Epidemiology of candidemia in Spain - Multicenter study

The results of the epidemiological study on candidemias with the highest number of cases carried out in Spain is presented. This study is included in the Epidemiological Survey of Candidemia in Europe supported by the ECMM in which another five countries take part. In the Spanish study, 19 hospitals participated, 290 candidemia episodes were analysed (80 in children under 15 years and 210 in adults), 293 strains of yeasts being isolated. Both in children and in adults, the risks factors more frequently observed were the intravenous catheter and previous antibiotic therapy. In adults, the most habitual underlying disease was the solid tumor and, in children, hematological diseases. Candida albicans was the most prevalent species isolated in adults (46.1%) and Candida parapsilosis in children (50%). As part of the therapy, the intravenous line was removed and antifungal treatment was prescribed to 74% and 92.5% of children, respectively and to 43.8% and 73.8% of adults. The antifungal agent of election in adults was fluconazole (54.8%) and liposomal amphotericin B (58.1%) in children. The global mortality of the study was 38.9%, which for ages was major in adults (41.4%) than in children (38.7%). The geographical distribution of the isolated species was homogeneous, C. albicans being the predominant species, with the exception of Galicia and Extremadura where C. parapsilosis was the most frequent.     

Prevalence of Human Papillomavirus (HPV) in Oesophageal Squamous Cell Carcinoma in Relation to Anatomical Site of the Tumour

Background

The prevalence and role of human papillomavirus (HPV) in the aetiology of oesophageal squamous cell carcinoma is uncertain. Based on the presence of HPV in the oral cavity and its causal association with squamous cell carcinoma of the oropharynx, we hypothesised that HPV is more strongly associated with proximal than distal oesophageal squamous cell carcinoma.

Methods

A population-based study comparing HPV infection in relation to tumour site in patients diagnosed with oesophageal squamous cell carcinomas in the Stockholm County in 1999–2006. Multiplex polymerase chain reaction genotyping (PCR) with Luminex was conducted on pre-treatment endoscopic biopsies to identify type specify HPV. Carcinogenic activity of HPV was assessed by p16^INK4a expression. Multivariable logistic regression was used to calculate odds ratios and 95% confidence intervals.

Results

Among 204 patients, 20 (10%) had tumours harbouring HPV DNA, almost all (90%) of HPV high-risk type, mainly HPV16. Tumours containing HPV were not overrepresented in the upper compared to the middle or lower third of the oesophagus (odds ratio 0.6, 95% confidence interval 0.2–1.9). P16^INK4a expression was similarly common (24% and 16%) in the HPV-positive and HPV-negative groups.

Conclusion

This study found a limited presence of HPV in oesophageal squamous cell carcinoma of uncertain oncogenic relevance and did not demonstrate that HPV was more strongly associated with proximal than distal tumours.     

Autolytic activities of the cell wall in rice coleoptiles. Effects of nojirimycin

Oryza sativa L. var. bahia coleoptile cell walls show sufficient autolytic activity for the release into the surrounding medium of amounts up to 60 μg of sugars per mg of dry weight of cell wall. The products released elute in Bio-gel P.2 as mono- and polysaccharides with glucose as the sole component. The polysaccharide component releases tri- and tetrasaccharides on treatment with a glucanase specific for β (1–3) (1–4) linkages in the same proportion as that of the mixed glucan of the cell wall. This supports the hypothesis that the polysaccharide component originates from the cell wall glucan and that autolysis is therefore related to the processes of the loss of rigidity of the cell wall. Nojirimycin (a specific glucanase inhibitor and inhibitor of auxin-induced elongation) decreases autolytic activity of the cell walls, reducing it to 30% of its normal value. Bio-gel P. 2 elution of the products released in autolysis in the presence of nojirimycin shows that only the monosaccharide fraction was affected.     

Reproductive and competitive interactions among gametophytes of the allotetraploid fern Dryopteris corleyi and its two diploid parents

Background and Aims

Several models predict that the establishment of polyploids within diploid populations is enhanced by non-random mating (i.e. selfing and assortative mating) of cytotypes and by a higher relative fitness of polyploids. This report assesses the role that antheridiogens (i.e. maleness-inducing pheromones) and intercytotype differences in growth rate have on polyploid performance.

Methods

Three buckler-fern species were studied: the allotetraploid Dryopteris corleyi and its diploid parents, D. aemula and D. oreades. In one experiment, gametophytes of these species were cultured under rich growth conditions to compare the timing of gametangia production. The substrata on which these gametophytes had grown were used as antheridiogen sources in a second experiment. The three species were combined as source and target of antheridiogen (i.e. nine species pairs). Timing of antheridia production and gametophyte size were determined after those antheridiogen treatments.

Key Results

Under rich growth conditions the allotetraploid produced archegonia earlier than those of diploid parents. Female gametophytes of the three species produced antheridiogens that inhibited growth and favoured maleness both within and among species. Gametophyte size was similar in the three species but antheridia formed earlier in the allotetraploid.

Conclusions

Unisexuality, promoted by non-specific antheridiogens, enhances random mating both within and among species. The resulting hybridization can favour the reproductive exclusion of the allopolyploid in sites where it is outnumbered by diploids. However, the earlier production of gametangia in the allotetraploid favours assortative mating and may thus counterbalance reproductive exclusion.Key words: Allopolyploidy, antheridiogen, assortative mating, Dryopteris aemula, Dryopteris corleyi, Dryopteris oreades, gametophytes, gender expression, minority cytotype exclusion     

Retail Survey of Brazilian Milk and Minas Frescal Cheese and a Contaminated Dairy Plant To Establish Prevalence, Relatedness, and Sources of Listeria monocytogenes Isolates

A study was designed to recover Listeria monocytogenes from pasteurized milk and Minas frescal cheese (MFC) sampled at retail establishments (REs) and to identify the contamination source(s) of these products in the corresponding dairy processing plant. Fifty milk samples (9 brands) and 55 MFC samples (10 brands) were tested from REs located in Juiz de Fora, Minas Gerais, Brazil. All milk samples and 45 samples from 9 of 10 MFC brands tested negative for L. monocytogenes; however, “brand F” of MFC obtained from REs 119 and 159 tested positive. Thus, the farm/plant that produced brand F MFC was sampled; all samples from the milking parlor tested negative for L. monocytogenes, whereas several sites within the processing plant and the MFC samples tested positive. All 344 isolates recovered from retail MFC, plant F MFC, and plant F environmental samples were serotype 1/2a and displayed the same AscI or ApaI fingerprints. Since these results established that the storage coolers served as the contamination source of the MFC, plant F was closed so that corrective renovations could be made. Following renovation, samples from sites that previously tested positive for the pathogen were collected from the processing environment and from MFC on multiple visits; all tested negative for L. monocytogenes. In addition, on subsequent visits to REs 159 and 119, all MFC samples tested negative for the pathogen. Studies are ongoing to quantify the prevalence, levels, and types of L. monocytogenes in MFC and associated processing plants to lessen the likelihood of listeriosis in Brazil.     

Analysis of protein content in pollen loads produced in north-west Spain

An analysis was made of the protein content of pollen loads produced by the bees in a hive situated in Viana do Bolo (Ourense, north-west Spain), to establish whether or not the relative quantity of protein in the pollen of each plant species influences the preference made by the bee of the flowers that supply pollen to the hive. This analysis was performed on all types of pollen that formed more than 5% of the pollen spectrum. Pollen load samples were collected directly from the hive from March to September. Pollen loads were separated by colour, and their specific homogeneity was confirmed microscopically. The Bradford method has been used for protein extraction and spectrophotometry was used for the determination of protein content. The results show that the different pollen loads have high protein content. Pollen of the plant species that reached relatively higher percentages in the pollen spectrum are also those that have the highest protein content. These were Cytisus scoparius type, uncultivated Poaceae, Quercus robur type, Sanguisorba minor, Salix fragilis and Spergularia rubra type. The pollen of the systematic units, which had pollen loads that could be identified at the level of species, maintained a constant value of protein content independently of the date the samples were obtained. The pollen of the systematic units, which had pollen loads that could be identified at the level of pollen type, has varied in protein content in the analyses performed on samples obtained on different dates. This result is due to the fact that the different species that integrate the pollen type flower on different dates, and thus have a pollenkitt with different characteristics.     

Calcium instabilities in mammalian cardiomyocyte networks

The degeneration of a regular heart rhythm into fibrillation (a chaotic or chaos-like sequence) can proceed via several classical routes described by nonlinear dynamics: period-doubling, quasiperiodicity, or intermittency. In this study, we experimentally examine one aspect of cardiac excitation dynamics, the long-term evolution of intracellular calcium signals in cultured cardiomyocyte networks subjected to increasingly faster pacing rates via field stimulation. In this spatially extended system, we observed alternans and higher-order periodicities, extra beats, and skipped beats or blocks. Calcium instabilities evolved nonmonotonically with the prevalence of phase-locking or Wenckebach rhythm, low-frequency magnitude modulations (signature of quasiperiodicity), and switches between patterns with occasional bursts (signature of intermittency), but period-doubling bifurcations were rare. Six ventricular-fibrillation-resembling episodes were pace-induced, for which significantly higher complexity was confirmed by approximate entropy calculations. The progressive destabilization of the heart rhythm by coexistent frequencies, seen in this study, can be related to theoretically predicted competition of control variables (voltage and calcium) at the single-cell level, or to competition of excitation and recovery at the cell network level. Optical maps of the response revealed multiple local spatiotemporal patterns, and the emergence of longer-period global rhythms as a result of wavebreak-induced reentries.