Dinoflagellate vertical migration fuels an intense red tide.

Harmful algal blooms (HABs) are increasing globally, causing economic, human health, and ecosystem harm. In spite of the frequent occurrence of HABs, the mechanisms responsible for their exceptionally high biomass remain imperfectly understood. A 50-y-old hypothesis posits that some dense blooms derive from dinoflagellate motility: organisms swim upward during the day to photosynthesize and downward at night to access deep nutrients. This allows dinoflagellates to outgrow their nonmotile competitors. We tested this hypothesis with in situ data from an autonomous, ocean-wave-powered vertical profiling system. We showed that the dinoflagellate Lingulodinium polyedra's vertical migration led to depletion of deep nitrate during a 2020 red tide HAB event. Downward migration began at dusk, with the maximum migration depth determined by local nitrate concentrations. Losses of nitrate at depth were balanced by proportional increases in phytoplankton chlorophyll concentrations and suspended particle load, conclusively linking vertical migration to the access and assimilation of deep nitrate in the ocean environment. Vertical migration during the red tide created anomalous biogeochemical conditions compared to 70 y of climatological data, demonstrating the capacity of these events to temporarily reshape the coastal ocean's ecosystem and biogeochemistry. Advances in the understanding of the physiological, behavioral, and metabolic dynamics of HAB-forming organisms from cutting-edge observational techniques will improve our ability to forecast HABs and mitigate their consequences in the future.

The impact of obesity on chronic oedema/lymphoedema of the leg - an international multicenter cross-sectional study (LIMPRINT).

BACKGROUND/OBJECTIVES: Obesity and chronic oedema/lymphoedema are two distinct but related conditions, rarely investigated together. The aim was to study the impact of increased weight on chronic oedema and related factors. SUBJECTS/METHODS: A cross-sectional study, 38 centers, nine countries. Patients with clinically confirmed chronic oedema/lymphoedema of the leg were included. Weight category was estimated as: normal weight (BMI 20-30), class I-II obesity (BMI 30-40), or class III obesity (BMI > 40). Factors were tested for an association with increased weight, using a multivariable model. RESULTS: A total of 7397 patients were included; 43% with normal weight, 36% class I-II obesity and 21% class III obesity. Increased weight was associated with more advanced stages of chronic oedema (ISL stage III; the most advanced form); affecting 14% in normal weight, 18% class I-II obesity and 39% class III obesity (p < 0.001). Ten factors were independently associated with increased weight: diabetes (OR 2.4), secondary lymphoedema (OR 2.7), cellulitis/erysipelas within 12 months (OR 1.2), bilateral lymphoedema (OR 3.6), compression therapy (OR 2.1), increased swelling duration (1-2 years OR 1.3, 2-5 years OR 2.5, 5-10 years OR 3.6, >10 years OR 3.5) decreased mobility (walking with aid OR 1.9, being chair bound OR 1.2) and age (reference<45 years; 45-64 years OR 1.5, 75-84 years OR 0.6, 85+ years OR 0.2). Increased weight was associated with a lower presentation of peripheral arterial disease (OR 0.7) and poorer chronic oedema control (OR 0.8). Patients with obesity had lower function, appearance and more severe symptoms (LYMQOL) and lower quality of life (EuroQol). CONCLUSIONS: Obesity negatively impacts chronic oedema, leading to more advanced stages. Achieving good control of swelling with compression is more difficult in these patients. Increased awareness of chronic oedema/lymphoedema as a complication of obesity is important for early detection and for developing effective strategies to prevent and manage them.

Land surface conductance linked to precipitation: Co-evolution of vegetation and climate in Earth system models.

Vegetation and precipitation are known to fundamentally influence each other. However, this interdependence is not fully represented in climate models because the characteristics of land surface (canopy) conductance to water vapor and CO2 are determined independently of precipitation. Working within a coupled atmosphere and land modelling framework (CAM6/CLM5; coupled Community Atmosphere Model v6/Community Land Model v5), we have developed a new theoretical approach to characterizing land surface conductance by explicitly linking its dynamic properties to local precipitation, a robust proxy for moisture available to vegetation. This will enable regional surface conductance characteristics to shift fluidly with climate change in simulations, consistent with general principles of co-evolution of vegetation and climate. Testing within the CAM6/CLM5 framework shows that climate simulations incorporating the new theory outperform current default configurations across several error metrics for core output variables when measured against observational data. In climate simulations for the end of this century the new, adaptive stomatal conductance scheme provides a revised prognosis for average and extreme temperatures over several large regions, with increased primary productivity through central and east Asia, and higher rainfall through North Africa and the Middle East. The new projections also reveal more frequent heatwaves than originally estimated for the south-eastern US and sub-Saharan Africa but less frequent heatwaves across east Europe and northeast Asia. These developments have implications for evaluating food security and risks from extreme temperatures in areas that are vulnerable to climate change.

Factors associated with cellulitis in lymphoedema of the arm - an international cross-sectional study (LIMPRINT).

BACKGROUND: Lymphoedema is a globally neglected health care problem and a common complication following breast cancer treatment. Lymphoedema is a well-known predisposing factor for cellulitis, but few have investigated the risk factors for cellulitis in this patient cohort on an international level. The aim of this study was to identify the frequency of cellulitis in patients with lymphoedema of the arm, including potential risk factors for cellulitis. METHODS: An international, multi-centre, cross-sectional study including patients with clinically assessed arm lymphoedema. The primary outcome was the incidence of cellulitis located to the arm with lymphoedema within the last 12 months, and its potential associated risk factors. The secondary outcome was life-time prevalence of cellulitis. Adults with clinically-assessed arm lymphoedema/chronic oedema (all causes) and able to give informed consent were included. End-of-life-patients or those judged as not in the patient's best interest were excluded. Both univariable and multivariable analysis were performed. RESULTS: A total of 2160 patients were included from Australia, Denmark, France, Ireland, Italy, Japan, Turkey and United Kingdom. Secondary lymphoedema was present in 98% of the patients; 95% of these were judged as related to cancer or its treatment. The lifetime prevalence of cellulitis was 22% and 1-year incidence 11%. Following multivariable analysis, factors associated with recent cellulitis were longer swelling duration and having poorly controlled lymphoedema. Compared to having lymphoedema less than 1 year, the risk increased with duration: 1-2 years (OR 2.15), 2-5 years (OR 2.86), 5-10 years (OR 3.15). Patients with well-controlled lymphoedema had a 46% lower risk of cellulitis (OR 0.54, 95% CI 0.39-0.73, p < 0.001). More advanced stages of lymphoedema were associated with cellulitis even after adjustment for swelling duration and control of swelling by logistic regression (stage II OR 5.44, stage III OR 9.13, p = 0.002), demonstrated in a subgroup analysis. CONCLUSION: Patients with advanced arm lymphoedema are at particular risk of developing cellulitis. Prevention of lymphoedema progression is crucial. The results lend towards a positive effect of having well-treated lymphoedema on the frequency of cellulitis.

Self-care treatment for lymphoedema of lymphatic filariasis using integrative medicine.

BACKGROUND: Lymphatic filariasis (LF) is a neglected tropical disease presenting mainly as lymphoedema (elephantiasis). At present, LF is not effectively treated. Integrative medicine (IM) treatment for lymphoedema uses a combination of Indian traditional medicine, Ayurveda, alongside yoga exercises, compression therapy, antibiotics and antifungal treatments, providing a useful combination where resources are limited and different practices are in use. OBJECTIVES: To assess the effectiveness of the IM in the existing clinical practice of lower-limb lymphoedema management and to determine whether the treatment outcomes align with the World Health Organization (WHO) global goal of LF management. METHODS: Institutional data from electronic medical records of all 1698 patients with LF between 2010 and 2019 were retrospectively analysed using pre- and post-treatment comparisons and the National Institute for Health and Care Excellence guidelines for clinical audit. The primary treatment outcomes evaluated were limb volume, bacterial entry points (BEEPs), episodes of cellulitis, and health-related quality of life (HRQoL). Secondary outcomes included the influence of the patient's sex, duration of illness, education and employment status on volume reduction. Multiple regression analysis, t-test, χ2-test, analysis of variance, Mann-Whitney U-test and the Kruskal-Wallis test were used to assess the association between IM and patients' treatment outcomes. RESULTS: Limb volume reduced by 24.5% [95% confidence interval (CI) 22.47-26.61; n = 1660] following an intensive supervised care period (mean 14.84 days, n = 1660). Limb volume further reduced by 1.42% (95% CI 0.76-2.07; n = 1259) at the first follow-up visit (mean 81.45 days), and by 2.3% between the first and second follow-up visits (mean 231.32 days) (95% CI 1.26-3.34; n = 796). BEEPs were reduced upon follow-up; excoriations (78.4%) and intertrigo (26.7%) were reduced at discharge and further improvements was achieved at the follow-up visits. In total, 4% of patients exhibited new BEEPs at the first follow-up [eczema (3.9%), folliculitis (6.5%), excoriations (11.9%) and intertrigo (15.4%); 4 of 7 BEEPs were recorded]. HRQoL, measured using the disease-specific Lymphatic Filariasis Specific Quality of Life Questionnaire, showed an average score of 73.9 on admission, which increased by 17.8 at the first follow-up and 18.6 at the second follow-up. No patients developed new cellulitis episodes at the first follow-up, and only five patients (5.3%) developed new episodes of cellulitis at the second follow-up. CONCLUSIONS: IM for lower-limb lymphoedema successfully reduces limb volume and episodes of cellulitis, and also reduces BEEPs, leading to improved HRQoL. IM aligns with the LF treatment goals of the WHO and is a low-cost, predominantly self-care management protocol. IM has the potential to change care models and improve the lives of patients with lymphoedema.

Evolution of chloroplast retrograde signaling facilitates green plant adaptation to land.

Chloroplast retrograde signaling networks are vital for chloroplast biogenesis, operation, and signaling, including excess light and drought stress signaling. To date, retrograde signaling has been considered in the context of land plant adaptation, but not regarding the origin and evolution of signaling cascades linking chloroplast function to stomatal regulation. We show that key elements of the chloroplast retrograde signaling process, the nucleotide phosphatase (SAL1) and 3'-phosphoadenosine-5'-phosphate (PAP) metabolism, evolved in streptophyte algae-the algal ancestors of land plants. We discover an early evolution of SAL1-PAP chloroplast retrograde signaling in stomatal regulation based on conserved gene and protein structure, function, and enzyme activity and transit peptides of SAL1s in species including flowering plants, the fern Ceratopteris richardii, and the moss Physcomitrella patens Moreover, we demonstrate that PAP regulates stomatal closure via secondary messengers and ion transport in guard cells of these diverse lineages. The origin of stomata facilitated gas exchange in the earliest land plants. Our findings suggest that the conquest of land by plants was enabled by rapid response to drought stress through the deployment of an ancestral SAL1-PAP signaling pathway, intersecting with the core abscisic acid signaling in stomatal guard cells.

Evolution of rapid blue-light response linked to explosive diversification of ferns in angiosperm forests.

Ferns appear in the fossil record some 200 Myr before angiosperms. However, as angiosperm-dominated forest canopies emerged in the Cretaceous period there was an explosive diversification of modern (leptosporangiate) ferns, which thrived in low, blue-enhanced light beneath angiosperm canopies. A mechanistic explanation for this transformative event in the diversification of ferns has remained elusive. We used physiological assays, transcriptome analysis and evolutionary bioinformatics to investigate a potential connection between the evolution of enhanced stomatal sensitivity to blue light in modern ferns and the rise of angiosperm-dominated forests in the geological record. We demonstrate that members of the largest subclade of leptosporangiate ferns, Polypodiales, have significantly faster stomatal response to blue light than more ancient fern lineages and a representative angiosperm. We link this higher sensitivity to levels of differentially expressed genes in blue-light signaling, particularly in the cryptochrome (CRY) signaling pathway. Moreover, CRYs of the Polypodiales examined show gene duplication events between 212.9-196.9 and 164.4-151.8 Ma, when angiosperms were emerging, which are lacking in other major clades of extant land plants. These findings suggest that evolution of stomatal blue-light sensitivity helped modern ferns exploit the shady habitat beneath angiosperm forest canopies, fueling their Cretaceous hyperdiversification.

Evolutionary Conservation of ABA Signaling for Stomatal Closure.

Abscisic acid (ABA)-driven stomatal regulation reportedly evolved after the divergence of ferns, during the early evolution of seed plants approximately 360 million years ago. This hypothesis is based on the observation that the stomata of certain fern species are unresponsive to ABA, but exhibit passive hydraulic control. However, ABA-induced stomatal closure was detected in some mosses and lycophytes. Here, we observed that a number of ABA signaling and membrane transporter protein families diversified over the evolutionary history of land plants. The aquatic ferns Azolla filiculoides and Salvinia cucullata have representatives of 23 families of proteins orthologous to those of Arabidopsis (Arabidopsis thaliana) and all other land plant species studied. Phylogenetic analysis of the key ABA signaling proteins indicates an evolutionarily conserved stomatal response to ABA. Moreover, comparative transcriptomic analysis has identified a suite of ABA-responsive genes that differentially expressed in a terrestrial fern species, Polystichum proliferum These genes encode proteins associated with ABA biosynthesis, transport, reception, transcription, signaling, and ion and sugar transport, which fit the general ABA signaling pathway constructed from Arabidopsis and Hordeum vulgare The retention of these key ABA-responsive genes could have had a profound effect on the adaptation of ferns to dry conditions. Furthermore, stomatal assays have shown the primary evidence for ABA-induced closure of stomata in two terrestrial fern species Pproliferum and Nephrolepis exaltata In summary, we report, to our knowledge, new molecular and physiological evidence for the presence of active stomatal control in ferns.

Comparing optimal and empirical stomatal conductance models for application in Earth system models.

Earth system models (ESMs) rely on the calculation of canopy conductance in land surface models (LSMs) to quantify the partitioning of land surface energy, water, and CO2 fluxes. This is achieved by scaling stomatal conductance, gw , determined from physiological models developed for leaves. Traditionally, models for gw have been semi-empirical, combining physiological functions with empirically determined calibration constants. More recently, optimization theory has been applied to model gw in LSMs under the premise that it has a stronger grounding in physiological theory and might ultimately lead to improved predictive accuracy. However, this premise has not been thoroughly tested. Using original field data from contrasting forest systems, we compare a widely used empirical type and a more recently developed optimization-type gw model, termed BB and MED, respectively. Overall, we find no difference between the two models when used to simulate gw from photosynthesis data, or leaf gas exchange from a coupled photosynthesis-conductance model, or gross primary productivity and evapotranspiration for a FLUXNET tower site with the CLM5 community LSM. Field measurements reveal that the key fitted parameters for BB and MED, g1B and g1M, exhibit strong species specificity in magnitude and sensitivity to CO2 , and CLM5 simulations reveal that failure to include this sensitivity can result in significant overestimates of evapotranspiration for high-CO2 scenarios. Further, we show that g1B and g1M can be determined from mean ci /ca (ratio of leaf intercellular to ambient CO2 concentration). Applying this relationship with ci /ca values derived from a leaf δ13 C database, we obtain a global distribution of g1B and g1M , and these values correlate significantly with mean annual precipitation. This provides a new methodology for global parameterization of the BB and MED models in LSMs, tied directly to leaf physiology but unconstrained by spatial boundaries separating designated biomes or plant functional types.

Chronic oedema: a prevalent health care problem for UK health services.

Chronic oedema (CO) is a major clinical problem worldwide, which has many important secondary consequences for health, activity and participation. Effective treatment planning and organisation of services is dependent on an understanding of the condition and its epidemiology. This cross-sectional study was designed to estimate the point prevalence of CO within the health services of one UK urban population and to determine the proportions that have concurrent leg ulceration. Patients with CO in all anatomic sites were ascertained by health care professionals in one acute and one community hospital, all relevant outpatient and community nursing services, general practices and all nursing/residential homes in one urban catchment area (Derby City). The presence and distribution of oedema was confirmed through a brief clinical examination. A battery of demographic and clinical details was recorded for each case. Within the study population of Derby City residents, 971 patients were identified with CO [estimated crude prevalence 3·93 per 1000, 95% confidence interval (CI) 3·69-4·19]. The prevalence was the highest among those aged 85 or above (28·75 per 1000) and was higher among women (5·37 per 1000) than men (2·48 per 1000). The prevalence among hospital inpatients was 28·5%. Only five (3%) patients in the community population had oedema related to cancer or cancer treatment. Of the 304 patients identified with oedema from the Derby hospitals or community health services, 121 (40%) had a concurrent leg ulcer. Prevalence statistics and current demographic trends indicate that CO is a major and growing health care problem.

No evidence of general CO2 insensitivity in ferns: one stomatal control mechanism for all land plants?

Stomatal regulation of plant carbon uptake and water loss under changing environmental conditions was a crucial evolutionary step in the colonization of land by plants. There are currently two conflicting models describing the nature of stomatal regulation across terrestrial vascular plants: the first is characterized by a fundamental mechanistic similarity across all lineages, and the second is characterized by the evolution of major differences in angiosperms compared with more ancient lineages. Specifically, the second model posits that stomata of ferns lack a response to elevated atmospheric CO2 concentration (ca ) and therefore cannot regulate leaf intercellular CO2 concentration (ci ). We compared stomatal sensitivity to changes in ca in three distantly related fern species and a representative angiosperm species. Fern and angiosperm stomata responded strongly and similarly to changes in ca . As a result, ci /ca was maintained within narrow limits during ca changes. Our results challenge the model in which stomata of ferns generally lack a response to elevated ca and that angiosperms evolved new dynamic mechanisms for regulating leaf gas exchange that differ fundamentally from ferns. Instead, the results are consistent with a universal stomatal control mechanism that is fundamentally conserved across ferns and angiosperms, and therefore likely all vascular plant divisions.

Optimal allocation of leaf epidermal area for gas exchange.

A long-standing research focus in phytology has been to understand how plants allocate leaf epidermal space to stomata in order to achieve an economic balance between the plant's carbon needs and water use. Here, we present a quantitative theoretical framework to predict allometric relationships between morphological stomatal traits in relation to leaf gas exchange and the required allocation of epidermal area to stomata. Our theoretical framework was derived from first principles of diffusion and geometry based on the hypothesis that selection for higher anatomical maximum stomatal conductance (gsmax ) involves a trade-off to minimize the fraction of the epidermis that is allocated to stomata. Predicted allometric relationships between stomatal traits were tested with a comprehensive compilation of published and unpublished data on 1057 species from all major clades. In support of our theoretical framework, stomatal traits of this phylogenetically diverse sample reflect spatially optimal allometry that minimizes investment in the allocation of epidermal area when plants evolve towards higher gsmax . Our results specifically highlight that the stomatal morphology of angiosperms evolved along spatially optimal allometric relationships. We propose that the resulting wide range of viable stomatal trait combinations equips angiosperms with developmental and evolutionary flexibility in leaf gas exchange unrivalled by gymnosperms and pteridophytes.

Management of Patients With Venous Leg Ulcers: Challenges and Current Best Practice.

Introduction It is well documented that the prevalence of venous leg ulcers (VLUs) is increasing, coinciding with an ageing population. Accurate global prevalence of VLUs is difficult to estimate due to the range of methodologies used in studies and accuracy of reporting. (1) Venous ulceration is the most common type of leg ulceration and a significant clinical problem, affecting approximately 1% of the population and 3% of people over 80 years of age (2) in westernised countries. Moreover, the global prevalence of VLUs is predicted to escalate dramatically, as people are living longer, often with multiple comorbidities. Recent figures on the prevalence of VLUs are based on a small number of studies, conducted in Western countries, and the evidence is weak. However, it is estimated that 93% of VLUs will heal in 12 months, and 7% remain unhealed after five years. (3) Furthermore, the recurrence rate within 3 months after wound closure is as high as 70%. (4) (-6) Thus, cost-effective adjunct evidence-based treatment strategies and services are needed to help prevent these ulcers, facilitate healing when they occur and prevent recurrence. The impact of a VLU represents social, personal, financial and psychological costs on the individual and further economic drain on the health-care system. This brings the challenge of providing a standardised leg ulcer service which delivers evidence-based treatment for the patient and their ulcer. It is recognised there are variations in practice and barriers preventing the implementation of best practice. There are patients not receiving appropriate and timely treatment in the initial development of VLUs, effective management of their VLU and preventing recurrence once the VLU has healed. Health-care professionals (HCPs) and organisations must have confidence in the development process of clinical practice guidelines and have ownership of these guidelines to ensure those of the highest quality guide their practice. These systematic judgments can assist in policy development, and decision making, improve communication, reduce errors and improve patient outcomes. There is an abundance of studies and guidelines that are available and regularly updated, however, there is still variation in the quality of the services offered to patients with a VLU. There are also variations in the evidence and some recommendations contradict each other, which can cause confusion and be a barrier to implementation. (7) The difference in health-care organisational structures, management support and the responsibility of VLU management can vary in different countries, often causing confusion and a barrier to seeking treatment. These factors further complicate the guideline implementation process, which is generally known to be a challenge with many diseases. (8).

Increasing water-use efficiency directly through genetic manipulation of stomatal density.

Improvement in crop water-use efficiency (WUE) is a critical priority for regions facing increased drought or diminished groundwater resources. Despite new tools for the manipulation of stomatal development, the engineering of plants with high WUE remains a challenge. We used Arabidopsis epidermal patterning factor (EPF) mutants exhibiting altered stomatal density to test whether WUE could be improved directly by manipulation of the genes controlling stomatal density. Specifically, we tested whether constitutive overexpression of EPF2 reduced stomatal density and maximum stomatal conductance (gw(max) ) sufficiently to increase WUE. We found that a reduction in gw(max) via reduced stomatal density in EPF2-overexpressing plants (EPF2OE) increased both instantaneous and long-term WUE without altering significantly the photosynthetic capacity. Conversely, plants lacking both EPF1 and EPF2 expression (epf1epf2) exhibited higher stomatal density, higher gw(max) and lower instantaneous WUE, as well as lower (but not significantly so) long-term WUE. Targeted genetic modification of stomatal conductance, such as in EPF2OE, is a viable approach for the engineering of higher WUE in crops, particularly in future high-carbon-dioxide (CO2 ) atmospheres.

Increasing leaf hydraulic conductance with transpiration rate minimizes the water potential drawdown from stem to leaf.

Leaf hydraulic conductance (k leaf) is a central element in the regulation of leaf water balance but the properties of k leaf remain uncertain. Here, the evidence for the following two models for k leaf in well-hydrated plants is evaluated: (i) k leaf is constant or (ii) k leaf increases as transpiration rate (E) increases. The difference between stem and leaf water potential (ΔΨstem-leaf), stomatal conductance (g s), k leaf, and E over a diurnal cycle for three angiosperm and gymnosperm tree species growing in a common garden, and for Helianthus annuus plants grown under sub-ambient, ambient, and elevated atmospheric CO2 concentration were evaluated. Results show that for well-watered plants k leaf is positively dependent on E. Here, this property is termed the dynamic conductance, k leaf(E), which incorporates the inherent k leaf at zero E, which is distinguished as the static conductance, k leaf(0). Growth under different CO2 concentrations maintained the same relationship between k leaf and E, resulting in similar k leaf(0), while operating along different regions of the curve owing to the influence of CO2 on g s. The positive relationship between k leaf and E minimized variation in ΔΨstem-leaf. This enables leaves to minimize variation in Ψleaf and maximize g s and CO2 assimilation rate over the diurnal course of evaporative demand.

Sensitivity of plants to changing atmospheric CO2 concentration: from the geological past to the next century.

The rate of CO(2) assimilation by plants is directly influenced by the concentration of CO(2) in the atmosphere, c(a). As an environmental variable, c(a) also has a unique global and historic significance. Although relatively stable and uniform in the short term, global c(a) has varied substantially on the timescale of thousands to millions of years, and currently is increasing at seemingly an unprecedented rate. This may exert profound impacts on both climate and plant function. Here we utilise extensive datasets and models to develop an integrated, multi-scale assessment of the impact of changing c(a) on plant carbon dioxide uptake and water use. We find that, overall, the sensitivity of plants to rising or falling c(a) is qualitatively similar across all scales considered. It is characterised by an adaptive feedback response that tends to maintain 1 - c(i)/c(a), the relative gradient for CO(2) diffusion into the leaf, relatively constant. This is achieved through predictable adjustments to stomatal anatomy and chloroplast biochemistry. Importantly, the long-term response to changing c(a) can be described by simple equations rooted in the formulation of more commonly studied short-term responses.

Smaller, faster stomata: scaling of stomatal size, rate of response, and stomatal conductance.

Maximum and minimum stomatal conductance, as well as stomatal size and rate of response, are known to vary widely across plant species, but the functional relationship between these static and dynamic stomatal properties is unknown. The objective of this study was to test three hypotheses: (i) operating stomatal conductance under standard conditions (g (op)) correlates with minimum stomatal conductance prior to morning light [g (min(dawn))]; (ii) stomatal size (S) is negatively correlated with g (op) and the maximum rate of stomatal opening in response to light, (dg/dt)(max); and (iii) g (op) correlates negatively with instantaneous water-use efficiency (WUE) despite positive correlations with maximum rate of carboxylation (Vc (max)) and light-saturated rate of electron transport (J (max)). Using five closely related species of the genus Banksia, the above variables were measured, and it was found that all three hypotheses were supported by the results. Overall, this indicates that leaves built for higher rates of gas exchange have smaller stomata and faster dynamic characteristics. With the aid of a stomatal control model, it is demonstrated that higher g (op) can potentially expose plants to larger tissue water potential gradients, and that faster stomatal response times can help offset this risk.

Evaluation of the performance of a new compression system in patients with lymphoedema.

In the acute phase of lymphoedema, patients require comprehensive decongestive therapy (CDT), which includes skin care, an exercise regimen, manual lymphatic drainage (MLD) and regular bandaging. This study was established to determine the effectiveness of a new system of bandage therapy, the 3M™ Coban™ 2 compression system. In total, 24 patients were entered into the study (12 from UK and 12 from Canada) with a variety of clinical presentations. The mean age of the groups was 57·4 years, which varied from 26 to 79 years. Body mass index (BMI) averaged 38·9 kg/m(2), with a range from 22·7 to 67·5 kg/m(2). Of the total, eight were women with arm lymphoedema, the remainder being men and women with lymphoedema of the lower limb. All were considered to be in need of CDT. After 19 days, the reduction of limb volume was measured, which indicated a mean limb volume reduction of 1210 ml (95% confidence interval, CI, 780-1641, P < 0·001). Leg affected patients experienced greater reduction than arm affected patients (1596 ml versus 438 ml), although both groups experienced significant reduction in limb volumes (both P < 0·001). Mean percentage changes in limb volume were 14·9% and 16·1% for legs and arms, respectively. The Measure Your Medical Outcome Profile questionnaire indicated significant improvement in symptoms considered important by the patient (P < 0·0001), which also led to improvements in skin quality by reducing skin thickness and firmness. The Coban 2 compression system provides good oedema reduction in both arms and legs to reduce limb volume and improvements in symptoms associated with lymphoedema.

A Prospective Preliminary Study Examining the Physiological Impact of Pneumatic Compression Dosing in the Treatment of Lower Extremity Lymphedema.

Background: Optimal frequency and duration of pneumatic compression device (PCD) therapy for lymphedema is undetermined. This prospective, randomized preliminary study evaluated the impact of different PCD dosing protocols on physiological and patient-reported outcomes (PROs) to estimate treatment effects, assess the responsiveness of various measurement techniques, and identify endpoints for a definitive PCD dosing trial. Methods and Results: Twenty-one patients with lower extremity lymphedema were randomized into three groups for treatment with the Flexitouch advanced PCD: (A) once per day for 1 hour, 12 consecutive days; (B) twice per day in 1-hour treatments, 5 consecutive days; or (C) twice per day in 2-hour treatments, 5 consecutive days. Outcomes measured were changes in limb volume (LV), tissue fluid, tissue tone, and PROs. Those in group A experienced mean (standard deviation) LV reductions of 109 (58) mL (p = 0.003) on day 1 and of 97 (86) mL (p = 0.024) on day 5. Group A also showed possible single-treatment decreases in extracellular fluid volume by bioimpedance spectroscopy (BIS) on day 5. There were no consistent changes in groups B and C. Long-term assessment of LV and BIS showed no clear change. Tonometry, ultrasound, local tissue water, and PROs showed wide variation among participants. Conclusions: LV measurements showed potential benefit for 1-hour daily PCD treatment. A definitive dosing trial should include LV, BIS, and PROs in a comparison of 1- and 2-hour daily treatment protocols conducted over a study period of 4 weeks. These data may inform appropriate outcome measures for other intervention studies in lymphedema.