Flavonol derivatives of Desmanthodium (compositae)

The flavonoids of three species of Desmanthodium are based upon kaempferol, quercetin and quercetagetin. Sugar substitutions comprise glucosides, galactosides, rhamnosides, rutinosides and diglucosides. Four different O-methylated compounds occur in field populations of the genus, but they are found in all species and are therefore not useful for sectional or subgeneric delimitations. The flavonoid profile of Desmanthodium is very similar to that of Clibadium, which parallels their close morphological affinity.     

Effect of fixation time on measurement of 2''-deoxyribonucleoside 5''-triphosphate pools in the rat embyro.

Values for the concentrations of deoxyribonucleoside triphosphates in rat embryos on day 12 of gestation, determined by high-pressure liquid chromatography, were artifactually two to three times as high in embryos fixed by cooling in ice/water followed by freezing on solid CO2, in 20s, as in those more rapidly/fixed in liquid N2, in 1 s.     

Stimulation of human vascular endothelial cell growth by a platelet-derived growth factor and thrombin

Repair of a vascular wound is mediated by migration and subsequent replication of the endothelial cells that form the inner lining of blood vessels. We have measured the growth response of human umbilical vein endothelial cells (HuE) to two polypeptides that are transiently produced in high concentrations at the site of a wound; the platelet-derived growth factor (PDGF) and the protease thrombin. When 10⁴ HuE cells are seeded as a dense island (2-mm diameter) in the center of a 16-mm tissue culture well in medium containing 20% human serum derived from platelet-poor plasma (PDS), no increase in cell number or colony size is observed. With the addition of 0.5 ng/ml partially purified PDGF, colony size increases and the number of cells after 8 days is 4.8 × 10⁴. When human thrombin (1 μg/ml) is added along with the PDGF, the cell number rises to 9.2 × 10⁴. Thrombin alone stimulates no increase in cell number. Although partially purified PDGF stimulates endothelial cells maintained in PDS as well as those maintained in whole blood serum (WBS), pure PDGF is active only when assayed in medium that contains WBS and is supplemented with thrombin. These results suggest the existence of a second class of platelet-derived factors that enable HuE cells to respond to the mitogenic activity of the purified platelet mitogen and thrombin.     

Physical characteristics of mouse sperm nuclei.

The nuclei of epididymal sperm, isolated from C57BL/6J and CBA/J inbred mice by their resistance to trypsin digestion, retain the shape differences of the intact sperm head. Various physical characteristics of these nuclei were measured and compared. The measurement of the projected dimensions of nuclei showed that the CBA nuclei are 13.5% longer than C57BL/6 nuclei (8.64 +/- 0.02 mum compared with 7.61 +/- 0.02 mum), 0.8% narrower (3.51 +/- 0.01 vs. 3.54 +/-0.01 mum) with 6.8% more area (22.34 +/- 0.10 vs. 20.91 +/- 0.09 mum2). However, the volumes of the nuclei as based on reconstructing calibrated electronmicrographs of serial sections of the nuclei indicated that CBA are about 7% smaller than C57BL/6 nuclei (3.72 +/- 0.08 vs. 4.01 +/- 0.03 mum3). The buoyant density of the CBA nuclei is 1.435 +/- 0.002 g/cm3 compared with 1.433 +/- 0.002 g/cm3 for the C57BL/6 nuclei as determined on linear CsCl and Renografin-76 density gradients and confirmed by a technique utilizing physiological tonicities. Therefore, the average mass of the CBA nuclei is less than that of the C57BL/6 nuclei (5.34 +/- 0.12 vs. 5.75 +/- 0.05 pg). The sedimentation velocities at unit gravity of nuclei from 11 inbred strains differ over a range of more than 6% with CBA nuclei sedimenting about 2.0% more slowly than C57BL/6 nuclei. We show that for these nuclei the sedimentation velocity can be related to their buoyant density, volume and a sedimentation shape factor. Within the errors of our measurements of these various characteristics, it was found that C57BL/6 and CBA nuclei have similar sedimentation shape factors. Therefore, the difference in sedimentation velocity between these nuclei appears to be primarily a result of differences in volume. The possible applications of these techniques to the physical separation of sperm are evaluated in the discussion.     

A scoping review of burden of disease studies estimating disability-adjusted life years due to Taenia solium

BackgroundTaenia solium is the most significant global foodborne parasite and the leading cause of preventable human epilepsy in low and middle-income countries in the form of neurocysticercosis.ObjectivesThis scoping review aimed to examine the methodology of peer-reviewed studies that estimate the burden of T. solium using disability-adjusted life years.Eligibility criteriaStudies must have calculated disability-adjusted life years relating to T. solium.Charting methodsThe review process was managed by a single reviewer using Rayyan. Published data relating to disease models, data sources, disability-adjusted life years, sensitivity, uncertainty, missing data, and key limitations were collected.Results15 studies were included for review, with seven global and eight national or sub-national estimates. Studies primarily employed attributional disease models that relied on measuring the occurrence of epilepsy before applying an attributable fraction to estimate the occurrence of neurocysticercosis-associated epilepsy. This method relies heavily on the extrapolation of observational studies across populations and time periods; however, it is currently required due to the difficulties in diagnosing neurocysticercosis. Studies discussed that a lack of data was a key limitation and their results likely underestimate the true burden of T. solium. Methods to calculate disability-adjusted life years varied across studies with differences in approaches to time discounting, age weighting, years of life lost, and years of life lived with disability. Such differences limit the ability to compare estimates between studies.ConclusionsThis review illustrates the complexities associated with T. solium burden of disease studies and highlights the potential need for a burden of disease reporting framework. The burden of T. solium is likely underestimated due to the challenges in diagnosing neurocysticercosis and a lack of available data. Advancement in diagnostics, further observational studies, and new approaches to parameterising disease models are required if estimates are to improve.     

Synchrony of Seed Dispersal, Hydrology and Local Climate in a Semi-arid River Reach in California

The temporal availability of propagules is a critical factor in sustaining pioneer riparian tree populations along snowmelt-driven rivers because seedling establishment is strongly linked to seasonal hydrology. River regulation in semi-arid regions threatens to decouple seed development and dispersal from the discharge regime to which they evolved. Using the lower Tuolumne River as a model system, we quantified and modeled propagule availability for Populus fremontii (POFR), Salix gooddingii (SAGO), and Salix exigua (SAEX), the tree and shrub species that dominate near-channel riparian stands in the San Joaquin Basin, CA. A degree-day model was fit to field data of seasonal seed density and local temperature from three sites in 2002–2004 to predict the onset of the peak dispersal period. To evaluate historical synchrony of seed dispersal and seasonal river hydrology, we compared peak spring runoff timing to modeled peak seed release periods for the last 75 years. The peak seed release period began on May 15 for POFR (range April 23–June 10), May 30 for SAGO (range May 19–June 11) and May 31 for SAEX (range May 8–June 30). Degree-day models for the onset of seed release reduced prediction error by 40–67% over day-of-year means; the models predicted best the interannual, versus site-to-site, variation in timing. The historical analysis suggests that POFR seed release coincided with peak runoff in almost all years, whereas SAGO and SAEX dispersal occurred during the spring flood recession. The degree-day modeling approach reduce uncertainty in dispersal timing and shows potential for guiding flow releases on regulated rivers to increase riparian tree recruitment at the lowest water cost.     

Ectomycorrhizal Colonization, Biomass, and Production in a Regenerating Scrub Oak Forest in Response to Elevated CO2

The effects of CO₂ elevation on the dynamics of fine root (FR) mass and ectomycorrhizal (EM) mass and colonization were studied in situ in a Florida scrub oak system over four years of postfire regeneration. Soil cores were taken at five dates and sorted to assess the standing crop of ectomycorrhizal and fine roots. We used ingrowth bags to estimate the effects of elevated CO₂ on production of EM roots and fine roots. Elevated CO₂ tended to increase EM colonization frequency but did not affect EM mass nor FR mass in soil cores (standing mass). However, elevated CO₂ strongly increased EM mass and FR mass in ingrowth bags (production), but it did not affect the EM colonization frequency therein. An increase in belowground production with unchanged biomass indicates that elevated CO₂ may stimulate root turnover. The CO₂-stimulated increase of belowground production was initially larger than that of aboveground production. The oaks may allocate a larger portion of resources to root/mycorrhizal production in this system in elevated rather than ambient CO₂.