Lack of effect of boar seminal vesicle fluid immunosuppressor factor on embryo development

The effects of an immunosuppressive factor (ISF) isolated from boar seminal vesicle fluid on in vitro and in vivo mouse development were investigated. It was found that the zona pellucida of porcine and mouse oocytes pre-incubated with ISF reacted in indirect immunofluorescence with antibodies against ISF. Further results indicated that the boar ISF had no effect on embryo development.     

G-Protein Modulation of Glycine-resistant NMDA Receptor Desensitization in Rat Cultured Hippocampal Neurons

Activation of N-methyl-D-aspartate (NMDA) subtype glutamate receptors increases the excitability of most neurons within the CNS. A common feature of ionotropic glutamate receptors is their ability to undergo desensitization. In the present experiments we have examined the role of guanine nucleotide-binding proteins(G-proteins) in the regulation of NMDA receptor desensitization. Repeated NMDA receptor activation with 2 mM extracellular Ca²+ increased the degree of glycine-resistant NMDA receptor desensitization of subsequent responses to NMDA recorded in the presence of 0.2 mM Ca²+. The recovery of glycine-resistant NMDA receptor desensitization after repeated NMDA receptor activation in the presence of 2 mM Ca²+ was significantly reduced in neurons intracellularly dialysed with guanosine-5'-0-(3-thiotriphosphate), guanosine-5'-triphosphate or AIC1₃ and CsF, compounds known to activate G-proteins. lntracellular dialysis with guanosine-5'-0(2thiodiphosphate), adenosine triphosphate, or adenosine-5'-G(3-thiotriphosphate) was ineffective. The calcium permeability of NMDA receptor-channels was not altered by intracellular dialysis with GTPyS. This suggests that modulation of NMDA receptor desensitization by G-proteins represents a novel mechanism forregulation of glutamate-gated ion channel activity.     

Origins of ultralow velocity zones through slab-derived metallic melt

Understanding the ultralow velocity zones (ULVZs) places constraints on the chemical composition and thermal structure of deep Earth and provides critical information on the dynamics of large-scale mantle convection, but their origin has remained enigmatic for decades. Recent studies suggest that metallic iron and carbon are produced in subducted slabs when they sink beyond a depth of 250 km. Here we show that the eutectic melting curve of the iron−carbon system crosses the current geotherm near Earth’s core−mantle boundary, suggesting that dense metallic melt may form in the lowermost mantle. If concentrated into isolated patches, such melt could produce the seismically observed density and velocity features of ULVZs. Depending on the wetting behavior of the metallic melt, the resultant ULVZs may be short-lived domains that are replenished or regenerated through subduction, or long-lasting regions containing both metallic and silicate melts. Slab-derived metallic melt may produce another type of ULVZ that escapes core sequestration by reacting with the mantle to form iron-rich postbridgmanite or ferropericlase. The hypotheses connect peculiar features near Earth''s core−mantle boundary to subduction of the oceanic lithosphere through the deep carbon cycle.Ultralow velocity zones (ULVZs) occur as isolated patches near the core−mantle boundary (CMB) and are generally associated with the large low shear velocity provinces (LLSVPs) (1, 2). The nonubiquitous distribution of ULVZs gives evidence for thermal and/or chemical heterogeneities at the base of the mantle (3, 4). The density excess of ULVZs likely arises from iron enrichment (5–7), whereas the velocity anomalies may indicate partial melting (3, 4, 8, 9) or iron enrichment (5–7). Elucidating the origin of ULVZs is therefore important for understanding the thermal and chemical state of the CMB, which, in turn, holds a key to unraveling the evolution history and dynamics of deep Earth.Given uncertainties in the melting behavior of mantle rocks (10), elastic properties of relevant phases (11, 12), and iron partitioning between them (13, 14), the origin of ULVZs remains enigmatic. Partial melt of silicate composition has been widely considered as the origin of ULVZs because the presence of partial melt reduces shear wave velocity (Vs) effectively, and partial melt was found to be denser than coexisting solids at deep mantle conditions (e.g., refs. 4, 13, 15, and 16). Models involving silicate partial melt face several challenges. First, the solidus temperatures of silicate compositions happen to fall into the ±500 K uncertainty margin of the CMB temperature. Consequently, nonubiquitous partial melting of a silicate composition critically depends on thermal structure of the lowermost mantle, and the presence of chemically distinct components is often invoked to explain the occurrence of patchy melts near the CMB. Given the controversy over the mantle solidus (3, 8–10) and CMB temperatures (17), these models are still under debate and remain to be tested. Second, Nomura et al. (13) found that silicate liquid is, at most, 8% denser than the coexisting solids, and therefore only fully molten pockets can marginally match the density excess of ULVZs, which would then give rise to a vanishing Vs that is too low to match the seismic observations. Similarly, Thomas et al. (18) concluded that residual liquids produced in a whole-mantle magma ocean are not dense enough to remain at the CMB on geological timescales. Furthermore, Thomas and Asimow (19) showed that dense silicate melt must be removed from its equilibrium solid matrix to combine with a denser solid to match the density excess of ULVZs.Iron-rich solid phases such as wüstite, postbridgmanite, or iron silicide have been proposed as alternative origins of ULVZs (e.g., refs. 5–7, 10, and 20). Candidate sources for iron enrichment include the core or core sediments, residual liquids from a putative basal magma ocean, or subducted banded iron formation. It remains unknown or controversial if iron-rich solids with required composition and properties can be produced near the CMB. For instance, Knittle and Jeanloz (20) attributed ULVZs to FeSi and FeO as core−mantle reaction products although a subsequent study did not produce FeSi from reaction between bridgmanite and molten iron (21). Some of these models showed that simultaneous match of density (ρ), compressional wave velocity (Vp), and Vs can be achieved for certain compositions at 300 K (7), but recent theoretical studies concluded that, at high temperatures, iron-rich wüstite or bridgmanite could not reproduce both Vp and Vs (11, 12).Seismic tomography revealed that subducted slabs sometimes penetrated the transition zone to reach the CMB (22). Carbonates in the crustal portion of the slab may melt at the mantle wedge or in the transition zone and return to shallow depths (23, 24). On the other hand, the slabs that sank beyond the depth of 250 km are expected to contain metallic iron as a result of stabilization of ferric iron in pyroxene, garnet, or bridgmanite (25–27), plus elemental carbon or carbide through the reduction of carbonates by the metallic iron (28). To assess whether an iron−carbon mixture carried by slabs to the lowermost mantle would contribute to the origin of ULVZs, we investigated the melting behavior of the Fe−C system under the pressures of the lower mantle.     

A delayed ATP-elicited K+ current in freshly isolated smooth muscle cells from mouse aorta

Adenosine 5'-triphosphate (ATP) activated two sequential responses in freshly isolated mouse aortic smooth muscle cells. In the first phase, ATP activated Ca(2+)-dependent K(+) or Cl(-) currents and the second phase was the activation of a delayed outward current with a reversal potential of -75.9 +/- 1.4 mV. A high concentration of extracellular K(+) (130 mM) shifted the reversal potential of the delayed ATP-elicited current to -3.5 +/- 1.3 mV. The known K(+)-channel blockers, iberiotoxin, charybdotoxin, glibenclamide, apamin, 4-aminopyridine, Ba(2+) and tetraethylammonium chloride all failed to inhibit the delayed ATP-elicited K(+) current. Removal of ATP did not decrease the amplitude of the ATP-elicited current back to the control values. The simultaneous recording of cytosolic free Ca(2+) and membrane currents revealed that the first phase of the ATP-elicited response is associated with an increase in intracellular Ca(2+), while the second delayed phase develops after the return of cytosolic free Ca(2+) to control levels.ATP did not activate Ca(2+)-dependent K(+) currents, but did elicit Ca(2+)-independent K(+) currents, in cells dialyzed with ethylene glycol-bis (2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA). The delay of activation of Ca(2+)-independent currents decreased from 10.5 + 3.4 to 1.27 +/- 0.33 min in the cells dialyzed with 2 mM EGTA. Adenosine alone failed to elicit a Ca(2+)-independent K(+) current but simultaneous application of ATP and adenosine activated the delayed K(+) current. Intracellular dialysis of cells with guanosine 5'-O-(2-thiodiphosphate) transformed the Ca(2+)-independent ATP-elicited response from a sustained to a transient one. A phospholipase C inhibitor, U73122 (1 microM), was shown to abolish the delayed ATP-elicited response. These results indicate that the second phase of the ATP-elicited response was a delayed Ca(2+)-independent K(+) current activated by exogenous ATP. This phase might represent a new vasoregulatory pathway in vascular smooth muscle cells.     

Immunohistochemical study of the apoptotic mechanisms in the intestinal mucosa during children's coeliac disease

Mechanisms leading to morphological changes of the small intestine during coeliac disease (CD) are not yet completely recognized; however, two main processes have been suggested recently: remodeling of mucosa by matrix metalloproteinases, and mucosal atrophy by apoptosis. The aim of this study was analysis of the expression of proteins regulating apoptosis in the small intestine of children with active CD (ACD) and potential CD (PCD). Jejunal biopsies of 43 children with PCD and untreated ACD and 21 control samples were analyzed by means of standard indirect immunohistochemical technique for Fas, Fas ligand (Fas-L), tissue transglutaminase (tTG), Bcl-2, and glutathione S-transferase (GST) expression. We found significantly lower numbers of Fas-expressing enterocytes in the ACD patients than in PCD patients and controls. Similarly, the number of Fas-positive mucosal lymphocytes was decreased in ACD when compared with PCD. The number of Fas-L- and tTG-expressing enterocytes and mucosal lymphocytes was higher in both PCD and ACD. On the other hand, the number of Bcl-2-positive mucosal lymphocytes in PCD as well as ACD was significantly lower. The expression of tTG in extracellular matrix was significantly higher in PCD and ACD when compared with controls. Our results showed that Fas and/or Fas-L, Bcl-2, and tTG may be involved in apoptotic pathways leading to mucosal atrophy in children with CD. tTG changes are in agreement with the presumed role of this protein in the pathogenesis of CD.     

Staggered development of GABAergic and glycinergic transmission in the MNTB

Maturation of some brain stem and spinal inhibitory systems is characterized by a shift from GABAergic to glycinergic transmission. Little is known about how this transition is expressed in terms of individual axonal inputs and synaptic sites. We have explored this issue in the rat medial nucleus of the trapezoid body (MNTB). Synaptic responses at postnatal days 5-7 (P5-P7) were small, slow, and primarily mediated by GABA(A) receptors. By P8-P12, an additional, faster glycinergic component emerged. At these ages, GABA(A), glycine, or both types of receptors mediated transmission, even at single synaptic sites. Thereafter, glycinergic development greatly accelerated. By P25, evoked inhibitory postsynaptic currents (IPSCs) were 10 times briefer and 100 times larger than those measured in the youngest group, suggesting a proliferation of synaptic inputs activating fast-kinetic receptors. Glycinergic miniature IPSCs (mIPSCs) increased markedly in size and decay rate with age. GABAergic mIPSCs also accelerated, but declined slightly in amplitude. Overall, the efficacy of GABAergic inputs showed little maturation between P5 and P20. Although gramicidin perforated-patch recordings revealed that GABA or glycine depolarized P5-P7 cells but hyperpolarized P14-P15 cells, the young depolarizing inputs were not suprathreshold. In addition, vesicle-release properties of inhibitory axons also matured: GABAergic responses in immature rats were highly asynchronous, while in older rats, precise, phasic glycinergic IPSCs could transmit even with 500-Hz stimuli. Thus development of inhibition is characterized by coordinated modifications to transmitter systems, vesicle release kinetics, Cl- gradients, receptor properties, and numbers of synaptic inputs. The apparent switch in GABA/glycine transmission was predominantly due to enhanced glycinergic function.     

Natural feed additive of Macleaya cordata: Safety assessment in rats a 90-day feeding experiment

Macleaya cordata (Willd.) (Papaveraceae) is used as an active component in the natural feed additive Sangrovit^®. Sangrovit^® contains mixture of the intact aerial parts and the fraction of quaternary benzo[c]phenanthridine alkaloids from M. cordata (FQBA). In a 90-day pilot toxicity trial, Sangrovit^® and the FQBA were tested for safety. Male Wistar rats were fed for 90 days with 100, 7000 or 14000 mg of Sangrovit^® or 600 mg of FQBA in 1 kg of feed. Body and organ weights, clinical chemistry and hematology markers, oxidative stress parameters, morphological structure of tongue, liver, ileum, kidney and heart samples, and total cytochrome P450 in liver were monitored. The results showed no statistically significant alterations in any parameter between control and treated animals, except for the group treated with 14000 ppm Sangrovit^® that resulted in elevation of reduced glutathione level and superoxide dismutase activity in liver.     

Objective response and time to progression on sequential treatment with sunitinib and sorafenib in metastatic renal cell carcinoma

Patients with metastatic renal cell carcinoma (mRCC) are often treated sequentially with targeted agents, although the optimal strategy is not known. A retrospective, registry-based study has been carried out to assess correlation between clinical response and progression-free survival in patients with mRCC treated sequentially with tyrosine-kinase inhibitors (TKIs) sunitinib and sorafenib. Data on 218 mRCC patients treated with sunitinib and sorafenib who completed therapy with both TKIs were obtained from a database of mRCC patients. Standard nonparametric methods were used to assess correlation between response, PFS and length of treatment on the two agents. A strong correlation between responses to first- versus second TKI was observed (p?<?0.001). No significant association was noted between the duration of therapy with the two TKIs (p?=?0.056), although there was a weak statistically significant correlation between progression-free survival times in the subgroup patients who discontinued treatment because of disease progression. In conclusion, the duration of response on first TKI is of limited value in selecting mRCC patients for sequential TKI therapy. There is a strong correlation between the types of tumour response on the first- versus the second TKI.     

Efficacy of everolimus in second- and third-line therapy for metastatic renal cell carcinoma: A registry-based analysis

ObjectivesThe aim of the present study was to describe the efficacy and safety of everolimus in the treatment of metastatic renal cell carcinoma (mRCC) after administration of 1 vs. 2 prior tyrosine kinase inhibitors (TKIs).Patients and methodsA national renal information system database was used as the data source for the retrospective study. There were 483 patients who received everolimus as the second (n = 350) or the third (n = 112) targeted agent following TKIs.ResultsMedian progression-free survival (PFS) from the start of everolimus in the second or the third line of targeted therapy was 6.1 months for both subgroups (P = 0.863). Median total PFS from the start of the first targeted agent to progression on the third targeted agent for patients receiving 3 lines of therapy with TKI-TKI-everolimus (n = 112) and TKI-everolimus-TKI (n = 27) sequences was 28.3 months vs. 31.3 months, respectively (P = 0.16), and there was no significant difference in overall survival. PFS on everolimus was associated with PFS on previous TKIs in patients receiving 1 but not 2 previous TKIs. Only 13% of 352 patients starting targeted therapy for mRCC in 2010 had received 3 sequential targeted agents by the data cutoff in March 2013.ConclusionPFS on everolimus correlated with PFS on TKIs in patients pretreated with 1 but not 2 TKIs. Everolimus can be deferred to the third line without loss of efficacy or increased toxicity. However, only a minority of patients with mRCC starting targeted treatment can be expected to receive third-line therapy.     

Phenolics-rich extracts from Silybum marianum and Prunella vulgaris reduce a high-sucrose diet induced oxidative stress in hereditary hypertriglyceridemic rats.

The study tested the effects of phenolics-rich extracts from the plants Silybum marianum (silymarin) and Prunella vulgaris (PVE) on blood and liver antioxidant status and lipoprotein metabolism. Hereditary hypertriglyceridemic rats fed on standard diet (STD) or high-sucrose diet (HSD, 70cal% of sucrose) for two weeks were used. HSD doubled plasma and liver triacylglycerol (TAG) and increased plasma VLDL-TAG and VLDL-cholesterol compared to STD. Administration of silymarin or PVE as 1% dietary supplements in HSD did not influence lipid levels in plasma or liver, but both extracts caused decrease in plasma VLDL-cholesterol levels. HSD-induced oxidative stress was manifested in increased TBARS and conjugated dienes (CD) content, decreased GSH levels and glutathione peroxidase (GPX) activity in blood and liver. In blood the activity of superoxide dismutase (SOD) decreased, whereas in liver the activity of catalase increased after HSD. Feeding on HSD containing phenolics-rich extracts resulted in reduction of TBARS and CD content and in increase of blood GPX activity and elevated GSH content in liver. Besides, silymarin increased the activity of SOD and level of GSH in blood. Catalase activity in blood or liver was not influenced by the presence of plant extracts in the diet. These results indicate that silymarin and PVE improve antioxidant status in blood and liver and positively affect plasma lipoprotein profile in an experimental model of dietary induced hypertriglyceridemia.