Effect of Spin Clustering on Basic and Relaxometric Properties of Magnetic Nanoparticles.

An increasing awareness about novel medical applications of smaller, inorganic-based nanoparticles, possessing unique properties at the nanoscale, has led to a burst of research activities in the development of "nanoprobes" for diagnostic medicine and agents for novel, externally activated therapies. In this research field magnetic nanoparticles are prominent due to fundamental peculiar properties particularly appealing for their use in materials and biomedical applications. Aiming to study the relationship between the topology of the magnetic nanoparticles and their efficacy as MRI contrast agents (relaxometric properties), we prepared three different stable colloidal suspension (ferrofluid) of magnetic nanobeads (MNBs) constituted by a discrete number of maghemite nanoparticles, arranged in disordered clusters or ordered in a polymeric matrix. An accurate morpho-dimensional and magnetic characterization displays the close correlation between the magnetic fundamental properties and the topology of our spin systems. The NMR relaxometry profiles confirmed the nature of the physical mechanisms inducing the increase of nuclear relaxation rates at low (magnetic anisotropy) and high (Curie relaxation) magnetic fields. Moreover the transverse relaxivity (r2) values for all the MNBs are higher than those of common contrast agents and the differences between the three MNBs are suggested to be due to the spin topology effect.

Specific subcutaneous immunotherapy with recombinant grass pollen allergens: first randomized dose-ranging safety study.

BACKGROUND: Allergen-specific immunotherapy (SIT) with native allergen extracts and allergoids has been performed successfully for decades. Preliminary studies revealed the use of recombinant allergen-preparations as a promising option for SIT. OBJECTIVE: The present study was designed to investigate the dose-ranging safety in SCIT with a mixture of five recombinant grass pollen allergens containing equimolar amounts of rPhl p 1, rPhl p2, rPhl p 5a, rPhl p 5b and rPhl p 6, adsorbed to aluminium hydroxide. METHODS: A randomized, double blind, placebo-controlled, dose-ranging safety study (EudraCT number 2007-002808-18) was performed in 50 patients with allergic rhinoconjunctivitis, with or without asthma. Patients were randomized to groups of 10 to receive maximum doses of 20, 40, 80 or 120 µg of total grass pollen recombinant protein or placebo. The primary end-point of this trial was the number of patients with at least one systemic reaction with possible, probable or definite relationship to the study medication determined at the end of the up-dosing phase. Secondary end-points included titrated intracutaneous test with natural six-grass pollen extract, allergen-specific conjunctival provocation test as well as IgG and IgE-levels throughout the study. RESULTS: Eight of the 50 patients revealed systemic reactions grade 1 or 2 corresponding to the primary end-point definition. No systemic reactions grade 3 or 4 occurred in any dosage group. The systemic reactions were well distributed among the active groups. Results of secondary end-points imply that the study medication is effective and provokes immunological effects. CONCLUSIONS AND CLINICAL RELEVANCE: The first DBPC SCIT-DRF with a mixture of recombinant Phleum allergens (Phl p 1, 2, 5a, 5b, 6) in patients with rhinoconjunctivitis plus/minus asthma showed no major side effects in very high doses up to 120 µg.

Assessment of incidence and trends in cerebrovascular disease in the healthcare district of Lleida (Spain) in the period 2010-2014. / Evaluación de la incidencia y tendencia de la enfermedad cerebrovascular en la región sanitaria de Lleida (España) en el periodo 2010-2014.

OBJECTIVES: This study aimed to determine the incidence and trends of cerebrovascular disease (CVD) in the healthcare district of Lleida. MATERIAL AND METHODS: We performed a population-based prospective cohort study including the entire population of the healthcare district of Lleida (440 000 people). Information was gathered from the minimum basic data set from the emergency department and hospital discharges for the period from January 2010 to December 2014. All types of stroke were included. We evaluated crude and age-standardised rates using the world population as a reference. Patients without neuroimaging confirmation of the diagnosis were excluded. RESULTS: We identified 4397 patients: 1617 (36.8%) were aged 80 years or over; 3969 (90.3%) presented ischaemic stroke, and 1741 (39.6%) were women. The crude incidence rate ranged from 192 (95% confidence interval [CI], 179-205) to 211 (95% CI, 197-224) cases per 100 000 population, in 2012 and 2013, respectively. Age-standardised rates ranged from 93 (95% CI, 86-100) to 104 (95% CI, 96-111) cases per 100 000 population, in 2012 and 2013, respectively. For all years, incidence rates increased with age, and were significantly higher among men than among women. CONCLUSION: The impact of CVD in Lleida is comparable to that observed in other European regions. However, population ageing induces a high crude incidence rate, which remained stable over the five-year study period.

Assessment of incidence and trends in cerebrovascular disease in the healthcare district of Lleida (Spain) in the period 2010-2014.

OBJECTIVES: This study aimed to determine the incidence and trends of cerebrovascular disease (CVD) in the healthcare district of Lleida. MATERIAL AND METHODS: We performed a population-based prospective cohort study including the entire population of the healthcare district of Lleida (440 000 people). Information was gathered from the minimum basic data set from the emergency department and hospital discharges for the period from January 2010 to December 2014. All types of stroke were included. We evaluated crude and age-standardised rates using the world population as a reference. Patients without neuroimaging confirmation of the diagnosis were excluded. RESULTS: We identified 4397 patients: 1617 (36.8%) were aged 80 years or over; 3969 (90.3%) presented ischaemic stroke, and 1741 (39.6%) were women. The crude incidence rate ranged from 192 (95% confidence interval [CI], 179-205) to 211 (95% CI, 197-224) cases per 100 000 population, in 2012 and 2013, respectively. Age-standardised rates ranged from 93 (95% CI, 86-100) to 104 (95% CI, 96-111) cases per 100 000 population, in 2012 and 2013, respectively. For all years, incidence rates increased with age, and were significantly higher among men than among women. CONCLUSION: The impact of CVD in Lleida is comparable to that observed in other European regions. However, population ageing induces a high crude incidence rate, which remained stable over the five-year study period.

Low doses of dexamethasone can produce a hypocorticosteroid state in the brain.

The synthetic glucocorticoid dexamethasone (dex) blocks stress-induced hypothalamic-pituitary-adrenal (HPA) activation primarily at the level of the anterior pituitary because multidrug resistance P-glycoprotein hampers its penetration in the brain. Here, we tested the hypothesis that central components of the HPA axis would escape dex suppression under conditions of potent peripheral glucocorticoid action. We subchronically treated rats with low or high doses of dex. The animals were subjected on the last day of treatment for 30 min to a restraint stressor after which central and peripheral markers of HPA axis activity were measured. Basal and stress-induced corticosterone secretion, body weight gain, adrenal and thymus weight, as well as proopiomelanocortin mRNA in the anterior pituitary were reduced in a dose-dependent manner by dex administered either 5 d sc or 3 wk orally. In the brain, the highest dose dex suppressed CRH mRNA and CRH heteronuclear RNA in the paraventricular nucleus (PVN). However, in the peripherally active low-dose range of dex CRH mRNA and heteronuclear RNA showed resistance to suppression, and CRH mRNA expression in the PVN was in fact enhanced under the long-term treatment condition. In the PVN, c-fos mRNA was suppressed by the highest dose of dex, but this effect showed a degree of resistance after long-term oral treatment. c-fos mRNA responses in the anterior pituitary followed those in PVN and reflect central drive of the HPA axis even if corticosterone responses are strongly reduced. The results support the concept that low doses of dex can create a hypocorticoid state in the brain.

5-HT2 receptors modulate excitatory neurotransmission to cardiac vagal neurons within the nucleus ambiguus evoked during and after hypoxia.

To examine the role of 5-HT2 receptors in the central cardiorespiratory network, and in particular the respiratory modulation of parasympathetic activity to the heart, we used an in vitro medullary slice that allowed simultaneous examination of rhythmic inspiratory-related activity recorded from hypoglossal rootlet and excitatory inspiratory-related neurotransmission to cardioinhibitory vagal neurons (CVNs) within the nucleus ambiguus (NA). Focal application of ketanserin, a 5-HT2 receptor antagonist, did not significantly alter the frequency of spontaneous excitatory postsynaptic excitatory currents (EPSCs) in CVNs in control conditions. However, ketanserin diminished spontaneous excitatory neurotransmission to CVNs during hypoxia. The inhibitory action of ketanserin was on 5-HT3 mediated EPSCs during hypoxia since these responses were blocked by the 5-HT3 receptor antagonist ondansetron. In addition, a robust inspiratory-related excitatory neurotransmission was recruited during recovery from hypoxia. Focal application of ketanserin during this posthypoxia period evoked a significant augmentation of the frequency of inspiratory-related, but not spontaneous EPSCs in CVNs. This excitatory effect of ketanserin was prevented by application of the purinergic receptor blocker pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS). These results demonstrate 5-HT2 receptors differentially modulate excitatory neurotransmission to CVNs during and after hypoxia. Activation of 5-HT2 receptors acts to maintain excitatory neurotransmission to CVNs during hypoxia, likely via presynaptic facilitation of 5-HT3 receptor-mediated neurotransmission to CVNs. However, activation of 5HT2 receptors diminishes the subsequent inspiratory-related excitatory neurotransmission to CVNs that is recruited during the recovery from hypoxia likely exerting an inhibitory action on inspiratory-related purinergic signaling.

Recruitment of excitatory serotonergic neurotransmission to cardiac vagal neurons in the nucleus ambiguus post hypoxia and hypercapnia.

Inhibitory GABAergic and glycinergic neurotransmission to cardioinhibitory cardiac vagal neurons (CVNs) increase during inspiratory activity and likely mediate respiratory sinus arrhythmia, while the frequency of excitatory postsynaptic currents (EPSCs) in CVNs are unaltered during the different phases of respiration. However, following hypoxia and hypercapnia (H/H), the parasympathetic activity to the heart increases and thus far, identification of the pathways and neurotransmitters that are responsible for exciting CVNs post H/H are unclear. This study identifies different excitatory pathways to CVNs recruited post H/H. Spontaneous and inspiratory-related EPSCs were recorded in CVNs before, during, and after 10 min of H/H in an in vitro slice preparation that retains rhythmic respiratory activity. Before and during H/H, EPSCs in CVNs were completely blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and d(-)-2-amino-5-phosphonopentanoic acid (AP5), selective AMPA/kainate and N-methyl-d-apartate (NMDA) receptor blockers, respectively. However, after H/H, there was a significant increase in EPSCs during each inspiratory burst. While some of the inspiratory-related EPSCs were blocked by the broad purinergic receptor antagonist pyridoxalphosphate-6-azophenyl-2', 4'-disulphonic acid (PPADS) and the specific P2X receptor antagonist 2',3'-O-(2,4,6-trinitrophenyl) adenosine 5'-triphosphate monolithium trisodium salt (TNP-ATP) a P2X receptor blocker, most of the recruited excitatory neurotransmission to CVNs is serotonergic because odansetron, a selective 5-HT3 antagonist, abolished the majority of the spontaneous and inspiratory-related EPSCs evoked during recovery from H/H. The results from this study suggest that following episodes of H/H, two nonglutamatergic excitatory pathways, purinergic and serotonergic, activating P2X and 5-HT3 receptors, respectively, are recruited to excite CVNs in the post H/H recovery period.

Effect of trifluoperazine on DNA synthesis during liver regeneration.

An intraperitoneal injection of the calcium-calmodulin blocker trifluoperazine into rats at 4 hr after a partial hepatectomy produced a strong inhibition of DNA synthesis observed at 24 hr after surgery; but when injection was administered at 20 hr after hepatectomy, it did not produce any effect on DNA replication. These observations indicate that trifluoperazine acted by blocking one or more events involved in triggering DNA replication but it did not affect on-going DNA synthesis. A more detailed study indicated that when trifluoperazine was injected at 4 hr after surgery, a 12 hr delay in the cytosolic calmodulin surge observed between 6 and 12 hr after partial hepatectomy (previous to initiation of DNA replication) and also in the starting of DNA synthesis was produced. These findings suggest that the pre-replicative surge of cytosolic calmodulin could be involved in triggering DNA synthesis observed after partial hepatectomy.

Induction of plasma membrane alkaline phosphatase in rat liver.

We have determined alkaline phosphatase activity in total liver plasma membrane fractions from rats subjected to a partial hepatectomy and sham operated with or without manipulation of the liver. In all these cases, an increase of the enzyme activity was observed. Kinetic studies of alkaline phosphatase activity performed on plasma membrane fractions from rats subjected to a partial hepatectomy suggest that alkaline phosphatase increase is produced by de novo biosynthesis of enzyme molecules. Determination of alkaline phosphatase activity in purified plasma membrane subfractions corresponding to each of the three functional regions of the hepatocyte surface (blood sinusoidal, lateral and bile canalicular), indicates that the increase of the enzyme activity observed after partial hepatectomy is selectively induced in the bile canalicular domain of the hepatocyte plasma membrane.