Showing papers by "David W. Johnson published in 2003"
Memorial Sloan Kettering Cancer Center1, Harvard University2, Indiana University3, University of Minnesota4, University of Utah5, Boston University6, University of California, San Diego7, Kaiser Permanente8, Virginia Commonwealth University9, Eastern Virginia Medical School10, University of Texas Southwestern Medical Center11, Mayo Clinic12
TL;DR: These guidelines differ from those published in 1997 in several ways: the screening interval for double contrast barium enema has been shortened to 5 years, and colonoscopy is the preferred test for the diagnostic investigation of patients with findings on screening and for screening patients with a family history of hereditary nonpolyposis colorectal cancer.
2,196 citations
TL;DR: Social interdependence theory is a classic example of the interaction among theory, research, and practice that the way in which goals are structured determines how individuals interact, which creates outcomes.
Abstract: Social interdependence theory is a classic example of the interaction among theory, research, and practice. The premise of the theory is that the way in which goals are structured determines how individuals interact, which in turn creates outcomes. Over 750 research studies have been conducted in the past 11 decades on the relative merits of cooperative, competitive, and individualistic efforts and the conditions under which each is appropriate. These studies have validated, modified, refined, and extended the theory. Social interdependence theory has been widely applied, especially in education. The applications have resulted in revisions of the theory and the generation of considerable new research.
260 citations
TL;DR: Immediate cost savings could be achieved by increasing the use of intermittent hemodialysis rather than CRRT for patients with acute renal failure in the intensive care unit, and CRRT may still be an economically efficient treatment if it improves renal recovery among survivors.
Abstract: ObjectiveAcute renal failure can be treated with continuous renal replacement therapy (CRRT) or intermittent hemodialysis. There is no difference in mortality, although patients treated with CRRT may have a higher rate of renal recovery. Given these considerations, an estimate of the costs by modali
252 citations
Clemson University1, University of Arizona2, Cold Spring Harbor Laboratory3, Washington University in St. Louis4, University of Wisconsin-Madison5, J. Craig Venter Institute6, Johns Hopkins University7, National Institutes of Health8, Rutgers University9, University of Georgia10, Northern Illinois University11, North Carolina State University12
TL;DR: In this article, the authors report the sequence of chromosome 10, the smallest of the 12 rice chromosomes (22.4 megabases), which contains 3471 genes and multiple insertions from organellar genomes were detected.
Abstract: Rice is the world's most important food crop and a model for cereal research. At 430 megabases in size, its genome is the most compact of the cereals. We report the sequence of chromosome 10, the smallest of the 12 rice chromosomes (22.4 megabases), which contains 3471 genes. Chromosome 10 contains considerable heterochromatin with an enrichment of repetitive elements on 10S and an enrichment of expressed genes on 10L. Multiple insertions from organellar genomes were detected. Collinearity was apparent between rice chromosome 10 and sorghum and maize. Comparison between the draft and finished sequence demonstrates the importance of finished sequence.
243 citations
TL;DR: Compared with CABG, OPCAB may reduce neurologic and clinical morbidity as well as cost and perform better on the Rey Auditory Verbal Learning Test (total and recognition scores) at both 2 weeks and at 1 year, whereas CabG performance was statistically unchanged for all cognitive measures.
227 citations
TL;DR: Obesity at the commencement of renal replacement therapy is a significant risk factor for death and technique failure in patients treated with peritoneal dialysis and should be considered for early transfer to an alternative renal replacement Therapy if difficulties are experienced.
Abstract: Although obesity is associated with increased risks of morbidity and death in the general population, a number of studies of patients undergoing hemodialysis have demonstrated that increasing body mass index (BMI) is correlated with decreased mortality risk. Whether this association holds true among patients treated with peritoneal dialysis (PD) has been less well studied. The aim of this investigation was to examine the association between BMI and outcomes among new PD patients in a large cohort, with long-term follow-up monitoring. Using data from the Australia and New Zealand Dialysis and Transplant Registry, an analysis of all new adult patients (n = 9679) who underwent an episode of PD treatment in Australia or New Zealand between April 1, 1991, and March 31, 2002, was performed. Patients were classified as obese (BMI of greater than or equal to30 kg/m(2)), overweight (BMI of 25.0 to 29.9 kg/m(2)), normal weight (BMI of 20 to 24.9 kg/m(2)), or underweight (BMI of <20 kg/m(2)). In multivariate analyses, obesity was independently associated with death during PD treatment (hazard ratio, 1.36; 95% confidence interval, 1.14 to 1.54; P < 0.05) and technique failure (hazard ratio, 1.17; 95% confidence interval, 1.07 to 1.26; P < 0.01), except among patients of New Zealand Maori/Pacific Islander origin, for whom there was no significant relationship between BMI and death during PD treatment. A supplementary fractional polynomial analysis modeled BMI as a continuous predictor and indicated a J-shaped relationship between BMI and patient mortality rates and a steady increase in death-censored technique failure rates up to a BMI of 40 kg/m(2); the mortality risk was lowest for BMI values of approximately 20 kg/m(2). In conclusion, obesity at the commencement of renal replacement therapy is a significant risk factor for death and technique failure. Such patients should be closely monitored during PD and should be considered for early transfer to an alternative renal replacement therapy if difficulties are experienced.
187 citations
TL;DR: The levels of brevetoxins in air and water samples were measured, personal interviews were conducted, and pulmonary function tests on people before and after they visited one of two Florida beaches were performed, and an inflammatory response was found in over 33% of participants.
165 citations
TL;DR: Regular applications of ammonium nitrate and ammonium sulphate to areas of acidic and calcareous grassland in the Derbyshire Peak District over a period of 6 years have resulted in significant losses in both overall plant cover and the abundance of individual species, associated with clear and dose-related increases in shoot nitrogen content.
143 citations
TL;DR: The experience with cyclosporine use during breast-feeding in five mother-infant pairs is reported, showing a wide range of infant exposures to the drug in milk, noting that one of the infants had therapeutic blood concentrations of cyclospora despite relatively low concentrations of theDrug in milk.
Abstract: Although many female patients of childbearing age who are receiving cyclosporine have successful pregnancies, these women may be advised not to breast-feed. During recent years, cases of uneventful pregnancies and subsequent successful breast-feeding have been reported in the literature. The infant's blood cyclosporine concentration was usually very low. Based on these findings and the lack of detectable adverse effects, some investigators have suggested that women on cyclosporine may breast-feed, challenging the conventional view that cyclosporine is contraindicated during breast-feeding. Here, we report our experience with cyclosporine use during breast-feeding in five mother-infant pairs. We show a wide range of infant exposures to the drug in milk, noting that one of the infants had therapeutic blood concentrations of cyclosporine despite relatively low concentrations of the drug in milk.
140 citations
TL;DR: The results of this study suggest that high baseline RRF and high D/P creat ratio are risk factors for rapid loss of RRF.
Abstract: ♦ ObjectiveThe aim of this study was to prospectively evaluate the risk factors for decline of residual renal function (RRF) in an incident peritoneal dialysis (PD) population.♦ DesignProspective o...
129 citations
TL;DR: It is hypothesized that the discriminating functional attribute leading to a reduction of bacterial diversity in these microcosms was the presence in the F. ovina and mixed-plant communities of an active arbuscular–mycorrhizal mycelium that is absent from bare soil and monocultures of C. flacca.
Abstract: Summary
The diversity and functional type of plants can affect the microbial biomass in the soil, its respiratory activity and the diversity of its bacterial population. We have studied these effects in microcosms of reconstituted limestone grassland containing (i) a 12-species mixture of graminoids and forbs, (ii) a monoculture of the sedge Carex flacca, (iii) a monoculture of the grass Festuca ovina, and (iv) similar soil without plants. Microbial biomass was significantly greater in soil under monocultures of F. ovina than in the other microcosms. Basal respiration was largest in the F. ovina and mixed-species treatments where values were more than double those in the C. flacca and bare soil microcosms. The basal respiration was strongly linearly related to plant productivity (r = 0.89). Analysis of the active bacterial population by denaturing gradient gel electrophoresis of 16S rRNA revealed its diversity to be significantly greater in the C. flacca and bare soil treatments than in the F. ovina or mixed-species microcosms. This suggests that the functional type of plants has a strong influence on the composition of the bacterial community. We hypothesize that the discriminating functional attribute leading to a reduction of bacterial diversity in these microcosms was the presence in the F. ovina and mixed-plant communities of an active arbuscular–mycorrhizal mycelium that is absent from bare soil and monocultures of C. flacca.
Book•
23 Dec 2003
TL;DR: In this article, the authors discuss the power of cooperative groups and develop an assessment plan for groups to assess groups individually and as a whole, and incorporate peer assessment in groups for self-assessment.
Abstract: Series Editors' Introduction Preface About the Author 1. The Power of Cooperative Groups 2. Structuring Productive Groups 3. Developing an Assessment Plan for Groups 4. Using Groups for Individual Assessment 5. Assessing Groups as a Whole 6. Incorporating Peer Assessment in Groups 7. Cultivating Self-Assessment in Groups 8. Designing Group Experiences for Assessment 9. Putting It All Together References Index
TL;DR: The National Spherical Torus Experiment (NSTX) multipoint Thomson scattering system has been in operation for nearly two years and provides routine Te(R,t) and ne(R) measurements as discussed by the authors, where the laser beams from two 30 Hz Nd:YAG lasers are imaged by a spherical mirror onto 36 fiber-optic bundles.
Abstract: The National Spherical Torus Experiment (NSTX) multipoint Thomson scattering system has been in operation for nearly two years and provides routine Te(R,t) and ne(R,t) measurements. The laser beams from two 30 Hz Nd:YAG lasers are imaged by a spherical mirror onto 36 fiber-optic bundles. In the present configuration, the output ends of 20 of these bundles are instrumented with filter polychromators and avalanche photodiode detectors. In this article, we discuss the laser implementation and the installed collection optics. We follow with examples of raw and analyzed data, and close with some comments about calibration.
TL;DR: The purpose of this study was to continue the concept of membership-based research within diverse practice settings by expanding the American College of Gastroenterology GI Bleeding Registry to assess the management and outcome of acute variceal bleeding.
TL;DR: Two mutations of HOXD13 are described that cause missense substitutions within the homeodomain that are associated with distinctive limb phenotypes in which brachydactyly of specific metacarpals, metatarsals, and phalangeal bones is the most constant feature.
Abstract: HOXD13, the most 5′ gene of the HOXD cluster, encodes a homeodomain transcription factor with important functions in limb patterning and growth. Heterozygous mutations of human HOXD13, encoding polyalanine expansions or frameshifts, are believed to act by dominant negative or haploinsufficiency mechanisms and are predominantly associated with synpolydactyly phenotypes. Here, we describe two mutations of HOXD13 (923C→G encoding Ser308Cys and 940A→C encoding Ile314Leu) that cause missense substitutions within the homeodomain. Both are associated with distinctive limb phenotypes in which brachydactyly of specific metacarpals, metatarsals, and phalangeal bones is the most constant feature, exhibiting overlap with brachydactyly types D and E. We investigated the binding of synthetic mutant proteins to double-stranded DNA targets in vitro. No consistent differences were found for the Ser308Cys mutation compared with the wild type, but the Ile314Leu mutation (which resides at the 47th position of the homeodomain) exhibited increased affinity for a target containing the core recognition sequence 5′-TTAC-3′ but decreased affinity for a 5′-TTAT-3′ target. Molecular modeling of the Ile314Leu mutation indicates that this mixed gain and loss of affinity may be accounted for by the relative positions of methyl groups in the amino acid side chain and target base.
TL;DR: Results showed that the variables related to constructive competition included the fairness of the rules, the motivation to win, having an advantage that enhanced one's chances of winning, a strong positive relationship among competitors, and a history of confirming each other's competence.
Abstract: An empirical analysis was conducted on the conditions under which competition can be constructive. The participants were 64 managers and 28 employees from organizations in mainland China. They were asked to describe specific incidents of competition between them and their fellow employees and rate on a 7-point Likert-type scale the conditions that they perceived affected the outcomes. The incidents could involve either a physical activity or an intellectual task or both. Results showed that the variables related to constructive competition included the fairness of the rules, the motivation to win, having an advantage that enhanced one's chances of winning, a strong positive relationship among competitors, and a history of confirming each other's competence. By controlling these factors, the constructiveness of competition may be enhanced.
TL;DR: Subclinical LV dysfunction occurs in patients with ESRD, but is evidenced as abnormal myocardial diastolic, rather than systolic, function.
TL;DR: Clinically significant complications associated with the use of multiple-dose activated charcoal occur infrequently and are judged to have had clinically significant pulmonary aspiration and gastrointestinal obstruction.
TL;DR: G gaps in understanding are highlighted so that future research can provide more conclusive evidence on the mechanisms and wider ecological implications of the impacts of elevated ultraviolet-B radiation on terrestrial microorganisms.
TL;DR: Pikuz et al. as mentioned in this paper used spherically bent crystal mirrors to obtain high spatial resolution and a narrow spectral bandwidth using the Si Heα line (1.865 keV).
Abstract: X-ray backlighting systems are being developed to diagnose z-pinch, inertial confinement fusion capsule, and complex hydrodynamics experiments on the 20 MA Sandia Z machine. The x-ray backlighter source is a laser-produced plasma created using the Z-Beamlet laser, a 2 TW, 2 kJ Nd:glass laser recently constructed at Sandia. As an alternative to point-projection radiography, we are investigating a different geometry [S. A. Pikuz et al., Rev. Sci. Instrum. 68, 740 (1997)] that uses spherically bent crystal mirrors to simultaneously obtain high spatial resolution and a narrow spectral bandwidth. Backlighting systems using the Si Heα line (1.865 keV) and the Mn Heα line (6.15 keV) are discussed. These systems are capable of spatial resolutions in the 5–10 μm range, a field of view as large as 5 mm by 20 mm, and a spectral bandwidth comparable to the width of the emission line used for backlighting.
TL;DR: It is concluded that PTLD is more likely, occurs earlier, and is more often fatal, in the setting of intensive immunosuppression, and excellent long-term outcomes are achievable with early recognition and institution of appropriate treatment.
Abstract: Post-transplant lymphoproliferative disorder (PTLD) complicates 1 to 10% of all transplantations. Previous clinicopathological studies of PTLD have been limited by small numbers, short follow-up times, outdated data, heterogeneity of pooled solid-organ transplant results, and selective inclusion of early-onset disease. We therefore undertake here a retrospective analysis and identify all cases of PTLD that complicated renal transplantation at the Princess Alexandra Hospital between 30 June 1969 and 31 May 2001. Tumour samples were subsequently retrieved for pathological review and for Epstein–Barr virus-encoded RNA in situ hybridisation (EBER-ISH). Of 2,030 renal transplantation patients, 29 (1.4%) developed PTLD after a median period of 0.5 years (range 0.1 to 23.3 years). PTLD patients were more likely to have received cyclosporine (76% versus 62%, P 1 (HR 2.7, 95% CI 1.1–6.8). Compared with other treatments, chemotherapy was associated with higher survival rates (100% versus 18% at 3 years, P=0.0001). In conclusion, PTLD is more likely, occurs earlier, and is more often fatal, in the setting of intensive immunosuppression. Nevertheless, excellent long-term outcomes are achievable with early recognition and institution of appropriate treatment.
TL;DR: Live-donor kidney transplant recipients had a higher rate and severity of rejection and a shorter rejection-free period than cadaveric renal transplant recipients and donor type did not independently influence graft survival, immunologic transplant survival, or patient survival.
Abstract: Background Live Donors are an increasingly important source of kidneys for transplantation in Australia The aim of this study was to compare the rate and severity of rejection between patients receiving kidney transplants from live versus cadaveric donors Methods A retrospective analysis was undertaken of all patients receiving live-donor (n=109) and cadaveric-donor (n=389) renal transplants at our institution between April 1, 1994, and March 31, 2000 Follow-up was completed on all patients until graft loss, death, or May 31, 2001 Results The baseline characteristics of the live-donor and cadaveric groups were similar, except for recipient age (mean±SD, 363±156 vs 445±144 years, respectively; P<0001); donor age (461±113 vs 361±164 years, P<0001); pretransplant dialysis duration (136±21 vs 34±44 years, P<0001); and the proportions of patients receiving first allografts (95% vs 88%, respectively; P<005), antibody induction (8% vs 20%, P<001), and mycophenolate mofetil (MNW) (60% vs 37%, P<0001) Acute rejection was observed in 48 (44%) live-donor and 108 (28%) cadaveric transplants (P=0001) Cadaveric donor type was independently predictive of less acute rejection both on logistic regression (adjusted odds ratio [AOR], 047; 95% confidence interval [CI], 030-073; P=0001) and multivariate Cox proportional hazards model analysis (hazard ratio, 049; 95% CI, 034-069; P<0001) Patients receiving cadaveric-donor transplants were also significantly less likely to receive antibody therapy for rejection (univariate, 18% vs 9%; P=0006; multivariate AOR, 045; 95% CI, -025-082; P<001), independent of recipient age, gender, race, transplant number, human leukocyte antigen mismatch, sensitization, induction therapy, delayed graft function, MMF use, tacrolimus or cyclosporine A use, sirolimuseverolimus use, year of transplant, donor age, or dialysis duration However, donor type did not independently influence graft survival, immunologic graft survival, or patient survival Conclusions Live-donor kidney transplant recipients had a higher rate and severity of rejection and a shorter rejection-free period than cadaveric renal transplant recipients Further consideration of the reasons for this difference and the use of alternative immunosuppressive strategies for live-donor transplants are recommended
TL;DR: Patients with impaired ultrafiltration, particularly in the settings of acute peritonitis, high transporter status and diabetes mellitus, appear to derive the greatest benefit from icodextrin with respect to augmentation of dialytic fluid removal, amelioration of symptomatic fluid retention and possible prolongation of technique survival.
Abstract: Icodextrin is a starch-derived, high molecular weight glucose polymer, which has been shown to promote sustained ultrafiltration equivalent to that achieved with hypertonic (3.86%/4.25%) glucose exchanges during prolonged intraperitoneal dwells (up to 16 h). Patients with impaired ultrafiltration, particularly in the settings of acute peritonitis, high transporter status and diabetes mellitus, appear to derive the greatest benefit from icodextrin with respect to augmentation of dialytic fluid removal, amelioration of symptomatic fluid retention and possible prolongation of technique survival. Glycaemic control is also improved by substituting icodextrin for hypertonic glucose exchanges in diabetic patients. Preliminary in vitro and ex vivo studies suggest that icodextrin demonstrates greater peritoneal membrane biocompatibility than glucose-based dialysates, but these findings need to be confirmed by long-term clinical studies. This paper reviews the available clinical evidence pertaining to the safety and efficacy of icodextrin and makes recommendations for its use in peritonal dialysis.
TL;DR: In this paper, a 3-month period during each of four seasons and measured mass loss and nitrogen (N) dynamics in Acer rubrum leaf litter by using a litterbag approach.
Abstract: Litter decomposition is a major component of nutrient cycling in forest ecosystems and is known to be sensitive to both temperature and moisture. A drought during periods of the year when moisture is normally abundant may impact decomposition more than moisture limitation during seasons that are routinely dry. We excluded precipitation for a 3-month period during each of four seasons and measured mass loss and nitrogen (N) dynamics in Acer rubrum leaf litter by using a litterbag approach. We hypothesized that rainfall exclusion would retard mass loss during the exclusion period, with the maximum effect occurring during the spring and summer months when moisture was normally adequate and temperatures optimum for decomposition, and that exclusion during these two periods would have the greatest impact on subsequent timing of decomposition events, particularly N mineralization. Mass loss in litterbags was initially reduced by precipitation exclusion in the spring treatment only. For each season, a set of bags exposed to drying in the same way and allowed to remain in the field under ambient conditions for an additional 9 months no longer showed a difference in mass loss relative to control bags. Nitrogen accumulation was immediately and significantly reduced in the exclusion treatments in all seasons; however, like mass loss, there was no difference 9 months later. We conclude that short-term effects of drought do occur, especially with regard to N accumulation, and that these effects do not persist and are unlikely to have any substantial effect on nutrient cycling.
TL;DR: A notable deficiency in the use of tandem mass spectrometry for newborn screening is the inability to screen for urea cycle defects, so measurements of glutamic and pyroglutamic acids in blood spots after derivatization are grossly inaccurate.
Abstract: A notable deficiency in the use of tandem mass spectrometry (MS/MS) for newborn screening is the inability to screen for urea cycle defects. The most common of these, with an incidence of 1 in 14 000 births (1), is the inherited X-linked disorder ornithine transcarbamylase deficiency (OTCD). A majority (60%) of hemizygous males risk death from hyperammonemic coma during the first week of life. The remainder, including 10% of heterozygous females, exhibit lethargy, vomiting episodes, and behavioral problems during childhood. The severity of the disorder and the potential for correction of OTCD by liver transplantation and gene therapy (2) provide adequate justification for newborn screening.
OTCD patients have low blood citrulline because of reduced conversion from carbamoyl phosphate. Citrulline is one of the amino acids routinely measured in MS/MS newborn-screening programs. Unfortunately, many protein-restricted newborns also have low blood citrulline (3). A more selective amino acid metabolite for OTCD is glutamine. The derivatization procedure used in many MS/MS screening programs (4), which uses butanol–hydrogen chloride, destroys glutamine. Approximately one-half of the glutamine is converted to glutamic acid dibutyl ester and is indistinguishable from that formed from endogenous glutamic acid in the blood. The surviving glutamine butyl ester is deaminated in acidic solution to a protonated form of pyroglutamic acid butyl ester in the electrospray source of the MS/MS. Again it is not possible to distinguish this pyroglutamic acid from what is already present in the blood. As a secondary consequence, the measurements of glutamic and pyroglutamic (and by analogy, aspartic) acids in blood spots after derivatization are grossly inaccurate. MS/MS newborn-screening programs that do not derivatize amino acids avoid solvolysis of glutamine and of pyroglutamic acid to glutamic acid. During electrospray ionization-MS/MS analysis, however, glutamine is again indistinguishable from pyroglutamic acid. Resolution is possible by separation with time-consuming liquid chromatography …
TL;DR: The proportions of callers who sought unadvised medical care and who received unad advised significant care were not significantly different in the advice nurse and pediatrician groups, which suggests that advice nurses do not delay significant medical treatment when compared with pediatricians.
Abstract: Background Advice nurse call centers are used to ensure access to medical advice, thereby potentially reducing the costs of health services. Objective To determine if medical advice from advice nurses and on-call physicians delays significant medical treatment in a general pediatrics population. Design Randomized controlled trial. Setting A university general pediatrics faculty practice. Participants Parents or guardians calling for after-hours advice regarding their children. Intervention After-hours medical advice calls were randomized at the time of the call to an advice nurse or an on-call pediatrician. Main Outcome Measures The proportion of callers who sought medical care not advised by the advice nurse or on-call pediatrician and the proportion who received unadvised significant care. Results There were 1182 advice calls: 566 in the pediatrician group and 616 in the advice nurse group. There were no significant differences in the types of telephone triage advice in the physician and advice nurse groups. There was no significant difference in the proportion of callers who sought unadvised care (108 [19.9%] in the physician group vs 110 [19.0%] in the advice nurse group) or in the proportion of callers who received unadvised significant care (23 [4.2%] in the physician group vs 25 [4.3%] in the advice nurse group). Conclusions The proportions of callers who sought unadvised medical care and who received unadvised significant care were not significantly different in the advice nurse and pediatrician groups. This suggests that advice nurses do not delay significant medical treatment when compared with pediatricians.
TL;DR: High pressure liquid chromatography with a narrow bore C8 column has been used to separate pristanic, phytanic and very long chain fatty acids, important in the diagnosis of peroxisomal disorders, for their accurate isotope dilution quantification by tandem mass spectrometry.
TL;DR: In this paper, the edge parameters play a critical role in high confinement mode (H-mode) access, which is a key component of discharge optimization in present day toroidal confinement experiments and the design of next generation devices.
Abstract: Edge parameters play a critical role in high confinement mode (H-mode) access, which is a key component of discharge optimization in present day toroidal confinement experiments and the design of next generation devices. Because the edge magnetic topology of a spherical torus (ST) differs from a conventional aspect ratio tokamak, H-modes in STs exhibit important differences compared with tokamaks. The dependence of the National Spherical Torus Experiment (NSTX) [C. Neumeyer et al., Fusion Eng. Des. 54, 275 (2001)] edge plasma on heating power, including the low confinement mode (L-mode) to H-mode (L-H) transition requirements and the occurrence of edge-localized modes (ELMs), and on divertor configuration is quantified. Comparisons between good L-modes and H-modes show greater differences in the ion channel than the electron channel. The threshold power for the H-mode transition in NSTX is generally above the predictions of a recent International Tokamak Experimental Reactor (ITER) [ITER Physics Basis Edi...