[show abstract][hide abstract] ABSTRACT: The use of biochar (BC) as an amendment for agricultural soils is a promising practice, because it improves some soil parameters and could contribute to increase crop yields. The aim of this study was to evaluate the use of BC on some soil physical-chemical parameters and yield of barley (Hordeum vulgare) in two volcanic soils of southern Chile. For the above, BC was produced using oat hulls processed at 300 °C and 2 h of pyrolysis. We evaluated the BC phytotoxic effect through a germination test. After that, doses of 5, 10 and 20 Mg ha -1 of BC were applied in both Ultisol and Inceptisol, using a treatment without BC application as a control. In the crop, relative chlorophyll concentration (SPAD) and grain yield production were determined, whereas in soil, pH, electrical conductivity (EC), bulk density, porosity and water holding capacity (WHC) were also measured. The results showed that the application of 20 Mg ha -1 of BC increased grain yield by 30.5% and 21.9% in the Inceptisol and Ultisol respectively. In addition, SPAD measurements were not affected by the application of BC. Finally, an increase in the soil pH and WHC was observed when the use of higher BC doses, whereas no difference was observed in bulk density, EC and porosity. Our results show that the use of biochar as amendment in agriculture soil can be an effective alternative of soil management improving physical and chemical soil properties, thus promoting a higher productivity of agricultural crops. Acknowledgements: FONDECYT Project 3120213.
17TH CONFERENCE OF THE INTERNACIONAL ORGANIZATION FOR SOIL, Medellín, Colombia; 07/2013
[show abstract][hide abstract] ABSTRACT: Purpose of the study: Switching to ritonavir-boosted darunavir (DRV/r) in patients treated with double ritonavir-boosted protease inhibitors (PI/r) may result in better tolerability, less pill burden, better lipid profile and a lower cost, while maintaining virologic efficacy. Methods: Multicentre, concurrent cohort observational study. HIV-infected adults with HIV RNA <50 copies/mL for at least the previous 12 months on a double PI/r-based therapy were offered to switch to DRV/r (DRV group) or to continue on the same regimen (control group). Visits (including blood tests, adherence and side effects assessment) were performed every 3 months, with a follow-up of at least one year. Descriptive values are described as n (%) or median (interquartile range). Changes from baseline in quantitative variables have been calculated with the Wilcoxon Signed Ranks Test and comparisons between groups have been performed with the Mann-Whitney test, using SPSS 20.0 statistical package. Summary of results: 65 patients were included (35 DRV group and 30 control group); median age was 46 (40-49) years, 76% were male. At baseline, double-boosted PI regimens were lopinavir-atazanavir/r 24%, lopinavir-saquinavir/r 46%, lopinavir-fosamprenavir/r 8%, atazanavir-saquinavir/r 18% and others 4%. There were no significant differences between groups in baseline characteristics, except for patients who switched to DRV had a higher number of prior antiretroviral regimens [6 (3-8) vs 2 (1-4), p=.002]. Of the patients who switched to DRV/r, 46% received DRV/r once-daily and 54% twice-daily. After 48 weeks, one patient in each arm had virologic failure and one patient in the DRV arm stopped treatment due to side effects (depressive syndrome); there were no episodes of rash or clinical hepatitis. Efficacy (HIV RNA <50 copies/mL) was similar in the DRV and control groups by intention-to-treat analysis (94 vs. 97%, p=NS). There were no significant differences in laboratory parameters between treatment groups except for a decrease in total bilirrubin in patients who switched to DRV/r (-0.69 vs +0.28 mg/dL, p=.028). Treatment switch represented a median saving of 157 (32-264) euros per patient per month. Conclusions: Switching from a double-boosted PI regimen to DRV maintains virologic efficacy, with good tolerability and a lower cost.
Journal of the International AIDS Society 01/2012; 15(6):18350. · 3.94 Impact Factor
[show abstract][hide abstract] ABSTRACT: This work deals with the characterization of a circulated fluidized bed combustion (CFCB) Chilean petroleum coke fly ash (FA) from a petroleum coke power plant, and its potential use in neutralization and heavy metals removal from acid wastewaters. FA presents a high Ca and content, being anhydrite the major crystalline mineral phase, with minor proportions of calcite, portlandite and lime. Regarding to environmental characterization of this fly ash, leaching tests allowed concluding that FA is a non-hazardous residue. Heavy metals removal tests indicate that FA is able to remove Cu2+ and Pb2+ mainly due to a precipitation process, while Cr(VI) is being removed probably due to a reduction process to Cr(III), at high liquid to solid ratios. Cu2+, Pb2+ and Cr(VI) kinetic experimental data present acceptable fit to a pseudo-second order kinetic model. According to these results, FA may be used to remove heavy metals and neutralize acid wastewaters, suggesting a possible replacement of pure and costly alkaline materials.
[show abstract][hide abstract] ABSTRACT: We have analyzed the developing expression pattern of x-Shh in the Xenopus forebrain, interpreting the results within the framework of the neuromeric model to assess evolutionary trends and clues. To achieve this goal, we have characterized phenotypically the developing x-Shh expressing forebrain subdivisions and neurons by means of the combination of in situ hybridization for x-Shh and immunohistochemistry for the detection of forebrain essential regulators and markers, such as the homeodomain transcription factors Islet 1, Orthopedia, NKX2.1 and NKX2.2 and tyrosine hydroxylase. Substantial evidence was found for x-Shh expression in the telencephalic commissural preoptic area and this is strongly correlated with the presence of a pallidum and/or a basal telencephalic cholinergic system. In the diencephalon, x-Shh was demonstrated in the zona limitans intrathalamica and the x-Shh expressing cells were extended into the prethalamus. Throughout development and in the adult hypothalamic x-Shh expression was strong in basal regions but, in addition, in the alar suprachiasmatic region. The findings obtained in the forebrain of Xenopus revealed a largely conserved pattern of Shh expression among tetrapods. However, interesting differences were also noted that could be related to evolutive changes in forebrain organization.
Brain research 08/2010; 1347:19-32. · 2.46 Impact Factor
[show abstract][hide abstract] ABSTRACT: We provide a detailed and exhaustive description of forebrain regions, nuclei, and neuronal populations which express the LIM-homeodomain transcription factor Islet1 during Xenopus development. To this end, Isl1 immunofluorescence staining was combined with other regional or neuronal markers such as Nkx2.1, Pax6, GABA, nitric oxide synthase, tyrosine hydroxylase or calretinin, and with tract tracing experiments to differentiate projection neurons from interneurons. We interpret and discuss the results with regard to the developmental origin of some previously "ambiguous" nuclei of the septum and the amygdala. Thus, Isl1 appears like a prominently expressed determinant of striatal and striatal-derived regions of the subpallium, including the central amygdala, together with the dorsal septal nucleus and the lateral septum. In the diencephalon, Isl1 is a conspicuous marker of the prethalamus, the chiasmatic regions, and the preoptic region (including important dopaminergic populations). The tuberal and mammillary parts of the hypothalamus also strongly express Isl1. From a comparative point of view, a major difference with mammals is the scarce expression of Isl1 in the embryonic medial ganglionic eminence, which is notably devoid of Isl1 expression in mammals, and the important retrochiasmatic and mammillary Isl1 expression, both also devoid of Isl1 expression in mammals. Finally, we provide evidence for the existence in Xenopus of a "new" caudal medial telencephalic nucleus, the POC (for preoptic commissural area), which was recently described in mammals.
[show abstract][hide abstract] ABSTRACT: In Xenopus laevis, we analyzed the origin of the projection neurons and interneurons in the developing olfactory bulbs by studying the expression patterns of the genes x-Eomes, x-Lhx5, x-Dll3 and x-Pax6. Olfactory bulb interneurons were characterized by using four conserved molecular markers for distinct subpopulations: gamma-aminobutyric acid, calretinin, calbindin, and tyrosine hydroxylase. Immunohistochemistry was combined with tract-tracing experiments to demonstrate the projection neurons and the interneurons of the olfactory bulbs simultaneously. Taken together, the results showed: (1) the pallial nature of the olfactory bulb and its projection neurons in Xenopus, like in mammals with comparable central projection areas, (2) the subpallial origin of the interneurons that, most likely, follow migratory pathways comparable to those described for mammals, (3) the different interneuron types possess neurochemical characteristics similar to mammals. Therefore, the present results show that the origin, chemoarchitecture and central connections of the olfactory bulbs are highly conserved in evolution.
Brain Research Bulletin 04/2008; 75(2-4):241-5. · 2.94 Impact Factor
[show abstract][hide abstract] ABSTRACT: A previous study in the lizard Gekko gecko has revealed that neuropeptide FF (NPFF, a neuropeptide involved in nociception, cardiovascular regulation, and endocrine function) is widely distributed throughout the brain and spinal cord. Although the distribution of NPFF immunoreactivity shares many features with that found in other vertebrates, it was noted that Gekko shared more features with anamniotes in terms of number of cell groups, more elaborate networks of fibers, and lack of colocalization with catecholamines, than with mammals. To assess the primitive or derived character of these features, NPFF and tyrosine hydroxylase (TH) antibodies have been applied to the brain and spinal cord of the turtle, Pseudemys scripta elegans, which belongs to a different radiation of reptiles. As in Gekko, major NPFF-ir cell groups were found in the diagonal band nucleus of Broca and in the hypothalamus, whereas additional cells were identified in the anterior olfactory nucleus, lateral and dorsal cortices, dorsal ventricular ridge, and the intergeniculate leaflet formation. Notable differences are the presence of NPFF-ir cells in the medial cortex and striatum of Pseudemys, which are lacking in Gekko. On the other hand, no NPFF-ir cells could be detected in the septal region and dorsal horn of the spinal cord in Pseudemys. Double staining with NPFF and TH antibodies revealed an intimate relationship between NPFF-ir and TH-ir structures but colocalization could not be established. In conclusion, the distribution of NPFF in the brain of Pseudemys has corroborated previous results in Gekko, but also revealed some notable species differences.
Brain Research Bulletin 04/2008; 75(2-4):256-60. · 2.94 Impact Factor
[show abstract][hide abstract] ABSTRACT: In the present study we have analyzed the distribution of the calcium binding proteins calbindin-D28k (CB) and calretinin (CR) immunoreactive cells in the retina of the anuran Rana perezi using poly- and mono-clonal antibodies that were proven to be specific in the amphibian brain, without cross-reactivity. Double immunohistofluorescence techniques were used to demonstrate colocalization of both proteins in the same retinal cells. In addition, retrograde tracing experiments from the optic nerve were conducted to labeled ganglion cells and these were observed in combination with CB and/or CR immunohistochemistry. Cells containing CB were identified as all cones, scattered bipolar and amacrine cells together with cells in the ganglion cell layer. The pattern of CR immunoreactivity was strikingly different. Abundant cells contained CR in the inner retinal layers including horizontal, bipolar and amacrine cells, and cells in the ganglion cell layer. By means of double immunohistochemistry it was found that only subpopulations of amacrine cells and cells in the ganglion cell layer contained both CB and CR. Tracing from the optic nerve revealed retrogradely labeled ganglion cells with different morphologies and most of them contained CB and/or CR. All these data taken together suggest that in amphibians CB and CR are distinctly and precisely distributed in retinal neurons showing, however, peculiar features not observed previously in other vertebrates.
Brain Research Bulletin 04/2008; 75(2-4):379-83. · 2.94 Impact Factor
[show abstract][hide abstract] ABSTRACT: A warning about the use of nevirapine (NVP) by its pharmaceutical manufacturer has been issued in which it has been recommended that NVP should not be prescribed in patients with increased risk of toxicity based on CD4 cut-offs and gender. The aim of this study was to determine whether these recommendations are of use in preventing side effects.
This retrospective study included antiretroviral drug-naïve patients who started treatment with NVP. Patients were divided into two groups: those with high CD4 counts (H; women: CD4 count >250 cells/microL; men: CD4 count >400 cells/microL) and those with low CD4 counts (L; women: CD4 count <250 cells/microL; men: CD4 count <400 cells/microL).
A total of 142 patients were included in the study, 61 in the H group and 81 in the L group. Skin rash developed in 6.56% of patients [95% confidence interval (CI) 2.67-15.70%] in the H group and in 14.81% of patients (95% CI 8.72-24.17%) in the L group (P=0.18). Hepatotoxicity developed in 4.92% (95% CI 1.79-13.50%) and 6.17% (95% CI 2.73-13.66%) of patients with high and low CD4 cell counts, respectively (P=1.0).
The recommendations not to use NVP in drug-naïve patients at increased risk of toxicity on the basis of gender and CD4 cell count do not seem to be of use in preventing the occurrence of side effects. However, a small number of patients were included in this study, and hence the possibility cannot be excluded that the recommendations are appropriate in another clinical practice setting.
HIV Medicine 01/2008; 9(1):14-8. · 3.16 Impact Factor
[show abstract][hide abstract] ABSTRACT: Although morphological data suggest that the amphibian forebrain contains similar subdivisions to those observed in birds and mammals, it is presently unclear whether the same patterning mechanisms are conserved among all three classes of tetrapods. Here we report that NKX2-1, a transcription factor that is essential for the ventral patterning of the forebrain in birds and mammals, is expressed in corresponding (homologous) domains in the developing Xenopus forebrain. NKX2-1 expression is restricted to two domains in the amphibian forebrain: (1) a ventral diencephalic domain, with expression limited to hypothalamic structures; and (2) a telencephalic domain, with expression in the medial ganglionic eminence, preoptic area and part of the septum. Thus, the detailed analysis of the distribution of NKX2-1 provides the first unequivocal evidence for distinct progenitor zones within the amphibian forebrain through embryonic and larval development.
[show abstract][hide abstract] ABSTRACT: The distribution of gene expression domains during development constitutes a novel tool for the identification of distinct brain regions. This is particularly useful in the brain of amphibians where cell migration is very limited and most neurons organize in a periventricular layer. Here we report the expression pattern of NKX2-1 protein in the developing Xenopus telencephalon. In mammals, the Nkx2-1 gene is expressed in distinct subpallial regions such as the septum, the medial ganglionic eminence and preoptic region. The results of the present study demonstrate that the expression of NKX2-1 delineates the pallidal anlage and its derivatives in amphibians, as in mammals and birds. In addition, double-labeling immunohistochemistry and the combination of tracing experiments with NKX2-1 immunohistochemistry demonstrate that the amphibian striatum contains interneurons, which express NKX2-1 and produce, among other possible neurotransmitters, nitric oxide and acetylcholine. In sum, the results of the present study strengthen the notion that similar developmental programs exist during basal ganglia development in all tetrapods.
[show abstract][hide abstract] ABSTRACT: Immunohistochemical studies during the last decade have revealed elaborate systems of vasotocinergic (AVT) and mesotocinergic (MST) neuronal elements in the brain of a variety of amphibians including anurans, urodeles, and gymnophionans. Apart from a well-developed hypothalamo-hypophysial system, the antibodies demonstrated the existence of extrahypothalamic AVT- and MST-immunoreactive cell groups as well as extensive extrahypothalamic networks of immunoreactive fibers. The wide distribution of AVT- and MST-immunoreactive fibers throughout the brains of amphibians suggests that the two neuropeptidergic systems are involved not only in hypothalamo-hypophysial interactions, but also in a variety of other brain functions. Moreover, there is now evidence that sex-related differences occur in amphibians as previously shown for amniotes. It should be noted, however, that substantial variation occurs in the relative densities of AVT- and MST-immunoreactive fibers and number of cells between species, even within a single order of amphibians. Similar observations have been made in other classes of vertebrates and prompt us, therefore, to critically evaluate conclusions with respect to specific functions of AVT and MST in the central nervous system of vertebrates.
Microscopy Research and Technique 09/2001; 54(3):125-36. · 1.59 Impact Factor
[show abstract][hide abstract] ABSTRACT: To assess the relationship between dopaminergic neuronal structures and dopaminoceptive structures in a reptile, single and double immunohistochemical procedures with antibodies directed against DARPP-32 (dopamine- and cAMP-regulated phosphoprotein with an apparent molecular mass of 32,000 daltons),a phosphoprotein related to the dopamine D(1)-receptor, and tyrosine hydroxylase (TH) were applied to the brain of the lizard, Gekko gecko. The DARPP-32 antibody yielded a well-differentiated pattern of staining in the brain of Gekko. In general, areas that are densely innervated by TH-immunoreactive, putative dopaminergic fibers, such as the nucleus accumbens, striatum, dorsal ventricular ridge, and amygdaloid complex, display strong immunoreactivity for DARPP-32 in somata and neuropil. Distinct cellular DARPP-32 immunoreactivity was also found in the lateral cortex, ventral hypothalamus, habenula, central nucleus of the torus semicircularis, midbrain tectum, parvicellular isthmic nucleus, raphe nuclei, caudal rhombencephalic tegmentum, and spinal cord. Striatal projections to the midbrain and their target, i.e., the substantia nigra pars reticulata, were found to be strongly immunoreactive. Double immunofluorescence staining revealed that dopaminergic cells generally do not stain for DARPP-32, except for cells in the ventral hypothalamus and at caudal rhombencephalic levels. In conclusion, the distribution of DARPP-32 in the brain of the lizard Gekko gecko largely resembles the pattern observed in birds and mammals, at least as far as basal ganglia structures are concerned. On the other hand, there are several specific features of DARPP-32 distribution in the gekkonid brain that deserve further attention, such as cellular colocalization of DARPP-32 and TH immunoreactivity in hypothalamic and caudal rhombencephalic areas, and cellular DARPP-32 immunoreactivity in the tectum and central nucleus of the torus semicircularis of the midbrain, the superior and inferior raphe nuclei, and the spinal cord.
The Journal of Comparative Neurology 07/2001; 435(2):194-210. · 3.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: Immunohistochemical studies with antibodies against tyrosine hydroxylase, dopamine, and noradrenaline have revealed that the spinal cord of anuran, urodele, and gymnophionan (apodan) amphibians is abundantly innervated by catecholaminergic (CA) fibers and terminals. Because intraspinal cells occur in all three orders of amphibians CA, it is unclear to what extent the CA innervation of the spinal cord is of supraspinal origin. In a previous study, we showed that many cell groups throughout the forebrain and brainstem project to the spinal cord of two anurans (the green frog, Rana perezi, and the clawed toad, Xenopus laevis), a urodele (the Iberian ribbed newt, Pleurodeles waltl), and a gymnophionan (the Mexican caecilian, Dermophis mexicanus). To determine the exact site of origin of the supraspinal CA innervation of the amphibian spinal cord, retrograde tracing techniques were combined with immunohistochemistry for tyrosine hydroxylase in the same sections. The double-labeling experiments demonstrated that four brain centers provide CA innervation to the amphibian spinal cord: 1.) the ventrolateral component of the posterior tubercle in the mammillary region, 2.) the periventricular nucleus of the zona incerta in the ventral thalamus, 3.) the locus coeruleus, and 4.) the nucleus of the solitary tract. This pattern holds for all three orders of amphibians, except for the CA projection from the nucleus of the solitary tract in gymnophionans. There are differences in the strength of the projections (based on the number of double-labeled cells), but in general, spinal functions in amphibians are controlled by CA innervation from brain centers that can easily be compared with their counterparts in amniotes. The organization of the CA input to the spinal cord of amphibians is largely similar to that described for mammals. Nevertheless, by using a segmental approach of the CNS, a remarkable difference was observed with respect to the diencephalic CA projections.
The Journal of Comparative Neurology 06/2001; 434(2):209-32. · 3.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: The present study is the first of a series on descending supraspinal pathways in amphibians in which hodologic and developmental aspects are studied. Representative species of anurans (the green frog, Rana perezi, and the clawed toad, Xenopus laevis), urodeles (the Iberian ribbed newt, Pleurodeles waltl), and gymnophionans (the Mexican caecilian, Dermophis mexicanus) have been used. By means of retrograde tracing with dextran amines, previous data in anurans were largely confirmed and extended, but the studies in P. waltl and D. mexicanus present the first detailed data on descending pathways to the spinal cord in urodeles and gymnophionans. In all three orders, extensive brainstem-spinal pathways were present with only minor representation of spinal projections originating in forebrain regions. In the rhombencephalon, spinal projections arise from the reticular formation, several parts of the octavolateral area, the locus coeruleus, the laterodorsal tegmental nucleus, the raphe nucleus, sensory nuclei (trigeminal sensory nuclei and the dorsal column nucleus), and the nucleus of the solitary tract. In all species studied, the cerebellar nucleus and scattered cerebellar cells innervate the spinal cord, predominantly contralaterally. Mesencephalic projections include modest tectospinal projections, torospinal projections, and extensive tegmentospinal projections. The tegmentospinal projections include projections from the nucleus of Edinger-Westphal, the red nucleus, and from anterodorsal, anteroventral, and posteroventral tegmental nuclei. In the forebrain, diencephalospinal projections originate in the ventral thalamus, posterior tubercle, the pretectal region, and the interstitial nucleus of the fasciculus longitudinalis medialis. The most rostrally located cells of origin of descending spinal pathways were found in the suprachiasmatic nucleus, the preoptic area and a subpallial region in the caudal telencephalic hemisphere, probably belonging to the amygdaloid complex. Our data are discussed in an evolutionary perspective.
The Journal of Comparative Neurology 06/2001; 434(2):186-208. · 3.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: Adrenomedullin (AM) is a recently discovered peptide widely distributed in the mammalian brain. By using an antiserum specific for human AM, we have analyzed the localization of AM-like immunoreactivity in the brain and spinal cord of the anuran amphibian Rana perezi. Cell bodies immunoreactive (AMi) for AM were located in the dorsal, lateral and medial pallial regions, diagonal band of Broca, medial septum, and above and rostral to the anterior commissure. A large population of AMi neurons was located in the anterior preoptic area, suprachiasmatic nucleus and in the infundibular hypothalamus. The processes of these latter cells are part of the hypothalamo-hypophysial pathway to the neural and intermediate lobes. Labeled cells were observed in the pretectal region, posterior tubercle and the mesencephalic anteroventral tegmental nucleus. Strikingly, Purkinje cells in the cerebellum also showed AM immunoreactivity, albeit not all of these cells were equally stained. Additional cells were located in the parabrachial region, principal trigeminal sensory nucleus, reticular nuclei medius and inferior, and the intermediolateral gray of the spinal cord. Immunolabeled fibers were widespread throughout the brain and spinal cord of the frog. They were particularly abundant in the medial amygdala, hypothalamus, mesencephalic tectum, periventricular gray and spinal cord. The distribution pattern of AM-like immunoreactivity in the brain of the frog is very selective and does not correspond with the pattern observed for any other transmitter or neuroactive molecule. The wide distribution of this peptide strongly suggests that it may play a significant role in the multiple neuronal functions in the amphibian brain.
Journal of Chemical Neuroanatomy 04/2001; 21(2):105-23. · 2.48 Impact Factor