Rhodolith primary and carbonate production in a changing ocean: The interplay of warming and nutrients.

Rhodolith beds, like many other marine ecosystems, are affected by climate change that is causing an increase in the magnitude and frequency of extreme high temperature events (heat waves). Unfortunately, this does not represent the sole peril for these communities, as coastal urbanization in conjunction with altered precipitation patterns can increase terrestrial-derived nutrient input. In Brazil, rhodolith beds are among the most extensive coastal benthic ecosystems, but despite their vast distribution and great ecological and economic importance, studies on the productivity of these communities and the impact of changing environmental conditions are almost non-existent. This study addressed the individual and combined effects of increases in temperature and nutrient concentration on the physiological performance of two widely distributed rhodolith species, Lithothamnion crispatum and Melyvonnea erubescens. The results showed species-specific responses in net photosynthetic performance, with no response in L. crispatum, while M. erubescens responded negatively to both increase in temperature and nutrients. In contrast, calcification in both species showed a significant decline at high temperature. No interactive effects were found between temperature and nutrients, yet their combined negative effects were additive, resulting in negative daily-integrated net productivity and a large decline in daily carbonate production in both species. This has strong implications for rhodolith bed primary productivity and carbonate production, as heat waves may potentially cause a strong decline in carbonate production (ca. 50% loss), accompanied by a severe drop in primary productivity that will be even more pronounced under high-nutrient conditions. Also, the species-specific responses to changes in temperature and nutrient concentration suggest that the magnitude of impact of these factors on rhodolith bed productivity will depend on the species dominating the community and may finally result in changes in rhodolith community composition.

Comment on 'Carbon and fullerene nanomaterials in plant system'.

A recent review article entitled "Carbon and fullerene nanomaterials in plant system" published in this journal, misinterprets a component of our (published) work on the interactions of carbon nanotubes with plants. In this comment, we provide the rationale to counter this misconstruction.

HNA antibody-mediated neutrophil aggregation is dependent on serine protease activity.

BACKGROUND AND OBJECTIVES: Transfusion-related acute lung injury (TRALI) is often caused by antibodies against human neutrophil alloantigen-2 (HNA-2) and HNA-3a. Neutrophil aggregation is considered as a major cause of TRALI, but little is known about how HNA antibodies initiate this process. We explored mechanisms involved in neutrophil aggregation induced by HNA-2 and HNA-3a antibodies. MATERIALS AND METHODS: Isolated neutrophils were pretreated with broad-spectrum or specific inhibitors against different cell functions or proteases. Granulocyte agglutination test (GAT) was performed with serially diluted anti-HNA-2 and anti-HNA-3a plasmas or control plasma, and reactivity was evaluated microscopically. Reactive oxygen species (ROS) production in neutrophils was investigated using a lucigenin-based chemiluminescence assay. RESULTS: HNA-2 and HNA-3a antibody-mediated neutrophil aggregation was inhibited by pretreatment with formaldehyde, iodoacetamide and the serine protease inhibitors Pefabloc-SC, N-p-tosyl-L-phenylalanine chloromethyl ketone (TPCK) and Nα-tosyl-L-lysine chloromethyl ketone hydrochloride (TLCK). In contrast, inhibition of actin polymerization, respiratory burst, cysteine proteases, metalloproteases or aspartic proteases did not affect neutrophil aggregation. Furthermore, HNA-3a antibodies did not directly cause ROS production in neutrophils. CONCLUSION: Aggregation of neutrophils induced by HNA-2 and HNA-3a antibodies is an active process and depends on trypsin- or chymotrypsin-like serine proteases but is not dependent on the production of ROS. These findings may open new prospects for the pharmacologic prevention of neutrophil-associated acute lung injury.

Naturally occurring heavy radioactive elements in the geothermal microcosm of the Los Azufres (Mexico) volcanic complex.

The Los Azufres geothermal complex of central Mexico is characterized by fumaroles and boiling hot-springs. The fumaroles form habitats for extremophilic mosses and ferns. Physico-chemical measurements of two relatively pristine fumarolic microcosms point to their resemblance with the paleo-environment of earth during the Ordovician and Devonian periods. These geothermal habitats were analysed for the distribution of elemental mass fractions in the rhizospheric soil (RS), the native volcanic substrate (VS) and the sediments (S), using the new high-sensitivity technique of polarized x-ray energy dispersive fluorescence spectrometry (PEDXRF) as well as instrumental neutron activation analysis (INAA) for selected elements. This work presents the results for the naturally occurring heavy radioactive elements (NOHRE) Bi, Th and U but principally the latter two. For the RS, the density was found to be the least and the total organic matter content the most. Bi was found to be negligibly present in all substrate types. The average Th and U mass fractions in the RS were higher than in the VS and about equal to their average mass fractions in the S. The VS mass fraction of Th was higher, and of U lower, than the mass fractions in the earth's crust. In fact for the fumaroles of one site, the average RS mass fractions of these elements were higher than the averaged values for S (without considering the statistical dispersion). The immobilization of the NOHRE in the RS is brought about by the bio-geochemical processes specific to these extremophiles. Its effectiveness is such that despite the small masses of these plants, it compares with, or may sometimes exceed, the immobilization of the NOHRE in the S by the abiotic and aggressive chemical action of the hot-springs. These results indicate that the fumarolic plants are able to transform the volcanic substrate to soil and to affect the NOHRE mass fractions even though these elements are not plant nutrients. Mirrored back to the paleo times when such plant types were ubiquitous, it would mean that the first plants contributed significantly to pedogenesis and the biogeochemical recycling of even the heaviest and radioactive elements. Such plants may potentially be useful for the phytostabilisation of soil moderately contaminated by the NOHRE. Furthermore where applicable, geochronology may require taking into account the influence of the early plants on the NOHRE distributions.

What determines health-related quality of life in hip fracture patients at the end of acute care?--a prospective observational study.

UNLABELLED: Hip fractures are associated with reduced health-related quality of life (HrQoL). We found pre-existing need of care or limited function, cognitive impairment, and depression to be independent factors associated with lower HrQoL during the postsurgical period. In contrast, joint replacement was associated with better HrQoL compared to internal fixation. Patients' treatment should be focused on functional recovery and treatment of depression. INTRODUCTION: The aim of the study was to identify independent factors that were correlated with health-related quality of life (HrQoL) after hip fracture. METHODS: A total of 402 patients with a mean age of 81 years suffering from a hip fracture were included in this prospective, observational cohort study. HrQoL (determined by the EuroQol instrument) was measured at admission and at discharge from an acute care hospital. Independent factors correlated with HrQoL at discharge and changes from pre-fracture to discharge were determined using multivariate analyses. The influence of antidepressants was evaluated by an ANOVA with repeated measurements. RESULTS: Need of care prior to fracture was the most important determinant of EQ-5D index at discharge (ß = -0.359, p = 0.003). Additionally, low Mini Mental Status Examination (MMSE) was associated with a lower EQ-5D index at discharge (MMSE 0-9: ß = -0.238, p <0.001; MMSE 10-19: ß = -0.294, p <0.001) and a greater decrease in EQ-5D during hospitalisation (MMSE 10-19: ß = 0.281, p <0.001), while joint replacement (compared to internal fixation) was associated with a higher EQ-5D index (ß = 0.188, p = 0.002) and a lower decrease in the index (ß = -0.216, p = 0.003). EQ VAS values at discharge were correlated with pre-fracture Barthel Index (ß = 0.253, p <0.001) and Geriatric Depression Scale scores (ß = -0.135, p = 0.026). Depressive patients on antidepressants demonstrated less of a decrease in the EQ-5D index compared to patients not receiving medication (F = 2.907, p = 0.090). CONCLUSIONS: Acute care of hip fracture patients should be focused on functional recovery and treatment of depression. When the preferred surgical strategy is unclear, joint replacement should be considered.

The effect of the symbiosis between Tagetes erecta L. (marigold) and Glomus intraradices in the uptake of Copper(II) and its implications for phytoremediation.

Phytoremediation is an environmental biotechnology that seeks to remediate pollution caused by bioaccumulative toxins like copper (Cu). Symbiotic mycorrhizal associations can increase the uptake and delivery of low mobility nutrients and micronutrients to the host plant because they solubilize these substances and increase their catchment area. To analyze the effect of mycorrhizae on the phytoaccumulation of Cu, we studied their ability to solubilize Cu(II) and enhance its absorption by the plant Tagetes erecta L. colonized with the arbuscular mycorrhizal fungus Glomus intraradices. Plants were grown for nine weeks in a growth chamber under controlled conditions of temperature, relative humidity and photoperiod. Cu was added in the insoluble form of CuO to simulate the insoluble Cu-O affixed species in soil. The biotic and abiotic parameters of colonization, foliar area, biomass and the pH of leachates were determined as functions of the Cu concentration that was measured in the roots, shoots and leachates by AAS. The results of Cu absorption showed that the colonized plants accumulated more Cu in the roots as well as the whole plant and that both the colonized and non-colonized plants displayed the typical behavior of Cu excluders. Mycorrhizal colonization of the roots resulted in a proliferation of vesicles and this was observed to scale with root tissue Cu concentrations. Also, the G. intraradices-T. erecta system displayed a higher resistance to the toxicity induced by Cu while nonetheless improving the indices of phytoaccumulative yields. These results suggest that G. intraradices possibly accumulates Cu in its vesicles thereby enhancing the Cu tolerance of T. erecta even while increasing root Cu accumulation. The parameters of bioconcentration factor and translocation factor measured in this work suggest that the system T. erecta-G. intraradices can potentially phytostabilize Cu in contaminated soils.

Light quanta modulated characteristics of Ni uptake by Brassica juncea seedlings: the interdependence of plant metal concentration and biomass.

The relationships between the concentration of metal in the growth medium, Cs, the concentration of metal absorbed by the plant, Cp, and the total biomass achieved, M, all of which are factors relevant to the efficiency of metal uptake and tolerance by the plant, have been investigated via the physiological response of Brassica juncea seedlings to Ni stress. The factorial growth experiments treated the Ni concentration in agar medium and the diurnal light quanta as independently variable parameters. Observations included the evidence of light enhancement of Ni toxicity in the root, as well as at the whole-plant level. The shoot mass index possibly is an indicator of the amount of shoot metal sequestration in B. juncea, as are the logarithmic variation of Cp with Cs and the power-law dependence of M on Cp. The sum total of these observations indicates that, for the Ni accumulating plant B. juncea, the overall metabolic allocation to either growth or metal tolerance of the plant is important. Neither a rapid biomass increase nor a high metal absorbed concentration favored the removal of high metal mass from the medium. Rather, the plants with a moderate rate of biomass growth and a moderate absorbed metal concentration demonstrated the ability to remove the maximum mass of metal from the medium. The implication of these results as related to the extant model of phyoextraction efficiency is discussed.

The hypotonic upper airway in obstructive sleep apnea: role of structures and neuromuscular activity.

The structural properties of the upper airway determine its collapsibility during periods of muscle hypotonia. Both rapid-eye-movement (REM) sleep and increases in nasal pressure (PN) produce hypotonia, which persists even after nasal pressure is abruptly reduced. To determine the factors that influence the collapsibility of the hypotonic airway, the critical pressure (Pcrit) and nasal resistance upstream to the site of pharyngeal collapse (RN) were measured in the first three breaths after abrupt reductions in PN during non-REM and REM sleep. PN was reduced abruptly from 15.2+/-3.2 cm H2O (mean +/- SD) for three breaths in 19 apneic patients. Upper-airway pressure-flow relationships were analyzed to determine Pcrit for each breath in non-REM and REM sleep. We found that Pcrit rose (collapsibility increased, p < 0.001) and RN fell (p = 0.02) between the first and third breath after the decrease in PN, whereas no difference in Pcrit was detected between sleep stages. In six patients, genioglossus-muscle electromyograms (EMGs) were recorded. Peak phasic activity rose between the first and third breath (p = 0.03), but tonic and peak phasic EMG activity fell in REM as compared with non-REM sleep (p < 0.001). We conclude that the hypotonic upper airway becomes most collapsible by the third breath after an abrupt decrease in PN, regardless of sleep stage and despite an increase in genioglossus-muscle activity. Our findings suggest that predominantly mechanical rather than neuromuscular factors modulate the properties of the pharynx after abrupt reductions in nasal pressure.

Night-to-night variability in CPAP use over the first three months of treatment.

The purpose of this study was to examine the relationship between night-to-night variability and nightly duration of continuous positive airway pressure (CPAP) therapy over the first 9 weeks of treatment and to determine when patients begin to establish a nonadherent pattern of use. Data were analyzed from a study of daily CPAP use covertly monitored in 32 diagnosed patients with obstructive sleep apnea (OSA) using a microprocessor monitor encased in a CPAP machine. Patterns of CPAP use were bimodal, based on the frequency of nightly use. Approximately half the subjects were consistent users of CPAP, applying it > 90% of the nights for an average of 6.22 +/- 1.21 hours per night, while the other half comprised intermittent users who had a wide range of daily use averaging 3.45 +/- 1.94 hours per night on the nights CPAP was used. The percent of days skipped was significantly correlated with decreased nightly duration (rho = -0.73, p < 0.0001). Analysis of the night-to-night pattern of use revealed that the two groups differed significantly in the nightly duration of CPAP use by the fourth day of treatment (p = 0.001). Exploration of factors that potentially differentiate the two groups revealed no reliable predictors. However, intermittent users continued to report significantly greater OSA symptoms (snoring, snorting, and apnea) posttreatment, suggesting that they continued to experience sleep disordered breathing.

Objective measurement of patterns of nasal CPAP use by patients with obstructive sleep apnea.

Obstruction of the upper airway during sleep (OSAS) is widely treated by having patients self-administer nasal continuous positive airway pressure (CPAP). To obtain objective evidence of the patterns of CPAP use, information was gathered from two urban sites on 35 OSAS patients who were prescribed CPAP for a total of 3,743 days. Patients were given CPAP machines that contained a microprocessor and monitor that measured actual pressure at the mask for every minute of each 24-h day for an average of 106 days per patient. They were not aware of the monitor inside the CPAP machines. Monitor output was compared with patients' diagnostic status, pretreatment clinical and demographic characteristics, and follow-up self-reports of CPAP use, problems, side effects, and aspects of daytime fatigue and sleepiness. Patients attempted to use CPAP an average of 66 +/- 37% of the days monitored. When CPAP was used, the mean duration of use was 4.88 +/- 1.97 h. However, patients' reports of the duration of CPAP use overestimated actual use by 69 +/- 110 min (p < 0.002). Both frequency and duration of CPAP use in the first month reliably predicted use in the third month (p < 0.0001). Although the majority (60%) of patients claimed to use CPAP nightly, only 16 of 35 (46%) met criteria for regular use, defined by at least 4 h of CPAP administered on 70% of the days monitored. Relative to less regular users, these 16 patients had more years of education (p = 0.05), and were more likely to work in professional occupations.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of uvulopalatopharyngoplasty on upper airway collapsibility in obstructive sleep apnea.

Previous investigators have demonstrated variable responses to uvulopalatopharyngoplasty (UPP) in patients with obstructive sleep apnea. We hypothesized that this variability is due to either (1) differences in baseline pharyngeal collapsibility preoperatively or (2) differences in magnitude of the decrease in pharyngeal collapsibility resulting from surgery. To determine the relationship between changes in collapsibility and the response to UPP surgery, we measured the upper airway critical pressure (Pcrit) before and after UPP in 13 patients with obstructive sleep apnea. During non-REM sleep, maximal inspiratory airflow (VImax) was quantitated by varying the level of nasal pressure (PN), and Pcrit was determined by the level of PN below which VImax ceased. A positive response to UPP was defined by a greater than or equal to 50% fall in non-REM disordered breathing rate (DBR). In the entire group, UPP resulted in significant decreases in DBR from 71.1 +/- 22.4 to 44.7 +/- 38.4 episodes/h (p = 0.025) and in Pcrit from 0.2 +/- 2.4 to -3.1 +/- 5.4 cm H2O (p = 0.016). Moreover, the percent change in DBR was correlated significantly with the change in Pcrit (p = 0.001). Subgroup analysis of responders and nonresponders demonstrated that significant differences in Pcrit were confined to the responders. Specifically, responders demonstrated a significant fall in Pcrit from -0.8 +/- 3.0 to -7.3 +/- 4.9 cm H2O (p = 0.01), whereas no significant change in Pcrit was detected in the nonresponders (1.1 +/- 1.6 versus 0.6 +/- 2.0 cm H2O. No clinical, polysomnographic, or physiologic predictors of a favorable response were found preoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of weight loss on upper airway collapsibility in obstructive sleep apnea.

Previous investigators have demonstrated in patients with obstructive sleep apnea that weight reduction results in a decrease in apnea severity. Although the mechanism for this decrease is not clear, we hypothesize that decreases in upper airway collapsibility account for decreases in apnea severity with weight loss. To determine whether weight loss causes decreases in collapsibility, we measured the upper airway critical pressure (Pcrit) before and after a 17.4 +/- 3.4% (mean +/- SD) reduction in body mass index in 13 patients with obstructive sleep apnea. Thirteen weight-stable control subjects matched for age, body mass index, gender (all men), and non-REM disordered breathing rate (DBR) also were studied before and after usual care intervention. During non-REM sleep, maximal inspiratory airflow was measured by varying the level of nasal pressure and Pcrit was determined by the level of nasal pressure below which maximal inspiratory airflow ceased. In the weight loss group, a significant decrease in DBR from 83.3 +/- 31.0 to 32.5 +/- 35.9 episodes/h and in Pcrit from 3.1 +/- 4.2 to -2.4 +/- 4.4 cm H2O (p less than 0.00001) was demonstrated. Moreover, decreases in Pcrit were associated with nearly complete elimination of apnea in each patient whose Pcrit fell below -4 cm H2O. In contrast, no significant change in DBR and a minimal reduction in Pcrit from 5.2 +/- 2.3 to 4.2 +/- 1.8 cm H2O (p = 0.031) was observed in the "usual care" group. We conclude that (1) weight loss is associated with decreases in upper airway collapsibility in obstructive sleep apnea, and that (2) the resolution of sleep apnea depends on the absolute level to which Pcrit falls.

Upper airway collapsibility in snorers and in patients with obstructive hypopnea and apnea.

During sleep, mild reduction in inspiratory airflow is associated with snoring, whereas obstructive hypopneas and apneas are associated with more marked reductions in airflow. We determined whether the degree of inspiratory airflow reduction was associated with differences in the collapsibility of the upper airway during sleep. Upper airway collapsibility was defined by the critical pressure (Pcrit) derived from the relationship between maximal inspiratory airflow and nasal pressure. In 10 asymptomatic snorers, six patients with obstructive hypopneas, and 10 patients with obstructive apneas, during nonrapid eye movement sleep, Pcrit ranged from -6.5 +/- 2.7 cm H2O to -1.6 +/- 1.4 and 2.5 +/- 1.5 cm H2O, respectively (mean +/- SD, p less than 0.001). Moreover, higher levels of Pcrit were associated with lower levels of maximal inspiratory airflow during tidal breathing during sleep (p less than 0.005). We conclude that differences in upper airway collapsibility distinguish among groups of normal subjects who snore and patients with periodic hypopneas and apneas. Moreover, the findings suggest that small differences in collapsibility (Pcrit) along a continuum are associated with reduced airflow and altered changes in pattern of breathing.