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Background: Grip strength is commonly used to assess hand function among older adults. While shown to be associated with disability, the degree to which grip strength specifically predicts hand limitations is unknown. Aims: The primary aim of this study was to evaluate grip strength as a predictor of hand limitations. Methods: Using the 2011–14 National Health and Nutrition Examination Survey (NHANES), we classified older adults reporting one or more hand limitations versus those with no limitations. Odds ratios were used to assess the association between grip strength (separated into quartiles) and the likelihood of a hand limitation while controlling for sex, race/ethnicity, education level, income, and pain. Receiver operator characteristic (ROC) curves were used to evaluate the degree to which grip strength discriminates between older adults with and without a hand limitation. Results: We identified 2064 older adults (age ≥ 65), 31% of whom reported a hand-related limitation. Older adults with very low grip strength (weakest quartile) were more likely to report at least one limitation (OR: 6.1, 95% CI: 3.2, 11.8) than those with high grip strength (strongest quartile). However, grip strength had poor to moderate discrimination of hand limitations (ROC area under curves: 0.65–0.81). Discussion: While self-reported hand limitations were associated with lower grip strength; overall, it is a relatively poor predictor of hand impairments among older adults. Conclusion: Better assessments are needed to adequately evaluate upper extremity impairments to help older adults maintain functional independence. [ABSTRACT FROM AUTHOR]

This article provides Section 2 of the 2017 Edition 2 Medical Writing Competency Model that describes the knowledge, skills, abilities, and behaviors that professional medical writers need in order to perform effectively within the life sciences industry. What a medical writer should know, what they should be able to do, and how they should use this knowledge and these skills to facilitate their primary work function is a focus. Regulatory, publication, and other scientific writing as well as management of writing activities are covered. The full Model also includes Section 1, which covers the core work functions and associated tasks and activities related to professional medical writing within the life sciences industry; Section 1 is included in a companion article. The Model was developed to aid medical writers and managers within the life sciences industry regarding medical writing hiring, training, expectation and goal setting, performance evaluation, career development, retention, and role value sharing to cross-functional partners. [ABSTRACT FROM AUTHOR]

This article provides Section 1 of the 2017 Edition 2 Medical Writing Competency Model that describes the core work functions and associated tasks and activities related to professional medical writing within the life sciences industry. The functions in the Model are scientific communication strategy; document preparation, development, and finalization; document project management; document template, standard, format, and style development and maintenance; outsourcing, alliance partner, and client management; knowledge, skill, ability, and behavior development and sharing; and process improvement. The full Model also includes Section 2, which covers the knowledge, skills, abilities, and behaviors needed for medical writers to be effective in their roles; Section 2 is presented in a companion article. Regulatory, publication, and other scientific writing as well as management of writing activities are covered. The Model was developed to aid medical writers and managers within the life sciences industry regarding medical writing hiring, training, expectation and goal setting, performance evaluation, career development, retention, and role value sharing to cross-functional partners. [ABSTRACT FROM AUTHOR]

Low capsule set is a major factor limiting the productivity of Eucalyptus globulus seed orchards. This study tested the effect of flower density, as well as two common irrigation techniques on capsule and seed set. Ramets with high flower density had significantly lower capsule set (69.7%) than those with low flower density (81.7%). In a regulated deficit irrigation trial, the non-irrigated ramets set a higher proportion of capsules (63.6%) than the ramets that received conventional irrigation (CI) (51.4%). In a partial root zone drying (PRD) trial, capsule set was highest in the absence of irrigation (74.7%) followed by the PRD treatment (67.8%) and then CI (53.7%). The CI treatment tended to produce the highest number of seed per capsule. Increased water availability resulted in increased vegetative growth, which was associated with higher levels of abortion in developing capsules but those surviving tended to have higher seed set. It is argued that the observed effects of irrigation and flower density can be explained by resource competition between vegetative and reproductive growth as well as competition among reproductive structures themselves. [ABSTRACT FROM AUTHOR]

Low capsule and seed set is a major factor limiting seed production in Eucalyptus globulus seed orchards. Controlled pollination studies showed that the reproductive success (number of seeds produced per flower pollinated) was primarily determined by the female. We aimed to identify the factors contributing to the differences in reproductive success between female genotypes in terms of the physical and anatomical properties of the flower. We studied pairs of genotypes of high and low reproductive success from each of three races (Furneaux Group, Strzelecki Ranges and Western Otways) growing in a seed orchard. Controlled pollinations were performed on six females and along with flower physical measurements, pollen tube growth and seed set were assessed. Overall tree reproductive success was positively correlated with flower size, ovule numbers, style size, cross-sectional area of conductive tissue within the style (all of which were inter-correlated) and the proportion of pollen tubes reaching the bottom of the style. Significant positive correlations of reproductive success and flower physical properties between different ramets of the same genotypes across seasons suggests a genetic basis to the variation observed. The majority of pollen tube attrition occurred within the first millimetre of the cut style and appeared to be associated with differences in style physiology. When examined as pairs within races the difference in reproductive success for the Western Otways pair was simply explained by differences in flower size and the number of ovules per flower. Physical features did not differ significantly for the Strzelecki Ranges pair, but the proportion of pollen tubes reaching the bottom of the style was lower in the less reproductively successful genotype, suggesting an endogenous physiological constraint to pollen tube growth. The difference in reproductive success between the females from the Furneaux Group was associated with a combination of these factors. [ABSTRACT FROM AUTHOR]

Retinoids, vitamin A analogues that bind to retinoic acid receptor (RAR) or retinoid X receptor (RXR), play important roles in regulating cell proliferation, apoptosis, and differentiation. Recently, RXR-selective ligands, also referred to as rexinoids, have been investigated as potential chemopreventive agents for breast cancer. Our previous studies demonstrated that the rexinoid bexarotene significantly prevented ER-negative mammary tumourigenesis with less toxicity than naturally occurring retinoids in animal models. To determine whether bexarotene prevents cancer at the early stages during the multistage process of mammary carcinogenesis, we treated MMTV-erbB2 mice with bexarotene for 2 or 4 months. The development of preinvasive mammary lesions such as hyperplasias and carcinoma-in-situ was significantly inhibited. This inhibition was associated with reduced proliferation, but no induction of apoptosis. We also examined the regulation of a number of rexinoid-modulated genes including critical growth and cell cycle regulating genes using breast cell lines and mammary gland samples from mice treated with rexinoids. We showed that two of these genes (DHRS3 and DEC2) were modulated by bexarotene both in vitro and in vivo. Identification of these rexinoid-modulated genes will help us understand the mechanism by which rexinoid prevents cancer. Such rexinoid-regulated genes also represent potential biomarkers to assess the response of rexinoid treatment in clinical trials. [ABSTRACT FROM AUTHOR]

The activating protein-1 (AP-1) transcription factor transduces growth signals through signal transduction pathways to the nucleus, leading to the expression of genes involved in growth and malignant transformation in many cell types. We have previously shown that overexpression of a dominant negative form of the cJun proto-oncogene, a cJun dominant negative mutant (Tam67), blocks AP-1 transcriptional activity, induces a G1 cell cycle block and inhibits breast cancer cell growth in vitro and in vivo. We found that AP-1 blockade by Tam67 in MCF-7 breast cancer cells downregulates cyclin D1 transcriptional activity by at least two mechanisms: by suppressing transcription at the known AP-1 binding site (−934/−928) and by suppressing growth factor-induced expression through suppressing E2F activation at the E2F-responsive site (−726/−719). AP-1 blockade also led to reduced expression of E2F1 and E2F2, but not E2F4, at the mRNA and protein levels. Chromatin immunoprecipitation and supershift assays demonstrated that AP-1 blockade caused decreased binding of E2F1 protein to the E2F site in the cyclin D1 promoter. We also found that Tam67 suppressed the expression of the E2F1 dimerizing partner, DP1 and E2F-upregulated cell cycle genes (cyclins E, A, B and D3) and enhanced the expression of E2F-downregulated cell cycle genes (cyclins G2 and I). Reduced expression of other E2F-regulated genes was also seen with AP-1 blockade and E2F suppression. Thus, the AP-1 factor regulates the expression of cyclin D and E2F (the latter in turn regulates E2F-downstream genes), leading to cell cycle progression and breast cancer cell proliferation.Oncogene (2008) 27, 366–377; doi:10.1038/sj.onc.1210643; published online 16 July 2007 [ABSTRACT FROM AUTHOR]

Background. Traditionally, pediatric radiologists have been advocates of fluoroscopy systems that provide diagnostic images at the lowest possible radiation dose to the pediatric patient. Manufacturers of fluoroscopic equipment vary as to their claims of “low radiation“ exposures.¶Objectives. To obtain comparative data on radiation exposure and image quality from four pediatric hospitals, across variants of fluoroscopic equipment (such as pulsed versus continuous fluoroscopy).¶Materials and methods. Images were acquired from phantoms that simulated the size of a 3-year-old child. Phantom results, both stationary and rotating dynamic, were evaluated for radiation exposure and for image resolution of high- and low-contrast objects.¶Results. Radiation exposure from the four fluoro units varied widely; the lowest-dose selectable fluoro mode produced exposures varying between 34 and 590 mrads/min among the four fluoro units, and the highest-dose selectable fluoro mode produced 540–2230 mrads/min. The lowest radiation exposures were produced by pulsed fluoro units, and the very lowest radiation exposure was produced by a fluoroscope that had been especially optimized for pediatric imaging. There was only a small variation in image quality among the hospitals for visualization of stationary objects. A wide variability was noted for detection of objects on the moving phantom.¶Conclusions. The variability in the number of detected objects was considerably smaller than the variability in radiation exposure. Pulsed fluoroscopy provides improved resolution for moving objects. Optimization of one hospital's fluoroscope especially for pediatric imaging produced the best ratio of image quality to radiation exposure. [ABSTRACT FROM AUTHOR]

Background. A new children's hospital provided the impetus to investigate radiation dose and image quality in a fluoroscope that was specially engineered for pediatric fluoroscopy. Radiation protection management recommends radiation exposures that are as low as reasonably achievable, while still maintaining diagnostic image quality.¶Objectives. To obtain comparative phantom imaging data on radiation exposure and image quality from a newly installed fluoroscope before and after optimization for pediatric imaging.¶Materials and methods. Images were acquired from various thickness phantoms, simulating differing patient sizes. The images were evaluated for visualization of high- and low-contrast objects and for radiation exposure. Effects due to use of the image intensifier anti-scatter grid were also investigated.¶Results. The optimization of the new fluoroscope for pediatric operation reduced radiation exposure by about 50 % (compared to the originally installed fluoroscope), with very little loss of image quality. Pulsed fluoroscopy was able to lower radiation dose to less than 10 % of continuous fluoroscopy, while still maintaining acceptable phantom image quality.¶Conclusion. Radiation exposure in pediatric fluoroscopy can be reduced to values well below the exposure settings that are typically found on unoptimized fluoroscopes. Pulsed fluoroscopy is considered a requisite for optimal pediatric fluoroscopy. [ABSTRACT FROM AUTHOR]

This study compares four sample dissolution methods for Boron determination in two National Institute of Standard and Technology (NIST) botanical Standard Reference Materials (SRMs) and three Agriculture Canada/NIST RMs, each having a reference (certified or best estimate) B concentration. The dissolution treatments consisted of: 1) dry ashing at 500° C, 2) wet digestion with HNO3 + H2O2, 3) extraction with hot HNO3 and 4) closed vessel microwave dissolution. The samples were spiked before and after imposing dissolution treatments to study B recovery by inductively coupled plasma mass spectrometric (ICP-MS) analysis. Microwave digests of NIST SRM 1515 and some in-house RMs were also used to compare the B values of ICP-MS and ICP-AES (atomic emission spectrometry). While all three digestion methods (dry ashing, wet ashing and microwave) dissolved botanical samples, only the microwave method worked well for animal tissues. In terms of B values in these materials, there was no significant difference among the three digestion treatments. Near 100% recovery of B spiked before and after the sample dissolution indicates that there may not be a significant loss of B during the dissolution process used in this study. Extraction with hot HNO3 was as effective as the three digestion treatments, and B values for this method agreed well with reference values. For the botanical materials studied, the B values determined by ICP-AES were not significantly different from ICP-MS values. This study shows that a simple, time and labor efficient hot HNO3 extraction is as effective as other digestion/dissolution methods for quantitative B recovery from biological materials. [ABSTRACT FROM AUTHOR]

N-acetylglutamate synthase (NAGS; E.C.2.3.1.1) catalyzes the formation of N-acetylglutamate (NAG) from acetyl coenzyme A and glutamate. In microorganisms and plants, NAG is the first intermediate of the L-arginine biosynthesis; in animals, NAG is an allosteric activator of carbamylphosphate synthetase I and III. In some bacteria bifunctional N-acetylglutamate synthase-kinase (NAGS-K) catalyzes the first two steps of L-arginine biosynthesis. L-arginine inhibits NAGS in bacteria, fungi, and plants and activates NAGS in mammals. L-arginine increased thermal stability of the NAGS-K from Maricaulis maris (MmNAGS-K) while it destabilized the NAGS-K from Xanthomonas campestris (XcNAGS-K). Analytical gel chromatography and ultracentrifugation indicated tetrameric structure of the MmMNAGS-K in the presence and absence of L-arginine and a tetramer-octamer equilibrium that shifted towards tetramers upon binding of L-arginine for the XcNAGS-K. Analytical gel chromatography of mouse NAGS (mNAGS) indicated either different oligomerization states that are in moderate to slow exchange with each other or deviation from the spherical shape of the mNAGS protein. The partition coefficient of the mNAGS increased in the presence of L-arginine suggesting smaller hydrodynamic radius due to change in either conformation or oligomerization. Different effects of L-arginine on oligomerization of NAGS may have implications for efforts to determine the three-dimensional structure of mammalian NAGS. [ABSTRACT FROM AUTHOR]

Species and cultivar differences in boron (B) uptake at low B availability and tolerance to high external B are known for many species but mechanisms explaining such differences remain obscure. Here we contrast B uptake and distribution between two cultivars of tomato and celery that differ significantly in their susceptibility to B deficiency. ne celery cultivar S48-54-1 and tomato cultivar 'Brittle' are known to be more susceptible to B deficiency (inefficient) than the closely related cultivars 'Emerson Pascal' and 'Rutgers' (efficient), respectively. B uptake and distribution was also compared in two wheat lines differing in tolerance to B excess ('Chinese Spring', sensitive and Lophopyrum Amphiploid, tolerant). Results showed that there is no significant difference in either the specific uptake rate (IM) of 10B or the relative growth rate (RGR) between the efficient cultivar (Emerson Pascal) and less efficient cultivar (S48-54-1) of celery. However, the distribution of 10B among plant organs (leaves, stems and roots) of Emerson Pascal was different from S48-54-1. In Emerson Pascal more than 63% of accumulated B was present in the shoots while in S48-54-1 only 45% of accumulated B was present in shoots. In tomato plants, in addition to differences in B distribution among plant organs between the efficient (Rutgers) and less efficient (Brittle) cultivars, the specific uptake rate of 10B was significantly higher in the efficient cultivar. In wheat, the tolerant line (Amphiploid) took up less B than the less tolerant cultivar (Chinese Spring), and the pattern of B distribution among plant organs was different with a greater percentage of B found in roots of Chinese Spring compared to Amphiploid. Differences in sensitivity to B deficiency and excess amongst cultivars and species were a consequence of either reduced B uptake as in wheat (Amphiploid), a restriction in B translocation from roots to shoot as in celery (S48-54- [ABSTRACT FROM AUTHOR]

In species in which boron (B) mobility is limited, B deficiency onlyoccurs in growing plant organs. As a consequence of the highly localized patterns of plant growth and the general immobility of B it has been extremely difficult to determine the primary function of B in plants. In species in which B is phloem mobile, the removal of B from the growth medium results in the depletion of B present in mature leaves. Thus, it is possible to develop mature leaves with increasingly severe levels of B depletion, thereby overcoming the complications of experiments based on growing tissues. Utilizing this approach we demonstrate here that B depletion of mature plum (Prunus salicina) leavesdid not result in any discernible change in leaf appearance, membrane integrity or photosynthetic capacity even though B concentrations were reduced to 6-8 5g/g dwt, which is less than 30% of the reported tissue B requirement. Boron depletion, however, results in a severe disruption of plant growth and metabolism in young growing tissues. This experimental evidence and theoretical considerations suggest that the primary and possibly sole function of B, is as a structural component of growing tissues. [ABSTRACT FROM AUTHOR]

This paper reviews techniques for determining B concentration and isotopic ratio and their application to soil and plant samples. Boron concentration has been determined utilising spectrophotometry, potentiometry, chromatography, flame atomic emission and absorption spectrometry, inductively coupled plasma (ICP) optical emission (OES) and mass spectrometry (MS), and neutron activation analysis using neutron radiography and prompt--gamma activation analysis. Isotopic ratios of Bhave been measured by ICP-MS, thermal ionisation mass spectrometry (TIMS) and secondary ion mass spectrometry (SIMS). For isotopic measurements, TIMS and SIMS are more sensitive and provide higher degrees of accuracy and resolution than ICP-MS, however, extensive sample preparation and purification, and time-consuming measurements limit theirusefulness for routine analyses. While the spectrophotometric technique using a colorimetric reaction of B with azomethine-H has been themost extensively applied B determination method for soil and plant samples, colorimetric methods, in general, suffer from numerous interferences and have poor sensitivity and precision. The prompt--gamma method can determine B concentration in intact samples which enables this method to be especially useful for some applications in agriculture. Research involving B behaviour in plant and soil environments would benefit from this technology. In recent years, the use of ICP-OES and ICP-MS for B determination in plant and soil samples has grown tremendously. The application of ICP-OES brought a significant improvement in B analysis because of its simplicity, sensitivity and multielement detection capability. However, besides matrix interferences, the two most sensitive emission lines for B suffer strong spectral interference from Fe. The ICP-OES is not adequately sensitive for some nutritional work involving low B concentrations and B translocation studies using the isotope tracer technique. Plasma is one of the most effecti [ABSTRACT FROM AUTHOR]

In the majority of plant species, B distribution between plant organs and the symptoms of B deficiency and toxicity indicate that B has restricted mobility. Nevertheless, B is present in phloem, and is retranslocated in phloem, often in sufficient amounts to satisfy the demands of developing sink regions that do not readily transpire. In species that produce significant amounts of polyols in source leaves, boron is readily translocated as a consequence of the formation of B- polyol complexes. Boron is thus unique among the essential plant nutrients in that it has restricted mobility in many plant species and is freely mobile in others. No other element is known to vary so greatly in mobility. The retranslocation of B has a profound effect on the expression of B deficiency and toxicity symptoms, and the approaches needed to diagnose and correct B imbalances. Examples of the impact of B mobility on B uptake, B diagnosis, B toxicity and the breeding of species for B tolerance, are discussed here and in the relevant chapters of this volume. In the following we provide a summary of current information on the mobility of B in plants and provide insights into the physiological and agronomic consequences of these findings. [ABSTRACT FROM AUTHOR]

Experimental evidence suggests that B uptake is the result of the passive assimilation of undissociated boric acid. Boron uptake by a particular species should, therefore, be primarily determined by the B concentration in the soil solution and the rate of water uptake by theplant. This simple explanation of B uptake, however, does not adequately explain field observations where dramatic differences in B concentrations are observed between species, even when these species are grown under similar environmental conditions. The apparent contradiction between experimental results and in field observations, suggests, that B uptake is determined by factors that are as yet unknown. In the following, we discuss experimental and field observations as they relate to B uptake and discuss the mechanisms that may be involved in determining B uptake in diverse species. [ABSTRACT FROM AUTHOR]