The impact of demographic changes on the epidemiology of herpes zoster: Spain as a case study

Varicella zoster virus (VZV) causes varicella upon first exposure and may reactivate later in life into herpes zoster (HZ), with a risk that is thought to be reduced by re-exposures to VZV. Given the decades-long time scales of reactivation and its dependence on the accumulation of re-exposure episodes, adopting a long-term perspective may be useful to correctly interpret current epidemiological trends of VZV. In this study, we investigate the possible impact of demographic changes on varicella and HZ in Spain, using an age-structured mathematical model informed with historical demographic data and calibrated against age-specific profiles of varicella seroprevalence and HZ incidence data. The model qualitatively reproduces the remarkable growth of HZ incidence observed in Spain between 1997 and 2004, before the introduction of varicella vaccination programmes. We demonstrate that this growth may be partially ascribed to the reduction of varicella circulation that followed the overall decline of the birth rate in the twentieth century. Model predictions further suggest that, even under the most optimistic projections, HZ incidence will continue its rise until at least 2040. Considering the effect of demographic changes can help interpreting variations in epidemiological trends of HZ, contributing to a more accurate evaluation of vaccination programmes against VZV.     

Efficient colonization of the endophytes Herbaspirillum huttiense RCA24 and Enterobacter cloacae RCA25 influences the physiological parameters of Oryza sativa L. cv. Baldo rice

Several important bacterial characteristics, such as biological nitrogen fixation, phosphate solubilization, 1-aminocyclopropane-1-carboxylate deaminase activity and production of siderophores and phytohormones, can be assessed as plant growth promotion traits. Our aim was to evaluate the effects of nitrogen fixing and indole-3-acetic acid (IAA) producing endophytes in two Oryza sativa cultivars (Baldo and Vialone Nano). Three bacteria, Herbaspirillum huttiense RCA24, Enterobacter asburiae RCA23 and Staphylococcus sp. 377, producing different IAA levels, were tested for their ability to enhance nifH gene expression and nitrogenase activity in Enterobacter cloacae RCA25. Results showed that H. huttiense RCA24 performed best. Improvement in nitrogen fixation and changes in physiological parameters such as chlorophyll, nitrogen content and shoot dry weight were observed for plants co-inoculated with strains RCA25 and RCA24 in a 10:1 ratio. Based on confocal laser scanning microscopy analysis, strain RCA24 was the best colonizer of the root interior and the only IAA producer located in the same root niche occupied by RCA25 cells. This work shows that the choice of a bio-inoculum having the right composition is one of the key aspects to be considered for the inoculation of a specific host plant cultivar with microbial consortia.     

Maternal Control of PIN1 Is Required for Female Gametophyte Development in Arabidopsis

Land plants are characterised by haplo-diploid life cycles, and developing ovules are the organs in which the haploid and diploid generations coexist. Recently it has been shown that hormones such as auxin and cytokinins play important roles in ovule development and patterning. The establishment and regulation of auxin levels in cells is predominantly determined by the activity of the auxin efflux carrier proteins PIN-FORMED (PIN). To study the roles of PIN1 and PIN3 during ovule development we have used mutant alleles of both genes and also perturbed PIN1 and PIN3 expression using micro-RNAs controlled by the ovule specific DEFH9 (DEFIFICENS Homologue 9) promoter. PIN1 down-regulation and pin1-5 mutation severely affect female gametophyte development since embryo sacs arrest at the mono- and/or bi-nuclear stages (FG1 and FG3 stage). PIN3 function is not required for ovule development in wild-type or PIN1-silenced plants. We show that sporophytically expressed PIN1 is required for megagametogenesis, suggesting that sporophytic auxin flux might control the early stages of female gametophyte development, although auxin response is not visible in developing embryo sacs.     

The effects of estrogen on cortisol metabolism in female baboons

We examined Cortisol (F) dynamics in female baboons $\text{(Papio anubis)}$ treated with diethylstilbestrol (DES) or estradiol (E₂) and compared values with those previously measured in nonpregnant and pregnant animals. Five regularly menstruating baboons (12–18 kg, BW) were administered 5 mg DES daily via fruit or 0.5 mg E₂/0.1ml oil sc for 30 days. Blood samples, obtained before and after treatment, were assayed for serum F concentrations and serum Cortisol binding capacity (CBC). The metabolic clearance (MCR) and production rate (PR) of F and the catabolism of i.v. administered [³H] F were examined 25 and 30 days after initiation of estrogen treatment. Compared with values in nonpregnant baboons, F metabolism in estrogen treated animals is significantly altered and is characterized by increased formation of unconjugated metabolites, decreased glucuronylation, increased excretion of unconjugated F, cortisone, and highly polar metabolites, and increased CBC. These changes induced by estrogen are similar to those observed in intact pregnant baboons and permit the suggestion that the pattern of F metabolism and the level of CBC in baboon pregnancy are the result of elevated estrogen production.However, estrogen also caused a significant decrease in the MCR and PR of F, parameters which, by contrast, are similar in intact pregnant and nonpregnant baboons. These findings indicate that while estrogen also influences the rate of F clearance and F production, these effects of estrogen are not apparent during pregnancy. Collectively, these findings allow the suggestion that estrogen is a major factor which alters F metabolism and increases serum CBC in baboon gestation. However, additional factors are operative in primate pregnancy which maintain PR and MCR of F at levels similar to those of nonpregnant baboons.     

Alterations in high-affinity binding characteristics and levels of opioids in invertebrate ganglia during aging: Evidence for an opioid compensatory mechanism

In Mytilus and Leucophaea the high-affinity binding site density is significantly lower in old animals than in young animals, whereas the low-affinity site density remains unchanged. In Mytilus the estimated met-enkephalin and met-enkephalin-Arg6-Phe7 levels are significantly higher in old than in young animals. In Leucophaea only the met-enkephalin level can be determined, and it is also higher in old animals. The decrease in the high-affinity binding site density and the corresponding increase in endogenous enkephalin levels suggest the existence of an opioid compensatory mechanism associated with the aging process. In Mytilus there is a demonstrated decrease with age in intraganglionic dopamine levels in response to applied opiates. In addition, the inhibition of dopamine-stimulated adenylate cyclase activity by opiates also decreases in older animals. In Leucophaea the sex difference in opioid binding densities diminishes with age.     

Increased Ca++ or mg++ concentration reduces relative tight-junction permeability to Na+ in the cortical thick ascending limb of Henle's loop of rabbit kidney

We have tested whether increased Ca++ and Mg++ concentrations have an effect on transepithelial voltage (PDte) and transepithelial resistance (Rte) in isolated perfused cortical thick ascending limbs (cTAL) of rabbit kidney. The divalent cations added at 2.5, 5.0 and 10.0 mmol.l-1 to the lumen or peritubular bath perfusate led to a concentration-dependent increase in Rte. The maximal response in Rte was observed between 5 and 10 mmol.l-1. No significant change in active transepithelial potential difference (PDte) was observed. The increase in Rte still occurred when the transcellular current was reduced by Ba++ (3 mmol.l-1) added to the lumen perfusate. This suggests that the increase in Rte caused by Ca++ and Mg++ is due to a modification of the paracellular shunt pathway. In the absence of active transport, i.e. when furosemide (5.10(-5) mol.l-1) was added to the lumen perfusate. Ca++ and Mg++ reduced the transepithelial diffusion potential generated by a NaCl gradient established across the epithelium, and thus produced a reduction of the relative permeability for Na+ over Cl- (PNa+/PCl-) of the paracellular shunt pathway. This indicates that divalent cations increase Rte by reducing the sodium permeability of the tight junctions. The observed Ca++ and Mg++ induced reduction of the sodium permeability of the paracellular pathway corresponds to a decrease in net Na+ reabsorption by 5-10%. Since it has been demonstrated that peptide hormones such as parathyrin (PTH) modulate divalent cation and NaCl reabsorptions, in a second series of experiments we tested the effects of PTH (2-20 USP.l-1) and dbcAMP (10(-3) mol.l-1) on PDte and Rte of isolated perfused cTAL segments of rabbit nephron. Neither Rte nor PDte were affected by PTH or dbcAMP.     

The AluI-induced bands in great apes and man: implication for heterochromatin characterization and satellite DNA distribution

Restriction endonucleases have recently been proved to be active on fixed chromatin, producing differences in staining of metaphase chromosomes. In this paper we show the results obtained by treating the metaphase chromosomes of Pan troglodytes, Pan paniscus, and Gorilla gorilla with the restriction enzyme AluI. These results demonstrate qualitative differences in the telomeric heterochromatin between Pan and Gorilla despite the fact that these areas appear homogeneous in the two genera by the C-banding method. The results found with individual chromosomes in the different species also appear relevant, in the light of the evolutionary relationships between these nonhuman primates and man. Lastly, the results suggest the presence, in great apes, of some highly repetitive DNA sequences different from the human satellites I-IV.