catalytic Capacity of Urease Extracted from Beans Samples (Effect of Germination on the Kinetics of Urease from Beans)

Time Series Dependent Analysis of Unparametrized Thomas Networks

This paper is concerned with the analysis of labeled Thomas networks using discrete time series. It focuses on refining the given edge labels and on assessing the data quality. The results are aimed at being exploitable for experimental design and include the prediction of new activatory or inhibitory effects of given interactions and yet unobserved oscillations of specific components in between specific sampling intervals. On the formal side, we generalize the concept of edge labels and introduce a discrete time series interpretation. This interpretation features two original concepts: 1) Incomplete measurements are admissible, and 2) it allows qualitative assumptions about the changes in gene expression by means of monotonicity. On the computational side, we provide a Python script, erda.py, that automates the suggested workflow by model checking and constraint satisfaction. We illustrate the workflow by investigating the yeast network IRMA.

Effect of the Proline-Rich Polypeptide Complex/Colostrinin™ on the Enzymatic Antioxidant System

Proline-rich polypeptide complex (PRP) and its constituent nonapeptide (NP) possess immunoregulatory and procognitive properties. PRP in the form of sublingually administered tablets called Colostrinin™ improves the outcome of patients with Alzheimer's disease (AD). Free radical-induced oxidative stress has been implicated in the pathogenesis of AD. It has been previously shown that PRP and NP inhibit overproduction of reactive oxygen species, nitric oxide and proinflammatory cytokines induced by lipopolysaccharide or PMA. Antioxidant defense includes both low molecular weight components and enzymatic systems including dismutases, catalase, glutathione reductase (GSSGR) and glutathione peroxidase (GSHPx). An early event during the development of AD is lipid and protein peroxidation. PRP and NP showed no modulatory effect on lipid peroxidation. A protective effect on protein oxidation was found only when high doses of NP were used. We have previously shown, in a model of human peripheral blood mononuclear cells, that PRP/NP affects activities of superoxide dismutase and NF-κB. In the present study with the use of the same cell model and whole blood cells we observed an activatory effect of PRP/NP on GSHPx and GSSGR activity but not catalase. The observed effect suggests that PRP/NP can act as a modulatory agent of the "first line" of antioxidant defense. It can be assumed therefore that PRP/Colostrinin by regulation of the early phase of the redox system does not reduce but rather prevents oxidative damage. This effect may shed some light on the beneficial effect of PRP/Colostrinin in AD patients.

Assesment of metal inhibition of antioxidant enzyme glutathione reductase from rainbow trout liver

Effects of Co+2, Zn+2, Ca+2, Fe+2, Mn+2, Cr+3, Sn+2 and Mg+2 exposure of rainbow trout liver on the enzymatic activity of glutathione reductase (GR) were investigated. GR was purified from rainbow trout liver 1419-fold with a yield of 38.41% and a specific activity of 22.846 U/mg protein. Following enzyme isolation, inhibitory effects of Co+2, Zn+2, Ca+2, Fe+2, Mn+2, Cr+3 and Sn+2 were analysed. IC50 values of the metal ions ranged from 42.2 to 657 µM, and the Ki constants ranged from 24.2 to 567µ. Co+2, Zn+2, Fe+2 and Cr+3 exhibited competitive inhibition whereas others inhibited the enzyme in non-competitive manner. Cobalt was the most powerful inhibitor among others having the lowest IC50 and Ki values. Magnesium exhibited activatory effect on the enzyme.

Carbonic Anhydrase Activators: Gold Nanoparticles Coated with Derivatized Histamine, Histidine, and Carnosine Show Enhanced Activatory Effects on Several Mammalian Isoforms

Lipoic acid moieties were attached to amine or amino acids showing activating properties against the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1). The obtained lipoic acid conjugates of histamine, L-histidine methyl ester, and L-carnosine methyl ester were attached to gold nanoparticles (NPs) by reaction with Au(III) salts in reducing conditions. The CA activators (CAAs)-coated NPs showed low nanomolar activation (K(A)s of 1-9 nM) of relevant cytosolic, membrane-bound, mitochondrial, and transmembrane CA isoforms, such as CA I, II, IV, VA, VII, and XIV. These NPs also effectively activated CAs ex vivo, in whole blood experiments, with an increase of 200-280% of the CA activity. This is the first example of enzyme activation with nanoparticles and may lead to biomedical applications for conditions in which the CA activity is diminished, such as aging, Alzheimer's disease, or CA deficiency syndrome.

CD148 enhances platelet responsiveness to collagen by maintaining a pool of active Src family kinases.

We have previously shown that the receptor-like protein tyrosine phosphatase (PTP) CD148 is essential for initiating glycoprotein VI (GPVI) signaling in platelets. We proposed that CD148 does so by dephosphorylating the C-terminal inhibitory tyrosine of Src family kinases (SFKs). However, this mechanism is complicated by CD148-deficient mouse platelets having a concomitant reduction in GPVI expression. To investigate the effect of CD148 on GPVI signaling independent of the decrease in GPVI expression and to further establish the molecular basis of the activatory effect of CD148 and downregulation of GPVI. CD148-deficient mouse platelets were investigated for functional and biochemical defects. The DT40/NFAT-lucifierase reporter assay was used to analyze the effect of CD148 on GPVI signaling. CD148-SFK interactions and dephosphorylation were quantified using biochemical assays. CD148-deficient mouse platelets exhibited reduced collagen-mediated aggregation, secretion and spreading in association with reduced expression of GPVI and FcR gamma-chain and reduced tyrosine phosphorylation. The phosphorylation status of SFKs suggested a global reduction in SFK activity in resting CD148-deficient platelets. Studies in a cell model confirmed that CD148 inhibits GPVI signaling independent of a change in receptor expression and through a mechanism dependent on tyrosine dephosphorylation. Recombinant CD148 dephosphorylated the inhibitory tyrosines of Fyn, Lyn and Src in vitro, although paradoxically it also dephosphorylated the activation loop of SFKs. CD148 plays a critical role in regulating GPVI/FcR gamma-chain expression and maintains a pool of active SFKs in platelets by directly dephosphorylating the C-terminal inhibitory tyrosines of SFKs that is essential for platelet activation.

Heparin versus prostacyclin in continuous hemodiafiltration for acute renal failure: Effects on platelet function in the systemic circulation and across the filter

Continuous venovenous hemodiafiltration (CVVHDF) is the treatment of choice for critically-ill patients suffering from acute renal failure (ARF). One major problem of extracorporeal circuits is their thrombogenicity, which requires pharmacological blockade of primary (platelet-dependent) or secondary (plasmatic) haemostasis, increasing the patient's bleeding risk. Our study assessed platelet function during CVVHDF, comparing anticoagulant versus antiplatelet pharmacological strategies, commonly used to avoid circuit clotting. Twenty-three critically-ill patients with ARF, requiring CVVHDF were randomized to a prostacyclin analogue (PGI) or to unfractionated heparin (UFH). Ex vivo platelet function, assessed by optical aggregometry (OPA) induced by collagen or ADP, was studied in peripheral blood at baseline, 4 and 24 hrs after starting CVVHDF, and at 4 hrs within the circuit, before and after the filter (n = 9). Coagulation was also monitored. PGI significantly inhibited ADP-induced OPA of peripheral platelets: maximal aggregation (T max) was reduced at 4 and 24 hrs by 20%, while collagen-induced T max was significantly reduced at 4 hrs only. In the UFH group, collagen-induced OPA in peripheral platelets was significantly inhibited: slopes of OPA tracings were decreased by 25%, lag time was prolonged by 22%, T max decreased by 10% already at 4 hrs. ADP-induced OPA showed a similar, but non-significant trend. UFH expectedly prolonged aPTT. In the UFH group, platelet responsiveness to collagen was significantly increased by 30% in post-filter versus pre-filter samples. This effect was blunted in the PGI group. UFH does not protect platelets from filter-induced activation and is associated with a reduced function of systemic platelets. Platelet-inhibiting agents might better prevent the activatory effect of the filter.

Characterization of the norepinephrine-activation of adenylate cyclase suggests a role in memory affirmation pathways: Overexposure to epinephrine inactivates adenylate cyclase, a causal pathway for stress-pathologies

Incubation with noradrenaline (norepinephrine) of isolated membranes of rat's brain corpus striatum and cortex, showed that ionic-magnesium (Mg 2+) is required for the neurotransmitter activatory response of adenylate cyclase [ATP pyrophosphate-lyase (cyclizing) (EC 4.6.1.1)], AC. An Mg 2+-dependent response to the activatory effects of adrenaline, and subsequent inhibition by calcium, suggest capability for a turnover, associated with cyclic changes in membrane potential and participation in a short-term memory pathway. In the cell, the neurotransmitter by activating AC generates intracellular cyclic AMP. Calcium entrance in the cell inhibits the enzyme. The increment of cyclic AMP activates kinase A and their protein phosphorylating activity, allowing a long-term memory pathway. Hence, consolidating neuronal circuits, related to emotional learning and memory affirmation. The activatory effect relates to an enzyme–noradrenaline complex which may participate in the physiology of the fight or flight response, by prolonged exposure. However, the persistence of an unstable enzyme complex turns the enzyme inactive. Effect concordant, with the observation that prolonged exposure to adrenaline, participates in the etiology of stress triggered pathologies. At the cell physiological level AC responsiveness to hormones could be modulated by the concentration of chelating metabolites. These ones produce the release of free ATP 4−, a negative modulator of AC and the Mg 2+ activated insulin receptor tyrosine kinase (IRTK), thus, allowing an integration of the hormonal response of both enzymes by ionic controls. This effect could supersede the metabolic feedback control by energy charge. Accordingly, maximum hormonal response of both enzymes, to high Mg 2+ and low free ATP 4−, allows a correlation with the known effects of low caloric intake increasing average life expectancy.

Activatory effect of substrates on the cholinesterase catalysis

Activatory effect of substrates on the cholinesterase catalysis

PI3K integrates the effects of insulin and leptin on large-conductance Ca2+-activated K+ channels in neuropeptide Y neurons of the hypothalamic arcuate nucleus

The adipocyte-derived hormone leptin and the pancreatic beta-cell-derived hormone insulin function as afferent signals to the hypothalamus in an endocrine feedback loop that regulates body adiposity. They act in hypothalamic centers to modulate the function of specific neuronal subtypes, such as neuropeptide Y (NPY) neurons, by modifying neuronal electrical activity. To investigate the intrinsic activity of these neurons and their responses to insulin and leptin, we used a combination of morphological features and immunocytochemical technique to identify the NPY neurons of hypothalamic arcuate nucleus (ARC) and record whole cell large-conductance Ca(2+)-activated potassium (BK) currents on them. We found that both of the hormones increase the peak amplitude of BK currents, shifting the steady-state activation curve to the left. The effect of both insulin and leptin can be prevented by pretreatment with inhibitors of tyrosine kinase and phosphatidylinositol 3-kinase (PI3K) but not MAPK. These data indicate that PI3K-mediated signals are the common regulators of BK channels by insulin and leptin and mediated the two hormones' identical activatory effects on ARC NPY neurons. The effect of insulin and leptin together was similar to that of insulin or leptin alone, and leptin or insulin pretreatment did not lead to insulin- or leptin-sensitizing effects, respectively. These intracellular signaling mechanisms may play key roles in regulating ARC NPY neuron activity and physiological processes such as the control of food intake and body weight, which are under the combined control of insulin and leptin.

Oral administration of a soluble 1–3, 1–6 β-glucan during prophylactic survivin peptide vaccination diminishes growth of a B cell lymphoma in mice

β-glucans are biological response modifiers with activatory effects on macrophages, dendritic cells (DC), granulocytes and NK cells. In this study, we investigated the effect of a soluble yeast-derived β-(1–3), (1–6)- d-glucan on prophylactic peptide vaccination against the B cell lymphoma A20 in syngeneic Balb/c mice. We found that repeated immunizations with two MHC class-I restricted peptides derived from the tumor antigen survivin combined with oral co-administration of β-glucan could significantly diminish intradermal tumor growth, whereas peptide vaccination alone failed to control tumor growth. β-glucan as single agent induced only a weak but non-significant growth inhibitory effect. To determine whether the tumor inhibitory effect of the combined treatment was associated with the induction of a tumor-specific immune response we quantified splenic DC and macrophages, analyzed the maturation of DC and measured the frequency of peptide-specific CD8 + and CD4 + T cells. Treated mice showed significantly increased numbers of splenic macrophages and mature DC compared to untreated tumor-bearing mice. After restimulation with both peptides in vitro elevated levels of interferon (IFN)-γ-secreting CD8 + T cells were found in two of four tested mice following treatment and one of four mice showed a strong increase of interleukin (IL)-4-secreting CD4 + T cells. Our data reveal a beneficial effect of β-(1–3), (1–6)- d-glucan in tumor growth inhibition by tumor-specific peptide vaccination which may rely on a function of the polymeric sugar as immunological adjuvant.

Catalytic activity and the stability of horseradish peroxidase increase as a result of its incorporation into a polyelectrolyte complex with chitosan

The incorporation of horseradish peroxidase into polyelectrolyte complexes with chitosans of different molecular weights (MW 5-150 kDa) yielded highly active and stable enzyme preparations. As a result of the selection of optimal conditions for the formation of peroxidase-chitosan complexes, it was found that 0.1% chitosan with a MW of 10 kDa had the strongest activatory effect on peroxidase (activation degree, > 70%) in the reaction of o-dianisidine oxidation by hydrogen peroxide. The complex formed by 0.001% chitosan with a molecular weight of 150 kDa was most stable: when immobilized on foamed polyurethane, it retained at least 50% of the initial activity for 550 days. The highest catalytic activity was exhibited in a 0.05 M phthalate buffer (pH 5.9-6.2) by the complex containing 0.006-0.009% chitosan in the indicator reaction. The activatory effect of the polysaccharide on the enzyme was determined by its influence on the binding and conversion of the reducting substrate peroxidase.