Cadmium speciation in cacao beans changes during a fermentation-like incubation

Cadmium (Cd) concentrations in cacao often exceed food limits. Recently, it was shown that cacao bean fermentation enhances Cd solubility, opening potential for Cd mitigation in cacao products. This study was set-up to identify changes in Cd speciation during fermentation. X-Ray absorption spectroscopy (XAS) complemented with speciation calculations, were used on samples collected from high and low Cd farms, that were subjected to a fermentation-like incubation that reached high temperatures (>45 °C) and acidic pH (<5). Incubation decreased nib Cd concentration up to a factor 1.5 and changed Cd complexation in high Cd beans from sulphur to oxygen ligands, likely due to pH changes. In beans with lower Cd concentrations, Cd was complexed before and after incubation with oxygen-ligands. A combination of pH changes and/or phytate breakdown may explain the migration of Cd outward from the nib. XAS and speciation calculations proved complimentary techniques and indicated similar speciation changes during fermentation.

Cadmium (Cd) distribution and soil-plant relationship in cacao farms in Costa Rica

The current cadmium (Cd) regulations in chocolate threaten the cacao supply chain in several Latin American countries. The factors contributing to Cd accumulation in cacao beans have been poorly studied in Central America. The objective of this research was to identify the location of Cd hotspots as well as soil properties and management practices influencing the Cd concentration in cacao beans. A survey was carried out and soil, leaf, and beans were sampled from 150 farms in the three principal cacao-producing regions in Costa Rica. Total soil Cd concentration ranged from <0.1 to 1.05 (average 0.22 mg kg-1) which is typical of uncontaminated soils. Bean Cd concentration ranged from 0.12 to 3.23 (average 0.56 mg kg-1) and 22% of the samples exceeded the selected threshold of 0.80 mg kg-1, located mostly in the Huetar Caribe and Huetar Norte regions. Variability in bean Cd concentration was better explained by total soil Cd and soil organic carbon (SOC) (R2 = 0.62, p < 0.05). In addition, bean Cd concentration was affected by leaf nutrient content and management practices. Leaf Zn and P were positively correlated with bean Cd while K and Mn were negatively correlated (p < 0.05). Farm altitude and orchard age were also negatively correlated with bean Cd. Overall, this study shows that bean Cd contamination does not reach the extent observed in other Latin American countries such as Ecuador, Colombia, or Honduras. Nevertheless, research is needed in hotspot areas to assess the feasibility of potential mitigation strategies, particularly the use of mineral or organic soil amendments, which may allow better for planning in existing plantations or the expansion into new cacao-growing areas in the country.

Monitoring cadmium concentrations in cacao: inter-laboratory variation and the effect of sample size on variability among ready-for-sale beans

Since the implementation of new EU limits on cadmium (Cd) in cacao-derived products, reliable measurements of the Cd concentration in cacao samples have become even more important. This study was set up to analyse the robustness of the measured Cd concentrations in cacao as affected by sampling strategy and by the laboratory receiving these samples. Six different homogenised cacao liquor samples were sent to 25 laboratories, mainly located in Latin America. On average, only 76% of the laboratories reported acceptable results per sample using internationally accepted criteria. More unreliable data was obtained when Atomic Absorption Spectroscopy (AAS) rather than Inductively Coupled Plasma (ICP) instruments were used or where concentrations were outside the calibration range. Subsequently, four commercial lots in Ecuadorian warehouses were sampled to identify the variation among beans, bags and replicate chemical analyses of ground samples. Simulations indicate that a composite sample should be made from at least 10 bags on a pallet and at least 60 beans should be ground prior to analysis to obtain an acceptable CV below 15%. This study shows that current Cd analyses in cacao on the market are neither sufficiently accurate nor precise and that more control on laboratory certifications is needed for reliable screening of Cd in cacao.

Soil amendments to reduce cadmium in cacao (Theobroma cacao L.): A comprehensive field study in Ecuador

The new EU regulations on maximum levels of cadmium (Cd) in cacao products sparked research on countermeasures to reduce Cd concentrations in cacao beans. This study was set up to test the effects of soil amendments in two established cacao orchards (soil pH 6.6 and 5.1) in Ecuador. Soil amendments included: 1) agricultural limestone at 2.0 and 4.0 Mg ha^-1 y^-1, 2) gypsum at 2.0 and 4.0 Mg ha^-1 y^-1 and 3) compost at 12.5 and 25 Mg ha^-1 y^-1, all amendments were applied at the surface during two subsequent years. Lime application increased the soil pH by one unit down to 20 cm depth. On the acid soil, leaf Cd concentrations decreased by lime application and the reduction factor gradually rose to 1.5 after 30 months. No effects of liming or gypsum on leaf Cd was found in the pH neutral soil. Compost application in the pH neutral soil reduced leaf Cd concentration with factor 1.2 at 22 months but that effect was absent at 30 months after application. Bean Cd concentrations were unaffected by any of the treatments at 22 months after application (acid soil) or 30 months (pH neutral soil) suggesting that any treatment effects on bean Cd might be even more delayed than in leaves. Soil columns experiments in the laboratory showed that mixing lime with compost largely enhanced the depth of lime penetration compared to lime only. Compost + lime reduced 10^-3 M CaCl₂ extractable Cd in soil without lowering extractable Zn. Our results suggest that soil liming has the potential to lower Cd uptake in cacao in the long term in acid soils and that the compost + lime treatment should be tested at field scale to accelerate the effects of the mitigation.

Revealing the pathways of cadmium uptake and translocation in cacao trees (Theobroma cacao L.): A 108Cd pulse-chase experiment

The pathways through which cadmium (Cd) is taken up and loaded into cacao beans (nibs) are yet to be revealed. Previous work suggested that Cd loading into cacao nibs may occur via direct xylem uptake rather than phloem-mediated redistribution from the leaves. A stable isotope (¹⁰⁸Cd) pulse-chase experiment was set up to identify the pathways of Cd loading into cacao nibs. The topsoil beneath two mature cacao trees in the field was enriched in ¹⁰⁸Cd via surface irrigation with a spiked solution. The increase in ¹⁰⁸Cd isotopic abundance (IA) in the plant tissues was followed up for 548 days after spiking. The ¹⁰⁸Cd IA in the plant tissues increased from natural abundance (0.89 %) to 7.0 % (tree A) and 10.1 % (tree B) at equilibrium. The tracer was taken up in the plant tissues in the order immature leaves > mature leaves > nibs in both trees, while tracer uptake in flowers and cherelles was less consistent between the trees. Half of the equilibrium ¹⁰⁸Cd IA was reached in the nibs at 191 days after spiking, significantly later than corresponding values for mature (151 days) and immature leaves (117 days). Pod maturation from flower stage takes about 6 months with most Cd entering the nibs at the last stage of development. The rather slow rise in the ¹⁰⁸Cd IA in the nibs compared to the leaves hence suggests that Cd in cacao nibs likely originates from phloem-redistribution from the stem, branches or mature leaves and not from direct root-to-nib transport via the xylem.

Heavy metal(loid)s contamination in water and sediments in a mining area in Ecuador: a comprehensive assessment for drinking water quality and human health risk

Elevated heavy metal(loid)s concentrations in water lower its quality posing a threat to consumers. This study aims to assess the human health risk caused by heavy metal(loid)s in tap water in Santa Rosa city, Ecuador, and the ecological risk of stream water and sediments in the Santa Rosa River. Concentrations of As, Cd, Cr, Cu, Ni, Pb, and Zn were evaluated in tap waters, stream waters, and sediment samples during the rainy and dry seasons. The Metal Index (MI), Geo-accumulation Index (I_geo), Potential Ecological Risk Index (PERI), and the levels of carcinogenic (CR) and non-carcinogenic risk (HQ) were determined. The results revealed severe pollution levels, mainly in Los Gringos and El Panteon streams, both tributaries of the Santa Rosa River, the primary water source for Santa Rosa inhabitants. More than 20% of the surface water samples showed severe contamination (MI > 6), and 90% of the tap water samples presented a MI value between 1 and 4, which indicates slight to moderate pollution. Drinking water displayed high levels of As, with 83% of the tap water samples collected from households in the dry season above the recommended concentration set by the World Health Organization and Ecuadorian legislation. The I_geo-Cd in the sediment samples was significantly high (I_geo > 3), and the PERI showed very high ecological risk (PERI > 600), with Cd as the main pollutant. HQ and CR were above the safe exposure threshold, suggesting that residents are at risk from tap water consumption, with As being the primary concern.

Reducing cadmium bioaccumulation in Theobroma cacao using biochar: basis for scaling-up to field

The intake of Cd-enriched food is the main Cd pathway for the nonsmoking population. In some cases, Cd bioaccumulates in edible plant parts which comprise risk to consumers, because of Cd is a harmful heavy metal that can cause potent environmental and health hazards. For instance, Cd enrichment of cacao seeds have led to Cd enrichment of cacao-based products. In Latin America and the Caribbean, Cd bioaccumulation in cacao seeds occurs in different regions with diverse edaphoclimatic conditions, which makes it difficult to select soil remediation alternatives. Limited resources require that potential amendments must be carefully investigated through laboratory and/or greenhouse conditions before scaling up to field experiments. In this study, we evaluated the effectiveness of four biochars: coffee-, quinoa-, and inoculated- and palm-biochar, derived from three feedstocks: coffee husk, quinoa straw, and oil palm residues, respectively. Biochars were applied in two rates (1 and 2% w/w) in two soils, one moderately acidic and one slightly alkaline (Cd-spiked and non-spiked). CCN-51 cacao plants were used for the greenhouse experiment. After 130 days, biometric parameters, the bioavailability of Cd in the soil, and the concentration of Cd and mineral nutrients in the plants were measured. Quinoa biochar at the 2% significantly decreased (P < 0.01), by ∼71%, bioavailable Cd in moderately acidic and slightly alkaline soils, and leaf-Cd by ∼48%. Soil pH, electrical conductivity, and effective cation exchange capacity were significantly (P < 0.01) correlated with bioavailable soil and leaf-Cd. Biochar characteristics, such as ash contents, basic cations content, and surface functional groups could be used as indicators for the selection of biochars to reduce Cd uptake by cacao. Additionally, application of quinoa derived biochar provided P and K, which could increase productivity to offset mitigation costs. Overall, incorporation of quinoa biochar at 2% rate is effective for lowering bioavailable Cd in different soil types which reduces leaf-Cd in cacao plants.

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Biochar ash content helps to increase soil pH and reduce Cd bioavailability.

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Quinoa biochar at 2% reduced up to 80% bioavailable Cd in moderately acidic and slightly alkaline soils.

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Quinoa biochar at 2% lowered, up to 48%, Cd concentration in cacao plants.

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Soil pH, CECe, and EC were significant and negative related to bioavailable and plant-Cd.

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Ash content could be used as a guide for selecting biochars for Cd remediation.

HB-EGF Plays a Pivotal Role in Mucosal Hyperplasia During Otitis Media Induced by a Viral Analog

Otitis media (OM), the most common childhood illness, can be caused by bacterial and/or viral infection. Hyperplasia of the middle ear (ME) mucosa is an important component of OM that contributes to its deleterious sequelae. Our previous research revealed that ME mucosal hyperplasia in bacterially induced OM was associated with expression of the heparin-binding epidermal growth factor (HB-EGF) gene, and that HB-EGF induced the proliferation of ME mucosal explants in culture. We used single-cell RNA-Seq to identify ME cells that express Hbegf and related genes involved in mediating responses to this factor. To determine the degree to which a viral infection might induce mucosal hyperplasia, and to assess the role of HB-EGF in hyperplasia in vivo, we used, Poly(I:C) to simulate a ME viral infection, Western blotting to confirm ME protein expression, and a specific inhibitor to block the effects of HB-EGF during OM. Genes for HB-EGF and its receptor were expressed in the ME primarily by epithelial, stromal and endothelial cells. Poly(I:C) induced prominent ME mucosal hyperplasia, peaking two days after ME injection. Immunostaining revealed that cleavage of proHB-EGF into its soluble form (sHB-EGF) was strongly induced in response to Poly(I:C). Inhibition of the sHB-EGF receptor dramatically reduced the hyperplastic response of the mucosa. The results demonstrate that a synthetic analog of viral double-stranded RNA interaction can induce OM including a strong proliferative response of the ME mucosa, independent of bacteria. They also indicate that HB-EGF is the dominant growth factor responsible for ME mucosal hyperplasia in vivo.

A transcytotic transport mechanism across the tympanic membrane

Drug treatments for middle ear diseases are currently delivered systemically, or locally after opening the impermeable tympanic membrane (TM). We previously used bacteriophage display to discover novel peptides that are actively transported across the intact TM, with a variety of transport rates. Peptide structures were analyzed for evidence regarding the mechanism for this unexpected transport, which was then tested by the application of chemical inhibitors. Primary sequences indicated that trans-TM peptides share one of two amino acid motifs. Secondary structures revealed that linear configurations associate with higher transport rates than coiled structures. Tertiary analysis indicated that the shared sequence motifs are prominently displayed at the free ends of rapidly transported peptide phage. The shared motifs were evaluated for similarity to known motifs. The highest probability matches were for protein motifs involved in transmembrane transport and exosomes. Overall, structural findings suggest that the shared motifs represent binding sequences. They also implicate transcytosis, a polarized cell transport mechanism consisting of endocytosis, transcellular transport, and exocytosis. Inhibitor studies indicated that macropinocytosis, retrograde transport through Golgi and exocytosis participate in transport across the TM, consistent with transcytosis. This process can be harnessed to noninvasively deliver therapeutics to the middle ear.

A Screen of Autophagy Compounds Implicates the Proteasome in Mammalian Aminoglycoside-Induced Hair Cell Damage

Introduction: Autophagy is a degradative pathway to safely break down and recycle dysfunctional cellular components. There is prior evidence of autophagy participation during hair cell (HC) damage. Our goal was to screen compounds targeting different aspects of autophagy for their effects on HC loss due to an ototoxic aminoglycoside, gentamicin (GM).

Methods: The SELLECKChem autophagy compound library, consisting of 154 compounds with defined autophagy inducing or inhibitory activity, was used for targeted screening in vitro model of ototoxicity. Organ of Corti from postnatal days 3–5 pou4f3/GFP transgenic mice (HCs express green fluorescent protein) were utilized. The organs were micro-dissected, and basal and middle turns divided into micro-explants individually placed into the single wells of a 96-well plate. Samples were treated with 200 μM of GM plus three dosages of tested compound and cultured for 72 h. Negative controls were treated with media only; positive ototoxicity controls were treated with GM only.

Results: The majority of the library compounds had no effect on GM-induced HC loss. However, 18 compounds exhibited a significant, protective effect, two compounds were protective at low dosage but showed enhanced GM toxicity at higher doses and one compound was toxic to HCs in the absence of GM.

Conclusions: This study evaluated many autophagy compounds that have not been tested previously on HCs. The disparate results obtained underscore the complexity of autophagy events that can influence HC responses to aminoglycosides, but also implicate the proteosome as an important damage mechanism. The screening results can serve as basis for further studies with protective compounds as potential drug targets.

Ecological and probabilistic human health risk assessment of heavy metal(loid)s in river sediments affected by mining activities in Ecuador

Gold mining is a significant source of metal(loid)s released into the environment. It is an issue of concern due to the potential adverse health effects associated with exposure to toxic elements. This study aimed to assess the ecological and human health risk caused by heavy metal(loid)s exposure in river sediments in Ponce Enríquez, one of the most important mining sites in Ecuador. Concentrations of As, Cd, Cu, Pb, and Zn were evaluated in 172 sediment samples to determine the Potential ecological risk (R_I) and the carcinogenic (CR) and non-carcinogenic risk (HQ). The human exposure to polluted sediments during recreational activities was computed using Bayesian probabilistic models. Residents were randomly surveyed to adjust the risk models to the specific population data. More than 68% of the sampling stations pose a severe As and Cd ecological risk index ([Formula: see text] > 320). Likewise, residents exposed to river sediments showed a non-acceptable carcinogenic risk by incidental ingestion, being As the primary contributor to overall cancer in both children and adults receptors. Moreover, non-carcinogenic risk through the incidental ingestion of sediments was above the safe limit for children. This is the first study conducted in a mining region in Ecuador that reveals the severe levels of ecological and human health risk to which the population is exposed. These results can be applied as a baseline to develop public health strategies to monitor and reduce the health hazards of the residents of mining communities.

Probabilistic multi-pathway human health risk assessment due to heavy metal(loid)s in a traditional gold mining area in Ecuador

Mining operations are important causes of environmental pollution in developing countries where mining waste management is not adequate. Consequently, heavy metal(loid)s are easily released into the environment, being a potential risk to human health. This study carries out a Bayesian probabilistic human health risk assessment, related to multi-pathway exposure to heavy metal(loid)s in a gold mining area in Southern Ecuador. Concentrations of As, Cd, Cr, Cu, Ni, Pb, and Zn in tap water, surface water, and soil samples, were analyzed to assess the potential adverse human health effects based on the Hazard Index (HI) and Total cancer risk (TCR). Adults and children residents were surveyed to adjust their exposure parameters to the site-specific conditions. Exposure to heavy metal(loid)s resulted in unacceptable risk levels for human health in the two age groups, both carcinogenic (TCR > 1 × 10-5) and non-carcinogenic (HI > 1) through ingestion of tap water and incidental ingestion of surface water. Sensitivity analysis showed that As concentration in waters and exposure frequency were the main contributors to risk outcome. Exposure to soil via accidental ingestion and dermal contact was below the safety limit, not posing a risk to human health. These findings can provide a baseline for the environmental management of the mining area and indicate the need for further research on As pollution in water and its implications on the health of the inhabitants of mining communities.

Surface soil liming reduces cadmium uptake in cacao seedlings but subsurface uptake is enhanced

Cadmium concentrations in cacao (Theobroma cacao L.) beans from South America often exceed trade limits. Liming soil is advocated as a remediation option, but amendments cannot be incorporated into the entire root zone without harming the trees. An experiment was set up to identify how Cd uptake varies within the root zone when surface and subsurface soil layers are either limed or not. The experiment used 22-cm-height pots with top and bottom layers using surface and subsurface soil samples from a cacao field. The potted soils were either surface limed or not or fully limed and layers spiked with stable ¹⁰⁸ Cd isotope in various combinations to trace the plant Cd provenance. The root distribution was neither affected by liming nor by soil source; 70% of the root biomass was present in the top layer. Plants grown on the fully limed surface soil had 1.7 times lower Cd concentrations in leaves than the unlimed treatments, whereas this concentration was 1.2 times lower when only the top layer was limed (surface soil used in both layers). The isotope dilution data showed that surface soil liming enhanced Cd uptake from the unlimed bottom layer compared with the unlimed soil, suggesting compensating mechanisms. The pots containing surface soil over subsurface soil also showed that compensating effect but, due to lower phytoavailable Cd in the subsurface soil, surface liming still effectively reduced foliar Cd. We conclude that liming might be a feasible mitigation strategy, but its effectiveness is limited when Cd phytoavailability remains untreated in the subsurface layer.

A kinase inhibitor screen identifies signaling pathways regulating mucosal growth during otitis media

Otitis media, the most common disease of childhood, is characterized by extensive changes in the morphology of the middle ear cavity. This includes hyperplasia of the mucosa that lines the tympanic cavity, from a simple monolayer of squamous epithelium into a greatly thickened, respiratory-type mucosa. The processes that control this response, which is critical to otitis media pathogenesis and recovery, are incompletely understood. Given the central role of protein phosphorylation in most intracellular processes, including cell proliferation and differentiation, we screened a library of kinase inhibitors targeting members of all the major families in the kinome for their ability to influence the growth of middle ear mucosal explants in vitro. Of the 160 inhibitors, 30 were found to inhibit mucosal growth, while two inhibitors enhanced tissue proliferation. The results suggest that the regulation of infection-mediated tissue growth in the ME mucosa involves multiple cellular processes that span the kinome. While some of the pathways and processes identified have been previously implicated in mucosa hyperplasia others are novel. The results were used to generate a global model of growth regulation by kinase pathways. The potential for therapeutic applications of the results are discussed.

Union of the European Phoniatricians' position statement on the exit strategy of phoniatric and laryngological services: staying safe and getting back to normal after the peak of coronavirus disease 2019 (issued on 25th May 2020)

BACKGROUND

The following position statement from the Union of the European Phoniatricians, updated on 25th May 2020 (superseding the previous statement issued on 21st April 2020), contains a series of recommendations for phoniatricians and ENT surgeons who provide and/or run voice, swallowing, speech and language, or paediatric audiology services.

OBJECTIVES

This material specifically aims to inform clinical practices in countries where clinics and operating theatres are reopening for elective work. It endeavours to present a current European view in relation to common procedures, many of which fall under the aegis of aerosol generating procedures.

CONCLUSION

As evidence continues to build, some of the recommended practices will undoubtedly evolve, but it is hoped that the updated position statement will offer clinicians precepts on safe clinical practice.

Soil properties and agronomic factors affecting cadmium concentrations in cacao beans: A nationwide survey in Ecuador

Recent cadmium (Cd) regulation in chocolate threatens the sustainability of cacao production in Southwest America. Cadmium contamination in cacao beans has not been assessed at a country level. A nationwide survey was conducted in Ecuador to identify the spatial distribution of Cd in cacao beans, as well as soil and agronomic factors involved. Paired soil and plant samples (pods and leaves) were collected at 560 locations. Information on agronomic practices was obtained through a prepared questionnaire for farmers. Total soil Cd averaged 0.44 mg kg^-1 which is typical for young and non-polluted soils. Mean Cd concentration in peeled beans was 0.90 mg kg^-1 and 45% of samples exceeded the 0.60 mg kg^-1 threshold. Bean Cd hotspots were identified in some areas in seven provinces. Multivariate regression analysis showed that bean Cd concentrations increased with increasing total soil Cd and with decreasing soil pH, oxalate-extractable manganese (Mn_ox) and organic carbon (OC) (R² = 0.65), suggesting that Cd solubility in soil mainly affects Cd uptake. Bean Cd concentration decreased a factor of 1.4 as the age of the orchard increased from 4 to 40 years. Bean Cd concentration was inconsistently affected by genotype (CCN-51 vs. Nacional), pruning or application of fertilizers. It is concluded that the relatively larger bean Cd concentrations in Ecuador are related to the high Cd uptake capacity of the plants combined with their cultivation on young soils, instead of Cd depleted weathered soils. Mitigation strategies should consider the application of amendments to modify such soil properties to lower soil Cd availability. There is scope for genetic mitigation strategy to reduce bean Cd, but this needs to be properly investigated.

A time-and-motion approach to micro-costing of high-throughput genomic assays

BACKGROUND

Genomic technologies are increasingly used to guide clinical decision-making in cancer control. Economic evidence about the cost-effectiveness of genomic technologies is limited, in part because of a lack of published comprehensive cost estimates. In the present micro-costing study, we used a time-and-motion approach to derive cost estimates for 3 genomic assays and processes-digital gene expression profiling (gep), fluorescence in situ hybridization (fish), and targeted capture sequencing, including bioinformatics analysis-in the context of lymphoma patient management.

METHODS

The setting for the study was the Department of Lymphoid Cancer Research laboratory at the BC Cancer Agency in Vancouver, British Columbia. Mean per-case hands-on time and resource measurements were determined from a series of direct observations of each assay. Per-case cost estimates were calculated using a bottom-up costing approach, with labour, capital and equipment, supplies and reagents, and overhead costs included.

RESULTS

The most labour-intensive assay was found to be fish at 258.2 minutes per case, followed by targeted capture sequencing (124.1 minutes per case) and digital gep (14.9 minutes per case). Based on a historical case throughput of 180 cases annually, the mean per-case cost (2014 Canadian dollars) was estimated to be $1,029.16 for targeted capture sequencing and bioinformatics analysis, $596.60 for fish, and $898.35 for digital gep with an 807-gene code set.

CONCLUSIONS

With the growing emphasis on personalized approaches to cancer management, the need for economic evaluations of high-throughput genomic assays is increasing. Through economic modelling and budget-impact analyses, the cost estimates presented here can be used to inform priority-setting decisions about the implementation of such assays in clinical practice.

Evaluation of soil amendments as a remediation alternative for cadmium-contaminated soils under cacao plantations

Elevated plant-available cadmium (Cd) in soils results in contamination to cacao (Theobroma cacao L) beans. Effectiveness of vermicompost and zeolite in reducing available Cd in three cacao-growing soils was studied under laboratory conditions. Sorption-desorption experiments were conducted in soils and amendments. Cadmium was added at 0 or 5 mg kg(-1) (spiked), then, amendments were incorporated at 0, 0.5, or 2 %. Amended soils were incubated at room temperature for 28 days. Plant-available Cd was determined using 0.01 M CaCl2 (WSE) and Mehlich 3 (M3) extraction procedures in subsamples taken from individual bags at six time intervals. Soils and amendments displayed different sorption characteristics and a better fit was attained with Freundlich model (R (2) > 0.82). Amendments were ineffective in reducing extractable Cd in non-spiked soils. In Cd-spiked soils, vermicompost at 2 % significantly reduced WSE-Cd (P < 0.01) from 3.36, 0.54, and 0.38 mg kg(-1) to values lower that instrument's detection in all the three soils and significantly diminished M3-extractable Cd (P < 0.05) from 4.62 to 4.11 mg kg(-1) in only one soil. Vermicompost at 0.5 % significantly decreased WSE-Cd (P < 0.01) from 3.04 and 0.31 to 1.69 and 0.20 mg kg(-1), respectively, in two soils with low sorption capacity for Cd. In contrast, zeolite failed to reduce WSE- or M3-extractable Cd in all studied soils. A negative correlation occurred between soil pH and WSE-Cd (r > -0.89, P < 0.01). The decrease in WSE-Cd appears to be associated with the increase in pH of the vermicompost-amended soils.

Chemical speciation of cadmium: An approach to evaluate plant-available cadmium in Ecuadorian soils under cacao production

Elevated concentration of cadmium (Cd) in cacao beans has raised serious concerns about the chocolate consumption on human health. Accumulation of Cd in cacao bean in southern Ecuador has been related to soil contamination. In this study, soil fractionation approach was used to identify available Cd pools in the soils and to correlate these Cd pools with bean Cd concentration and soil test indexes. The distribution of soil Cd fractions decreased in the order: oxidizable > acid-soluble > residual > reducible >> water-soluble (+exchangeable). Oxidizable and acid-soluble fractions accounted for 59 and 68% of the total recoverable Cd for the 0-5 and 5-15 cm soil depth, respectively. Acid-soluble fraction was closely related to bean-Cd, with correlation coefficients (r) of 0.70 and 0.81 (P < 0.01) for the 0-5 and 5-15 cm soil depth, respectively. Acid-soluble Cd was significantly correlated with 0.01 M HCl- (r = 0.99, P < 0.01) or Mehlich 3- extractable Cd (r = 0.97, P < 0.01). These results indicate that acid-soluble Cd fraction is an important part of available Cd pool. Since approximately 60% of Cd in the cacao-growing soils is related to the acid-soluble fraction and bound to organic matter, remediation of the contaminated soils should consider to the dynamics of soil pH and organic matter content.

Transcription factors with conserved binding sites near ATOH1 on the POU4F3 gene enhance the induction of cochlear hair cells

Overexpression of the transcription factor (TF) ATOH1 is known to induce the transformation of nonsensory cells in the organ of Corti into hair cells (HCs). Evaluating DNA 5Œ to the coding sequence of the pou4f3 gene, a target of ATOH1 in HCs, we identified in three regions containing clustered binding sites for ATOH1 and several other TFs that are expressed in developing inner ear sensory epithelia at the time of HC specification. These regions and sites are highly conserved across evolutionarily distant mammalian species. To test the hypothesis that the identified TFs act in combination to regulate the pou4f3 gene, we transfected by electroporation neonatal cochlear sensory epithelium from mice expressing green fluorescent protein (GFP) under the control of an 8.5-kb 5' pou4f3 genomic fragment. Plasmids encoding 21 TFs c-transfected with human ATOH1 (hATOH1). Cotransfection with hETV4, hNMYC, or hETS2 produced significantly more pou4f3/GFP and myosin 7A-positive nonsensory cells than hATOH1 alone. Co-transfection of hATOH1 with hHES1, hHES5, or hNEUROD1 reduced the effects of hATOH1. Chromatin immunoprecipitation (ChIP)of DNA from an inner ear cell line transfected with hNMYC,hETV4, or hETS2 revealed binding to a conserved region immediately proximal to the coding sequence. ChIP similarly revealed binding of hGATA3, hNMYC, and hTFE2 to a region several kilobases distal to the coding sequence, which we have previously shown to bind ATOH1. The results suggest that ATOH1 acts in concert with a subset of other TFs to directly regulate the pou4f3 gene and more broadly to regulate the HC phenotype.

Concentration of cadmium in cacao beans and its relationship with soil cadmium in southern Ecuador

Cadmium (Cd) content in cacao beans above a critical level (0.6 mg kg(-1)) has raised concerns in the consumption of cacao-based chocolate. Little is available regarding Cd concentration in soil and cacao in Ecuador. The aim of this study was to determine the status of Cd in both, soils and cacao plants, in southern Ecuador. Soil samples were collected from 19 farms at 0-5, 5-15, 15-30, and 30-50 cm depths, whereas plant samples were taken from four nearby trees. Total recoverable and extractable Cd were measured at the different soil depths. Total recoverable Cd ranged from 0.88 to 2.45 and 0.06 to 2.59, averaged 1.54 and 0.85 mg kg(-1), respectively in the surface and subsurface soils whereas the corresponding values for M3-extractable Cd were 0.08 to 1.27 and 0.02 to 0.33 with mean values of 0.40 and 0.10 mg kg(-1). Surface soil in all sampling sites had total recoverable Cd above the USEPA critical level for agricultural soils (0.43 mg kg(-1)), indicating that Cd pollution occurs. Since both total recoverable and M3-extractable Cd significantly decreased depth wise, anthropogenic activities are more likely the source of contamination. Cadmium in cacao tissues decreased in the order of beans>shell>>leaves. Cadmium content in cacao beans ranged from 0.02 to 3.00, averaged 0.94 mg kg(-1), and 12 out of 19 sites had bean Cd content above the critical level. Bean Cd concentration was highly correlated with M3- or HCl-extractable Cd at both the 0-5 and 5-15 cm depths (r=0.80 and 0.82 for M3, and r=0.78 and 0.82 for HCl; P<0.01). These results indicate that accumulation of Cd in surface layers results in excessive Cd in cacao beans and M3- or HCl-extractable Cd are suitable methods for predicting available Cd in the studied soils.

A mouse model of otitis media identifies HB-EGF as a mediator of inflammation-induced mucosal proliferation

Objective

Otitis media is one of the most common pediatric infections. While it is usually treated without difficulty, up to 20% of children may progress to long-term complications that include hearing loss, impaired speech and language development, academic underachievement, and irreversible disease. Hyperplasia of middle ear mucosa contributes to the sequelae of acute otitis media and is of important clinical significance. Understanding the role of growth factors in the mediation of mucosal hyperplasia could lead to the development of new therapeutic interventions for this disease and its sequelae.

Methods

From a whole genome gene array analysis of mRNA expression during acute otitis media, we identified growth factors with expression kinetics temporally related to hyperplasia. We then tested these factors for their ability to stimulate mucosal epithelial growth in vitro, and determined protein levels and histological distribution in vivo for active factors.

Results

From the gene array, we identified seven candidate growth factors with upregulation of mRNA expression kinetics related to mucosal hyperplasia. Of the seven, only HB-EGF (heparin-binding-epidermal growth factor) induced significant mucosal epithelial hyperplasia in vitro. Subsequent quantification of HB-EGF protein expression in vivo via Western blot analysis confirmed that the protein is highly expressed from 6 hours to 24 hours after bacterial inoculation, while immunohistochemistry revealed production by middle ear epithelial cells and infiltrating lymphocytes.

Conclusion

Our data suggest an active role for HB-EGF in the hyperplasia of the middle ear mucosal epithelium during otitis media. These results imply that therapies targeting HB-EGF could ameliorate mucosal growth during otitis media, and thereby reduce detrimental sequelae of this childhood disease.

Inhibition of MMP-2 but not MMP-9 influences inner ear spiral ganglion neurons in vitro

Matrix metalloproteinases (MMPs) play an important role in modeling of the extracellular matrix. There is increasing evidence that these proteases are important in neurite elongation and axonal guidance during development in the central nervous system and retina. Moreover, they are also expressed after acute injury and can be the key mediators of pathogenesis. However, the role of MMPs in the inner ear is largely unknown. Our group recently demonstrated that general inhibition of MMPs resulted in auditory hair cell loss in vitro. In the present study, we investigated the role of MMPs in inner ear spiral ganglion neuron (SGN) survival, neuritogenesis and neurite extension by blocking MMPs known to be involved in axonal guidance, neurite elongation, and apoptosis in other neuronal systems. Spiral ganglion (SG) explants from 5-day-old Wistar rats were treated with different concentrations of the general MMP inhibitor GM6001, a specific MMP-2 inhibitor, and a specific MMP-9 inhibitor, in vitro. The general inhibitor of MMPs and the specific inhibition of MMP-2 significantly reduced both the number of neurites that extended from SG explants, as well as the length of individual neurites. However, neither the general inhibitor of MMPs nor the specific inhibition of MMP-2 influenced SGN survival. Inhibition of MMP-9 had no influence on SGNs. The data suggest that MMPs, and more specifically MMP-2, influence the growth of developing afferent neurites in the mammalian inner ear in vivo.

Neural cell adhesion molecule L1 modulates type I but not type II inner ear spiral ganglion neurite outgrowth in an in vitro alternate choice assay

L1, a neural cell adhesion molecule of the immunoglobulin superfamily, is widely expressed in the nervous system and important in axonal outgrowth, guidance, synapse formation, and signaling. Gene deletion studies emphasize the significance of L1 during development of the central nervous system and L1 is crucial for the topographic targeting of retinal axons. In contrast to the brain and retina, the role of L1 in the inner ear is largely unknown. While previous studies have localized L1 in the developing inner ear of the chicken and mouse, its function during the innervation of the cochlea still remains largely unclear. We therefore investigated the functional role of L1 in the mammalian inner ear. Our aim was to determine whether or not L1 can modulate type I and/or type II spiral ganglion neuron outgrowth using an in vitro alternate choice assay. We found that L1, presented in stripe micropatterns, provide directional cues to neonatal rodent type I but not type II inner ear spiral ganglion neurites. The results suggest that L1 may play a role in axonal pathfinding of type I spiral ganglion dendrites toward their inner hair cell targets but not of type II toward the outer hair cells.

Changes in responsiveness of rat spiral ganglion neurons to neurotrophins across age: differential regulation of survival and neuritogenesis

Developmental changes in responsiveness of rat spiral ganglion neurons (SGNs) to neurotrophin-3 (NT-3) and brain-derived neurotrophic factor (BDNF) were examined using an explant culture system. Spiral ganglion (SG) explants at embryonic Day 18 (E18), postnatal Day 0 (P0), P5, P10 and P20 were cultured with the addition of either NT-3 or BDNF at various concentrations (0.1-100 ng/ml) and analyzed the dose-response characteristics of three parameters: SGN survival, the number of neurites emanating from the explants and the length of neurite extension. In E18 cultures, SGN survival and neurite number were enhanced more strongly by NT-3 than by the BDNF. As the explants became more mature, the effects of NT-3 decreased, whereas those of BDNF increased, peaking at P0. Although the intrinsic capacity of SGNs to produce and extend neurites declined considerably by P20, they still retained the capacity to respond to both NT-3 and BDNF. These temporal patterns in responsiveness of SGNs to neurotrophins correspond well to the expression pattern of the two neurotrophins in cochlear sensory epithelium in vivo and also correlate with the time course of developmental events in SGNs such as cell death and the establishment of mature hair cell innervation patterns.

New vaccine adoption: qualitative study of national decision-making processes in seven low- and middle-income countries

As more new and improved vaccines become available, decisions on which to adopt into routine programmes become more frequent and complex. This qualitative study aimed to explore processes of national decision-making around new vaccine adoption and to understand the factors affecting these decisions. Ninety-five key informant interviews were conducted in seven low- and middle-income countries: Bangladesh, Cameroon, Ethiopia, Guatemala, Kenya, Mali and South Africa. Framework analysis was used to explore issues both within and between countries. The underlying driver for adoption decisions in GAVI-eligible countries was the desire to seize GAVI windows of opportunity for funding. By contrast, in South Africa and Guatemala, non-GAVI-eligible countries, the decision-making process was more rooted in internal and political dynamics. Decisions to adopt new vaccines are, by nature, political. The main drivers influencing decisions were the availability of funding, political prioritization of vaccination or the vaccine-preventable disease and the burden of disease. Other factors, such as financial sustainability and feasibility of introduction, were not as influential. Although GAVI procedures have established more formality in decision-making, they did not always result in consideration of all relevant factors. As familiarity with GAVI procedures increased, questioning by decision-makers about whether a country should apply for funding appeared to have diminished. This is one of the first studies to empirically investigate national processes of new vaccine adoption decision-making using rigorous methods. Our findings show that previous decision-making frameworks (developed to guide or study national decision-making) bore little resemblance to real-life decisions, which were dominated by domestic politics. Understanding the realities of vaccine policy decision-making is critical for developing strategies to encourage improved evidence-informed decision-making about new vaccine adoptions. The potential for international initiatives to encourage evidence-informed decision-making should be realised, not assumed.

Ras/p38 and PI3K/Akt but not Mek/Erk signaling mediate BDNF-induced neurite formation on neonatal cochlear spiral ganglion explants

Neurotrophins participate in regulating the survival, differentiation, and target innervation of many neurons, mediated by high-affinity Trk and low-affinity p75 receptors. In the cochlea, spiral ganglion (SG) neuron survival is strongly dependent upon neurotrophic input, including brain-derived neurotrophic factor (BDNF), which increases the number of neurite outgrowth in neonatal rat SG in vitro. Less is known about signal transduction pathways linking the activation of neurotrophin receptors to SG neuron nuclei. In particular, the p38 and cJUN Kinase (JNK), mitogen-activated protein kinase (MAPK) pathways, which participate in JNK signaling in other neurons, have not been studied. We found that inhibition of Ras, p38, phosphatidyl inositol 3 kinase (PI3K) or Akt signaling reduced or eliminated BDNF mediated increase in number of neurite outgrowth, while inhibition of Mek/Erk had no influence. Inhibition of Rac/cdc42, which lies upstream of JNK, modestly enhanced BDNF induced formation of neurites. Western blotting implicated p38 and Akt signaling, but not Mek/Erk. The results suggest that the Ras/p38 and PI3K/Akt are the primary pathways by which BDNF promotes its effects. Activation of Rac/cdc42/JNK signaling by BDNF may reduce the formation of neurites. This is in contrast to our previous results on NT-3, in which Mek/Erk signaling was the primary mediator of SG neurite outgrowth in vitro. Our data on BDNF agree with prior results from others that have implicated PI3K/Akt involvement in mediating the effects of BDNF on SG neurons in vitro, including neuronal survival and neurite extension. However, the identification of p38 and JNK involvement is entirely novel. The results suggest that neurotrophins can exert opposing effects on SG neurons, the balance of competing signals influencing the generation of neurites. This competition could provide a potential mechanism for the control of neurite number during development.

Simvastatin protects auditory hair cells from gentamicin-induced toxicity and activates Akt signaling in vitro

Background

Inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, known as statins, are commonly used as cholesterol-lowering drugs. During the past decade, evidence has emerged that statins also have neuroprotective effects. Research in the retina has shown that simvastatin, a commonly used statin, increases Akt phosphorylation in vivo, indicating that the PI3K/Akt pathway contributes to the protective effects achieved. While research about neuroprotective effects have been conducted in several systems, the effects of statins on the inner ear are largely unknown.

Results

We evaluated whether the 3-hydroxy-3-methylglutaryl-coenzyme A reductase is present within the rat cochlea and whether simvastatin is able to protect auditory hair cells from gentamicin-induced apoptotic cell death in a in vitro mouse model. Furthermore, we evaluated whether simvastatin increases Akt phosphorylation in the organ of Corti. We detected 3-hydroxy-3-methylglutaryl-coenzyme A reductase mRNA in organ of Corti, spiral ganglion, and stria vascularis by reverse transcriptase-polymerase chain reaction (RT-PCR). Moreover, we observed a dose-dependent and significant reduction of hair cell loss in organs of Corti treated with simvastatin in addition to gentamicin, as compared to samples treated with gentamicin alone. The protective effect of simvastatin was reversed by addition of mevalonate, a downstream metabolite blocked by simvastatin, demonstrating the specificity of protection. Finally, Western blotting showed an increase in organ of Corti Akt phosphorylation after simvastatin treatment in vitro.

Conclusion

These results suggest a neuroprotective effect of statins in the inner ear, mediated by reduced 3-hydroxy-3-methylglutaryl-coenzyme A reductase metabolism and Akt activation.

Histone deacetylase inhibition enhances adenoviral vector transduction in inner ear tissue

Adenovirus vectors (AdVs) are efficient tools for gene therapy in many tissues. Several studies have demonstrated successful transgene transduction with AdVs in the inner ear of rodents [Kawamoto K, Ishimoto SI, Minoda R, Brough DE, Raphael Y (2003) J Neurosci 23:4395-4400]. However, toxicity of AdVs [Morral N, O'Neal WK, Rice K, Leland MM, Piedra PA, Aguilar-Cordova E, Carey KD, Beaudet AL, Langston C (2002) Hum Gene Ther 13:143-154.] or lack of tropism to important cell types such as hair cells [Shou J, Zheng JL, Gao WQ (2003) Mol Cell Neurosci 23:169-179] appears to limit their experimental and potential clinical utility. Histone deacetylase inhibitors (HDIs) are known to enhance AdV-mediated transgene expression in various organs [Dion LD, Goldsmith KT, Tang DC, Engler JA, Yoshida M, Garver RI Jr (1997) Virology 231:201-209], but their effects in the inner ear have not been documented. We investigated the ability of one HDI, trichostatin A (TSA), to enhance AdV-mediated transgene expression in inner ear tissue. We cultured neonatal rat macular and cochlear explants, and transduced them with an AdV encoding green fluorescent protein (Ad-GFP) under the control of a constitutive promoter for 24 h. In the absence of TSA, GFP expression was limited, and very few hair cells were transduced. TSA did not enhance transduction when applied at the onset of Ad-GFP transduction. However, administration of TSA during or just after Ad-GFP application increased GFP expression in supporting cells approximately fourfold. Moreover, vestibular hair cell transduction was enhanced approximately sixfold, and that of inner hair cells by more than 17-fold. These results suggest that TSA increases AdV-mediated transgene expression in the inner ear, including the successful transduction of hair cells. HDIs, some of which are currently under clinical trials (Sandor et al., 2002), could be useful tools in overcoming current limitations of gene therapy in the inner ear using Ad-GFP.

R443 – Organotypic Co-Culture of Spiral Ganglion and Organ of Corti

Problem

The ability to carry out in vitro culture of the auditory neuroepithelium has provided a powerful means of studying inner ear development. Recently, we have developed an organotypic culture technique that mimics the perinatal cochlea in vivo.

Methods

Using sterile microdissection and in vitro methods, we have been able to co-culture explanted spiral ganglion (SG) with separate explanted organ of Corti (oC) from different neonatal mice. The SG and oC were co-cultured in their correct anatomical positions. Success of the technique appears dependent on the use of culture plate inserts which prevent cellular attachment to the plastic culture surface and the resulting migration of neurons and hair cells (HCs).

Results

Using this technique, we have noted an average of 5–10 neurites per SG explant growing into the oC via the spiral lamina, following the anatomic pathway used during development. Confocal microscopy was used to visualize the contact area between dendritic growth and HCs. This demonstrates branching of neurites to multiple inner HCs as well as some branches extending to outer HCs. This pattern is consistent with early cochlear development. In contrast, with alternate techniques, neurites followed very different paths to the oC, sometimes innervating inner hair cells from the outer hair cell side of the epithelium.

Conclusion

This culture system offers a unique capacity to evaluate factors affecting spiral ganglion neurite guidance via manipulation of either the oC or SG.

Significance

The use of separated SG and oC will allow tissue from knockout mice to be paired with wild-type tissue, to explore fundamental mechanisms involved in cochlear innervation. Clinical implications include the ability to optimize SG ingrowth to cochlear implant electrodes offering tremendous potential for improving frequency resolution and dynamic range, as well as the ability to direct SG dendrites to regenerated/transplanted HCs as such advances develop.

Role of inhibitor of apoptosis protein in gentamicin-induced cochlear hair cell damage

Apoptotic cell death is considered to play a key role in gentamicin-induced cochlear hair cell loss. Inhibitor of apoptosis proteins (IAPs) are important regulators of apoptosis that can prevent activation of effector caspases. This study was designed to investigate the possible involvement of X-linked inhibitor of apoptosis protein (XIAP) in hair cell death due to gentamicin. Basal turn organ of Corti explants from postnatal day (p) p3 or p4 rats were maintained in tissue culture and were exposed to 35 muM gentamicin for up to 48 h. Effects of specific XIAP inhibitors on gentamicin-induced hair cell loss and caspase-3 activation were examined. XIAP inhibitors increased gentamicin-induced hair cell loss but an inactive analog had no effect. Caspase-3 activation was primarily observed at 36 or 48 h in gentamicin-treated hair cells, whereas caspase-3 activation peaked at 24-36 h when explants were treated with gentamicin and an XIAP inhibitor. The inhibitors alone had no effect on hair cells. Finally, a caspase-3 inhibitor decreased caspase-3 activation and hair cell loss induced by gentamicin and an XIAP inhibitor, but caspase-8 and -9 inhibitors did not. The results indicate that XIAP normally acts to decrease caspase-3 activation and hair cell loss during gentamicin ototoxicity, as part of a protective response to potentially damaging stimuli.

Laminin and fibronectin modulate inner ear spiral ganglion neurite outgrowth in anin vitro alternate choice assay

Extracellular matrix (ECM) molecules have been shown to function as cues for neurite guidance in various populations of neurons. Here we show that laminin (LN) and fibronectin (FN) presented in stripe micro-patterns can provide guidance cues to neonatal (P5) inner ear spiral ganglion (SG) neurites. The response to both ECM molecules was dose-dependent. In a LN versus poly-L-lysine (PLL) assay, neurites were more often observed on PLL at low coating concentrations (5 and 10 microg/mL), while they were more often on LN at a high concentration (80 microg/mL). In a FN versus PLL assay, neurites were more often on PLL than on FN stripes at high coating concentrations (40 and 80 microg/mL). In a direct competition between LN and FN, neurites were observed on LN significantly more often than on FN at both 10 and 40 microg/mL. The data suggest a preference by SG neurites for LN at high concentrations, as well as avoidance of both LN at low and FN at high concentrations. The results also support a potential model for neurite guidance in the developing inner ear in vivo. LN, in the SG and osseus spiral lamina may promote SG dendrite growth toward the organ of Corti. Within the organ of Corti, lower concentrations of LN may slow neurite growth, with FN beneath each row of hair cells providing a stop or avoidance signal. This could allow growth cone filopodia increased time to sample their cellular targets, or direct the fibers upward toward the hair cells.

Breast tumor resembling the tall cell variant of papillary thyroid carcinoma: a case report

The breast tumor resembling the tall cell variant of papillary thyroid carcinoma is a very unusual mammary carcinoma whose histologic and predominant nuclear features mimic a papillary thyroid carcinoma. We report the case of a 64-year-old woman who presented with a palpable nodule in the right breast. Fine needle aspiration disclosed abundant cellularity with isolated cells, sheets, and papillary formations of epithelial cells with nuclear grooves. Histologically, the neoplastic cells were arranged in a solid to papillary architecture, with follicular-like and cribriform areas. The cells were columnar to cuboidal with eosinophilic cytoplasm, clear chromatin, nuclear grooves, and occasional nuclear pseudoinclusions. Tumor cells were positive for cytokeratins, alpha and beta-estrogen receptors, progesterone receptor, androgen receptor, CEA, and bcl-2. We searched for BRAF mutations with negative results. Recognizing the cytologic and histologic characteristics of these peculiar mammary tumors that mimic thyroid carcinomas can avoid unnecessary clinical investigations.

Nematodes as indicators of wetland pollution

Since diversity suggests that changes in nematode populations or communities may be useful indicators of environmental changes including anthropogenic disturbances, in this study the following measurements were done: pH, predominant plant taxa, nematode density and diversity at different wetland points along La Tapera creek. A random sampling was carried out and data were subject to analysis t-test. In this work, neither the diversity nor the pH changed, however the latter was high and nematode density and taxa were small but without significative oscillations between stations. However, other population indices showed consistent differences between sites, which are pointing out environmental alteration throughout the creek. These preliminary results from the wetland present a description of nematode communities existing under a particular set of conditions that have not been reported previously.

Gastric permeability is not increased in children colonized by CagA-positive strains of Helicobacter pylori

BACKGROUND

Sucrose permeability has been used as a marker to detect gastric lesions in children. As CagA status of Helicobacter pylori is an important factor in determining the evolution of the gastric lesion, CagA-positive strains being more frequently associated with severe mucosal lesions, the aim of this study was to determine the prevalence of CagA-positive strains in Helicobacter pylori-colonized children and to evaluate whether the sucrose permeability test might discriminate between colonization by CagA-positive or negative strains.

PATIENTS AND METHODS

A series of 38 children (11.1+/-3.6 years) who required upper endoscopy for diagnostic purposes were included in the study. Endoscopy was carried out after the sucrose permeability test, and gastric biopsies were obtained for histologic examination, Helicobacter pylori detection by Giemsa staining and CLO-test, and determination of CagA status of the colonizing Helicobacter pylori strains by polymerase chain reaction.

RESULTS

Helicobacter pylori was detected in 26 subjects (68.4%) and of these, 16 (61.5%) were colonized by CagA-positive strains. The intensity of the histologic findings was significantly associated with the presence of Helicobacter pylori and with CagA status of the infecting strains (chi2=21.2, p=0.0017). However no significant difference in the urinary excretion of sucrose between children not colonized and children with CagA- negative or positive strains was observed (0.027% [0.012-0.035%]; 0.027% [0.016-0.047%] and 0.026% [0.016-0.038], median [range], respectively; Kruskal-Wallis analysis of variance F=0.75, p=0.69).

CONCLUSIONS

These results indicate that in Chile, about 60% of the Helicobacter pylori infected children are colonized by CagA-positive strains, in association with more intense lesions of the gastric mucosa, but that gastric permeability to sucrose does not discriminate between colonization by CagA-negative and positive strains of Helicobacter pylori.

Bedside markers of coronary artery patency and short-term prognosis of patients with acute myocardial infarction and thrombolysis

BACKGROUND

In this study we have evaluated the prognostic power of noninvasive markers of coronary artery reperfusion in patients with acute myocardial infarction who were treated with intravenous streptokinase.

METHODS

In 967 consecutive patients with acute myocardial infarction who were treated within 6 hours of symptoms, we analyzed the prognostic power of resolution of chest pain and ST-segment elevation >50% at 90 minutes, abrupt creatine kinase rise before 12 hours, and T-wave inversion in infarct-related electrocardiographic leads within the first 24 hours after thrombolysis.

RESULTS

Global in-hospital mortality rate was 12.0%. Each reperfusion marker was associated with improved outcome. Multivariate logistic regression analysis showed that 3 of the 4 markers of coronary artery reperfusion were significantly and independently associated to low in-hospital mortality rate. The presence of early T-wave inversion was associated with the lowest in-hospital mortality rate (odds ratio 0.25, confidence interval 0. 10-0.56). When all markers of coronary artery reperfusion were included in the regression model, T-wave inversion (odds ratio 0.29, confidence interval 0.11-0.68) and abrupt creatine kinase rise (odds ratio 0.36, confidence interval 0.16-0.77) continued to be significantly associated with better outcome.

CONCLUSION

A systemic analysis of noninvasive markers of coronary artery reperfusion can provide the clinician with an excellent tool to predict clinical outcomes when treating myocardial infarction.

Telomeres in the haemopoietic system

The limited life span of most blood cells requires the continuous production of cells, which in adults exceeds 10(12) cells/day. This impressive production of cells (approximately 4 x 10(16) cells over a lifetime) is achieved by the proliferation and differentiation of committed progenitor cells, which themselves are derived from a population of pluripotent stem cells with self-renewal potential. Paradoxically, the large majority of stem cells in adult bone marrow are quiescent cells. One possibility is that stem cells, like other somatic cells, have only a limited replicative potential (< 100 divisions). This hypothesis is supported by two key observations and the consideration that, in theory, 55 divisions can yield 4 x 10(16) cells. First, it was shown that 'candidate' stem cells purified from fetal and adult tissue showed dramatic functional differences in turn-over time and the ability to produce cells with stem cell properties, Second, these functional differences were found to correlate with a measurable loss of telomere repeats despite the presence of low but readily detectable levels of telomerase in all purified cell fractions. In order to address questions about the role of telomeres in normal and malignant haemopoiesis, we developed a quantitative fluorescence in situ hybridization technique. Here we review the characteristics of this novel tool to assess the number of telomere repeats at the end of individual chromosomes and provide an overview of recent observations.

Further studies on the recoupling effect of 6-ketocholestanol upon oxidative phosphorylation in uncoupled liver mitochondria

The effect of 6-ketocholestanol was studied on CCCP-induced uncoupling in liver mitochondria, submitochondrial particles and cytochrome oxidase proteoliposomes. It was found that 6-ketocholestanol prevents and reverses uncoupling induced by nM concentrations of CCCP on the three systems assayed. As it was reported on kidney mitochondrial membranes [Chavez et al. (1996) FEBS Lett. 379, 305-308], the recoupling effect caused by 6-ketocholestanol on submitochondrial particles and proteoliposomes could be due to a diminution of membrane fluidity.

Sucrose permeability in children with gastric damage and Helicobacter pylori infection

BACKGROUND

Increased permeability to sucrose has been recently shown to be a good marker of gastric mucosal damage in adults.

METHODS

This test was evaluated in 40 children consulting for recurrent abdominal pain and the results were correlated with endoscopic and histologic findings and with the presence of H. pylori.

RESULTS

The gastric mucosa was considered endoscopically normal in 31 children; 3 had duodenitis and 6 had mild gastritis. Abnormal endoscopic findings were associated with increased urinary sucrose excretion (MANOVA F = 7.30; p = 0.002). In the 6 children with mild gastritis, mean sucrose excretion was twice that of controls (0.060 +/- 0.024 vs. 0.029 +/- 0.018, respectively; p = 0.019) and significantly higher than the group with duodenitis (0.037 +/- 0.013; p = 0.038). The specificity and sensitivity of sucrose permeability test for detection of gastric damage were 90.3% and 83.3%, respectively. H. pylori was detected in 62.5% of children including all patients with mild gastritis, in 2 out of 3 with duodenitis and 17 out of 31 endoscopically normal controls. No differences in sucrose excretion were observed in relation with the presence of H. pylori or histological findings in the control group.

CONCLUSIONS

Urinary sucrose excretion is a good marker of mucosal gastric damage in children and may be used as a screening test in large groups of populations.