Formation of biomineral iron oxides compounds in a Fe hyperaccumulator plant: Imperata cylindrica (L.) P. Beauv.

We report a detailed work of composition and location of naturally formed iron biominerals in plant cells tissues grown in iron rich environments as Imperata cylindrica. This perennial grass grows on the Tinto River banks (Iberian Pyritic Belt) in an extreme acidic ecosystem (pH∼2.3) with high concentration of dissolved iron, sulphate and heavy metals. Iron biominerals were found at the cellular level in tissues of root, stem and leaf both in collected and laboratory-cultivated plants. Iron accumulated in this plant as a mix of iron compounds (mainly as jarosite, ferrihydrite, hematite and spinel phases) was characterized by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), Mössbauer spectroscopy (MS), magnetometry (SQUID), electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX; TEM-EDX; HRSTEM). A low fraction of phosphorous was detected in this iron hyperaccumulator plant. Root and rhizomes tissues present a high proportion of ferromagnetic iron oxide compounds. Iron oxides-rich zones are localized in electron dense intra and inter-cellular aggregates that appear as dark deposits covering the inner membrane and organelles of the cell. This study aims to contribute to a better understanding of the mechanisms of accumulation, transport, distribution of iron in Imperata cylindrica.

Synthesis and characterization of CoFe2O4 ferrite nanoparticles obtained by an electrochemical method.

Uniform size cobalt ferrite nanoparticles have been synthesized in one step using an electrochemical technique. Synthesis parameters such as the current density, temperature and stirring were optimized to produce pure cobalt ferrite. The nanoparticles have been investigated by means of magnetic measurements, Mössbauer spectroscopy, x-ray powder diffraction and transmission electron microscopy. The average size of the electrosynthesized samples was controlled by the synthesis parameters and this showed a rather narrow size distribution. The x-ray analysis shows that the CoFe(2)O(4) obtained presents a totally inverse spinel structure. The magnetic properties of the stoichiometric nanoparticles show ferromagnetic behavior at room temperature with a coercivity up to 6386 Oe and a saturation magnetization of 85 emu g(-1).

X-ray absorption and Mössbauer spectroscopies characterization of iron nanoclusters prepared by the gas aggregation technique.

Partially oxidized iron nanoclusters have been prepared by the gas-phase aggregation technique with typical sizes of 2-3 nm. This preparation technique has been reported to obtain clusters with interesting magnetic properties such as very large exchange bias. In this paper, a sample composition study carried out by Mössbauer and X-ray absorption spectroscopies is reported. The information reached by these techniques, which is based on the iron short range order, results to be an ideal way to have a characterization of the whole sample since the obtained data are an average over a very large amount of the clusters. In addition, our results indicate the presence of ferrihydrite, which is a compound typically ignored when studying this type of systems.

Direct 3D printing of zero valent iron@polylactic acid catalyst for tetracycline degradation with magnetically inducing active persulfate.

Catalyst stability has become a challenging issue for advanced oxidation processes (AOPs). Herein, we report an alternative method based on 3D printing technology to obtain zero-valent iron polylactic acid prototypes (ZVI@PLA) in a single step and without post etching treatment. ZVI@PLA was used to activate persulfate (PS) for the removal of Tetracycline (TC) in recirculating mode under two different heating methodologies, thermal bath and contactless heating promoted by magnetic induction (MIH). The effect of both heating methodologies was systematically analysed by comparing the kinetic constant of the degradation processes. It was demonstrated that the non-contact heating of ZVI by MIH reactivates the surface of the catalyst, renewing the surface iron content exposed to the pollutant solution, which makes the ZVI@PLA catalyst reusable up to 10 cycles with no efficiency reduction. In contrast, by using a conventional thermal bath, the kinetic constant gradually decreases over the 10 cycles, because of the superficial iron consumption, being the kinetic constant 5 times lower in the 10th run compared to MIH experiment. X-ray diffraction and Mössbauer spectroscopy confirmed the presence of metallic iron embedded in the ZVI@PLA prototype, whose crystalline structure remained unchanged for 10th cycles of MIH. Moreover, it was proven that with no contact heating technology at low magnetic fields (12.2 mT), the solution temperature does not increase, but only the surface of the catalyst does. Under these superficial heated conditions, kinetic rate is increased up to 0.016 min-1 compared to the value of 0.0086 min-1 obtained for conventional heating at 20 °C. This increase is explained not only by PS activation by iron leaching but also by the contribution of ZVI in the heterogeneous activation of persulfate.

Cerebral and conjunctival haemorrhages associated with von Willebrand factor deficiency and canine angiostrongylosis.

A case of angiostrongylosis is described in a 14-month-old golden retriever bitch. Conjunctival haemorrhage and neurological signs, referable to a space-occupying cerebral lesion, were associated with defective primary haemostasis caused by low levels of von Willebrand factor. Full clinical recovery followed treatment with desmopressin, fresh whole blood transfusion, fenbendazole and supportive care. The magnetic resonance image of the suspected organising haematoma is described. Similarities to the human condition, acquired von Willebrand syndrome, and a possible role for aberrant larval migration in haematoma formation are suggested.

Nicotinamide adenine dinucleotides mimic adenosine inhibition on synaptic transmission by decreasing glutamate release in rat hippocampal slices.

To assess the possible inhibitory action of nicotinamide adenine dinucleotides on the synaptic release of glutamate, electrophysiological and biochemical experiments were performed on rat hippocampal slices. Perfusion of adenosine, beta-nicotinamide adenine dinucleotide (NAD) or beta-nicotinamide adenine dinucleotide phosphate (NADP), reversibly inhibited the field excitatory postsynaptic potentials (fEPSP). Dose-response curves for their inhibitory action showed that these three substances had a similar potency in the range of concentrations from 0.1 microM to 100 microM. NADP and adenosine (100 microM) halved the K(+)-induced release of endogenous glutamate and aspartate, leaving gamma-amino-butyric acid (GABA) levels unchanged. 3-Isobutyl-1-methylxanthine (IBMX) 200 microM, an antagonist of the P1-purinoreceptors, antagonized the depressant effects of these coenzymes on both fEPSP and also on amino acid release. Based on these results we propose that nicotinamide adenine dinucleotides, similar to adenosine, inhibit excitatory synaptic transmission in the rat hippocampus by decreasing glutamate release from synaptic terminals.

Extracellular taurine increase in rat hippocampus evoked by specific glutamate receptor activation is related to the excitatory potency of glutamate agonists.

Taurine increases in brain extracellular space due to glutamate agonists were studied in vivo in the rat hippocampus using a dialysis technique, both in the absence and in the presence of glutamate receptor antagonists. Extracellular taurine levels increased during perfusions of agonists, listed in descending order of potency: kainate (KA), N-methyl-D-aspartate (NMDA), and quisqualate (QA). While taurine increases due to KA or QA perfusions were inhibited by 6,7-dinitro-quinoxaline-2,3-dione (DNQX), those induced by NMDA were abolished in the presence of 3-(carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP). These results indicate that increases in extracellular taurine levels evoked by NMDA, KA or QA in the rat hippocampus are caused by activation of their specific receptors. Field potentials, concomitantly recorded, were quickly abolished during NMDA or KA perfusions (0.1 mM), while QA (0.25 mM) induced the appearance of bicuculline-like evoked responses. Since taurine has been proposed as an osmoregulatory substance in the rat brain, and cell swelling is known to be an early component of glutamate agonists neurotoxicity, the increases in extracellular taurine reported here could be due to taurine released through an osmoregulatory process, counteracting the neurotoxic cellular oedema induced by glutamate agonists.

Synaptic transmission at the Schaffer-CA1 synapse is blocked by 6,7-dinitro-quinoxaline-2,3-dione. An in vivo brain dialysis study in the rat.

6,7-Dinitro-quinoxaline-2,3-dione (DNQX, FG 9041), a new non-N-methyl-D-aspartate (NMDA) glutamate receptor antagonist, has been reported to block non-NMDA receptor-mediated excitatory amino acidic responses in cultured neurons. We have perfused this compound in vivo through a dialysis fiber placed in the CA1 regions of anesthetized rats to test its effects on CA1 field-evoked potentials. Perfusions of 25-100 microM DNQX completely abolished field excitatory postsynaptic potentials (EPSP) and orthodromic population spikes (PS). This effect was dose-dependent and was reversed after washing with fresh Krebs-Ringer-bicarbonate. Antidromic population spikes and fiber volley potentials were unaffected by perfusions of DNQX up to 100 microM. On the contrary, perfusion of 50 microM D-2-amino-5-phosphonovalerate, a specific NMDA receptor antagonist, left unchanged both field EPSP and orthodromic PS. Results demonstrate that low-frequency transmission at the Schaffer collaterals-CA1 synapse is mediated by non-NMDA glutamate receptors.

Experimental egg-transmission of avian reovirus.

Two experiments with an avian reovirus (FDO isolant), serologically identical to the Fahey-Crawley and WVU 2937 isolants, provided conclusive proof that egg-transmission can occur. In the first experiment, 4-day-old chicken embryos were inoculated into the yolk sac with serial dilutions of virus and subsequently hatched. High virus doses killed all embryos, whereas low doses (14 or less plaque-forming units) allowed some embryos to hatch normally although infected. In the second experiment, virus was administered by the nasal, esophageal, and tracheal routes to twenty 15-month-old breeders. Eggs from -6 to 21 days and 58 to 64 days postinoculation were incubated. Three newly hatched chicks from eggs laid on successive days (17, 18, and 19 days postinoculation) and one infertile egg (61 days postinoculation) were found infected. Active infection, as judged by virus isolations from cloacal swabs, was over by the 17th day postinoculation.

Localization of avian reovirus (FDO isolant) in tissues of mature chickens.

Mature hens were exposed to a reovirus (FDO isolant) serologically related to the viral arthritis agent. Examination of 23 tissues from the respiratory, alimentary, and reproductive tracts and tendons from the hock joint revealed widespread infection 4 days after inoculation via the respiratory and alimentary tracts. By 14-15 days, infection had largely subsided but was still detectable in the tendons, oviduct, and alimentary tract of some birds. No infection was found at 30 days. Virus isolation attempts in chick kidney cultures were more reliable than fluorescent-antibody tests for detecting infection. None of 156 chicks hatched from eggs laid between 12 and 33 days postinoculation were infected.

Serological cross-reactivity of avian adenovirus serotypes in an enzyme-linked immunosorbent assay.

Fowl adenoviruses free of avian adenovirus-associated virus, representing 10 serotypes, were tested for cross-reactivity in an enzyme-linked immunosorbent assay (ELISA). All antigens and antisera prepared in chickens, along with uninfected control antigen and normal chicken serum, were reacted in a checkerboard pattern with ELISA. There was considerable cross-reactivity among all serotypes tested. Homologous reactions were generally, but not always, stronger than heterologous reactions. ELISA was about as sensitive as virus neutralization in detecting antibodies. The high sensitivity plus broad-spectrum reactivity should make ELISA a preferred test for the detection of adenovirus antibodies in poultry flocks.

Avian adenoviruses: effect on egg production, shell quality, and feed consumption.

Four avian adenovirus isolants (Indiana C, DPI-2, IBH-2, and B-3)were examined for pathogenicity in laying birds. None affected shell quality, and only one (IBH-2) had even a minimal effect on egg production (faster decline). Of three isolants tested (Indiana C, DPI-2, and IBH-2), only IBH-2 caused feed intake to be reduced. No other clinical signs were observed during these experiments. Egg transmission, virus excretion, and antibody production were found to mimic patterns reported for serotype-1 avian adenoviruses.

Concurrent torsion of the right cranial and right middle lung lobes in a whippet.

A four-year-old, entire male whippet was presented with a three-day history of lethargy, inappetence, occasional retching, a soft cough and intermittent episodes of haemoptysis. Clinical and laboratory findings, and thoracic radiographic and ultrasonographic studies suggested a diagnosis of lung lobe torsion. A concurrent lung lobe torsion of the right cranial and right middle lung lobes was confirmed at exploratory thoracotomy. Management included resection of both the affected lung lobes. No obvious underlying aetiology for the condition was apparent. The dog made a full recovery from the procedure and at the time of writing (11 months postoperatively) was reported to be well, exercising normally and showing no breathing abnormalities.

Vascular hamartoma within the flexor muscles of the left carpus in a dog.

A three-year-old male bearded collie was presented with a history of left thoracic limb lameness and a fluctuant non-painful swelling within the flexor tendons of the left carpus. Investigations included ultrasonography, laboratory analysis of fluid aspirated from the lesion and positive contrast radiography. Treatment involved surgical resection of the lesion from the local flexor muscles of the carpus. Histologically, the resected tissue was considered to represent a vascular hamartoma associated with the pronator quadratus muscle.

[Hepatitis B virus markers in alcoholics: clinical importance]. / Marcadores de virus de la hepatitis B en alcohólicos: importancia clínica.

The prevalence of HBV markers is greater in alcoholics, with or without liver disease, than in general population. The high prevalence of HBsAg carriers in alcoholics suggests an inadequate immune response or a different expression of the HBV genome. Some studies suggest that in alcoholics HBsAg carriers, the HBV plays an important role in the progression of the liver disease, while others indicate that continuous alcohol consumption could intensify the liver damage caused by HBV. Active HBV infection has been demonstrated in alcoholics, even in absence of usual serologic markers. Finally, the integration of HBV in the hepatocites is frequent in alcoholics with liver disease; this could have importance in the development of hepatocellular carcinoma.

[Epidemiology of peptic ulcer at the "Salvador Zubirán" National Institute of Nutrition]. / Epidemiología de la úlcera péptica en el Instituto Nacional de la Nutrición "Salvador Zubirán".

In order to know the variations on the epidemiology of peptic ulcer in the INNSZ we have studied 850 patients with peptic ulcer between January 1980 and July 1988, in comparison with 1,000 patients studied in 1960 and in a similar group in 1980. In the 1988 group, we analyze the characteristics such as: sex, age, localization of the ulcer, occupation and habits and we compare them with a control group of 850 patients studied in the same time in the INNSZ. According with these results, we can appreciate that the duodenal ulcer (DU) has decreased from 77.5% in 1960 to 57.5% in 1988. The difference is statistic significant (p less than 0.005). About gastric ulcer (GU), its frequency has been increased from 17.6% to 29.6% with a statistic significant difference (p less than 0.005). The esophageal ulcers has been increased too. Other observation is that the general proportion of ulcers in the hospital population has been decreased from 7% in 1960 to 3.6% in 1988.

Profilaxis preexposición al VIH. Una controversia no demorable / No disponible

No disponible

Internal iron biomineralization in Imperata cylindrica, a perennial grass: chemical composition, speciation and plant localization.

* The analysis of metal distribution in Imperata cylindrica, a perennial grass isolated from the banks of Tinto River (Iberian Pyritic Belt), an extreme acidic environment with high content in metals, has shown a remarkable accumulation of iron. This property has been used to study iron speciation and its distribution among different tissues and structures of the plant. * Mossbauer (MS) and X-ray diffraction (XRD) were used to determine the iron species, scanning electron microscopy (SEM) to locate iron biominerals among plant tissue structures, and energy-dispersive X-ray microanalysis (EDAX), X-ray fluorescence (TXRF) and inductively coupled plasma emission spectroscopy (ICP-MS) to confirm their elemental composition. * The MS spectral analysis indicated that iron accumulated in this plant mainly as jarosite and ferritin. The presence of jarosite was confirmed by XRD and the distribution of both minerals in structures of different tissues was ascertained by SEM-EDAX analysis. * The convergent results obtained by complementary techniques suggest a complex iron management system in I. cylindrica, probably as a consequence of the environmental conditions of its habitat.

Role of endogenous taurine on the glutamate analogue-induced neurotoxicity in the rat hippocampus in vivo.

The glutamate analogues N-methyl-D-aspartate (NMDA), kainic acid (KA), and quisqualic acid (QA), prepared in different hypertonic media, were perfused in vivo in the hippocampal CA1 field of rats using a microdialysis technique. Extracellular taurine levels, estimated after analysis of the taurine content of dialysates, increased during perfusion of all three agonists but varied according to the osmolarity of the medium. The NMDA-induced increase in extracellular taurine content was only slightly inhibited by perfusion of 150 and 300 mM sucrose. The KA-evoked increase was partially dependent on extracellular osmolarity, because addition of 50 and 150 mM sucrose caused a dose-dependent inhibition that was not augmented using higher sucrose concentrations. QA caused a taurine increase that was totally abolished by addition of 50 mM sucrose. These results indicate that the rise in extracellular taurine level elicited by QA and part of the increase elicited by KA are probably due to a release caused by the cellular swelling that these substances evoke, a finding substantiating the previously proposed osmoregulatory role of taurine. However, almost all the increase in extracellular taurine content caused by NMDA and all the osmotically insensitive part of the KA-evoked rise cannot be explained as release triggered by cell swelling and may reflect a function of taurine other than osmoregulation.