Mature iPSC-derived astrocytes of an ALS/FTD patient carrying the TDP43A90V mutation display a mild reactive state and release polyP toxic to motoneurons

Astrocytes play a critical role in the maintenance of a healthy central nervous system and astrocyte dysfunction has been implicated in various neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). There is compelling evidence that mouse and human ALS and ALS/FTD astrocytes can reduce the number of healthy wild-type motoneurons (MNs) in co-cultures or after treatment with astrocyte conditioned media (ACM), independently of their genotype. A growing number of studies have shown that soluble toxic factor(s) in the ACM cause non-cell autonomous MN death, including our recent identification of inorganic polyphosphate (polyP) that is excessively released from mouse primary astrocytes (SOD1, TARDBP, and C9ORF72) and human induced pluripotent stem cells (iPSC)-derived astrocytes (TARDBP) to kill MNs. However, others have reported that astrocytes carrying mutant TDP43 do not produce detectable MN toxicity. This controversy is likely to arise from the findings that human iPSC-derived astrocytes exhibit a rather immature and/or reactive phenotype in a number of studies. Here, we have succeeded in generating a highly homogenous population of functional quiescent mature astrocytes from control subject iPSCs. Using identical conditions, we also generated mature astrocytes from an ALS/FTD patient carrying the TDP43A90V mutation. These mutant TDP43 patient-derived astrocytes exhibit key pathological hallmarks, including enhanced cytoplasmic TDP-43 and polyP levels. Additionally, mutant TDP43 astrocytes displayed a mild reactive signature and an aberrant function as they were unable to promote synaptogenesis of hippocampal neurons. The polyP-dependent neurotoxic nature of the TDP43A90V mutation was further confirmed as neutralization of polyP in ACM derived from mutant TDP43 astrocytes prevented MN death. Our results establish that human astrocytes carrying the TDP43A90V mutation exhibit a cell-autonomous pathological signature, hence providing an experimental model to decipher the molecular mechanisms underlying the generation of the neurotoxic phenotype.

Excessive release of inorganic phosphate by ALS/FTD astrocytes causes non-cell-autonomous toxicity to motoneurons

Non-cell-autonomous mechanisms contribute to neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), in which astrocytes release unidentified factors that are toxic to motoneurons (MNs). We report here that mouse and patient iPSC-derived astrocytes with diverse ALS/FTD-linked mutations (SOD1, TARDBP, and C9ORF72) display elevated levels of intracellular inorganic polyphosphate (polyP), a ubiquitous, negatively charged biopolymer. PolyP levels are also increased in astrocyte-conditioned media (ACM) from ALS/FTD astrocytes. ACM-mediated MN death is prevented by degrading or neutralizing polyP in ALS/FTD astrocytes or ACM. Studies further reveal that postmortem familial and sporadic ALS spinal cord sections display enriched polyP staining signals and that ALS cerebrospinal fluid (CSF) exhibits increased polyP concentrations. Our in vitro results establish excessive astrocyte-derived polyP as a critical factor in non-cell-autonomous MN degeneration and a potential therapeutic target for ALS/FTD. The CSF data indicate that polyP might serve as a new biomarker for ALS/FTD.

Widespread loss of the silencing epigenetic mark H3K9me3 in astrocytes and neurons along with hippocampal-dependent cognitive impairment in C9orf72 BAC transgenic mice

Background

Hexanucleotide repeat expansions of the G₄C₂ motif in a non-coding region of the C9ORF72 gene are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Tissues from C9ALS/FTD patients and from mouse models of ALS show RNA foci, dipeptide-repeat proteins, and notably, widespread alterations in the transcriptome. Epigenetic processes regulate gene expression without changing DNA sequences and therefore could account for the altered transcriptome profiles in C9ALS/FTD; here, we explore whether the critical repressive marks H3K9me2 and H3K9me3 are altered in a recently developed C9ALS/FTD BAC mouse model (C9BAC).

Results

Chromocenters that constitute pericentric constitutive heterochromatin were visualized as DAPI- or Nucblue-dense foci in nuclei. Cultured C9BAC astrocytes exhibited a reduced staining signal for H3K9me3 (but not for H3K9me2) at chromocenters that was accompanied by a marked decline in the global nuclear level of this mark. Similar depletion of H3K9me3 at chromocenters was detected in astrocytes and neurons of the spinal cord, motor cortex, and hippocampus of C9BAC mice. The alterations of H3K9me3 in the hippocampus of C9BAC mice led us to identify previously undetected neuronal loss in CA1, CA3, and dentate gyrus, as well as hippocampal-dependent cognitive deficits.

Conclusions

Our data indicate that a loss of the repressive mark H3K9me3 in astrocytes and neurons in the central nervous system of C9BAC mice represents a signature during neurodegeneration and memory deficit of C9ALS/FTD.

Cellular Metrology: Scoping for a Value Proposition in Extra- and Intracellular Measurements

The symptomatic irreproducibility of data in biomedicine and biotechnology prompts the need for higher order measurements of cells in their native and near-native environments. Such measurements may support the adoption of new technologies as well as the development of research programs across different sectors including healthcare and clinic, environmental control and national security. With an increasing demand for reliable cell-based products and services, cellular metrology is poised to help address current and emerging measurement challenges faced by end-users. However, metrological foundations in cell analysis remain sparse and significant advances are necessary to keep pace with the needs of modern medicine and industry. Herein we discuss a role of metrology in cell and cell-related R&D activities to underpin growing international measurement capabilities. Relevant measurands are outlined and the lack of reference methods and materials, particularly those based on functional cell responses in native environments, is highlighted. The status quo and current challenges in cellular measurements are discussed in the light of metrological traceability in cell analysis and applications (e.g., a functional cell count). An emphasis is made on the consistency of measurement results independent of the analytical platform used, high confidence in data quality vs. quantity, scale of measurements and issues of building infrastructure for end-users.

210 Horse allogeneic mesenchymal stem cells perform homing and ameliorate endometrial inflammation after induced endometritis of mares

Post-mating induced endometritis (PMIE) is an acute inflammatory response of the endometrium to spermatozoa, linked to an incapability of some mares to drain out the fluids associated with inflammation. This is of pivotal importance for reproductive success in mares. Mesenchymal stem cells (MSCs) are potential candidates for anti-inflammatory uterine therapies. Here, we aimed to study inflammatory markers in the endometrium of healthy mares and of those with induced endometritis, before and after intrauterine inoculation of MSCs, and to characterise their homing potential invivo in an induced endometritis horse model. Nine mares during their ovulatory season were selected after gynaecologic examination (absence of free liquid in the uterus, no polymorphonuclear leucocytes (PMNs) at cytology, negative bacteriology, and grade I in Kenney's scale on uterine biopsies). Mares were infused in the uterine body with 2mL of 500×106 spermmL−1 previously killed by repeated frozen-thawing cycles. At 3h, uteri were flushed with 250mL of sterile saline and the inflammatory response was monitored in the lavages and biopsies. Parameters measured included cytology, protein expression of inflammatory markers (supernatant) after lavage centrifugation (800×g, 10min), ELISA, and immunostaining for interleukin (IL)-6 and tumor necrosis factor alpha (TNFα). The mares were divided into three groups (3 mares each). Then, 24h after dead sperm challenge, group 1 received intrauterine infusion of 2×107 adipose MSC in 0.9% sterile saline; group 2, received the same amount of endometrial MSCs in the same vehicle; and group 3 received only saline. The volume of infusion in the uterine body was 20mL for all groups. Cells (passage 4) were previously labelled with 10μM Vybrant CFDA SE Cell Tracer Kit (ThermoFisher Scientific). After 48h, the same lavages, biopsies, and measurements as described above were performed. Additional biopsies were taken at Days 10 and 30 after intrauterine infusions. Biopsies were split in two, one for confocal microscopy and the other for quantitative PCR. Endometritis was induced in all mares, as judged by cytology and expression of protein markers of inflammation. After 48h, reduction in IL-6 and TNFα was detected by immunostaining of biopsies and confirmed by ELISA in the lavages, as well as by PCR. Homing was detected in all mares infused with MSC and it persisted at Days 10 and 30 after infusion. No homing was found in the control mares. As a result of these experiments, we conclude that inoculation of MSCs significantly reduced inflammation independently of the origin of the cells (adipose or endometrial). Both types of cells were nested in the endometrium at low quantities, although the number of cells actually detected at fixed time points was not quantified. Overall, we can propose that, given the number of homed cells detected and the marked decrease in inflammatory markers after inoculation of cells, MSCs exert their anti-inflammatory function preferentially by a paracrine mechanism and not necessarily by nesting and proliferation, although both events occur. Funding for this study was provided by Fondecyt 1150757.

αVβ3 Integrin regulates astrocyte reactivity

Background

Neuroinflammation involves cytokine release, astrocyte reactivity and migration. Neuronal Thy-1 promotes DITNC1 astrocyte migration by engaging α_Vβ₃ Integrin and Syndecan-4. Primary astrocytes express low levels of these receptors and are unresponsive to Thy-1; thus, inflammation and astrocyte reactivity might be necessary for Thy-1-induced responses.

Methods

Wild-type rat astrocytes (TNF-activated) or from human SOD1^G93A transgenic mice (a neurodegenerative disease model) were used to evaluate cell migration, Thy-1 receptor levels, signaling molecules, and reactivity markers.

Results

Thy-1 induced astrocyte migration only after TNF priming. Increased expression of α_Vβ₃ Integrin, Syndecan-4, P2X7R, Pannexin-1, Connexin-43, GFAP, and iNOS were observed in TNF-treated astrocytes. Silencing of β₃ Integrin prior to TNF treatment prevented Thy-1-induced migration, while β₃ Integrin over-expression was sufficient to induce astrocyte reactivity and allow Thy-1-induced migration. Finally, hSOD1^G93A astrocytes behave as TNF-treated astrocytes since they were reactive and responsive to Thy-1.

Conclusions

Therefore, inflammation induces expression of α_Vβ₃ Integrin and other proteins, astrocyte reactivity, and Thy-1 responsiveness. Importantly, ectopic control of β₃ Integrin levels modulates these responses regardless of inflammation.

Electronic supplementary material

The online version of this article (10.1186/s12974-017-0968-5) contains supplementary material, which is available to authorized users.

Chronic infusion of SOD1G93A astrocyte-secreted factors induces spinal motoneuron degeneration and neuromuscular dysfunction in healthy rats

Amyotrophic lateral sclerosis is a fatal neurodegenerative disease and studies in vitro show that motoneuron degeneration is triggered by non-cell-autonomous mechanisms. However, whether soluble toxic factor(s) released by mutant superoxide dismutase 1 (SOD1) expressing astrocytes induces death of motoneurons and leads to motor dysfunction in vivo is not known. To directly test this, healthy adult rats were treated with conditioned media derived from primary mouse astrocytes (ACM) that express human (h) SOD1^G93A (ACM-hG93A) via chronic osmotic pump infusion in the lumbar spinal cord. Controls included ACM derived from transgenic mice expressing hSOD1^WT (ACM-hWT) or non-transgenic mouse SOD1^WT (ACM-WT) astrocytes. Rats chronically infused with ACM-hG93A started to develop motor dysfunction at 8 days, as measured by rotarod performance. Additionally, immunohistochemical analyses at day 16 revealed reactive astrogliosis and significant loss of motoneurons in the ventral horn of the infused region. Controls did not show significant motor behavior alterations or neuronal damage. Thus, we demonstrate that factors released in vitro from astrocytes derived from ALS mice cause spinal motoneuron death and consequent neuromuscular dysfunction in vivo.

Chemotaxonomic discrimination of lichen species using an infrared chalcogenide fibre optic sensor: a useful tool for on-field biosourcing

Spectral analysis of lichen extracts obtained by MIR-FEWS permits to discriminate species and the identification of their major compounds. MIR-FEWS is a rapid, efficient and convenient tool for metabolic profiling.

Higher adenoma recurrence rate after left- versus right-sided colectomy for colon cancer

BACKGROUND

Patients with history of colonic resection for cancer have an increased risk of the development of metachronous malignant and premalignant lesions. Scanty data are reported on detection rates of premalignant lesions during colonoscopy surveillance in this setting.

OBJECTIVE

To assess the risk of metachronous precancerous lesions developing in patients with previous colonic surgery for cancer according to the resection type.

DESIGN

Retrospective study.

SETTING

Two academic centers in Italy.

PATIENTS

A total of 441 patients; 256 with previous left-sided colectomy (LCR) (LCR group) and 185 with previous right-sided colectomy (RCR) (RCR group).

INTERVENTIONS

Second surveillance colonoscopy.

MAIN OUTCOME MEASUREMENTS

Polyp and adenoma detection rates.

RESULTS

At least 1 adenoma was diagnosed in 76 of 256 patients (30% adenoma detection rate) and in 35 of 185 patients (19% adenoma detection rate) in the LCR and RCR groups, respectively (P=.014), yielding an odds ratio of 1.83 (95% confidence interval, 1.16-2.89). Corresponding figures for the polyp detection rate were 39% and 25%, respectively (P=.002; odds ratio 1.97; 95% confidence interval, 1.30-3.00).

LIMITATIONS

Retrospective study with colonoscopy baseline information missing.

CONCLUSIONS

Patients who have undergone LCR are at higher risk of the development of adenomas than those who have undergone RCR. If this result is confirmed by large prospective studies, surveillance programs could be targeted according to the type of colonic resection, with longer intervals for patients with previous RCR compared with LCR.

Reactive oxygen species trigger motoneuron death in non-cell-autonomous models of ALS through activation of c-Abl signaling

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease in which pathogenesis and death of motor neurons are triggered by non-cell-autonomous mechanisms. We showed earlier that exposing primary rat spinal cord cultures to conditioned media derived from primary mouse astrocyte conditioned media (ACM) that express human SOD1^G93A (ACM-hSOD1^G93A) quickly enhances Na_v channel-mediated excitability and calcium influx, generates intracellular reactive oxygen species (ROS), and leads to death of motoneurons within days. Here we examined the role of mitochondrial structure and physiology and of the activation of c-Abl, a tyrosine kinase that induces apoptosis. We show that ACM-hSOD1^G93A, but not ACM-hSOD1^WT, increases c-Abl activity in motoneurons, interneurons and glial cells, starting at 60 min; the c-Abl inhibitor STI571 (imatinib) prevents this ACM-hSOD1^G93A-mediated motoneuron death. Interestingly, similar results were obtained with ACM derived from astrocytes expressing SOD1^G86R or TDP43^A315T. We further find that co-application of ACM-SOD1^G93A with blockers of Na_v channels (spermidine, mexiletine, or riluzole) or anti-oxidants (Trolox, esculetin, or tiron) effectively prevent c-Abl activation and motoneuron death. In addition, ACM-SOD1^G93A induces alterations in the morphology of neuronal mitochondria that are related with their membrane depolarization. Finally, we find that blocking the opening of the mitochondrial permeability transition pore with cyclosporine A, or inhibiting mitochondrial calcium uptake with Ru360, reduces ROS production and c-Abl activation. Together, our data point to a sequence of events in which a toxic factor(s) released by ALS-expressing astrocytes rapidly induces hyper-excitability, which in turn increases calcium influx and affects mitochondrial structure and physiology. ROS production, mediated at least in part through mitochondrial alterations, trigger c-Abl signaling and lead to motoneuron death.

Molecular characterization of infectious bursal disease virus (IBDV) isolated in Argentina indicates a regional lineage

In Argentina, classical vaccines are used to control infectious bursal disease virus (IBDV); however, outbreaks of IBDV are frequently observed. This could be due to failures in the vaccination programs or to the emergence of new strains, which would be able to break through the protection given by vaccines. Hence, genetic characterization of the viruses responsible for the outbreaks that occurred in recent years is crucial for the evaluation of the control programs and the understanding of the epidemiology and evolution of IBDV. In this study, we characterized 51 field samples collected in Argentina (previously identified as IBDV positive) through the analysis of previously identified apomorphic sequences. Phylogenetic analysis of regVP2 showed that 42 samples formed a unique cluster (Argentinean lineage), seven samples were typical classical strains (one of them was a vaccine strain), and two belonged to the very virulent lineage (vvIBDV). Interestingly, when the analysis was performed on the regVP1 sequences, the field samples segregated similarly to regVP2; thus, we observed no evidence of a reassortment event in the Argentinean samples. Amino acid sequence analysis of regVP2 showed a particular pattern of residues in the Argentinean lineage, particularly the presence of T272, P289 and F296, which had not been reported before as signature sequences for any IBDV phenotype. Notably, the residue S254, characteristic of the antigenic variant, was not present in any of the Argentinean samples.

Observation of Room Temperature Photoluminescence from Asymmetric CuGaO2/ZnO/ZnMgO Multiple Quantum Well Structures

Asymmetric (CuGaO2/ZnO/ZnMgO) and symmetric (ZnMgO/ZnO/ZnMgO) multiple quantum well (MQW) structures were successfully fabricated using pulsed laser deposition (PLD) and their comparison were made. Efficient room temperature photoluminescent (PL) emission was observed from these MQWs and temperature dependent luminescence of asymmetric and symmetric MQWs can be explained using the existing theories. A systematic blue shift was observed in both MQWs with decrease in the confinement layer thickness which could be attributed to the quantum confinement effects. The PL emission from asymmetric and symmetric MQW structures were blue shifted compared to 150 nm thick ZnO thin film grown by PLD due to quantum confinement effects.

Astrocytes expressing mutant SOD1 and TDP43 trigger motoneuron death that is mediated via sodium channels and nitroxidative stress

Amyotrophic lateral sclerosis (ALS) is a fatal paralytic disorder caused by dysfunction and degeneration of motor neurons. Multiple disease-causing mutations, including in the genes for SOD1 and TDP-43, have been identified in ALS. Astrocytes expressing mutant SOD1 are strongly implicated in the pathogenesis of ALS: we have shown that media conditioned by astrocytes carrying mutant SOD1^G93A contains toxic factor(s) that kill motoneurons by activating voltage-sensitive sodium (Na_v) channels. In contrast, a recent study suggests that astrocytes expressing mutated TDP43 contribute to ALS pathology, but do so via cell-autonomous processes and lack non-cell-autonomous toxicity. Here we investigate whether astrocytes that express diverse ALS-causing mutations release toxic factor(s) that induce motoneuron death, and if so, whether they do so via a common pathogenic pathway. We exposed primary cultures of wild-type spinal cord cells to conditioned medium derived from astrocytes (ACM) that express SOD1 (ACM-SOD1^G93A and ACM-SOD1^G86R) or TDP43 (ACM-TDP43^A315T) mutants; we show that such exposure rapidly (within 30–60 min) increases dichlorofluorescein (DCF) fluorescence (indicative of nitroxidative stress) and leads to extensive motoneuron-specific death within a few days. Co-application of the diverse ACMs with anti-oxidants Trolox or esculetin (but not with resveratrol) strongly improves motoneuron survival. We also find that co-incubation of the cultures in the ACMs with Na_v channel blockers (including mexiletine, spermidine, or riluzole) prevents both intracellular nitroxidative stress and motoneuron death. Together, our data document that two completely unrelated ALS models lead to the death of motoneuron via non-cell-autonomous processes, and show that astrocytes expressing mutations in SOD1 and TDP43 trigger such cell death through a common pathogenic pathway that involves nitroxidative stress, induced at least in part by Na_v channel activity.

Trehalose delays the progression of amyotrophic lateral sclerosis by enhancing autophagy in motoneurons

Amyotrophic lateral sclerosis (ALS) is a fatal motoneuron disease with no current effective treatment. Accumulation of abnormal protein inclusions containing SOD1, TARDBP, FUS, among other proteins, is a pathological hallmark of ALS. Autophagy is the major degradation pathway involved in the clearance of damaged organelles and protein aggregates. Although autophagy has been shown to efficiently degrade ALS-linked mutant protein in cell culture models, several studies suggest that autophagy impairment may also contribute to disease pathogenesis. In this report, we tested the potential use of trehalose, a disaccharide that induces MTOR-independent autophagy, in the development of experimental ALS. Administration of trehalose to mutant SOD1 transgenic mice significantly prolonged life span and attenuated the progression of disease signs. These effects were associated with decreased accumulation of SOD1 aggregates and enhanced motoneuron survival. The protective effects of trehalose were associated with increased autophagy levels in motoneurons. Cell culture experiments demonstrated that trehalose led to mutant SOD1 degradation by autophagy in NSC34 motoneuron cells and also protected primary motoneurons against the toxicity of conditioned media from mutant SOD1 transgenic astrocytes. At the mechanistic level, trehalose treatment led to a significant upregulation in the expression of key autophagy-related genes at the mRNA level including Lc3, Becn1, Sqstm1 and Atg5. Consistent with these changes, trehalose administration enhanced the nuclear translocation of FOXO1, an important transcription factor involved in the activation of autophagy in neurons. This study suggests a potential use of trehalose and enhancers of MTOR-independent autophagy for the treatment of ALS.

Mutant SOD1-expressing astrocytes release toxic factors that trigger motoneuron death by inducing hyperexcitability

Amyotrophic lateral sclerosis (ALS) is a devastating paralytic disorder caused by dysfunction and degeneration of motoneurons starting in adulthood. Recent studies using cell or animal models document that astrocytes expressing disease-causing mutations of human superoxide dismutase 1 (hSOD1) contribute to the pathogenesis of ALS by releasing a neurotoxic factor(s). Neither the mechanism by which this neurotoxic factor induces motoneuron death nor its cellular site of action has been elucidated. Here we show that acute exposure of primary wild-type spinal cord cultures to conditioned medium derived from astrocytes expressing mutant SOD1 (ACM-hSOD1(G93A)) increases persistent sodium inward currents (PC(Na)), repetitive firing, and intracellular calcium transients, leading to specific motoneuron death days later. In contrast to TTX, which paradoxically increased twofold the amplitude of calcium transients and killed motoneurons, reduction of hyperexcitability by other specific (mexiletine) and nonspecific (spermidine and riluzole) blockers of voltage-sensitive sodium (Na(v)) channels restored basal calcium transients and prevented motoneuron death induced by ACM-hSOD1(G93A). These findings suggest that riluzole, the only FDA-approved drug with known benefits for ALS patients, acts by inhibiting hyperexcitability. Together, our data document that a critical element mediating the non-cell-autonomous toxicity of ACM-hSOD1(G93A) on motoneurons is increased excitability, an observation with direct implications for therapy of ALS.

Sertaconazole antifungal profile determined by a microdilution method versus nine topical substances against dermatophyte fungi

Antifungal activity and in vitro inhibition time for sertaconazole (STZ) and 9 other topical drugs, namely amorolfine, bifonazole, clotrimazole, econazole, ketoconazole, miconazole, oxiconazole, terbinafine, and tioconazole were determined against 124 clinical isolates of dermatophyte (12 species) fungi by the microdilution method in a liquid medium and the measurement of optical density. STZ's antifungal activity was not always affected by the tested dermatophyte genus, as was the case with the remaining antifungals. In vitro antifungal activity was at the same level for all the studied azole derivatives, but, in terms of partial inhibitory concentrations, STZ starts its in vitro inhibitory activity in a shorter time than the other tested substances, particularly in those incubation periods when the growth of the dermatophyte fungi was more developed.

Effects of the Rashba spin-orbit coupling on Hofstadter's butterfly

We study the effect of Rashba spin-orbit coupling on the Hofstadter spectrum of a two-dimensional tight-binding electron system in a perpendicular magnetic field. We obtain the generalized coupled Harper spin-dependent equations which include the Rashba spin-orbit interaction and solve for the energy spectrum and spin polarization. We investigate the effect of spin-orbit coupling on the fractal energy spectrum and the spin polarization for some characteristic states as a function of the magnetic flux α and the spin-orbit coupling parameter. We characterize the complexity of the fractal geometry of the spin-dependent Hofstadter butterfly with the correlation dimension and show that it grows quadratically with the amplitude of the spin-orbit coupling. We study some ground state properties and the spin polarization shows a fractal-like behavior as a function of α, which is demonstrated with the exponent close to unity of the decaying power spectrum of the spin polarization. Some degree of spin localization or distribution around +1 or -1, for small spin-orbit coupling, is found with the determination of the entropy function as a function of the spin-orbit coupling. The excited states show a more extended (uniform) distribution of spin states.

Trapping of BTX compounds by SiO2, Ag-SiO2, Cu-SiO2, and Fe-SiO2 porous substrates

Adsorption isotherms of BTX aromatic hydrocarbons (benzene, toluene, and p-xylene) on pristine (SiO2) and metal-doped (Ag-SiO2, Cu-SiO2 and Fe-SiO2) mesoporous and microporous substrates were measured and interpreted. These adsorbents were synthesized by the sol-gel procedure and their BTX sorption isotherms were obtained by the gas chromatographic technique (GC) at several temperatures in the range 423-593 K. The uptake amount of these hydrocarbon adsorptives on SiO2, Ag-SiO2, Cu-SiO2 and Fe-SiO2 mesoporous and microporous substrates was temperature-dependent. Additionally, the interaction of BTX molecules with the pore walls was evaluated by means of the corresponding isosteric heat of adsorption (qst), which was found to follow the next increasing sequence: qst (benzene)<qst (toluene)<qst (p-xylene). In general, the isosteric heat of adsorption of aromatic BTX compounds on microporous silica depicted an increasing tendency when the amount adsorbed was raised. This was a consequence of the existence of cohesive interactions (adsorbate-adsorbate) besides of the adhesive ones (adsorbate-adsorbent). The inclusion of silver or iron atoms within the SiO2 structure leads to an increased adsorbed amount of BTX molecules on the solid surface if compared with the Cu-SiO2 adsorbent. The adsorption of benzene, but not of toluene and p-xylene, molecules on pristine SiO2 is facilitated by the pore size of this substrate since this is the highest of all materials.

Specific pattern of flea antigen recognition by IgG subclass and IgE during the progression of papular urticaria caused by flea bite

BACKGROUND

Papular urticaria caused by flea bite presents clinical symptoms of a hypersensitivity reaction accompanied by skin lesions. However, the pattern of recognition by different antibody isotypes during the progression of the disease is unknown. This study evaluated variations in immunoglobulin E and immunoglobulin G subclass antibody responses to flea antigens during the progression of papular urticaria caused by flea bite

METHODS

Twenty-five patients clinically diagnosed with papular urticaria due to flea bite were included. Ten healthy children were included as controls. Recognition of antigens from complete flea body extract by patients and healthy controls was determined using immunoblot assays.

RESULTS

The results revealed that patients with 2-5 years of papular urticaria evidenced more IgE bands than those with shorter or longer durations of symptoms. In contrast, healthy children showed a predominance of immunoglobulin G1 and immunoglobulin G3. The majority of the recognised antigens were low molecular weight proteins (<90 kDa). Proteins with molecular weights between 16-20, 21-25, and 31-35 kDa showed different patterns of recognition between patients and healthy children.

CONCLUSION

The predominant specific antibody isotypes vary according to the time elapsed since the onset of symptoms in papular urticaria caused by flea bite.

Chlorobenzene, chloroform, and carbon tetrachloride adsorption on undoped and metal-doped sol-gel substrates (SiO(2), Ag/SiO(2), Cu/SiO(2) and Fe/SiO(2))

Adsorption isotherms of chlorobenzene, chloroform and carbon tetrachloride vapors on undoped SiO(2), and metal-doped Ag/SiO(2), Cu/SiO(2) and Fe/SiO(2) substrates were measured in the temperature range of 398-593K. These substrates were prepared from a typical sol-gel technique in the presence of metal dopants that rendered an assortment of microporous-mesoporous solids. The relevant characteristic of these materials was the different porosities and micropore to mesopore volume ratios that were displayed; this was due to the effect that the cationic metal valence exerts on the size of the sol-gel globules that compose the porous solid. The texture of these SiO(2) materials was analyzed by X-ray diffraction (XRD), FTIR, and diverse adsorption methods. The pore-size distributions of the adsorbents confirmed the existence of mesopores and supermicropores, while ultramicropores were absent. The Freundlich adsorption model approximately fitted the chlorinated compounds adsorption data on the silica substrates by reason of a heterogeneous energy distribution of adsorption sites. The intensity of the interaction between these organic vapors and the surface of the SiO(2) samples was analyzed through evaluation of the isosteric heat of adsorption and standard adsorption energy; from these last results it was evident that the presence of metal species within the silica structure greatly affected the values of both the amounts adsorbed as well as of the isosteric heats of adsorption.

Azole resistance in neonatal intensive care units in Argentina

The aim of this study was to determine the antifungal susceptibility profile and to detect resistant strains of yeast species isolated from neonates in Intensive Care Units. 92 strains isolated from 25 bloodstream cultures, 20 venous catheters, 23 suprapubic aspirations and 24 rectal swabs were studied. A Candida glabrata strain resistant to fluconazole was detected. Candida krusei appeared with its inherent resistance to fluconazole and showed cross-resistance to itraconazole. Two Candida albicans strains were resistant to azoles, one to itraconazole and the other to fluconazole with a high minimum inhibitory concentration (MIC) for itraconazole. All Candida tropicalis strains were susceptible to fluconazole but two of them showed resistance to itraconazole. The detection of resistant strains in neonates whom had not received previous antifungal therapy is noteworthy. The variations in the epidemiology of fungal infections observed and the antifungal resistance detected emphasize the importance of performing a regular surveillance to observe and to assess them.

Yeasts species distribution in Neonatal Intensive Care Units in northeast Argentina. Das Hefeartenspektrum in Neugeborenen-Intensivstationen in Nordost-Argentinien

The aim of this study was to determine the distribution and antifungal susceptibility profile of yeast species isolated from neonates in Neonatal Intensive Care Units (NICU) in northeast of Argentina. With this purpose 92 strains isolated from 25 blood stream cultures, 20 venous catheters, 23 suprapubic aspirations and 24 rectal swabs were studied. Candida albicans and C. parapsilosis appeared with similar frequencies (36%) in blood stream isolates. Candida parapsilosis (50%) was the most frequent catheters colonizer and C. tropicalis (54.2%) was the most frequent yeast associated with gastrointestinal tract colonization. Candida krusei, C. glabrata and Trichosporon cutaneum appeared with a very low frequency. A high rate of susceptibility to amphotericin B, fluconazole, and itraconazole was observed.

Gene Frequency Distribution of the BoLA-DRB3 Locus in Saavedreño Creole Dairy Cattle

The objective of this study is to describe the gene frequency distribution of the bovine lymphocyte antigen (BoLA)-DRB3 locus in Saavedreño Creole dairy cattle and to compare it with previously reported patterns in other cattle breeds. One hundred and twenty-five Saavedreño Creole dairy cattle were genotyped for the BoLA-DRB3.2 allele by polymerase chain reaction and restriction fragment length polymorphism. Twenty-two out of 53 previously identified BoLA-DRB3.2 alleles were detected, with gene frequencies ranging from 0.4 to 16.8%. Seventy percent of the variation corresponded to the seven most frequent alleles (BoLA-DRB3.2*7, *8, *11, *16, *27, *36, and *37). The studied population exhibits a high degree of expected heterozygosity (he = 0.919). The FIS index did not show significant deviation from Hardy-Weinberg equilibrium. However, the neutrality test showed an even gene frequency distribution. This result could be better explained assuming balancing selection instead of neutral or positive selection for one or a few alleles. In conclusion, the results of this study demonstrated that BoLA-DRB3.2 is a highly polymorphic locus in Saavedreño Creole dairy cattle, with significant variation in allele frequency among cattle breeds.

Comparative immunohistochemical study of normal, hyperplastic and neoplastic C cells of the rat thyroid gland

In rats, the frequency of spontaneous C-cell tumours is very high and is both age and gender dependent. The three specific stages of neoplastic progression can be distinguished into diffuse C-cell hyperplasia, focal C-cell hyperplasia and bona fide C-cell tumours. Based on this hypothetical model of human medullary thyroid carcinoma (MTC), we carried out an immunohistochemical study using different markers (calcitonin, calcitonin gene-related peptide, somatostatin and chromogranin) to verify the existence of any relationship between their expression and the successive steps of tumour development. We found a characteristic immunohistochemical staining pattern, particularly for calcitonin and somatostatin, which distinguishes C-cell tumours from both normal and hyperplastic C cells, with no differences related to the gender of the animals under study. Specifically, a considerable heterogeneity in calcitonin expression was only displayed by C-cell carcinomas, being less pronounced in C-cell adenomas. As for somatostatin, this regulatory peptide was found only in a minority of calcitonin-positive cells in normal and hyperplastic glands. However, in some C-cell adenomas and most C-cell carcinomas nearly all calcitonin-positive cells also coexpressed somatostatin. We conclude that rat C-cell neoplasms constitute a very particular tumour entity which shares many but not all immunohistochemical features with human MTC.