Understanding Low-Acuity Visits to the Pediatric Emergency Department

Background

Canadian pediatric emergency department visits are increasing, with a disproportionate increase in low-acuity visits locally (33% of volume in 2008-09, 41% in 2011-12). We sought to understand: 1) presentation patterns and resource implications; 2) parents’ perceptions and motivations; and 3) alternate health care options considered prior to presenting with low-acuity problems.

Methods

We conducted a prospective cohort study at our tertiary pediatric emergency department serving two provinces to explore differences between patients with and without a primary care provider. During four, 2-week study periods over 1 year, parents of low-acuity visits received an anonymous survey. Presentation times, interventions, diagnoses and dispositions were captured on a data collection form linked to the survey by study number.

Results

Parents completed 2,443 surveys (74.1% response rate), with survey-data collection form pairs available for 2,146 visits. Overall, 89.7% of respondents had a primary care provider; 68% were family physicians. Surprisingly, 40% of visits occurred during weekday office hours and 27.3% occurred within 4 hours of symptom onset; 67.5% of those early presenters were for injuries. Few parents sought care from their primary care provider (25%), health information line (20.7%), or urgent care clinic (18.5%); 36% reported that they believed their child’s problem required the emergency department. Forty-five percent required only a history, physical exam and reassurance; only 11% required an intervention not available in an office setting. Patients without a primary care provider were significantly more likely to present during weekday office hours (p = 0.003), have longer symptom duration (p<0.001), and not know of other options (p = 0.001).

Conclusions

Many parents seek pediatric emergency department care for low-acuity problems despite their child having a primary care provider. Ensuring timely access to these providers may help reduce pediatric emergency department overuse. Educational initiatives should inform parents about low-acuity problems and where appropriate care can/should be accessed.     

Revision of Launaea Cass. (Compositae) in Egypt with special references to cypselar diversity

A systematic revision for the species of Launaea Cass. in Egypt has revealed the presence of fourteen taxa belonging to 12 species, of which L. acanthodes (Boiss.) Kuntze is a new recorded. One new combination “L. fragilis subsp. tenuiloba (Boiss.) Zareh & Mohamed” is made. Achene diversity of the studied taxa of Launaea was studied using light and scanning electron microscopy. The taxonomic relationships between the studied taxa were discussed as well as SEM micrographs of achenes are provided. Synonyms and key for the identification of the investigated taxa based on morphological characters as well as notes on distribution are provided.     

Temtamy preaxial brachydactyly syndrome is caused by loss-of-function mutations in chondroitin synthase 1, a potential target of BMP signaling

Altered Bone Morphogenetic Protein (BMP) signaling leads to multiple developmental defects, including brachydactyly and deafness. Here we identify chondroitin synthase 1 (CHSY1) as a potential mediator of BMP effects. We show that loss of human CHSY1 function causes autosomal-recessive Temtamy preaxial brachydactyly syndrome (TPBS), mainly characterized by limb malformations, short stature, and hearing loss. After mapping the TPBS locus to chromosome 15q26-qterm, we identified causative mutations in five consanguineous TPBS families. In zebrafish, antisense-mediated chsy1 knockdown causes defects in multiple developmental processes, some of which are likely to also be causative in the etiology of TPBS. In the inner ears of zebrafish larvae, chsy1 is expressed similarly to the BMP inhibitor dan and in a complementary fashion to bmp2b. Furthermore, unrestricted Bmp2b signaling or loss of Dan activity leads to reduced chsy1 expression and, during epithelial morphogenesis, defects similar to those that occur upon Chsy1 inactivation, indicating that Bmp signaling affects inner-ear development by repressing chsy1. In addition, we obtained strikingly similar zebrafish phenotypes after chsy1 overexpression, which might explain why, in humans, brachydactyly can be caused by mutations leading either to loss or to gain of BMP signaling.     

A morphological and molecular study of <Emphasis Type="Italic">Anaplasma phagocytophilum</Emphasis> transmission events at the time of <Emphasis Type="Italic">Ixodes ricinus</Emphasis> tick bite

Background  

Anaplasma phagocytophilum is the causative agent of human granulocytic anaplasmosis (HGA) in humans and tick-borne fever (TBF) in ruminants. The bacterium invades and replicates in phagocytes, especially in polymorphonuclear granulocytes.     

Imaging Cell Wall Architecture in Single Zinnia elegans Tracheary Elements

The chemical and structural organization of the plant cell wall was examined in Zinnia elegans tracheary elements (TEs), which specialize by developing prominent secondary wall thickenings underlying the primary wall during xylogenesis in vitro. Three imaging platforms were used in conjunction with chemical extraction of wall components to investigate the composition and structure of single Zinnia TEs. Using fluorescence microscopy with a green fluorescent protein-tagged Clostridium thermocellum family 3 carbohydrate-binding module specific for crystalline cellulose, we found that cellulose accessibility and binding in TEs increased significantly following an acidified chlorite treatment. Examination of chemical composition by synchrotron radiation-based Fourier-transform infrared spectromicroscopy indicated a loss of lignin and a modest loss of other polysaccharides in treated TEs. Atomic force microscopy was used to extensively characterize the topography of cell wall surfaces in TEs, revealing an outer granular matrix covering the underlying meshwork of cellulose fibrils. The internal organization of TEs was determined using secondary wall fragments generated by sonication. Atomic force microscopy revealed that the resulting rings, spirals, and reticulate structures were composed of fibrils arranged in parallel. Based on these combined results, we generated an architectural model of Zinnia TEs composed of three layers: an outermost granular layer, a middle primary wall composed of a meshwork of cellulose fibrils, and inner secondary wall thickenings containing parallel cellulose fibrils. In addition to insights in plant biology, studies using Zinnia TEs could prove especially productive in assessing cell wall responses to enzymatic and microbial degradation, thus aiding current efforts in lignocellulosic biofuel production.The organization and molecular architecture of plant cell walls represent some of the most challenging problems in plant biology. Although much is known about general aspects of assembly and biosynthesis of the plant cell wall, the detailed three-dimensional molecular cell wall structure remains poorly understood. The highly complex and dynamic nature of the plant cell wall has perhaps limited the generation of such detailed structural models. This information is pivotal for the successful implementation of novel approaches for conversion of biomass to liquid biofuels, given that one of the critical processing steps in biomass conversion involves systematic deconstruction of cell walls. Therefore, a comprehensive understanding of the architecture and chemical composition of the plant cell wall will not only help develop molecular-scale models, but will also help improve the efficiency of biomass deconstruction.The composition and molecular organization of the cell wall is species and cell type dependent (Vorwerk et al., 2004). Thus, the development of a model plant system, which utilizes a single cell type, has enhanced our capacity to understand cell wall architecture. The ability to generate a population of single Zinnia elegans plant cells that were synchronized throughout cell wall deposition during xylogenesis was developed in the 1980s (Fukuda and Komamine, 1980). Mesophyll cells isolated from the leaves of Zinnia and cultured in the presence of phytohormones will transdifferentiate into tracheary elements (TEs), which are individual components of the xylem vascular tissue (Fukuda and Komamine, 1980). During this transdifferentiation process, TEs gradually develop patterned secondary wall thickenings, commonly achieving annular, spiral, reticulate, scalariform, and pitted patterns (Bierhorst, 1960; Falconer and Seagull, 1988; Roberts and Haigler, 1994). These secondary wall thickenings serve as structural reinforcements that add strength and rigidity to prevent the collapse of the xylem under the high pressure created by fluid transport. During the final stages of transdifferentiation, TEs accumulate lignin in their secondary walls and undergo programmed cell death, which results in the removal of all cell contents, leaving behind a “functional corpse” (Roberts and McCann, 2000; Fukuda, 2004).In broad terms, the primary cell wall of higher plants is mainly composed of three types of polysaccharides: cellulose, hemicelluloses, and pectins (Cosgrove, 2005). Cellulose is composed of unbranched β-1,4-Glc chains that are packed together into fibrils by intermolecular and intramolecular hydrogen bonding. Hemicelluloses and pectins are groups of complex polysaccharides that are primarily composed of xyloglucans/xylans and galacturonans, respectively. Hemicelluloses are involved in cross-linking and associating with cellulose microfibrils, while pectins control wall porosity and help bind neighboring cells together. The patterned deposits of secondary wall in Zinnia TEs primarily consist of cellulose microfibrils, along with hemicelluloses, and also lignin, a complex aromatic polymer that is characteristic of secondary walls and provides reinforcement (Turner et al., 2007). All the molecular components in the cell wall correspond to a multitude of different polysaccharides, phenolic compounds, and proteins that become arranged and modified in muro, yielding a structure of great strength and resistance to degradation.Currently, electron microscopy is the primary tool for structural studies of cell walls and has provided remarkable information regarding wall organization. Fast-freeze deep-etch electron microscopy in combination with chemical and enzymatic approaches have generated recent models of the architecture of the primary wall (McCann et al., 1990; Carpita and Gibeaut, 1993; Nakashima et al., 1997; Fujino et al., 2000; Somerville et al., 2004). Direct visualization of secondary wall organization has been focused toward the examination of multiple wall layers in wood cells (Fahlen and Salmen, 2005; Zimmermann et al., 2006). However, few studies have examined the secondary wall, so our knowledge regarding the higher order architecture of this type of wall is limited. Over the past few decades, atomic force microscopy (AFM) has provided new opportunities to probe biological systems with spatial resolution similar to electron microscopy techniques (Kuznetsov et al., 1997; Muller et al., 1999), with additional ease of sample preparation and the capability to probe living native structures. AFM has been successfully applied to studies of the high-resolution architecture, assembly, and structural dynamics of a wide range of biological systems (Hoh et al., 1991; Crawford et al., 2001; Malkin et al., 2003; Plomp et al., 2007), thus enabling the observation of the ultrastructure of the plant cell wall, which is of particular interest to us (Kirby et al., 1996; Morris et al., 1997; Davies and Harris, 2003; Yan et al., 2004; Ding and Himmel, 2006).To generate more detailed structural models, knowledge about the structural organization of the cell wall can be combined with spatial information about chemical composition. Instead of utilizing chromatography techniques to analyze cell wall composition by extracting material from bulk plant samples (Mellerowicz et al., 2001; Pauly and Keegstra, 2008), Fourier transform infrared (FTIR) spectromicroscopy can be used to directly probe for polysaccharide and aromatic molecules in native as well as treated plant material (Carpita et al., 2001; McCann et al., 2001). FTIR spectromicroscopy is not only able to identify chemical components in a specific system but also can determine their distribution and relative abundance. This technique also improves the sensitivity and spatial resolution of cellular components without the derivatization needed by chemical analysis using chromatography. Polysaccharide-specific probes, such as carbohydrate-binding modules (CBMs), can also be used to understand the chemical composition of the plant cell wall. CBMs are noncatalytic protein domains existing in many glycoside hydrolases. Based on their binding specificities, CBMs are generally categorized into three groups: surface-binding CBMs specific for insoluble cellulose surfaces, chain-binding CBMs specific for single chains of polysaccharides, and end-binding CBMs specific for the ends of polysaccharides or oligosaccharides. A surface-binding CBM with high affinity for the planar faces of crystalline cellulose (Tormo et al., 1996; Lehtio et al., 2003) has been fluorescently labeled and used to label crystals as well as plant tissue (Ding et al., 2006; Porter et al., 2007; Liu et al., 2009; Xu et al., 2009). The binding capacity of the CBM family has been further exploited for the detection of different polysaccharides, such as xylans and glucans, and can thus be used for the characterization of plant cell wall composition (McCartney et al., 2004, 2006).In this study, we used a combination of AFM, synchrotron radiation-based (SR)-FTIR spectromicroscopy, and fluorescence microscopy using a cellulose-specific CBM to probe the cell wall of Zinnia TEs. The Zinnia TE culture system proved ideal for observing the structure and chemical composition of the cell wall because it comprises a single homogeneous cell type, representing a simpler system compared with plant tissues, which may contain multiple cell types. Zinnia TEs were also advantageous because they were analyzed individually, and population statistics were generated based on specific conditions. Furthermore, cultured Zinnia TEs were used for the consistent production of cell wall fragments for analysis of the organization of internal secondary wall structures. In summary, we have physically and chemically dissected Zinnia TEs using a combination of imaging techniques that revealed primary and secondary wall structures and enabled the reconstruction of TE cell wall architecture.     

Synthesis and antimicrobial activity of 2-fluorophenyl-4,6-disubstituted [1,3,5]triazines

A series of 2-fluorophenyl-4,6-disubstituted [1,3,5]triazines (1) and (2) were synthesized and evaluated for their antimicrobial activity against three representative gram-positive bacteria and two fungi. The structure–activity relationship (SAR) demonstrates that the 3- or 4-fluorophenyl component attached directly to the triazine ring was essential for activity. Of these compounds, 14, 15, and 25 demonstrated significant activity against all selected organisms compared to control. These compounds were generally nontoxic and may prove useful as antimicrobial agents.     

Acaricidal activity of spinosad and abamectin against two-spotted spider mites

Spinosad is a bioinsecticide with a high degree of selective toxicity towards insects of different orders, but its toxicity towards the two-spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae) is under debate. In this study, we compared the acaricidal properties of spinosad with the commercial bioacaricide abamectin on the life stages of TSSM. Adulticide and ovicide bioassays were performed on a susceptible laboratory strain using direct spraying of leaf disks with five rates of spinosad (20, 25, 30, 35 and 40 mg/l), five rates of abamectin (0.125, 0.25, 0.5, 1 and 2.5 mg/l), sublethal concentrations or a combination of spinosad and abamectin. Both adulticidal and ovicidal effects of spinosad against T. urticae in the laboratory were apparent, based on morality rates of the adults, reduction of female fecundity and death of offspring. Abamectin was also found to significantly reduce female fecundity and killed offspring when applied directly on the eggs. Interestingly, sublethal concentrations of spinosad reduced female fecundity stronger than abamectin. When a mixture of spinosad and abamectin was applied at LC_50, mortality was 74%, fecundity reduction was comparable to abamectin alone and egg hatching rate was lower than by either compound alone. In conclusion, spinosad was more harmful than abamectin for TSSM life stages and the combined application is recommended.     

Is microbial community composition in boreal forest soils determined by pH,C-to-N ratio,the trees,or all three?

In Fennoscandian boreal forests, soil pH and N supply generally increase downhill as a result of water transport of base cations and N, respectively. Simultaneously, forest productivity increases, the understory changes from ericaceous dwarf shrubs to tall herbs; in the soil, fungi decrease whereas bacteria increase. The composition of the soil microbial community is mainly thought to be controlled by the pH and C-to-N ratio of the substrate. However, the latter also determines the N supply to plants, the plant community composition, and should also affect plant allocation of C below ground to roots and a major functional group of microbes, mycorrhizal fungi. We used phospholipid fatty acids (PLFAs) to analyze the potential importance of mycorrhizal fungi by comparing the microbial community composition in a tree-girdling experiment, where tree belowground C allocation was terminated, and in a long-term (34 years) N loading experiment, with the shifts across a natural pH and N supply gradient. Both tree girdling and N loading caused a decline of ca. 45% of the fungal biomarker PLFA 18:2ω6,9, suggesting a common mechanism, i.e., that N loading caused a decrease in the C supply to ectomycorrhizal fungi just as tree girdling did. The total abundance of bacterial PLFAs did not respond to tree girdling or to N loading, in which cases the pH (of the mor layer) did not change appreciably, but bacterial PLFAs increased considerably when pH increased across the natural gradient. Fungal biomass was high only in acid soil (pH < 4.1) with a high C-to-N ratio (>38). According to a principal component analysis, the soil C-to-N ratio was as good as predictor of microbial community structure as pH. Our study thus indicated the soil C-to-N ratio, and the response of trees to this ratio, as important factors that together with soil pH influence soil microbial community composition.     

Factors that influence the radiofrequency power output of GSM mobile phones

Epidemiological studies of mobile phone use and risk of brain cancer have relied on self-reported use, years as a subscriber, and billing records as exposure surrogates without addressing the level of radiofrequency (RF) power output. The objective of this study was to measure environmental, behavioral and engineering factors affecting the RF power output of GSM mobile phones during operation. We estimated the RF-field exposure of volunteer subjects who made mobile phone calls using software-modified phones (SMPs) that recorded output power settings. Subjects recruited from three geographic areas in the U.S. were instructed to log information (place, time, etc.) for each call made and received during a 5-day period. The largest factor affecting energy output was study area, followed by user movement and location (inside or outside), use of a hands-free device, and urbanicity, although the two latter factors accounted for trivial parts of overall variance. Although some highly statistically significant differences were identified, the effects on average energy output rate were usually less than 50% and were generally comparable to the standard deviation. These results provide information applicable to improving the precision of exposure metrics for epidemiological studies of GSM mobile phones and may have broader application for other mobile phone systems and geographic locations.