Foliar water uptake does not contribute to embolism repair in beech (Fagus sylvatica L.)

BACKGROUND AND AIMS

Foliar water uptake has recently been suggested as a possible mechanism for the restoration of hydraulically dysfunctional xylem vessels. In this paper we used a combination of ecophysiological measurements, X-ray microcomputed tomography and cryo-scanning electron microscopy during a drought treatment to fully evaluate this hypothesis.

KEY RESULTS

Based on an assessment of these methods in beech (Fagus sylvatica L.) seedlings we were able to (1) confirm an increase in the amount of hydraulically redistributed water absorbed by leaves when the soil water potential decreased, and (2) locate this redistributed water in hydraulically active vessels in the stem. However, (3) no embolism repair was observed irrespective of the organ under investigation (i.e. stem, petiole or leaf) or the intensity of drought.

CONCLUSIONS

Our data provide evidence for a hydraulic pathway from the leaf surface to the stem xylem following a water potential gradient, but this pathway exists only in functional vessels and does not play a role in embolism repair for beech.

Identifying the pathways for foliar water uptake in beech (Fagus sylvatica L.): a major role for trichomes

Foliar water uptake (FWU), the direct uptake of water into leaves, is a global phenomenon, having been observed in an increasing number of plant species. Despite the growing recognition of its functional relevance, our understanding of how FWU occurs and which foliar surface structures are implicated, is limited. In the present study, fluorescent and ionic tracers, as well as microcomputed tomography, were used to assess potential pathways for water entry in leaves of beech, a widely distributed tree species from European temperate regions. Although none of the tracers entered the leaf through the stomatal pores, small amounts of silver precipitation were observed in some epidermal cells, indicating moderate cuticular uptake. Trichomes, however, were shown to absorb and redistribute considerable amounts of ionic and fluorescent tracers. Moreover, microcomputed tomography indicated that 72% of empty trichomes refilled during leaf surface wetting and microscopic investigations revealed that trichomes do not have a cuticle but are covered with a pectin-rich cell wall layer. Taken together, our findings demonstrate that foliar trichomes, which exhibit strong hygroscopic properties as a result of their structural and chemical design, constitute a major FWU pathway in beech.

Ideal Cardiovascular Health in the southern cone of Latin America

OBJECTIVE

The American Heart Association developed the concept of 'Ideal Cardiovascular Health', which is based on the presence of ideal levels across seven health factors. The goal of this study is to assess the prevalence of Ideal Cardiovascular Health in the Southern Cone of Latin America.

STUDY DESIGN

We conducted a cross-sectional analysis as part of CESCAS I cohort.

METHODS

This report included 5458 participants aged between 35 and 75 years who were selected using stratified multistage probability sampling in Argentina, Chile and Uruguay. Interviews included demographic information, the International Physical Activity Questionnaire, and a food frequency questionnaire on dietary habits. Participants were classified as current, former or non-smokers. Weight, height and blood pressure were measured by trained personnel, and fasting cholesterol and glucose plasma levels were measured.

RESULTS

Only 0.1% (95% confidence interval [CI]: 0.0-0.2) met the seven criteria that define the Ideal Cardiovascular Health. The least prevalent healthy behaviour was having a healthy diet: 0.5% (95% CI: 0.3-0.7), while the least prevalent health factor was having blood pressure < 120/80 mmHg: 23.6% (95% CI: 22.1-25.0).

CONCLUSIONS

The prevalence of Ideal Cardiovascular Health is very low in a representative sample of population from the Southern Cone of Latin America, and the levels of healthy lifestyle behaviours are even lower than ideal biochemical parameters. These results highlight the challenge of developing strategies to improve the levels of Ideal Cardiovascular Health at primary prevention levels.

Prevention of childhood obesity and food policies in Latin America: from research to practice

BACKGROUND

Addressing childhood obesity in Latin America requires a package of multisectoral, evidence-based policies that enable environments conducive to healthy lifestyles.

OBJECTIVE

Identify and examine key elements to translating research into effective obesity policies in Latin America.

METHODS

We examined obesity prevention policies through case studies developed with an expert in the specific policy. Policies were selected based on their level of implementation, visibility and potential impact to reduce childhood obesity. They include: (i) excise taxes on sugar sweetened beverages and energy-dense foods; (ii) front-of-package food label legislation; (iii) trans fatty acids removal from processed foods; and (iv) Ciclovías recreativas or 'open streets'. Case studies were coded to identify components that explained successful implementation and sustainability using the Complex Adaptive Health Systems framework.

RESULTS

The analysis identified key elements for effective and sustainable policy, including evidence justifying policy; evidence-based advocacy by civil society; political will; and legislation and skillful negotiations across government, academia, the private sector and civil society. Scientific evidence and evaluation played an important role in achieving tipping points for policies' launch and sustain effective implementation.

CONCLUSIONS

Well-coordinated, intersectoral partnerships are needed to successfully implement evidence-based anti-obesity policies. Prospective policy research may be useful for advancing knowledge translation.

Lower tract respiratory infection in children younger than 5 years of age and adverse pregnancy outcomes related to household air pollution in Bariloche (Argentina) and Temuco (Chile)

The main objective of this study was to evaluate the association between household air pollution with lower tract respiratory infection (LRTI) in children younger than 5 years old and adverse pregnancy outcomes. This retrospective cohort study took place in two cities in Patagonia. Using systemic random sampling, we selected households in which at least one child <5 years had lived and/or a child had been born alive or stillborn. Trained interviewers administered the questionnaire. We included 926 households with 695 pregnancies and 1074 children. Household cooking was conducted indoors in ventilated rooms and the use of wood as the principal fuel for cooking was lower in Temuco (13% vs. 17%). In exposed to biomass fuel use, the adjusted OR for LRTI was 1.87 (95% CI 0.98-3.55; P = 0.056) in Temuco and 1.12 (95% CI 0.61-2.05; P = 0.716) in Bariloche. For perinatal morbidity, the OR was 3.11 (95% CI 0.86-11.32; P = 0.084) and 1.41 (95% CI 0.50-3.97; P = 0.518), respectively. However, none of the effects were statistically significant (P > 0.05). The use of biomass fuel to cook in traditional cookstoves in ventilated dwellings may increase the risk of perinatal morbidity and LRTI.

Single point mutation detection in living cancer cells by far-red emitting PNA-FIT probes

Peptide nucleic acid bis-quinoline conjugates are reported as attractive far-red emitting probes that detect mutated mRNA in living cells at SNP resolution.

Effect of the ordered interfacial water layer in protein complex formation: A nonlocal electrostatic approach

Using a nonlocal electrostatic approach that incorporates the short-range structure of the contacting media, we evaluated the electrostatic contribution to the energy of the complex formation of two model proteins. In this study, we have demonstrated that the existence of an ordered interfacial water layer at the protein-solvent interface reduces the charging energy of the proteins in the aqueous solvent, and consequently increases the electrostatic contribution to the protein binding (change in free energy upon the complex formation of two proteins). This is in contrast with the finding of the continuum electrostatic model, which suggests that electrostatic interactions are not strong enough to compensate for the unfavorable desolvation effects.

Feasibility of day-case vitreoretinal surgery

PURPOSE

The indications for vitreoretinal (VR) surgery are increasing as equipment and techniques available improve. In order to decrease demand on limited health resources, day-case surgery would be beneficial in many cases. This study combines a retrospective and prospective arm to examine the feasibility and safety of routine day-case VR surgery.

METHODS

One hundred consecutive patients (50 retrospective and 50 prospective) undergoing VR surgery within the Royal Berkshire NHS trust were included. The retrospective arm aimed to identify the frequency and type of acute ophthalmic or medical intervention during postop overnight stay and the results were used to alter management in the prospective group. The prospective group consisted of patients undergoing a mixture of overnight stay and day-case surgery. All patients in the prospective group had routine subtenon marcaine anaesthesia together with prophylactic pre-operative intravenous acetazolamide. Patients deemed fit postoperatively were offered overnight ward discharge, with obligatory next-day review.

RESULTS

In the retrospective arm, 56% required oral nonsteroidal analgesia on the day of surgery and one patient required narcotic analgesia. Twenty-two per cent patients required intraocular pressure (IOP) control on the day of surgery and one patient required medical intervention in the form of urinary catheterisation. Nineteen patients required intervention on next-day review. In the prospective arm, 86% preferred day case and were suitable, 6% were suitable for day-case but preferred overnight stay and 8% were deemed not fit for discharge. No patient required narcotic analgesics. No patient discharged returned as a casualty overnight. Only one patient required topical beta-blocker for the control of IOP on next-day review.

CONCLUSIONS

These data suggest that many patients who are hospitalised overnight for VR surgery could be safely treated as day cases. Such a shift in the pattern of care for VR surgery could provide a significant improvement in health-care efficiency and minimise patient inconvenience.

Iatrogenic eccentric full thickness macular holes following vitrectomy with ILM peeling for idiopathic macular holes

PURPOSE

To document a previously unreported complication after vitrectomy with peeling of the internal limiting membrane (ILM) for idiopathic macular holes.

METHOD

Retrospective review of notes of 232 consecutive patients who underwent vitrectomy with peeling of the ILM for idiopathic macular holes from 1996 to 2001. Four patients were found to have eccentric iatrogenic macular holes postoperatively. Optical coherence tomography was used to evaluate these holes.

RESULTS

The idiopathic macular holes were graded from stages II to IV preoperatively with visual acuities from 6/18 to 6/60. All patients had surgery within 6 months of presentation. They underwent vitrectomy with complete separation of the posterior cortical vitreous, peeling of the ILM, injection of platelets (0.1 ml), and gas tamponade with SF6 20%. Postoperatively the patients postured strictly face down for 10 days. Follow-up ranged from 8 months to 6 years. Iatrogenic eccentric macular holes were noted postoperatively. The holes were located between 3 and 6 o'clock in three patients and at 9 o'clock in the fourth patient, relative to the macula. Optical coherence tomography showed them to be full thickness and completely flat. No further intervention was necessary. No complications have arisen during follow-up.

COMMENT

To our knowledge iatrogenic eccentric full thickness macular holes after macular hole surgery have never been reported. We believe that the location of the holes represents the initial site of ILM elevation. These holes are asymptomatic, have not required any treatment and have not caused any complications in up to 6 years of follow-up.