The effect of age on the pathogenesis of a highly pathogenic avian influenza (HPAI) H5N1 virus in Pekin ducks (Anas platyrhynchos) infected experimentally

Background  Highly pathogenic avian influenza (HPAI) H5N1 viruses have recently displayed increased virulence for wild waterfowl.

Objectives  To study the effect of host age on the shedding and tissue dissemination of a HPAI H5N1 virus in infected Pekin ducks.

Methods  Pekin ducks in two age‐matched groups (n = 18), 8 and 12 weeks old (wo) were each infected with 10⁶ EID₅₀/0·1 ml of HPAI A/turkey/Turkey/1/05 (H5N1, clade 2·2). Each day for 5 days, birds were monitored clinically, and cloacal and oropharyngeal swabs collected, before three birds from each group were selected randomly for post‐mortem examination. Tissue samples were collected for examination by real‐time RT‐PCR, histopathology and immunohistochemistry (IHC).

Results  Severe clinical signs, including incoordination and torticollis were observed in the 8 wo group resulting in 100% mortality by 4 dpi. Mild clinical signs were observed in the 12 wo group with no mortality. Real‐time RT‐PCR and IHC results demonstrated the systemic spread of H5N1 virus in birds of both age groups. Higher levels of virus shedding were detected in oropharyngeal swabs than in cloacal swabs, with similar levels of shedding detected in both age groups. Variations in level and temporal dissemination of virus within tissues of older ducks, and the presence of the virus in brain and heart were observed, which coincided with the appearance of clinical signs preceding death in younger birds.

Conclusions  These results are consistent with reports of natural infections of wild waterfowl and poultry possibly indicating an age‐related association with dissemination and clinical outcome in ducks following infection with H5N1 HPAI virus.

Kounis syndrome secondary to amoxicillin use in an asthmatic patient

A sixty-four year old man with a past history of hypercholesterolemia, asthma, food allergy, epilepsy and myocardial infarction was admitted to the emergency department because of a generalized erythema, nausea, vomiting, and chest pain after taking an oral dose of amoxicillin. Electrocardiography showed ST segment elevation in anterior leads. After coronary angiography, type 2 variant of Kounis syndrome was diagnosed. We present the first case of oral amoxicillin induced Kounis syndrome in an asthmatic patient with severe anaphylactic shock. The present report also shows that atopic people expressing an amplified mast cell degranulation may have more serious hemodynamic decompensation during hypersensitivity reactions. Case selective mast cell surface membrane stabilization should be considered a potential therapeutic strategy for people with food induced allergy, for atopic patients and for patients who have already experienced a first Kounis syndrome.

Replication, pathogenesis and transmission of pandemic (H1N1) 2009 virus in non-immune pigs

The declaration of the human influenza A pandemic (H1N1) 2009 (H1N1/09) raised important questions, including origin and host range [1], [2]. Two of the three pandemics in the last century resulted in the spread of virus to pigs (H1N1, 1918; H3N2, 1968) with subsequent independent establishment and evolution within swine worldwide [3]. A key public and veterinary health consideration in the context of the evolving pandemic is whether the H1N1/09 virus could become established in pig populations [4]. We performed an infection and transmission study in pigs with A/California/07/09. In combination, clinical, pathological, modified influenza A matrix gene real time RT-PCR and viral genomic analyses have shown that infection results in the induction of clinical signs, viral pathogenesis restricted to the respiratory tract, infection dynamics consistent with endemic strains of influenza A in pigs, virus transmissibility between pigs and virus-host adaptation events. Our results demonstrate that extant H1N1/09 is fully capable of becoming established in global pig populations. We also show the roles of viral receptor specificity in both transmission and tissue tropism. Remarkably, following direct inoculation of pigs with virus quasispecies differing by amino acid substitutions in the haemagglutinin receptor-binding site, only virus with aspartic acid at position 225 (225D) was detected in nasal secretions of contact infected pigs. In contrast, in lower respiratory tract samples from directly inoculated pigs, with clearly demonstrable pulmonary pathology, there was apparent selection of a virus variant with glycine (225G). These findings provide potential clues to the existence and biological significance of viral receptor-binding variants with 225D and 225G during the 1918 pandemic [5].

Effect of low doses of atorvastatin on the urinary peptide profile of kidney transplant patients

Statins are prescribed to reduce posttransplant dyslipidemia, which is frequent among kidney graft recipients. Their efficacy to reduce cholesterol levels has been accompanied by pleiotropic effects. Proteomics is the study of the expressed complement of proteins in tissues or biological fluids. It includes the identification of changes in proteins that occur in various states, eg, after drug administration. Our study objectives were: (1) to analyze the effect of atorvastatin (10 mg/d) on lipid profile, renal function, proteinuria, and inflammation parameters, such as C-reactive protein (CRP), and (2) to use proteomics to ascertain whether this treatment modified the patients' urinary peptide profiles seeking to understand the molecular actions of the drug. Urinary peptide profiles, lipids, renal function parameters (creatinine clearance), proteinuria, and CRP were determined in 39 patients at baseline and at 12 weeks after atorvastatin treatment (10 mg/d). The peptide fraction of each sample acquired using magnetic beads was analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Our results showed that treatment with atorvastatin produced a significant reduction in lipid profile, but did not modify renal function (creatinine clearance), proteinuria, or CRP. The proteomic study showed that statin treatment did not produce significant changes in the urinary peptidome, although there was a tendency for some peptides to increase or decrease after the treatment.

[Peripheral vitreoretinal traction exploration by Staurenghi 230 lens and HRA-II]

PURPOSE

To report a new technique to explore peripheral vitreous-retinal tractions in patients with acute posterior vitreous detachment.

MATERIAL AND METHODS

A population of 65 patients with acute posterior vitreous detachment was studied by panfunduscopic SLO 230 lens and HRA-II to detect peripheral retinal tears and vitreous-retinal tractions.

RESULTS

In our study, using indirect ophthalmoscopic exploration, we identified eleven patients with at least one retinal tear. HRA-II combined with the Staurenghi SLO 230 lens was capable of detecting 100% of these lesions. In addition, by means of this technology, we identified dark retinal zones that corresponded to peripheral retinal traction in six patients. None of the 65 patients complained of pain or photophobia during the exploration with this contact lens. Retinal tears and peripheral vitreous-retinal traction were treated by argon laser photocoagulation to create a firm chorioretinal adhesion. In two patients we found new retinal tears in the follow-up, with these new lesions detected by indirect ophthalmoscopy and HRA-II with SLO 230 lens.

CONCLUSION

HRA-II with the panfunduscopic Staurenghi SLO 230 lens can complement the exploration of patients with acute posterior vitreous detachment and can help to detect tractional zones that could develop into retinal tears.

Serum-dependent transcriptional networks identify distinct functional roles for H-Ras and N-Ras during initial stages of the cell cycle

BACKGROUND

Using oligonucleotide microarrays, we compared transcriptional profiles corresponding to the initial cell cycle stages of mouse fibroblasts lacking the small GTPases H-Ras and/or N-Ras with those of matching, wild-type controls.

RESULTS

Serum-starved wild-type and knockout ras fibroblasts had very similar transcriptional profiles, indicating that H-Ras and N-Ras do not significantly control transcriptional responses to serum deprivation stress. In contrast, genomic disruption of H-ras or N-ras, individually or in combination, determined specific differential gene expression profiles in response to post-starvation stimulation with serum for 1 hour (G0/G1 transition) or 8 hours (mid-G1 progression). The absence of N-Ras caused significantly higher changes than the absence of H-Ras in the wave of transcriptional activation linked to G0/G1 transition. In contrast, the absence of H-Ras affected the profile of the transcriptional wave detected during G1 progression more strongly than did the absence of N-Ras. H-Ras was predominantly functionally associated with growth and proliferation, whereas N-Ras had a closer link to the regulation of development, the cell cycle, immunomodulation and apoptosis. Mechanistic analysis indicated that extracellular signal-regulated kinase (ERK)-dependent activation of signal transducer and activator of transcription 1 (Stat1) mediates the regulatory effect of N-Ras on defense and immunity, whereas the pro-apoptotic effects of N-Ras are mediated through ERK and p38 mitogen-activated protein kinase signaling.

CONCLUSIONS

Our observations confirm the notion of an absolute requirement for different peaks of Ras activity during the initial stages of the cell cycle and document the functional specificity of H-Ras and N-Ras during those processes.

RasGRF1 disruption causes retinal photoreception defects and associated transcriptomic alterations

RasGRF1 null mutant mice display impaired memory/learning and their hippocampus transcriptomic pattern includes a number of differentially expressed genes playing significant roles in sensory development and function. Odour avoidance and auditory brainstem response tests yielded normal results but electroretinographic analysis showed severe light perception impairment in the RasGRF1 knockouts. Whereas no structural alterations distinguished the retinas of wild-type and knockout mice, microarray transcriptional analysis identified at least 44 differentially expressed genes in the retinas of these Knockout animals. Among these, Crb1, Pttg1, Folh1 and Myo7a have been previously related to syndromes involving retina degeneration. Interestingly, over-expression of Folh1 would be expected to result in accumulation of its enzymatic product N-acetyl-aspartate, an event known to be linked to Canavan disease, a human cerebral degenerative syndrome often involving blindness and hearing loss. Consistently, in vivo brain nuclear magnetic resonance spectroscopy identified higher levels of N-acetyl-aspartate in our RasGRF1-/- mice and immunohistochemical analysis detected reduced levels of aspartoacylase, the enzyme which degrades N-acetyl-aspartate. These studies demonstrate for the first time the functional relevance of Ras signalling in mammalian photoreception and warrant further analysis of RasGRF1 Knockout mice as potential models to analyse molecular mechanisms underlying defective photoreception human diseases.

Prevalence of serum antibodies to bovine herpesvirus-1 and bovine viral diarrhea virus in beef cattle in Uruguay

Our objective was to determine the prevalence of serum antibodies to bovine herpesvirus-1 (BHV-1) and bovine viral diarrhea (BVD) virus in beef cattle in Uruguay. A random sample of 230 herds selected with probability proportional to population size based on the number of cattle was chosen from a list frame of all registered livestock farms as of June 1999. Sera from up to 10 heifers, cows and bulls (up to 30 sera total per herd) were collected on selected farms between March 2000 and March 2001 and evaluated by means of enzyme-linked immunosorbent assays (ELISAs). Overall, 6358 serum samples were evaluated. We also collected data on previous diagnosis of BHV-1 or BVD infections and on the use of vaccines against these agents. The estimated prevalence of exposure to BHV-1 and BVD at the herd level for the Uruguayan beef population was 99% and 100%, respectively. Approximately 37% of beef cattle in Uruguay have been exposed to BHV-1 and 69% to BVD virus. Only 3% of beef herds in Uruguay regularly (typically, annually) use vaccines against either of these agents.

An immunohistochemical study of the tonsils in pigs with acute African swine fever virus infection

An immunohistochemical study of the tonsils was carried out to gain further insight in the pathogenesis of acute African swine fever (ASF). Twenty-one pigs were inoculated by intramuscular route with a highly virulent isolate of ASF virus and painlessly killed at 1-7dpi. Viral antigen was highly distributed in the tonsil from 3 to 4dpi and an increase in the number of monocyte-macrophages was very evident at the same days post inoculation. This phenomenon was observed together with an increase of the expression of proinflammatory cytokines (Tumour necrosis factor alpha and Interleukin-1 alpha) and the apoptosis of lymphocytes studied by the terminal deoxynucleotidyltransferase-mediated dUTP nick end labelling (TUNEL) technique and haemorrhages. With these results, we can conclude that the tonsil is suffering similar lesions than those observed in other lymphoid organs in acute African swine fever, even when the route of inoculation is the intramuscular and not oral-nasal.

Serum concentrations of C-reactive protein, serum amyloid A, and haptoglobin in pigs inoculated with African swine fever or classical swine fever viruses

OBJECTIVE

To determine serum concentrations of the selected acute-phase proteins (APPs) haptoglobin, serum amyloid A (SAA), and C-reactive protein (CRP) in pigs experimentally inoculated with classical swine fever (CSF) and African swine fever (ASF) viruses.

ANIMALS

8 crossbred (Large White x Landrace) 10-week-old pigs.

PROCEDURES

Pigs were allocated to 2 groups (4 pigs/group). One group was inoculated with the CSF virus Alfort 187 strain, whereas the other groupwas inoculated with the ASF virus Spain 70 isolate. Blood samples were collected at various time points. At the end of the study, pigs were euthanized and a complete necropsy was performed, including histologic and immunohistochemical analyses.

RESULTS

Serum concentrations of APPs increased in pigs inoculated with CSF and ASF viruses, which suggested an acute-phase response in the course of both diseases. The most noticeable increase in concentration was recorded for SAA in both groups (up to a 300-fold increase for CSF virus and an approx 40-fold increase for ASF virus), followed by CRP and then haptoglobin, which each had only 3- to 4-fold increases.

CONCLUSIONS AND CLINICAL RELEVANCE

Serum concentrations of APPs increased significantly in pigs inoculated with CSF and ASF viruses. However, differences were evident in serum concentrations of the proteins evaluated in this study.

[Exploration of the anterior segment by optical coherence tomography-3]

PURPOSE

To show the utility of optical coherence tomography (OCT) for studying the anterior segment and to explain its potential advantages as compared to ultrasonic biomicroscopy (UBM).

MATERIALS AND METHODS

We have described the findings in 5 patients with different pathologies of the anterior segment, all of whom were studied with UBM and OCT-3 adjusted for the anterior segment. There were 2 cases of an acute attack of closed angle glaucoma, 1 case of rubeosis iridis, 1 case of penetrating ocular trauma and 1 case of a primary stromal iris cyst.

RESULTS

OCT was found to be as useful as UBM in detecting angle closure in patients affected by an acute attack of glaucoma. In addition, OCT was more comfortable for the patient and faster than UBM in obtaining images, with the exploration mean time using OCT being less than five minutes while that with UBM was over ten minutes. OCT has also been demonstrated to be a safe and valuable non-contact examination in other iris pathologies such as rubeosis iridis, for checking the permeability of iridotomies and even for studying iris masses such as primary stromal iris cysts. In these entities OCT may reach a higher resolution than ultrasonic biomicroscopy.

CONCLUSION

OCT-3, with an adjustable focus, can obtain images from the scleral angle, as well as from other ocular structures like the iris, thus assisting in the diagnosis of numerous pathologies.

Cytokine Expression in Paraffin Wax-embedded Tissues from Conventional Calves

The cross-reactivity of antibodies against human tumour necrosis factor (TNF)alpha, interleukin (IL)-1alpha, IL-1beta and porcine IL-6, and the distribution of immunolabelled cells were evaluated on paraffin wax-embedded tissues from five healthy calves. The tissues were fixed in 10% buffered formalin or Bouin's solution and processed for structural studies and immunohistochemical studies by the avidin-biotin-peroxidase technique. Bouin's solution proved to be the more suitable fixative and Tween 20 the most effective antigen unmasking technique for increasing detectable antigenicity. Constitutive expression of TNFalpha, IL-1alpha, IL-1beta and IL-6 by different cell populations, mainly macrophage-like cells, was detected. Lymphoid organs displayed a higher presence of immunolabelled cells than did lung, liver or kidney. TNFalpha and IL-1alpha appeared as the predominant cytokines, especially in the gut-associated lymphoid tissue of the ileum and in the regional mesenteric lymph nodes. The results will facilitate investigation of the role of these cytokine-producing cells in inflammatory disease processes in calves.

Solubilization and characterization of a cell wall-bound trehalase from ascospores of the fission yeast Schizosaccharomyces pombe

The genome of the fission yeast Schizosaccharomyces pombe lacks sequence homologs to ath1 genes coding for acid trehalases in other yeasts or filamentous fungi. However, acid trehalase activity is present at the spore stage in the life cycle of the fission yeast. The enzyme responsible for this activity behaves as a surface enzyme covalently linked to the spore cell walls in both wild-type and ntp1 mutant strains devoid of neutral trehalase. Lytic treatment of particulated cell wall fractions allowed the solubilization of the enzyme into an active form. We have characterized this soluble enzyme and found that its kinetic parameters, optimum pH and temperature, thermal denaturation and salt responses are closely similar to other conventional acid trehalases. Hence, this rather unusual enzyme can be recognized as acid trehalase by its biochemical properties although it does not share genetic homology with other known acid trehalases. The potential role of such acid trehalase in the mobilization of trehalose is discussed.

Laser microdissection and microarray analysis of the hippocampus of Ras-GRF1 knockout mice reveals gene expression changes affecting signal transduction pathways related to memory and learning

We used manual macrodissection or laser capture microdissection (LCM) to isolate tissue sections of the hippocampus area of Ras-GRF1 wild type and knockout mice brains, and analyzed their transcriptional patterns using commercial oligonucleotide microarrays. Comparison between the transcriptomes of macrodissected and microdissected samples showed that the LCM samples allowed detection of significantly higher numbers of differentially expressed genes, with higher statistical rates of significance. These results validate LCM as a reliable technique for in vivo genomic studies in the brain hippocampus, where contamination by surrounding areas (not expressing Ras-GRF1) increases background noise and impairs identification of differentially expressed genes. Comparison between wild type and knockout LCM hippocampus samples revealed that Ras-GRF1 elimination caused significant gene expression changes, mostly affecting signal transduction and related neural processes. The list of 36 most differentially expressed genes included loci concerned mainly with Ras/G protein signaling and cytoskeletal organization (i.e. 14-3-3gamma/zeta, Kcnj6, Clasp2) or related, cross-talking pathways (i.e. jag2, decorin, strap). Consistent with the phenotypes shown by Ras-GRF1 knockout mice, many of these differentially expressed genes play functional roles in processes such as sensory development and function (i.e. Sptlc1, antiquitin, jag2) and/or neurological development/neurodegeneration processes affecting memory and learning. Indeed, potential links to neurodegenerative diseases such as Alzheimer disease (AD) or Creutzfeldt-Jacobs disease (CJD), have been reported for a number of differentially expressed genes identified in this study (Ptma, Aebp2, Clasp2, Hebp1, 14-3-3gamma/zeta, Csnk1delta, etc.). These data, together with the previously described role of IRS and insulin (known Ras-GRF1 activators) in AD, warrant further investigation of a potential functional link of Ras-GRF1 to neurodegenerative processes.

[Multidetector row CT in assessment of coronary artery calcification on hemodialisis]

Vascular calcification is a strong predictor of cardiovascular and all-cause mortality. Coronary artery calcification is more frequent, more extensive and progresses more rapidly in CKD than in general population. They are also considered a marker of coronary heart disease, with high prevalence and functional significance. It suggests that detection and surveillance may be worthwhile in general clinical practice. New non-invasive image techniques, like Multi-detector row CT, a type of spiral scanner, assess density and volume of calcification at multiple sites and allow quantitative scoring of vascular calcification using calcium scores analogous to those from electron-beam CT. We have assessed and quantified coronary artery calcification with 16 multidetector row CT in 44 patients on hemodialysis and their relationship with several cardiovascular risk factors. Coronary artery calcification prevalence was of 84 % with mean calcium score of 1580 +/- 2010 ( r 0-9844) with calcium score > 400 in 66% of patients. It was usually multiple, affecting more than two vessels in more than 50%. In all but one patient, left anterior descending artery was involved with higher calcium score level at right coronary artery. Advanced age, male, diabetes, smoking, more morbidity, cerebrovascular disease previous, and calcium-binders phosphate and analogous vitamin D treatment would seem to be associated with coronary artery calcification. Coronary artery calcification is very frequent and extensive, usually multiple and associated to modifiable risk factors in hemodialysis patients. Multi-detector-row CT seems an effective, suitable, readily applicable method to assess and quantify coronary artery calcification.

Proprioception in the ACL-ruptured knee: the contribution of the medial collateral ligament and patellar ligament. An in vivo experimental study in the cat

In the absence of anterior cruciate ligament (ACL), secondary restraints such as menisci, ligaments, and tendons restrict anterior knee laxity. Strain detection at these sites could define the contribution of this alternative signalling system to knee proprioception after ACL injury. The hypothesis in this study questions if measurements of anterior tibial translation (ATT) from surface strain gauges on the insertions of the medial collateral ligament (MCL) and the patellar tendon (PT) are sufficiently sensitive and specific to differentiate normal, stable knees from acutely unstable knees due to ACL section. Twelve cats received miniaturized strain gauges on the surface of MCL and PT distal insertions. A purpose-made receiver transformed into measurements any voltage variation obtained during passive knee flexion-extension and anterior tibial translation manoeuvres. Variables under evaluation included first peak latency, normalized amplitude, and slope of voltage along time. Femorotibial displacements were video recorded, digitized, and used as the ATT reference. The proposed system detected significant changes in the slope of the voltage/time signal, with higher specificity and sensitivity during ATT after experimental ACL section. Changes were not significant during flexion or extension. It was found that a pattern of earlier and more intense strain in MCL and PT distal insertions was found during ATT in the ACL deficient knee. Enhanced pattern recognition learning from these structures could be a future target for proprioceptive training after ACL injury.

[Good virological response to pegylated interferon alfa monotherapy of chronic hepatitis C infection in hemodialysis patient]

Liver disease caused by hepatitis C virus infection is associated to significant morbidity and mortality among patient with end stage renal disease on maintenance hemodialysis (HD). Therapy in these patients consists of Interferon, preferably pegylated Interferon (pIFN), thus Ribavirin (RBV) is not recommended for patients with impaired renal function, outside its use in controlled trials. We report a case of 35 years young woman on HD treatment, renal transplantation candidate with chronic hepatitis C virus infection, HCV RNA positive (by PCR), genotype 3a, moderate viral load, light increase of aminotransferases. Pegylated Interferon alfa-2a (135 mcg/weekly/SC) was initiated. She achieved HVC RNA negative within 12 weeks, following with pINF as monotherapy to complete 24 weeks (6 months). Sustained virologic response persisted to 24 and 48 weeks. Most important side effects were light detriment of anemia, moderate neutropenia and thombocytopenia, transitory elevation of transaminases and "flu-like" syndrome. Adverse events were well tolerated with total compliance with pIFN dose, no requiring reduce or stop the treatment. These findings confirm that hemodialysis patients with chronic hepatitis C respond well to pegylated IFN monotherapy and a long-term sustained virologic response is achieved, appears to be better tolerated with less side effects, so combination therapy with pINF plus ribavirin is not necessary in all cases.

Neuropathologic study of experimental classical swine fever

The aim of this study was to report on the lesions occurring in the central nervous system (CNS) during experimental classical swine fever (CSF) to clarify the spatial and chronologic distribution of the lesions and virus antigen in the CNS. To learn more about the pathogenetic mechanisms of the lesions during CSF in the CNS and to investigate the role of the virus in these mechanisms, cellular infiltrates and infected cells have been characterized. Twenty-eight pigs were inoculated with the virulent CSF virus isolate Alfort 187 and slaughtered from 2 to 15 postinoculation days; 4 animals of similar background served as a control group. Immunohistochemistry, electron microscopy, and the transferase-mediated deoxyuridine triphosphate nick-end labeling method were used to detect viral antigens and apoptosis. The results showed the presence of nonpurulent meningoencephalitis, occasional microhemorrhages, and apoptosis of the lymphocytes forming the perivascular and interstitital infiltrate in swine with CSF. Macrophages appeared to display little involvement in CNS lesions. The infected cells observed at the early stage of disease were lymphocytes and microglial cells in the rostral portion of the telencephalon, with infection of these cells in other areas in the next stages. The relationship between these lesions and the presence of viral antigen varied according to the type of lesion: hemorrhages were not associated with the presence of antigen in endothelial cells, but infiltrate-cell apoptosis was temporally and spacially associated to viral infection. However, the link between viral infection and the presence of cell infiltrate was far from clear.

Endogenous Lipid Pneumonia in a Dog

Endogenous lipid pneumonia has previously been diagnosed in dogs only once. This report describes a case in a dog with a persistent cough, in which the histological diagnosis was based on the presence of numerous foamy macrophages that filled the alveoli and contained small sudanophilic vacuoles. The appearance of endogenous lipid pneumonia in this animal was accompanied by Dirofilaria immitis infection and chronic bronchitis.

Fatal toxoplasmosis and concurrent Calodium hepaticum infection in Korean squirrels (Tanias sibericus)

Four Korean squirrels (Tanias siberius) imported in Spain from People's Republic of China died 2 days after their arrival at a pet shop. They had neurological signs associated with generalized toxoplasmosis involving brain, lungs, liver, and the heart. Toxoplasma gondii-like tachyzoites and tissue cysts were found in organs of all four squirrels. The protozoa stained positively with T. gondii polyclonal antibodies and were ultrastructurally similar to T. gondii. Calodium (Capillaria) hepaticum infection was found in the liver of one squirrel.

Retention of phosphorus by iron and aluminum-oxides-coated quartz particles

The capacity of adsorption of P on Fe and Al-oxides-coated quartz sand has been studied. The adsorption process has been described as Freundlich and Langmuir isotherms. In all cases Langmuir equation yields better fits than Freundlich equation. The covering quartz particles with Fe and Al oxides provide a high capacity adsorption and immobilization of P from natural and waste waters. The values obtained for adsorption, desorption and adsorption/desorption cycles show that Al oxides particles provide an excellent material for construction of a P removal system for waste waters. The characteristics of this material would allow the design of a complementary filtration system to reduce P levels in the effluent, reducing contamination risks and combating eutrophication of nearby watercourses.