Formation of intraneuronal iron deposits following local release from nanostructured silica injected into rat brain parenchyma.

Nanostructured materials with controllable properties have been used to cage and release various types of compounds. In the present study, iron-loaded nanostructured sol-gel SiO2-Fe materials were prepared and injected into the rat brain to develop a method for gradual iron delivery into the neurons with the aims to avoid acute iron toxicity and develop an animal model of gradual, metal-induced neurodegeneration. Nanoparticles were prepared by the traditional method of hydrolysis and condensation reactions of tetraethyl orthosilicate at room temperature and subsequent heat treatment at 200 °C. FeSO4 was added in situ during the silica preparation. The resulting materials were characterized by UV-VIS and infrared spectroscopies, X-ray diffraction, and N2 adsorption-desorption. An in vitro ferrous sulfate release test was carried out in artificial cerebrospinal fluid as the release medium showing successful ferrous sulfate loading on nanostructured silica and sustained iron release during the test time of 10 h. Male Wistar rats administered with SiO2-Fe nanoparticles in the substantia nigra pars compacta (SNpc) showed significant intraneuronal increase of iron, in contrast to the animals administered with FeSO4 that showed severe neuronal loss, 72 h post-treatment. Both treatments induced lipid fluorescent product formation in the ventral midbrain, in contrast to iron-free SiO2 and PBS-only injection controls. Circling behavior was evaluated six days after the intranigral microinjection, considered as a behavioral end-point of brain damage. The apomorphine-induced ipsilateral turns in the treated animals presented significant differences in relation to the control groups, with FeSO4 administration leading to a dramatic phenotype, compared to a milder impact in SiO2-Fe administrated animals. Thus, the use of SiO2-Fe nanoparticles represents a slow iron release system useful to model the gradual iron-accumulation process observed in the SNpc of patients with idiopathic Parkinson's disease.

Prognostic importance of DNA from human papillomavirus in patients with oral squamous cell carcinoma.

BACKGROUND: Survival of patients with oral squamous cell carcinoma (OSCC) is generally low, with the likelihood of locoregional recurrence or disease progression (LR/DP). Knowledge of prognostic factors for survival is key to achieving an understanding and increased survival. The present study aimed to identify prognostic factors for patients with OSCC, especially the presence of DNA from human papillomavirus (HPV). MATERIAL AND METHODS: Retrospective cohort study including 119 patients with OSCC treated at the National Cancer Institute in Mexico City (2009-2013). Clinical information was obtained from patient records including LR/DP. Formalin-fixed, paraffin-embedded tissues were obtained and used for detecting DNA from different types of HPV. Potential prognostic factors for Overall Survival (OS) were analyzed using the Cox proportional hazards model. RESULTS: After model adjustment, factors associated with longer OS were a pre-treatment platelet count above 400,000/mm3 (HR=0.09, p=0.026) and response to primary treatment (HR=0.26, p=0.001). HPV DNA was present in 23 (19.3%) of the patients and importantly, type 16 found in 19 of them. Although survival of HPV-positive patients was longer, difference was not significant. However, among patients with LR/DP, HPV positivity was significantly associated with increased survival (HR=0.23, p=0.034). Importantly, survival was significantly different for HPV-positive patients with LR/DP > 6 months (HR=0.20, p=0.002), had higher absolute lymphocyte count at start of treatment (HR=0.50, p=0.028) or had local rescue treatment (HR=0.24, p=0.019). CONCLUSIONS: Although HPV positivity was not associated with a longer OS of OSCC patients, a better prognosis was significantly associated with HPV positivity and recurring or progressing disease, particularly with HPV type 16.

Respiratory sinus arrhythmia in growth restricted fetuses with normal Doppler hemodynamic indices.

BACKGROUND: The autonomic behavior of growth-restricted fetuses at different evolving hemodynamic stages has not been fully elicited. AIM: To analyze the respiratory sinus arrhythmia (RSA) of growth-restricted fetuses that despite this severe condition show normal Doppler hemodynamics. SUBJECTS: 10 growth-restricted fetuses (FGR group) with normal arterial pulsatility indices (umbilical, uterine, middle cerebral, ductus venosus and aortic isthmus), and 10 healthy fetuses (Control group), 32-37weeks of gestation. METHOD: B-mode ultrasound images for visualizing fetal breathing movements (FBM) or breathing akinesis (FBA), and the simultaneous RR-interval time series from maternal abdominal ECG recordings were obtained. The root-mean-square of successive differences of RR-intervals (RMSSD) was considered as a RSA-related parameter among the instantaneous amplitude of the high-frequency component (AMPHF) and its corresponding instantaneous frequency (IFHF), both computed by using empirical mode decomposition. Mean fetal heart-periods and RSA-related parameters were assessed during episodes of FBM and FBA in 30s length windows. RESULTS: FGR and Control groups presented RSA-related fluctuations during FBM and FBA. Also, both groups showed significant higher (p<0.001) values for the mean heart-period, RMSSD and AMPHF during FBM. No-significant differences (p>0.05) were found for the IFHF regardless of breathing activity (FBM vs. FBA). CONCLUSION: Growth-restricted fetuses without evident hemodynamic compromise exhibit a preserved autonomic cardiovascular regulation, characterized by higher values of RSA and mean heart-period in the presence of FBM. This physiological response reflects a compensatory strategy that may contribute to preserve blood flow redistribution to vital organs.

Mechanisms involved in the vasorelaxant effects produced by the acute application of amfepramone in vitro to rat aortic rings

Amfepramone (diethylpropion) is an appetite-suppressant drug used for the treatment of overweight and obesity. It has been suggested that the systemic and central activity of amfepramone produces cardiovascular effects such as transient ischemic attacks and primary pulmonary hypertension. However, it is not known whether amfepramone produces immediate vascular effects when applied in vitro to rat aortic rings and, if so, what mechanisms may be involved. We analyzed the effect of amfepramone on phenylephrine-precontracted rat aortic rings with or without endothelium and the influence of inhibitors or blockers on this effect. Amfepramone produced a concentration-dependent vasorelaxation in phenylephrine-precontracted rat aortic rings that was not affected by the vehicle, atropine, 4-AP, glibenclamide, indomethacin, clotrimazole, or cycloheximide. The vasorelaxant effect of amfepramone was significantly attenuated by NG-nitro-L-arginine methyl ester (L-NAME) and tetraethylammonium (TEA), and was blocked by removal of the vascular endothelium. These results suggest that amfepramone had a direct vasorelaxant effect on phenylephrine-precontracted rat aortic rings, and that inhibition of endothelial nitric oxide synthase and the opening of Ca2+-activated K+ channels were involved in this effect.

Mechanisms involved in the vasorelaxant effects produced by the acute application of amfepramone in vitro to rat aortic rings.

Amfepramone (diethylpropion) is an appetite-suppressant drug used for the treatment of overweight and obesity. It has been suggested that the systemic and central activity of amfepramone produces cardiovascular effects such as transient ischemic attacks and primary pulmonary hypertension. However, it is not known whether amfepramone produces immediate vascular effects when applied in vitro to rat aortic rings and, if so, what mechanisms may be involved. We analyzed the effect of amfepramone on phenylephrine-precontracted rat aortic rings with or without endothelium and the influence of inhibitors or blockers on this effect. Amfepramone produced a concentration-dependent vasorelaxation in phenylephrine-precontracted rat aortic rings that was not affected by the vehicle, atropine, 4-AP, glibenclamide, indomethacin, clotrimazole, or cycloheximide. The vasorelaxant effect of amfepramone was significantly attenuated by NG-nitro-L-arginine methyl ester (L-NAME) and tetraethylammonium (TEA), and was blocked by removal of the vascular endothelium. These results suggest that amfepramone had a direct vasorelaxant effect on phenylephrine-precontracted rat aortic rings, and that inhibition of endothelial nitric oxide synthase and the opening of Ca2+-activated K+ channels were involved in this effect.

On the antioxidant properties of kynurenic acid: free radical scavenging activity and inhibition of oxidative stress.

Kynurenic acid (KYNA) is an endogenous metabolite of the kynurenine pathway for tryptophan degradation and an antagonist of both N-methyl-D-aspartate (NMDA) and alpha-7 nicotinic acetylcholine (α7nACh) receptors. KYNA has also been shown to scavenge hydroxyl radicals (OH) under controlled conditions of free radical production. In this work we evaluated the ability of KYNA to scavenge superoxide anion (O(2)(-)) and peroxynitrite (ONOO(-)). The scavenging ability of KYNA (expressed as IC(50) values) was as follows: OH=O(2)(-)>ONOO(-). In parallel, the antiperoxidative and scavenging capacities of KYNA (0-150 µM) were tested in cerebellum and forebrain homogenates exposed to 5 µM FeSO(4) and 2.5 mM 3-nitropropionic acid (3-NPA). Both FeSO(4) and 3-NPA increased lipid peroxidation (LP) and ROS formation in a significant manner in these preparations, whereas KYNA significantly reduced these markers. Reactive oxygen species (ROS) formation were determined in the presence of FeSO(4) and/or KYNA (0-100 µM), both at intra and extracellular levels. An increase in ROS formation was induced by FeSO(4) in forebrain and cerebellum in a time-dependent manner, and KYNA reduced this effect in a concentration-dependent manner. To further know whether the effect of KYNA on oxidative stress is independent of NMDA and nicotinic receptors, we also tested KYNA (0-100 µM) in a biological preparation free of these receptors - defolliculated Xenopus laevis oocytes - incubated with FeSO(4) for 1 h. A 3-fold increase in LP and a 2-fold increase in ROS formation were seen after exposure to FeSO(4), whereas KYNA attenuated these effects in a concentration-dependent manner. In addition, the in vivo formation of OH evoked by an acute infusion of FeSO(4) (100 µM) in the rat striatum was estimated by microdialysis and challenged by a topic infusion of KYNA (1 µM). FeSO(4) increased the striatal OH production, while KYNA mitigated this effect. Altogether, these data strongly suggest that KYNA, in addition to be a well-known antagonist acting on nicotinic and NMDA receptors, can be considered as a potential endogenous antioxidant.

Effects of ionotropic glutamate receptor antagonists on rat dural artery diameter in an intravital microscopy model.

BACKGROUND AND PURPOSE: During migraine, trigeminal nerves may release calcitonin gene-related peptide (CGRP), inducing cranial vasodilatation and central nociception; hence, trigeminal inhibition or blockade of craniovascular CGRP receptors may prevent this vasodilatation and abort migraine headache. Several preclinical studies have shown that glutamate receptor antagonists affect the pathophysiology of migraine. This study investigated whether antagonists of NMDA (ketamine and MK801), AMPA (GYKI52466) and kainate (LY466195) glutamate receptors affected dural vasodilatation induced by alpha-CGRP, capsaicin and periarterial electrical stimulation in rats, using intravital microscopy. EXPERIMENTAL APPROACH: Male Sprague-Dawley rats were anaesthetized and the overlying bone was thinned to visualize the dural artery. Then, vasodilator responses to exogenous (i.v. alpha-CGRP) and endogenous (released by i.v. capsaicin and periarterial electrical stimulation) CGRP were elicited in the absence or presence of the above antagonists. KEY RESULTS: alpha-CGRP, capsaicin and periarterial electrical stimulation increased dural artery diameter. Ketamine and MK801 inhibited the vasodilator responses to capsaicin and electrical stimulation, while only ketamine attenuated those to alpha-CGRP. In contrast, GYKI52466 only attenuated the vasodilatation to exogenous alpha-CGRP, while LY466195 did not affect the vasodilator responses to endogenous or exogenous CGRP. CONCLUSIONS AND IMPLICATIONS: Although GYKI52466 has not been tested clinically, our data suggest that it would not inhibit migraine via vascular mechanisms. Similarly, the antimigraine efficacy of LY466195 seems unrelated to vascular CGRP-mediated pathways and/or receptors. In contrast, the cranial vascular effects of ketamine and MK801 may represent a therapeutic mechanism, although the same mechanism might contribute, peripherally, to cardiovascular side effects.

Donitriptan, but not sumatriptan, inhibits capsaicin-induced canine external carotid vasodilatation via 5-HT1B rather than 5-HT1D receptors.

BACKGROUND AND PURPOSE: It has been suggested that during a migraine attack capsaicin-sensitive trigeminal sensory nerves release calcitonin gene-related peptide (CGRP), resulting in cranial vasodilatation and central nociception; hence, trigeminal inhibition may prevent this vasodilatation and abort migraine headache. This study investigated the effects of the agonists sumatriptan (5-HT(1B/1D) water-soluble), donitriptan (5-HT(1B/1D) lipid-soluble), PNU-142633 (5-HT(1D) water-soluble) and PNU-109291 (5-HT(1D) lipid-soluble) on vasodilator responses to capsaicin, alpha-CGRP and acetylcholine in dog external carotid artery. EXPERIMENTAL APPROACH: 59 vagosympathectomized dogs were anaesthetized with sodium pentobarbitone. Blood pressure and heart rate were recorded with a pressure transducer, connected to a cannula inserted into a femoral artery. A precalibrated flow probe was placed around the common carotid artery, with ligation of the internal carotid and occipital branches, and connected to an ultrasonic flowmeter. The thyroid artery was cannulated for infusion of agonists. KEY RESULTS: Intracarotid infusions of capsaicin, alpha-CGRP and acetylcholine dose-dependently increased blood flow through the carotid artery. These responses remained unaffected after intravenous (i.v.) infusions of sumatriptan, PNU-142633, PNU-109291 or physiological saline; in contrast, donitriptan significantly attenuated the vasodilator responses to capsaicin, but not those to alpha-CGRP or acetylcholine. Only sumatriptan and donitriptan dose-dependently decreased the carotid blood flow. Interestingly, i.v. administration of the antagonist, SB224289 (5-HT(1B)), but not of BRL15572 (5-HT(1D)), abolished the inhibition by donitriptan. CONCLUSIONS AND IMPLICATIONS: Our results suggest that the inhibition produced by donitriptan of capsaicin-induced external carotid vasodilatation is mainly mediated by 5-HT(1B), rather than 5-HT(1D), receptors, probably by a central mechanism.

A novel role for endogenous pituitary adenylate cyclase activating polypeptide in the magnocellular neuroendocrine system.

Central release of vasopressin (VP) by the magnocellular neuroendocrine cells (MNCs) responsible for systemic VP release is believed to be important in modulating the activity of these neurons during dehydration. Central VP release from MNC somata and dendrites is stimulated by both dehydration and pituitary adenylate cyclase activating polypeptide (PACAP). Although PACAP is expressed in MNCs, its potential role in the magnocellular response to dehydration is unexplored. The current study demonstrates that prolonged dehydration increases immunoreactivity for PACAP-27, PACAP-38, and the type I PACAP receptor in the supraoptic nucleus (SON) of the rat. In addition, PACAP stimulates local VP release in the euhydrated rat SON in vitro, and this effect is reduced by the PACAP receptor antagonist PAC(6-27) (100 nm), suggesting the participation of PACAP receptors. Concomitant with its effects on local VP release, PACAP also reduces basal glutamate and aspartate release in the euhydrated rat SON. Furthermore, somatodendritic VP release elicited by acute dehydration is blocked by PAC(6-27), suggesting that endogenous PACAP participates in this response. Consistent with this, RIA revealed that local PACAP-38 release within the SON is significantly elevated during acute dehydration. These results suggest that prolonged activation of hypothalamic MNCs is accompanied by up-regulation of PACAP and the type I PACAP receptor in these cells and that somatodendritic VP release in response to acute dehydration is mediated by activation of PACAP receptors by endogenous PACAP released within the SON. A potential role for PACAP in promoting efficient, but not exhaustive, systemic release of VP from MNCs during physiological challenge is discussed.

Histochemical and immunohistochemical localization of neuronal nitric oxide synthase in the olfactory epithelium of the axolotl, Ambystoma mexicanum.

The aim of this study was to describe the anatomic distribution of neuronal nitric oxide synthase immunoreactivity (nNOS-IR) and nicotinamide-adenine dinucleotide phosphate-diaphorase (NADPH-d) staining in the olfactory epithelium of the axolotl, juvenile, and neotenic adult, Ambystoma mexicanum. Nitric oxide (NO, nitrogen monoxide) is a widespread molecule that has been identified both as a neuromodulator and as an intracellular messenger. In the olfactory system, NO has been proposed to play a role in olfactory transduction. Nitric oxide synthase (NOS) can be detected by histochemical (NADPH-d) and immunohistochemical techniques. NADPH-d staining has been described in olfactory receptor neurons (ORN) of several species; however, nNOS-IR has not always been found at ORN. Present results show intense NADPH-d staining and nNOS-IR in the dendrites and cell bodies of ORN in both the nasal cavity and the vomeronasal organ of axolotls. Unilateral olfactory axotomy was conducted to confirm that labels were at ORN. Two weeks after this procedure an important decrease in NADPH-d staining and nNOS-IR was observed. The remaining labels were mostly in basal cells. By 5 weeks postaxotomy both labels were almost totally absent. Thus, both NADPH-d staining and nNOS-IR were mainly localized in ORN. NADPH-d staining and nNOS-IR were also found in nerve fibers surrounding arterioles, as well as in secretory and duct cells of the Bowman's glands. This last anatomical localization suggests that in the A. mexicanum NO might be involved in functions other than only olfactory transduction, such as regulation of local blood flow, glandular secretion, and ORN development.

[Hematologic changes associated with infection of mice by Cryptococcus neoformans]. / Cambios hematológicos asociados a la infección de ratones con Cryptococcus neoformans.

The pathogenicity of the L, P and E strains of C. neoformans was studied in 3-5 weeks old CD1 male mice. Cell suspensions containing the most (L), and the least (E) pathogenic strains were inoculated intracerebrally (IC), and intraperitoneally (IP). After 14 days total and differential counts were made for erythrocytes, leukocytes and platelets, yeasts from infected organs were recovered in Sabouraud Dextrose Agar (SDA). The capsular material from C. neoformans was used to stimulate in vivo and in vitro platelet production. Mice inoculated with the L strain, showed increase of neutrophils and platelets, decrease of lymphocytes, the yeast was recovered from spleen, liver and lungs and from brain of mice injected by the IC route. In contrast, strain E produced an increase of neutrophils, reduction of lymphocytes, and was only isolated from the brain of mice inoculated IC. The capsular material stimulated the production and maturation of megakaryocytes only in vitro. The development of the infection and the yeast dissemination were associated with increases in the number of platelets, probably as a result of the stimulant effect of the capsular material on the maturation of megakaryocytes.

Histochemical distribution of NADPH-diaphorase in the cerebral ganglion of the crayfish Cambarellus montezumae.

The presence and localization of NADPH-diaphorase in the cerebral ganglion of the crayfish Cambarellus montezumae was shown. The reactivity of this enzyme was found in the deuterocerebrum, mainly in the commissure, in fibers of olfactory and accessory lobes, and in the laterodorsal group of cells. The presence of this enzyme in these cerebral regions suggests that nitric oxide is involved in primary sensory afferents in the crayfish.

Distribution of NADPH-diaphorase in the perioesophageal ganglia of the snail, Helix aspersa.

In this paper we discuss the anatomical localization of NADPH-diaphorase using Nitroblue tetrazolium in perioesophageal ganglia of Helix aspersa. Our results show that the reaction is present in neurons and fibers of the procerebrum, some positive neurons are found in mesocerebrum, and there were positive fibers in the neuropile of postcerebrum and mesocerebrum; likewise, immunopositive fibers were found in the neuropile of pedal, pleural and parietal ganglia. The presence of NADPH-diaphorase in the interneurons of procerebrum suggests the participation of this enzyme in the production of nitric oxide for the processing of the olfactory information, as has been suggested in mammalian olfactory tissue.

Estudio comparativo de sueros antiglobulina humana de uso en Chile. / Comparative study of human antiglobulin serum used in Chile

Se hace un estudio comparativo de cinco sueros antiglobulina humana de amplio espectro o poliespecifico de uso mas frecuente en el pais, procedente de diferentes laboratorios. Se valora su contenido de anti IgG por medio de hematies D positivo y Duffy a (Fya) positivo, sensibilisados con Anti D Anti Fya, respectivamente y su actividad anticomplemento referida principalmente a su reactividad Anti C3d necesaria para el test directo de antiglobulina, cuando se estudian anemias hemoliticas autoinmune