Functions of maize genes encoding pyruvate phosphate dikinase in developing endosperm.

Maize opaque2 (o2) mutations are beneficial for endosperm nutritional quality but cause negative pleiotropic effects for reasons that are not fully understood. Direct targets of the bZIP transcriptional regulator encoded by o2 include pdk1 and pdk2 that specify pyruvate phosphate dikinase (PPDK). This enzyme reversibly converts AMP, pyrophosphate, and phosphoenolpyruvate to ATP, orthophosphate, and pyruvate and provides diverse functions in plants. This study addressed PPDK function in maize starchy endosperm where it is highly abundant during grain fill. pdk1 and pdk2 were inactivated individually by transposon insertions, and both genes were simultaneously targeted by endosperm-specific RNAi. pdk2 accounts for the large majority of endosperm PPDK, whereas pdk1 specifies the abundant mesophyll form. The pdk1- mutation is seedling-lethal, indicating that C4 photosynthesis is essential in maize. RNAi expression in transgenic endosperm eliminated detectable PPDK protein and enzyme activity. Transgenic kernels weighed the same on average as nontransgenic siblings, with normal endosperm starch and total N contents, indicating that PPDK is not required for net storage compound synthesis. An opaque phenotype resulted from complete PPDK knockout, including loss of vitreous endosperm character similar to the phenotype conditioned by o2-. Concentrations of multiple glycolytic intermediates were elevated in transgenic endosperm, energy charge was altered, and starch granules were more numerous but smaller on average than normal. The data indicate that PPDK modulates endosperm metabolism, potentially through reversible adjustments to energy charge, and reveal that o2- mutations can affect the opaque phenotype through regulation of PPDK in addition to their previously demonstrated effects on storage protein gene expression.

Implementation of a Peer Learning Program Replacing Score-Based Peer Review in a Multispecialty Integrated Practice.

OBJECTIVE: The aim of this study was to compare the efficacy of a peer learning program to score-based peer review in a radiology department. MATERIALS AND METHODS: Our score-based peer review program was transitioned to an open, inclusive, education- and improvement-oriented peer learning program. Program performance was evaluated by learning opportunity submissions, program participation, number of learning opportunity distributions to radiologists, number of practice improvement projects resulting from program, and radiologist survey results before and after interventions. RESULTS: Outcomes for the score-based peer review program compared with those of the peer learning program were as follows. The mean number of radiologists participating monthly increased from 5.0 to 35.2 (p < 0.01); submissions increased from 3.0 discrepancies per month to 36.0 learning opportunities per month (p < 0.01); the mean monthly learning opportunity distributions to radiologists increased from 18 to 352 (p < 0.01); improvement projects performed during the study periods increased from 5 to 61 (p < 0.01); and mean monthly continuing medical education credits earned by radiologists increased from 7.7 to 50.6 (p < 0.01). Radiologists felt peer learning accomplished goals better than did score-based peer review. CONCLUSION: In transitioning our score-based peer review program to a peer learning program, our radiologists identified, discussed, and converted more learning opportunities into practice improvement and perceived peer learning to be of higher value than score-based peer review.

Digestion of glycogen by a glucosidase released by Trichomonas vaginalis.

Trichomonas vaginalis is a protozoan parasite that is the causative agent of trichomoniasis, a widespread sexually transmitted disease. In vitro culture of T. vaginalis typically employs a medium supplemented with either maltose or glucose and carbohydrates are considered essential for growth. Although the nature of the carbohydrates utilized by T. vaginalis in vivo is undefined, the vaginal epithelium is rich in glycogen, which appears to provide a source of carbon for the vaginal microbiota. Here, we show that T. vaginalis grows equally well in growth media supplemented with simple sugars or with glycogen. Analysis of conditioned growth medium by thin layer chromatography indicates that growth on glycogen is accompanied by glycogen breakdown to a mixture of products including maltose, glucose, and oligosaccharides. Enzymatic assays with conditioned growth medium show that glycogen breakdown is accomplished via the release of a glucosidase activity having the properties of an α-amylase into the growth medium. Furthermore, we find that released glucosidase activity increases upon removal of carbohydrate from the growth medium, indicating regulation of synthesis and/or secretion in response to environmental cues. Lastly, we show that addition of T. vaginalis glucosidase activity to a growth medium containing glycogen generates sufficient simple sugar to support the growth of lactobacilli which, themselves, are unable to degrade glycogen. Thus, not only does the glucosidase activity likely play an important role in allowing T. vaginalis to secure simple sugars for its own use, it has the potential to impact the growth of other members of the vaginal microbiome.

Applying Implementation Science Principles to Systematize High-Quality Care for Potentially Significant Imaging Findings.

OBJECTIVE: Use principles of implementation science to improve the diagnosis and management of potentially significant imaging findings. METHODS: Multidisciplinary stakeholders codified the diagnosis and management of potentially significant imaging findings in eight organs and created a finding tracking management system that was embedded in radiologist workflows and IT systems. Radiologists were trained to use this system. An automated finding tracking management system was created to support consistent high-quality care through care pathway visualizations, increased awareness of specific findings in the electronic medical record, templated notifications, and creation of an electronic safety net. Primary outcome was the rate of quality reviews related to eight targeted imaging findings. Secondary outcome was radiologist use of the finding tracking management tool. RESULTS: In the 4 years after implementation, the tool was used to track findings in 7,843 patients who received 10,015 ultrasound, CT, MRI, x-ray, and nuclear medicine examinations that were interpreted by all 34 radiologists. Use of the tool lead to a decrease in related quality reviews (from 8.0% to 0.0%, P < .007). Use of the system increased from 1.7% of examinations in the early implementation phase to 3.1% (+82%, P < .00001) in the postimplementation phase. Each radiologist used the tool on an average of 294.6 unique examinations (SD 404.8). Overall, radiologists currently use the tool approximately 4,000 times per year. DISCUSSION: Radiologists frequently used a finding tracking management system to ensure effective communication and raise awareness of the importance of recommended future follow-up studies. Use of this system was associated with a decrease in the rate of quality review requests in this domain.

The performance of outside readings by radiology practices.

OBJECTIVE: The purpose of our study was to determine how many radiology practices perform outside readings, what characteristics affect the prevalence and volume of outside readings, and how practices are paid for outside readings. MATERIALS AND METHODS: We analyzed data from the American College of Radiology's 2007 Survey of Radiologists, a stratified random sample e-mail and telephone survey. A total of 480 survey responses were evaluated; responses were weighted to make them representative of all U.S. radiology practices. We provide descriptive statistics and multivariable regression analysis results. RESULTS: Overall, 40% of radiology practices in the United States performed outside readings in 2007. Outside readings constituted an average of 11% of the workload of these practices and 4% of the total workload of radiologists in the United States. Other practice characteristics being equal, academic practices, government practices, radiology units of multispecialty groups, and small practices had particularly low odds of performing outside readings. If they did perform outside readings, then, other practice characteristics being equal, small practices, solo practices, radiology units of multispecialty groups, practices in the main cities of large metropolitan areas, and those in nonmetropolitan areas had, on average, a relatively large portion of their workload consisting of outside readings. By far, the most common methods of payment were directly billing for the professional component or receiving a flat fee per study. CONCLUSION: Outside readings were a common activity among radiology practices in 2007. There was substantial variability among practice types, sizes, and locations in whether practices performed outside readings and, if so, how much outside reading they did.

A Pectin Methylesterase ZmPme3 Is Expressed in Gametophyte factor1-s (Ga1-s) Silks and Maps to that Locus in Maize (Zea mays L.).

The ga1 locus of maize confers unilateral cross incompatibility, preventing cross pollination between females carrying the incompatible Ga1-s allele and males not carrying a corresponding compatible allele. To characterize this system at the molecular level, we carried out a transcript profiling experiment in which silks from near isogenic lines carrying the Ga1-s and ga1 alleles were compared. While several differentially expressed genes were identified, only one mapped to the known location of ga1. This gene is a pectin methylesterase (PME), which we designated as ZmPme3, and is present and expressed only in Ga1-s genotypes. While a functional ZmPME3 is not present in the ga1 genotypes examined, a pectin methylesterase gene cluster is found in ga1 genotypes. The gene cluster in W22 contains 58 tandem full-length or partial PME pseudo genes. These data combined with a wealth of previously published data on the involvement of PMEs in pollen tube growth suggest a role for cell wall modification enzymes in the pollen exclusion component of Ga1-s gametophytic incompatibility. Consistent with this role, a third allele which lacks the female function of Ga1-s, Ga1-m, has a mutationally inactivated version of ZmPme3.

Subretinal fibrosis and uveitis syndrome in a patient with ectodermal dysplasia.

PURPOSE: To report a case of subretinal fibrosis and uveitis syndrome in association with ectodermal dysplasia. METHODS: Chart review of a patient with subretinal fibrosis and uveitis syndrome and ectodermal dysplasia. RESULTS: The authors identified one case of a patient with the diagnoses of subretinal fibrosis and uveitis syndrome and ectodermal dysplasia. CONCLUSIONS: This represents an uncommon case of a patient with the diagnoses of both subretinal fibrosis and uveitis syndrome and ectodermal dysplasia.