Macrophyte abundance in Waquoit Bay : effects of land-derived nitrogen loads on seasonal and multi-year biomass patterns

Author Posting. © The Author(s), 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Estuaries and Coasts 31 (2008): 532-541, doi:10.1007/s12237-008-9039-6.Anthropogenic inputs of nutrients to coastal waters have rapidly restructured coastal ecosystems. To examine the response of macrophyte communities to land-derived nitrogen loading, we measured macrophyte biomass monthly for six years in three estuaries subject to different nitrogen loads owing to different land uses on the watersheds. The set of estuaries sampled had nitrogen loads over the broad range of 12 to 601 kg N ha-1 y-1. Macrophyte biomass increased as nitrogen loads increased, but the response of individual taxa varied. Specifically, biomass of Cladophora vagabunda and Gracilaria tikvahiae increased significantly as nitrogen loads increased. The biomass of other macroalgal taxa tended to decrease with increasing load, and the relative proportion of these taxa to total macrophyte biomass also decreased. The seagrass, Zostera marina, disappeared from the higher loaded estuaries, but remained abundant in the estuary with the lowest load. Seasonal changes in macroalgal standing stock were also affected by nitrogen load, with larger fluctuations in biomass across the year and higher minimum biomass of macroalgae in the higher loaded estuaries. There were no significant changes in macrophyte biomass over the six years of this study, but there was a slight trend of increasing macroalgal biomass in the latter years. Macroalgal biomass was not related to irradiance or temperature, but Z. marina biomass was highest during the summer months when light and temperatures peak. Irradiance might, however, be a secondary limiting factor controlling macroalgal biomass in the higher loaded estuaries by restricting the depth of the macroalgal canopy. The relationship between the bloom-forming macroalgal species, C. vagabunda and G. tikvahiae, and nitrogen loads suggested a strong connection between development on watersheds and macroalgal blooms and loss of seagrasses. The influence of watershed land uses largely overwhelmed seasonal and inter-annual differences in standing stock of macrophytes in these temperate estuaries.This research was supported by the National Oceanic and Atmospheric Administration (NOAA), Cooperative Institute for Coastal and Estuarine Environmental Technologies (CICEET-UNH#99-304, NOAA NA87OR512), NOAA National Estuarine Research Reserve Graduate Research Fellowship NERRS GRF, #NA77OR0228), and an Environmental Protection Agency (EPA) STAR Fellowship for Graduate Environmental Study (U-915335-01-0) awarded to J. Hauxwell. S. Fox was supported by a NOAA NERRS GRF (#NA03NOS4200132) and an EPA STAR Graduate Research Fellowship. We also thank the Quebec-Labrador Foundation Atlantic Center for the Environment's Sounds Conservancy Program and the Boston University Ablon/Bay Committee for their awarding research funds

Mönckeberg's medial calcific sclerosis in diabetic and non-diabetic foot infections

The aim of this study was to evaluate the prevalence and extent of lower extremity Mönckeberg's Medial Calcific Sclerosis (MMCS) in patients with and without diabetes in patients admitted to the hospital for foot infections. This study retrospectively reviewed 446 patients admitted to the hospital with a moderate or severe foot infection. We defined diabetes based on ADA criteria and reviewed electronic medical records for demographics, medical history and physical examination data. Anterior–posterior and lateral foot radiographs were examined to identify the presence and extent of vascular calcification. We categorised MMCS based on anatomical location: ankle joint to the navicular-cuneiform joint, Lis Franc joint to metatarsophalangeal joints and distal to the metatarsophalangeal joints. The prevalence of MMCS was 40.6%. The anatomic extent of MMCS was 19.3% in the toes, 34.3% in the metatarsals and 40.6% in the hindfoot/ankle. Calcification was not common solely in the dorsalis pedis artery (DP) (3.8%) or solely in the posterior tibial artery (PT) (7.0%). Usually, both DP and PT arteries were affected by MMCS (29.8%). The prevalence of MMCS was higher in people with diabetes (in hindfoot and ankle [50.1% vs. 9.9%, p ≤ 0.01]; metatarsals [42.6% vs. 5.9%, p ≤ 0.01]; and toes [23.8% vs. 4.0%, p ≤ 0.01]). People with diabetes were 8.9 (CI: 4.5–17.8) times more likely to have MMCS than those without diabetes. This is a group that often has poor perfusion and needs vascular assessment. The high prevalence of MMCS raises questions about the reliability of the conventional segmental arterial Doppler studies to diagnose PAD

Are surrogate markers for diabetic foot osteomyelitis remission reliable?

Background: We aimed to evaluate surrogate markers commonly used in the literature for diabetic foot osteomyelitis remission after initial treatment for diabetic foot infections (DFIs). Methods: Thirty-five patients with DFIs were prospectively enrolled and followed for 12 months. Osteomyelitis was determined from bone culture and histologic analysis initially and for recurrence. Fisher exact and X2 tests were used for dichotomous variables and Student t and Mann-Whitney U tests for continuous variables (α=.05). Results: Twenty-four patients were diagnosed as having osteomyelitis and 11 as having softtissue infections. Four patients (16.7%) with osteomyelitis had reinfection based on bone biopsy. The success of osteomyelitis treatment varied based on the surrogate marker used to define remission: Osteomyelitis infection (16.7%), failed wound healing (8.3%), reulceration (20.8%), readmission (16.7%), amputation (12.5%). There was no difference in outcomes among patients who were initially diagnosed as having osteomyelitis versus soft-tissue infections. There were no differences in osteomyelitis reinfection (16.7% versus 45.5%; P=.07), wounds that failed to heal (8.3% versus 9.1%; P=.94), reulceration (20.8% versus 27.3%; P=.67), readmission for DFIs at the same site (16.7% versus 36.4%; P =.20), amputation at the same site after discharge (12.5% versus 36.4%; P=.10). Osteomyelitis at the index site based on bone biopsy indicated that failed therapy was 16.7%. Indirect markers demonstrated a failure rate of 8.3% to 20.8%. Conclusions: Most osteomyelitis markers were similar to markers in soft-tissue infection. Commonly reported surrogate markers were not shown to be specific to identify patients who failed osteomyelitis treatment compared with patients with softtissue infections. Given this, these surrogate markers are not reliable for use in practice to identify osteomyelitis treatment failure