Living jewels: iterative evolution of iridescent blue leaves from helicoidal cell walls.

BACKGROUND AND AIMS: Structural colour is responsible for the remarkable metallic blue colour seen in the leaves of several plants. Species belonging to only ten genera have been investigated to date, revealing four photonic structures responsible for structurally coloured leaves. One of these is the helicoidal cell wall, known to create structural colour in the leaf cells of five taxa. Here we investigate a broad selection of land plants to understand the phylogenetic distribution of this photonic structure in leaves. METHODS: We identified helicoidal structures in the leaf epidermal cells of 19 species using transmission electron microscopy. Pitch measurements of the helicoids were compared with the reflectance spectra of circularly polarized light from the cells to confirm the structure-colour relationship. RESULTS: By incorporating species examined with a polarizing filter, our results increase the number of taxa with photonic helicoidal cell walls to species belonging to at least 35 genera. These include 19 monocot genera, from the orders Asparagales (Orchidaceae) and Poales (Cyperaceae, Eriocaulaceae, Rapateaceae) and 16 fern genera, from the orders Marattiales (Marattiaceae), Schizaeales (Anemiaceae) and Polypodiales (Blechnaceae, Dryopteridaceae, Lomariopsidaceae, Polypodiaceae, Pteridaceae, Tectariaceae). CONCLUSIONS: Our investigation adds considerably to the recorded diversity of plants with structurally coloured leaves. The iterative evolution of photonic helicoidal walls has resulted in a broad phylogenetic distribution, centred on ferns and monocots. We speculate that the primary function of the helicoidal wall is to provide strength and support, so structural colour could have evolved as a potentially beneficial chance function of this structure.

Using structural colour to track length scale of cell-wall layers in developing Pollia japonica fruits.

Helicoidally arranged layers of cellulose microfibrils in plant cell walls can produce strong and vivid coloration in a wide range of species. Despite its significance, the morphogenesis of cell walls, whether reflective or not, is not fully understood. Here we show that by optically monitoring the reflectance of Pollia japonica fruits during development we can directly map structural changes of the cell wall on a scale of tens of nanometres. Visible-light reflectance spectra from individual living cells were measured throughout the fruit maturation process and compared with numerical models. Our analysis reveals that periodic spacing of the helicoidal architecture remains unchanged throughout fruit development, suggesting that interactions in the cell-wall polysaccharides lead to a fixed twisting angle of cellulose helicoids in the cell wall. By contrast with conventional electron microscopy, which requires analysis of different fixed specimens at different stages of development, the noninvasive optical technique we present allowed us to directly monitor live structural changes in biological photonic systems as they develop. This method therefore is applicable to investigations of photonic tissues in other organisms.

Embolism resistance in petioles and leaflets of palms.

BACKGROUND AND AIMS: Hydraulic studies are currently biased towards conifers and dicotyledonous angiosperms; responses of arborescent monocots to increasing temperature and drought remain poorly known. This study aims to assess xylem resistance to drought-induced embolism in palms. METHODS: We quantified embolism resistance via P50 (xylem pressure inducing 50 % embolism or loss of hydraulic conductivity) in petioles and leaflets of six palm species differing in habitat and phylogenetic relatedness using three techniques: in vivo X-ray-based microcomputed tomography, the in situ flow centrifuge technique and the optical vulnerability method. KEY RESULTS: Our results show that P50 of petioles varies greatly in the palm family, from -2.2 ± 0.4 MPa in Dypsis baronii to -5.8 ± 0.3 MPa in Rhapis excelsa (mean ± s.e.). No difference or weak differences were found between petioles and leaf blades within species. Surprisingly, where differences occurred, leaflets were less vulnerable to embolism than petioles. Embolism resistance was not correlated with conduit size (r = 0.37, P = 0.11). CONCLUSIONS: This study represents the first estimate of drought-induced xylem embolism in palms across biomes and provides the first step towards understanding hydraulic adaptations in long-lived arborescent monocots. It showed an almost 3-fold range of embolism resistance between palm species, as large as that reported in all angiosperms. We found little evidence for hydraulic segmentation between leaflets and petioles in palms, suggesting that when it happens, hydraulic segregation may lack a clear relationship with organ cost or replaceability.

[Management of puncture pain in hospitalized children]. / Manejo del dolor por punción en niños hospitalizados.

Punctures are the main cause of pain during hospitalization in pediatrics. The application of a protocolized management improves the hospitalization experience. OBJECTIVE: To describe the in troduction of different strategies aimed at relieving pain associated with punctures in a pediatric middle care unit. PATIENTS AND METHOD: Descriptive retrospective study carried out between Octo ber 2018 and May 2020 in a pediatric intermediate care unit of the HCUC (Santiago, Chile). Data analysis included demographic information, type of painful procedure, therapeutic intervention, duration of the procedure, pain scales (CHEOPS and Frankl), and parent/caregiver opinion survey. RESULTS: 89 procedures, in 72 children, mean age 4.5 years. The most frequent painful procedure was Peripheral venous catheter insertion in 41.6% (n = 37) of children, with a mean duration of 7.5 min. The most used therapeutic intervention was the application of topical 4% lidocaine in 76% (n = 68); 73% of the patients presented an evident positive behavior according to the FRANKL scale and, according to CHEOPS, 77.5% presented mild pain. The parent/caregiver survey showed that 79% reported less pain compared with previous puncture episodes, and 98% would request the same measures next time. CONCLUSIONS: The application of different strategies to manage pain caused by punctures is associated with low pain scores and favorable parental acceptance. The use of standardized management protocols could allow better approaches and experiences for patients and their parents/caregivers at low cost and easy applicability.

Impact of COVID-19 lockdown on glucemic control in children and adolescents with type 1 diabetes mellitus.

BACKGROUND AND AIMS: To face the rapid spread of SARS-CoV2 coronavirus pandemic, home lockdown in Spain was decreed on 15th March 2020. The main objective of this study is to evaluate the impact of this constraint on glycemic control in children and adolescents with type 1 diabetes mellitus (T1D). PATIENTS AND METHODS: Observational, retrospective study in children and adolescents with T1D users of interstitial glucose monitoring systems. The following information corresponding to the last 2 weeks of lockdown was collected for subsequent comparison with data of 2 weeks prior to quarantine: daily insulin needs, mean interstitial glucose, estimated HbA1c, coefficient of variation (CV), time in range (70-180mg/dl), hypoglycemia (<70 and <54mg/dl) and hyperglycemia (>180 and> 250mg/dl), sensor use and number of blood glucose measurements. Data about meal routines, physical exercise, need for adjustments in therapy, acute complications and lockdown of caregivers were assessed via a survey. RESULTS: 80 patients were studied (mean age 12.61±3.32 years, mean time of evolution of the disease 5.85±3.92 years), 66.2% treated with an insulin pump, users of following glucose monitoring systems: Guardian 3 (65%), FreeStyle Libre (18.8%) and Dexcom G6 (16.2%). Time in range in the cohort increased significantly during confinement (72.1±10.5 vs 74.8±10.5%; P=0.011) with lower time in hypoglycemia both <70mg/dl (4.6±3.2 vs 3.2±2.7%; P<0.001) and <54mg/dl (1.2±1.6 vs 0.7±1.2%; P<0.001) and hyperglycemia >250mg/dl (4.6±3.9 vs 3.7±3.7%; P=0.038). CV also decreased (35.8±6.3 vs 33.1±6.1%; P<0.001). Patients treated with multiple doses of insulin and poorer baseline glycemic control experienced greatest improvement. Daily insulin requirements remained stable. Regular practice of physical exercise and caregivers' confinement did not have a significant impact. CONCLUSIONS: Glycemic control in children and adolescents with T1D improved during quarantine, particularly in those with worse baseline control.

Retrospective clinical evaluation of root canal treatment with or without photodynamic therapy for necrotic teeth and teeth subjected to retreatment.

PURPOSE: To compare the effect of photodynamic therapy (PDT) as a procedure to complement root canal treatment (RCT), for both primary treatment and retreatment. METHODS: This was a retrospective study based on analysis of clinical records. A total of 214 teeth that had undergone RCT on either a primary or retreatment basis, with or without complementary PDT, were evaluated. For 118 teeth that met the previously established inclusion criteria, the time until healing was evaluated. Complementarily, the need for application of calcium hydroxide (CaHy) between visits and the number of visits necessary for completing the treatment were assessed. Data were analyzed using the Mann-Whitney and χ2 tests with a significance level of P < 0.05. RESULTS: Periapical radiolucency resolution was achieved at 15 ± 9.33 months in the RCT + PDT group and 20.35 ± 22.1 months in the RCT group (P = 0.07). For primary treatment, CaHy was necessary in 72.4% of the RCT cases and 16.4% of the RCT + PDT cases (P < 0.01). For retreatment cases, CaHy was used in 82.7% of the RCT cases and 17% of the RCT + PDT cases (P < 0.01). In the RCT group, more than two visits were necessary for primary treatment in 18.6% of the cases, compared with 13.10% in the RCT + PDT group (P = 0.31), whereas for retreatment, more than two visits were necessary for 64.9% and 49.1% of cases, respectively (P = 0.05). CONCLUSION: In comparison with RCT alone, teeth receiving RCT + PDT showed less variation in the time needed for periapical lesion healing, fewer cases required CaHy, and fewer cases required more than two visits to complete the treatment.

[Impact of COVID-19 lockdown on glucemic control in children and adolescents with type 1 diabetes mellitus]. / Repercusión del confinamiento por COVID-19 sobre el control glucémico en niños y adolescentes con diabetes mellitus tipo 1.

BACKGROUND AND AIMS: To face the rapid spread of SARS-CoV-2 coronavirus pandemic, home lockdown in Spain was decreed on 15th March 2020. The main objective of this study is to evaluate the impact of this constraint on glycemic control in children and adolescents with type 1 diabetes mellitus (T1D). PATIENTS AND METHODS: Observational, retrospective study in children and adolescents with T1D users of interstitial glucose monitoring systems. The following information corresponding to the last 2 weeks of lockdown was collected for subsequent comparison with data of 2 weeks prior to quarantine: daily insulin needs, mean interstitial glucose, estimated HbA1c, coefficient of variation (CV), time in range (70-180mg/dl), hypoglycemia (<70 and <54mg/dl), and hyperglycemia (>180 and>250mg/dl), sensor use and number of blood glucose measurements. Data about meal routines, physical exercise, need for adjustments in therapy, acute complications, and lockdown of caregivers were assessed via a survey. RESULTS: 80 patients were studied (mean age 12.61±3.32 years, mean time of evolution of the disease 5.85±3.92 years), 66.2% treated with an insulin pump, users of following glucose monitoring systems: GuardianTM 3 (65%), FreeStyle LibreTM (18.8%) and Dexcom G6TM (16.2%). Time in range in the cohort increased significantly during confinement (72.1±10.5 vs. 74.8±10.5%; P=.011) with lower time in hypoglycemia both<70mg/dl (4.6±3.2 vs. 3.2±2.7%; P<.001) and<54mg/dl (1.2±1.6 vs. 0.7±1.2%; p<0.001) and hyperglycemia >250mg/dl (4.6±3.9 vs. 3.7±3.7%; P=.038). CV also decreased (35.8±6.3 vs. 33.1±6.1%; P<.001). Patients treated with multiple doses of insulin and poorer baseline glycemic control experienced greatest improvement. Daily insulin requirements remained stable. Regular practice of physical exercise and caregivers' confinement did not have a significant impact. CONCLUSIONS: Glycemic control in children and adolescents with T1D improved during quarantine, particularly in those with worse baseline control.

[Pediatric tracheostomy: Ten year experience in an Intensive Care Unit]. / Traqueostomía en niños: Experiencia de 10 años en una Unidad de Cuidados Intensivos Pediátricos.

INTRODUCTION: Pediatric tracheostomy indications have changed over the last 30 years, from acute and transient pro cedures secondary to airway obstruction to programmed tracheostomies indicated due to the need for chronic use of mechanical ventilation (MV). OBJECTIVE: To describe indications and morbidity associated with pediatric tracheostomies during a ten-year period. PATIENTS AND METHODS: Descrip tive study. Clinical records review of discharged patients (< 15 years old) tracheostomized during their hospital stay between 2005 and 2015. Demographic and clinical variables were evaluated before and after tracheostomy, stay in intensive care unit, age at the time of the tracheostomy, indication of tracheostomy, early complications (< 7 days), late complications (> 7 days), and mortality. RESULTS: 59 children with tracheostomy were analyzed, 36 (59%) tracheostomies were performed in children under 6 months, and 39 (60%) in males. 23 (39%) had a confirmed or under study genopathy and 25 (42%) had congenital heart disease. The main indications for tracheostomy were 58% secondary to airway disease and 42% due to chronic use of MV. Within the airway disease group, subglottic steno sis, vocal cord paralysis, and tracheobronchomalacia were the principal reasons for indication, and in the group of chronic use of MV, the main causes were bronchopulmonary dysplasia and chronic lung disease. We did not find tracheostomy-related mortality. 89% of the patients were discharged with tracheostomy and 59% with chronic use of MV. The probability of being discharged with a tracheos tomy was higher in younger patients while the chronic use of MV at discharge was higher in patients with a greater number of extubation failures before tracheostomy. CONCLUSION: Tracheostomy is a safe procedure in children, where the predominant causes of indication are airway disease and the need for chronic use of MV. Most children with tracheostomies are discharged with tracheostomy and chronic use of MV. Younger children, those with difficult weaning, confirmed or suspected ge nopathy, or special health needs are at greater risk of needing tracheostomy and chronic use of MV.

Viburnum tinus Fruits Use Lipids to Produce Metallic Blue Structural Color.

Viburnum tinus is an evergreen shrub that is native to the Mediterranean region but cultivated widely in Europe and around the world. It produces ripe metallic blue fruits throughout winter [1]. Despite its limited fleshy pulp [2], its high lipid content [3] makes it a valuable resource to the small birds [4] that act as its seed-dispersers [5]. Here, we find that the metallic blue appearance of the fruits is produced by globular lipid inclusions arranged in a disordered multilayer structure. This structure is embedded in the cell walls of the epicarp and underlaid with a dark layer of anthocyanin pigments. The presence of such large, organized lipid aggregates in plant cell walls represents a new mechanism for structural coloration and may serve as an honest signal of nutritional content.

Assessing Extreme Seed Longevity: The Value of Historic Botanical Collections to Modern Research.

Botanical, historical, and archaeological collections have been the source of extraordinarily long-lived seeds, which have been used to revive extinct genotypes or species. The longest-lived example of a viable seed of known age is the date palm, Phoenix dactylifera L., of which an estimated 2000-year-old seed was germinated in 2005. Seed longevity is important for agriculture and biodiversity conservation, and understanding the basis for the extraordinary longevity of seeds from botanical collections could help improve seed banking technology. In this work, we studied the viability and structural features of date palm seeds collected in Baghdad in 1873 and stored in the Economic Botany Collection (EBC) at the Royal Botanic Gardens, Kew, and seeds collected in 2004 and stored dry at -20°C in the Millennium Seed Bank (MSB). Viability was studied by attempted seed germination and in vitro culture of embryos, and structural features were studied by X-rays, transmission electron microscopy, and differential scanning calorimetry. We found that the seeds preserved in the MSB did not decrease in viability, with ultrastructural features similar to those in freshly harvested seeds. In contrast, the 144-year-old seeds were dead, and large ultrastructural changes were observed, particularly in the storage lipids (size, distribution, and melting properties) and other storage constituents. These results contrast with previous reports that date seeds could remain viable for ∼2000 years in uncontrolled storage environments. We did not find that the postharvest treatment of the EBC seeds in the 19th century, or their storage conditions at Kew, was more deleterious than that which was likely encountered by the ∼2000-year-old seeds. These results highlight the role of well-documented collections in establishing whether reports of extraordinary longevity are ordinarily repeatable.

A Target Capture-Based Method to Estimate Ploidy From Herbarium Specimens.

Whole genome duplication (WGD) events are common in many plant lineages, but the ploidy status and possible occurrence of intraspecific ploidy variation are unknown for most species. Standard methods for ploidy determination are chromosome counting and flow cytometry approaches. While flow cytometry approaches typically use fresh tissue, an increasing number of studies have shown that recently dried specimens can be used to yield ploidy data. Recent studies have started to explore whether high-throughput sequencing (HTS) data can be used to assess ploidy levels by analyzing allelic frequencies from single copy nuclear genes. Here, we compare different approaches using a range of yam (Dioscorea) tissues of varying ages, drying methods and quality, including herbarium tissue. Our aims were to: (1) explore the limits of flow cytometry in estimating ploidy level from dried samples, including herbarium vouchers collected between 1831 and 2011, and (2) optimize a HTS-based method to estimate ploidy by considering allelic frequencies from nuclear genes obtained using a target-capture method. We show that, although flow cytometry can be used to estimate ploidy levels from herbarium specimens collected up to fifteen years ago, success rate is low (5.9%). We validated our HTS-based estimates of ploidy using 260 genes by benchmarking with dried samples of species of known ploidy (Dioscorea alata, D. communis, and D. sylvatica). Subsequently, we successfully applied the method to the 85 herbarium samples analyzed with flow cytometry, and successfully provided results for 91.7% of them, comprising species across the phylogenetic tree of Dioscorea. We also explored the limits of using this HTS-based approach for identifying high ploidy levels in herbarium material and the effects of heterozygosity and sequence coverage. Overall, we demonstrated that ploidy diversity within and between species may be ascertained from historical collections, allowing the determination of polyploidization events from samples collected up to two centuries ago. This approach has the potential to provide insights into the drivers and dynamics of ploidy level changes during plant evolution and crop domestication.

Arterial switch operation with separate coronary arteries arising from a single aortic sinus.

In some patients, the coronary arteries originate in a single aortic sinus, and this anatomical configuration is regarded as a significant risk factor in the arterial switch operation for transposition of the great arteries. In these cases, the coronary transfer technique has to be individualized to suit the coronary anatomy (i.e., a single ostium or separate ostia). Since 2001, we have operated on three patients who had separate coronary arteries arising from a single sinus. In one, coronary transfer was carried out using the double-button technique and, in the other two, using the aortocoronary flap technique. The aortocoronary flap procedure gave excellent results in patients with this coronary artery configuration.