Microbial Community Structure and Oxidative Enzyme Activity in Nitrogen-amended North Temperate Forest Soils

Large regions of temperate forest are subject to elevated atmospheric nitrogen (N) deposition which can affect soil organic matter dynamics by altering mass loss rates, soil respiration, and dissolved organic matter production. At present there is no general model that links these responses to changes in the organization and operation of microbial decomposer communities. Toward that end, we studied the response of litter and soil microbial communities to high levels of N amendment (30 and 80 kg ha −1 yr −1 ) in three types of northern temperate forest: sugar maple/basswood (SMBW), sugar maple/red oak (SMRO), and white oak/black oak (WOBO). We measured the activity of extracellular enzymes (EEA) involved directly in the oxidation of lignin and humus (phenol oxidase, peroxidase), and indirectly, through the production of hydrogen peroxide (glucose oxidase, glyoxal oxidase). Community composition was analyzed by extracting and quantifying phospholipid fatty acids (PLFA) from soils. Litter EEA responses at SMBW sites diverged from those at oak-bearing sites (SMRO, BOWO), but the changes were not statistically significant. For soil, EEA responses were consistent across forests types: phenol oxidase and peroxidase activities declined as a function of N dose (33–73% and 5–41%, respectively, depending on forest type); glucose oxidase and glyoxal oxidase activities increased (200–400% and 150–300%, respectively, depending on forest type). Principal component analysis (PCA) ordinated forest types and treatment responses along two axes; factor 1 (44% of variance) was associated with phenol oxidase and peroxidase activities, factor 2 (31%) with glucose oxidase. Microbial biomass did not respond to N treatment, but nine of the 23 PLFA that formed >1 mol% of total biomass showed statistically significant treatment responses. PCA ordinated forest types and treatment responses along three axes (36%, 26%, 12% of variance). EEA factors 1 and 2 correlated negatively with PLFA factor 1 ( r = −0.20 and −0.35, respectively, n = 108) and positively with PLFA factor 3 ( r = +0.36 and +0.20, respectively, n = 108). In general, EEA responses were more strongly tied to changes in bacterial PLFA than to changes in fungal PLFA. Collectively, our data suggests that N inhibition of oxidative activity involves more than the repression of ligninase expression by white-rot basidiomycetes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48115/1/248_2003_Article_9001.pd

Latex allergy in patients with spinal dysraphism: The role of multiple surgery

Objective To investigate whether multiple surgery is responsible for the high prevalence of latex hypersensitivity in patients with spinal dysraphism by comparing the results of a skin-prick test in three groups of patients with different surgical histories

Randomized Phase III Trial of Trastuzumab Plus Capecitabine With or Without Pertuzumab in Patients With Human Epidermal Growth Factor Receptor 2-Positive Metastatic Breast Cancer Who Experienced Disease Progression During or After Trastuzumab-Based Therapy

Purpose To assess the efficacy and safety of trastuzumab plus capecitabine with or without pertuzumab in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer who experienced disease progression during or after trastuzumab-based therapy and received a prior taxane. Patients and Methods Patients were randomly assigned to arm A: trastuzumab 8 mg/kg. 6 mg/kg once every 3 weeks plus capecitabine 1,250 mg/m(2) twice a day (2 weeks on, 1 week off, every 3 weeks); or arm B: pertuzumab 840 mg. 420 mg once every 3 weeks plus trastuzumab at the same dose and schedule as arm A plus capecitabine 1,000 mg/m(2) on the same schedule as arm A. The primary end point was independent review facility-assessed progression-free survival (IRF PFS). Secondary end points included overall survival (OS) and safety. Hierarchical testing procedures were used to control type I error for statistical testing of IRF PFS, OS, and objective response rate. Results Randomly assigned (intent-to-treat) populations were 224 and 228 patients in arms A and B, respectively. Median IRF PFS at 28.6 and 25.3 months' median follow-up was 9.0 v 11.1 months (hazard ratio, 0.82; 95% CI, 0.65 to 1.02; P =.0731) and interim OS was 28.1 v 36.1 months (hazard ratio, 0.68; 95% CI, 0.51 to 0.90). The most common adverse events (all grades; incidence of$10$ 5% difference between arms) were hand-foot syndrome, nausea, and neutropenia in arm A, and diarrhea, rash, and nasopharyngitis in arm B. Conclusion The addition of pertuzumab to trastuzumab and capecitabine did not significantly improve IRF PFS. An 8-month increase in median OS to 36.1 months with pertuzumab was observed. Statistical significance for OS cannot be claimed because of the hierarchical testing of OS after the primary PFS end point; however, the magnitude of OS difference is in keeping with prior experience of pertuzumab in metastatic breast cancer. No new safety signals were identified. (C) 2017 by American Society of Clinical Oncolog