Trace Elements in Surface Soils and Megascolecidae Earthworms in Urban Forests Within Four Land-Uses Around Poughkeepsie, New York, USA.

Amynthas agrestis and Metaphire hilgendorfi are being distributed across North America with unknown ecosystem impacts. Forest soils in urban areas sequester trace elements and earthworms may be bioaccumulating them. This study examined Cd, Cr, Co, Cu, Mn, Ni, Pb, V, and Zn in soils and earthworm tissues at 28 urban forest sites in and surrounding Poughkeepsie, NY, USA. Megascolecidae were present at 22 sites with means of 12 to 27 individuals m-2 and 4 to 12 dry weight g m-2. Urban forest soils within commercial uses had Mn, Pb, and Zn concentrations higher than within residential and agricultural uses. Earthworm trace element concentrations were poorly predicted by their respective soil concentrations, except for Pb. Urban forests in commercial uses and land-preserves, earthworm Cd and Pb concentrations were at or above concentrations known to negatively impact small mammal and bird health ( > 10 mg kg-1) with Co and V approaching toxic concentrations.

Impact of human platelet lysate on the expansion and chondrogenic capacity of cultured human chondrocytes for cartilage cell therapy.

High hopes have been pinned on regenerative medicine strategies in order to prevent the progression of cartilage damage to osteoarthritis, particularly by autologous chondrocyte implantation (ACI). The loss of chondrocyte phenotype during in vitro monolayer expansion, a necessary step to obtain sufficient cell numbers, may be a key limitation in ACI. In this study, it was determined whether a shorter monolayer expansion approach could improve chondrogenic differentiation. The effects of two supplement types, foetal bovine serum (FBS) and Stemulate™ (a commercial source of human platelet lysate), on the expansion and re-differentiation potential of human chondrocytes, isolated from five individuals, were compared. Chondrocytes were expanded with 10 % FBS or 10 % Stemulate™. Pellets were cultured for 28 d in chondrogenic differentiation medium and assessed for the presence of cartilage matrix molecules and genes associated with chondrogenicity. Stemulate™ significantly enhanced the proliferation rate [average population doubling times: FBS, 25.07 ± 6.98 d (standard error of the mean, SEM) vs. Stemulate™, 13.10 ± 2.57 d (SEM)]. Sulphated glycosaminoglycans (sGAG), total collagen and qRT-PCR analyses of cartilage genes showed that FBS-expanded chondrocytes demonstrated significantly better chondrogenic capacity than Stemulate™-expanded chondrocytes. Histologically, FBS-expanded chondrocyte pellets appeared to be more stable, with a more intense staining for toluidine blue, indicating a greater chondrogenic capacity. Although Stemulate™ positively influenced chondrocyte proliferation, it had a negative effect on chondrogenic differentiation potential. This suggested that, in the treatment of cartilage defects, Stemulate™ might not be the ideal supplement for expanding chondrocytes (which maintained a chondrocyte phenotype) and, hence, for cell therapies (including ACI).

Exotic Earthworms Decrease Cd, Hg, and Pb Pools in Upland Forest Soils of Vermont and New Hampshire USA.

Exotic earthworms are present in the forests of northeastern USA, yet few studies have documented their effects on pollutant metals in soil. The objective of this study was to identify if Cd, Hg, and Pb strong-acid extractable concentrations and pools (bulk inventories) in forest soils decreased with the presence of exotic earthworms. We compared 'Low Earthworm Abundance' (LEA) sites (≤10 g m-2 earthworms, n = 13) and 'High Earthworm Abundance' (HEA) (>10 g m-2 earthworms, n = 17) sites at five watersheds across Vermont and New Hampshire. Organic horizon Cd, Hg, and Pb concentrations were lower at HEA than LEA sites. Organic horizon and total soil pools of Cd and Hg were negatively correlated with earthworm biomass. Soil profile Cd and Hg concentrations were lower at HEA than LEA sites. Our results suggest earthworms are decreasing accumulation of Cd, Hg, and Pb in forest soils, potentially via greater mobilization through organic matter disruption or bioaccumulation.

Nutrient and pollutant metals within earthworm residues are immobilized in soil during decomposition.

Earthworms are known to bioaccumulate metals, making them a potential vector for metal transport in soils. However, the fate of metals within soil upon death of earthworms has not been characterized. We compared the fate of nutrient (Ca, Mg, Mn) and potentially toxic (Cu, Zn, Pb) metals during decomposition of Amynthas agrestis and Lumbricus rubellus in soil columns. Cumulative leachate pools, exchangeable pools (0.1 M KCl + 0.01 M acetic acid extracted), and stable pools (16 M HNO3 + 12 M HCl extracted) were quantified in the soil columns after 7, 21, and 60 days of decomposition. Soil columns containing A. agrestis and L. rubellus had significantly higher cumulative leachate pools of Ca, Mn, Cu, and Pb than Control soil columns. Exchangeable and stable pools of Cu, Pb, and Zn were greater for A. agrestis and L. rubellus soil columns than Control soil columns. However, we estimated that > 98 % of metals from earthworm residues were immobilized in the soil in an exchangeable or stable form over the 60 days using a mass balance approach. Micro-XRF images of longitudinal thin sections of soil columns after 60 days containing A. agrestis confirm metals immobilization in earthworm residues. Our research demonstrates that nutrient and toxic metals are stabilized in soil within earthworm residues.

ADAMTS-4 activity in synovial fluid as a biomarker of inflammation and effusion.

OBJECTIVE: To evaluate the potential of ADAMTS-4 (aggrecanase -1) activity in synovial fluid (SF) as a biomarker of knee injury and joint disease. DESIGN: We have measured ADAMTS-4 activity in the synovial fluid of 170 orthopaedic patients with different degrees of joint pathology, using a commercial ADAMTS-4 fluorescence resonance energy transfer (FRET) substrate assay. Patients were classified at arthroscopy as (i) macroscopically normal, (ii) with an injury of the meniscus, anterior cruciate ligament or chondral/osteochondral defects or (iii) with osteoarthritis, and the influence of independent factors (age, patient group, effusion and synovial inflammation) on ADAMTS-4 activity levels was assessed. RESULTS: In most patients (106/170) ADAMTS-4 activity was undetectable; ADAMTS-4 ranged from 0 to 2.8 ng/mL in synovial fluid from patients with an injury, 0-4.1 ng/mL in osteoarthritic patients and 4.0-12.3 ng/mL in patients with large effusions. Four independent variables each significantly influenced ADAMTS-4 activity in synovial fluid (all P < 0.001): age (concordance = 0.69), presence of osteoarthritis (OA) (concordance = 0.66), level of effusion (concordance = 0.78) and inflammation (concordance = 0.68). Not only did effusion influence the amount of ADAMTS-4 activity most strongly, but it also did this in an ordered manner (P < 0.001). CONCLUSIONS: The main finding of this study is that ADAMTS-4 levels in synovial fluid are most strongly correlated with inflammation and severity of effusion in the knee. Further study is required to determine if it could provide a useful tool to aid clinical diagnoses, indicate treatment, to monitor progression of joint degeneration or OA or alternatively the success of treatment.

Trace Metals and Metalloids in Forest Soils and Exotic Earthworms in Northern New England, USA.

Trace metals and metalloids (TMM) in forest soils and invasive earthworms were studied at 9 uncontaminated sites in northern New England, USA. Essential (Cu, Mo, Ni, Zn, Se) and toxic (As, Cd, Pb, Hg and U) TMM concentrations (mg kg-1) and pools (mg m-2) were quantified for organic horizons (forest floor), mineral soils and earthworm tissues. Essential TMM tissue concentrations were greatest for mineral soil-feeding earthworm Octolasion cyaneum. Toxic TMM tissue concentrations were highest for organic horizon-feeding earthworms Dendobaena octaedra, Aporrectodea rosea and Amynthas agrestis. Most earthworm species had attained tissue concentrations of Pb, Hg and Se potentially hazardous to predators. Bioaccumulation factors were Cd > Se > Hg > Zn > Pb > U > 1.0 > Cu > As > Mo > Ni. Only Cd, Se Hg and Zn were considered strongly bioaccumulated by earthworms because their average bioaccumulation factors were significantly greater than 1.0. Differences in bioaccumulation did not appear to be caused by soil concentrations as earthworm TMM tissue concentrations were poorly correlated with TMM soil concentrations. Instead, TMM bioaccumulation appears to be species and site dependent. The invasive Amynthas agrestis had the greatest tissue TMM pools, due to its large body mass and high abundance at our stands. We observed that TMM tissue pools in earthworms were comparable or exceeded organic horizon TMM pools; earthworm tissue pools of Cd were up 12 times greater than in the organic horizon. Thus, exotic earthworms may represent an unaccounted portion and flux of TMM in forests of the northeastern US. Our results highlight the importance of earthworms in TMM cycling in northern forests and warrant more research into their impact across the region.

NASHA hyaluronic acid vs. methylprednisolone for knee osteoarthritis: a prospective, multi-centre, randomized, non-inferiority trial.

OBJECTIVE: To compare NASHA hyaluronic acid gel as single-injection intra-articular (IA) treatment for knee osteoarthritis (OA) against methylprednisolone acetate (MPA). DESIGN: This was a prospective, multi-centre, randomized, active-controlled, double-blind, non-inferiority clinical trial. A unique, open-label extension phase (OLE) was undertaken to answer further important clinical questions. Subjects with painful unilateral knee OA were treated and followed for 26 weeks (blinded phase). All patients attending the clinic at 26 weeks were offered NASHA treatment, with a subsequent 26-week follow-up period (extension phase). The primary objective was to show non-inferiority of NASHA vs MPA in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain responder rate (percentage of patients with ≥40% improvement from baseline in WOMAC pain score and an absolute improvement of ≥5 points) at 12 weeks. RESULTS: In total, 442 participants were enrolled. The primary objective was met, with NASHA producing a non-inferior response rate vs MPA at 12 weeks (NASHA: 44.6%; MPA: 46.2%; difference [95% CI]: 1.6% [-11.2%; +7.9%]). Effect size for WOMAC pain, physical function and stiffness scores favoured NASHA over MPA from 12 to 26 weeks. In response to NASHA treatment at 26 weeks, sustained improvements were seen in WOMAC outcomes irrespective of initial treatment. No serious device-related adverse events (AEs) were reported. CONCLUSIONS: This study shows that single-injection NASHA was well tolerated and non-inferior to MPA at 12 weeks. The benefit of NASHA was maintained to 26 weeks while that of MPA declined. An injection of NASHA at 26 weeks conferred long-term improvements without increased sensitivity or risk of complications. STUDY IDENTIFIER: NCT01209364 (www.clinicaltrials.gov).

Forest Floor Lead Changes from 1980 to 2011 and Subsequent Accumulation in the Mineral Soil across the Northeastern United States.

Quantifying the transport rate of anthropogenic lead (Pb) in forest soils is essential for predicting air pollution impacts on northeastern United States soil quality. In 2011, we resampled the forest floor at 16 sites across the northeastern United States previously sampled in 1980, 1990, and 2002 and also sampled the upper two mineral soil horizons. The mean forest floor Pb concentration decreased from 151 ± 29 mg kg in 1980 to 68 ± 13 mg kg in 2011. However, the mean forest floor Pb amount per unit area remained similar (10 ± 2 kg ha in 1980 and 11 ± 4 kg ha in 2011). Study sites were divided into three geographic regions: western, central, and northern. The modeled forest floor Pb response time (1/) was longer at frigid soil temperature regime sites (61 ± 15 yr) compared with mesic sites (29 ± 4 yr). Mineral soil Pb concentration and amount were approximately four times greater at western and central sites compared with northern sites for both mineral horizons. Furthermore, mean isotope ratios of Pb/Pb (1.201 ± 0.006) and Pb/Pb (2.060 ± 0.021) indicated that Pb in the western and central forest floor and mineral soil was primarily gasoline derived. Our combined analytical approach using long-term forest floor monitoring and stable Pb isotopes suggest that the majority of anthropogenic Pb deposited on soils in the western and central sites has been transported to the mineral soil, whereas it continues to reside in the forest floor at northern sites.

Hip resurfacing arthroplasty: A new method to assess and quantify learning phase.

Hip resurfacing had initially gained acceptance and popularity as it helps preserve femoral bone stock. In this study we tried to answer the following questions; 1. Whether there is a learning curve for hip resurfacing? 2. Is it present in surgeons from non-developer centres? 3. Is it present in surgeons from developer centres as well? The Oswestry outcome centre was setup to serve an independent international registry for collecting, analysing and reporting outcomes following hip resurfacing. Over a 10 year period, 4535 patients (5000 hips) were recruited from different countries and within the UK from different centres in this study by 139 surgeons from 37 different countries. Our study has shown that function can be used to assess the level of surgical competence. The results from this multilevel analysis have helped to answer the questions posed in the introduction. Hip resurfacing is a surgical procedure with a learning phase and this learning effect is more pronounced in non-developer surgeons as compared to developer surgeons. Hip scores can be used to assess proficiency and competence of surgeons undertaking hip resurfacing arthroplasty.

Clinical outcome of autologous chondrocyte implantation is correlated with infrared spectroscopic imaging-derived parameters.

OBJECTIVE: To investigate whether Fourier transform infrared imaging spectroscopy (FT-IRIS), a modality based on molecular vibrations, is a viable alternative to histology and immunohistochemistry (IHC) for assessment of tissue quality and patient clinical outcome. METHODS: Osteochondral biopsies were obtained from patients (9-65 months post-surgery) who underwent an autologous chondrocyte implantation (ACI) procedure to repair a cartilage defect (N = 14). The repair tissue was evaluated histologically by OsScore grading, for the presence of types I and II collagen by IHC, and for proteoglycan (PG) distribution and collagen quality parameters by FT-IRIS. Patient clinical outcome was assessed by the Lysholm score. RESULTS: Improvement in Lysholm score occurred in 79% of patients. IHC staining showed the presence of types I and II collagen in all samples, with a greater amount of collagen type II in the deep zone. The amount and location of immunostaining for type II collagen correlated to the FT-IRIS-derived parameters of relative PG content and collagen helical integrity. In addition, the improvement in Lysholm score post-ACI correlated positively with the OsScore, type II collagen (IHC score) and FT-IRIS-determined parameters. Regression models for the relation between improvement in Lysholm score and either OsScore, IHC area score or the FT-IRIS parameters all reached significance (p < 0.01). However, the FT-IRIS model was not significantly improved with inclusion of the OsScore and IHC score parameters. CONCLUSION: Demonstration of the correlation between FT-IRIS-derived molecular parameters of cartilage repair tissue and patient clinical outcome lays the groundwork for translation of this methodology to the clinical environment to aid in the management of cartilage disorders and their treatment.

Synthesis of earthworm trace metal uptake and bioaccumulation data: Role of soil concentration, earthworm ecophysiology, and experimental design.

Trace metals can be essential for organo-metallic structures and oxidation-reduction in metabolic processes or may cause acute or chronic toxicity at elevated concentrations. The uptake of trace metals by earthworms can cause transfer from immobilized pools in the soil to predators within terrestrial food chains. We report a synthesis and evaluation of uptake and bioaccumulation empirical data across different metals, earthworm genera, ecophysiological groups, soil properties, and experimental conditions (metal source, uptake duration, soil extraction method). Peer-reviewed datasets were extracted from manuscripts published before June 2019. The 56 studies contained 3513 soil-earthworm trace metal concentration paired data sets across 11 trace metals (As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Sb, U, Zn). Across all field and laboratory experiments studied, the median concentrations of Hg, Pb, and Cd in earthworm tissues that were above concentrations known to be hazardous for consumption by small mammals and avian predators but not for Cu, Zn, Cr, Ni, and As. Power regressions show only Hg and Cd earthworm tissue concentrations were well-correlated with soil concentrations with R2 > 0.25. However, generalized linear mixed-effect models reveal that earthworm concentrations were significantly correlated with soil concentrations for log-transformed Hg, Cd, Cu, Zn, As, Sb (p < 0.05). Factors that significantly contributed to these relationships included earthworm genera, ecophysiological group, soil pH, and organic matter content. Moreover, spiking soils with metal salts, shortening the duration of exposure, and measuring exchangeable soil concentrations resulted in significantly higher trace metal uptake or greater bioaccumulation factors. Our results highlight that earthworms are able to consistently bioaccumulate toxic metals (Hg and Cd only) across field and laboratory conditions. However, future experiments should incorporate greater suites of trace metals, broader genera of earthworms, and more diverse laboratory and field settings to generate data to devise universal quantitative relationships between soil and earthworm tissue concentrations.

Modification and validation of the Lysholm Knee Scale to assess articular cartilage damage.

OBJECTIVE: The Lysholm Knee Scale is an 8-item questionnaire originally designed as an outcome measure for ligament reconstruction but is commonly used as a measure for knee chondral damage. This study tests the scale's internal construct validity using the Rasch model, a measurement model which sets strict standards for the quality of measurement derived from the scale. The study also investigates the level of agreement between scores from patients and physiotherapists; and reviews the present weighting system. DESIGN: One hundred and fifty-seven patients with knee chondral damage awaiting surgery completed the Lysholm as part of a multicentre clinical trial based in 16 UK and two Norwegian hospitals. The patients were assessed by a physiotherapist who independently completed the Lysholm on the same day. RESULTS: Fit to the Rasch model was achieved [mean item fit -0.26, standard deviation (SD) 1.01] after removal of one item (Swelling). With no differential item functioning (DIF) by rater, the intraclass correlation coefficient was 0.9 [95% confidence interval (CI): 0.86-0.93] and a Bland-Altman plot showed no consistent difference in rating. CONCLUSIONS: The Lysholm Knee Scale satisfies Rasch model expectations after removal of the swelling item. Generally there is a high degree of agreement between the patient and professional ratings. By removing the swelling item and using unweighted scores, a modified version of the Lysholm Knee Scale is recommended as an outcome measure for knee chondral damage.

The cellular site of action of angiotensin.

The site of action and the distribution of angiotensin II have been studied in the mouse. A comparison of the ratios of angiotensin-(14)C and inulin-(3)H at the time of the pressor effect reveals an extracellular pattern of distribution. Morphological studies were made using angiotensin coupled to exogenous enzymes which can be demonstrated histochemically. Coupling of angiotensin to horseradish peroxidase or cytochrome c, with glutaraldehyde or difluorodinitrodiphenylsulfone (FNPS) as the coupling agent, does not alter the pattern of its vasopressor response or that of its inactivation; nor are differences present between angiotensin and the angiotensin-enzyme complexes in the stimulation of in vitro tissue preparations. Dissociation of the complexes was shown not to occur in vitro, but the possibility of a serum factor splitting the complexes immediately after intravenous injection cannot be excluded. Since these complexes are localized on the endothelium and not on the smooth muscle at the time of maximum hypertension, the endothelium is proposed as the site of action for angiotensin.

Computational simulation of fracture healing: influence of interfragmentary movement on the callus growth.

Bone fractures heal through a complex process involving several cellular events. This healing process can serve to study factors that control tissue growth and differentiation from mesenchymal stem cells. The mechanical environment at the fracture site is one of the factors influencing the healing process and controls size and differentiation patterns in the newly formed tissue. Mathematical models can be useful to unravel the complex relation between mechanical environment and tissue formation. In this study, we present a mathematical model that predicts tissue growth and differentiation patterns from local mechanical signals. Our aim was to investigate whether mechanical stimuli, through their influence on stem cell proliferation and chondrocyte hypertrophy, predict characteristic features of callus size and geometry. We found that the model predicted several geometric features of fracture calluses. For instance, callus size was predicted to increase with increasing movement. Also, increases in size were predicted to occur through increase in callus diameter but not callus length. These features agree with experimental observations. In addition, spatial and temporal tissue differentiation patterns were in qualitative agreement with well-known experimental results. We therefore conclude that local mechanical signals can probably explain the shape and size of fracture calluses.

Successful treatment of refractory tibial nonunion using calcium sulphate and bone marrow stromal cell implantation.

Successful healing of a nine-year tibial nonunion resistant to six previous surgical procedures was achieved by tissue engineering. We used autologous bone marrow stromal cells (BMSCs) expanded to 5 x 10(6) cells after three weeks' tissue culture. Calcium sulphate (CaSO4) in pellet form was combined with these cells at operation. The nonunion was clinically and radiologically healed two months after implantation. This is the description of on healing of a long-standing tibial nonunion by tissue engineering. The successful combination of BMSCs and CaSO4 has not to our knowledge been reported in a clinical setting.

Combined autologous chondrocyte implantation and allogenic meniscus transplantation: a biological knee replacement.

Meniscus deficient knees develop early osteoarthritis in the knee. Autologous Chondrocyte Implantation has provided a new dimension to the treatment of chondral defects in the knee, with 85% good to excellent results and a long-term durable outcome of up-to 11 years. However, it is contraindicated in meniscus deficient knees. Allogenic Meniscus Transplantation gives good symptomatic relief in meniscus deficient knees, with a success rate of 89%. However, it is contraindicated in advanced cartilage degeneration. We hypothesized that combination of these two might be a solution for bone-on-bone arthritis in young individuals. We studied a consecutive series of eight patients, with mean age of 43 years, presenting with large kissing chondral defects, secondary to the previous meniscectomy. All the patients were treated with a combination of Autologous Chondrocyte Implantation and Allogenic Meniscus Transplantation. Mean pre-operative Lysholm score was 49, which rose to mean of 66 at 1 year, an average increase by 16.4 points. Six patients showed significant improvement at one year. MRI scans showed good integration of the menisci with the capsule, without any rejection. Histology confirmed the integration. All the patients could lead an active life-style. Five patients maintained the improvement at a mean follow-up of 3.2 years. We could not find any deleterious effects of the combination of these two techniques. So we conclude that the combination of these two techniques together may act a one step towards a true biological knee replacement.

Can cobalt levels estimate in-vivo wear of metal-on-metal bearings used in hip arthroplasty?

High levels of cobalt and chromium ions are detected in the blood and urine of patients with metal-on-metal (MoM) hip replacement. These elements are released as a result of wear at the bearing surfaces. Wear rates depend on a multitude of factors, which include the bearing geometry, carbon content, manufacturing processes, lubrication, speed and direction of sliding of the surfaces, pattern of loading, and orientation of the components. In-vivo wear of MoM bearings cannot be reliably measured on X-rays because no distinction can be made between the bearing surfaces. Hip simulator studies have shown that wear rates are higher during the initial bedding-in phase and subsequently drop to very low levels. Accordingly, metal ion levels would be expected to decrease with the use of the bearing, measured as implantation time following surgery. However, several clinical studies have found that metal ion levels either gradually rise or fluctuate instead of decreasing to lower levels. Moreover, hip simulator studies predict that large-diameter bearings have lower wear rates than small-diameter bearings. In clinical studies, however, metal levels in patients with large-diameter bearings are unexpectedly higher than those in patients with small-diameter bearings. As a consequence, high cobalt ion levels in patients do not necessarily imply that their MoM bearings produce much wear debris at the time that their levels were measured; it may simply be due to accumulation of wear debris from the preceding time. Exercise-related cobalt rise may overcome this limitation and give a better assessment of the current wear status of a MoM bearing surface than a measure of cobalt levels only.

Manganese and Mn/Ca ratios in soil and vegetation in forests across the northeastern US: Insights on spatial Mn enrichment.

Manganese (Mn) cycling in the Critical Zone is important because of its role as an essential nutrient and potential toxicity to plants and organisms. Quantifying Mn enrichment in terrestrial environments has been limited since Mn is monoisotopic. However, elemental ratios of Mn/Ca ratios may be used to determine spatial Mn enrichment and in aboveground and belowground pools. The objectives of this study were to quantify the spatial variation in Mn concentrations and Mn/Ca ratios in foliage, bolewood, forest floor, and mineral soil horizons across the northeastern United States and compare Mn/Ca ratios to estimate enrichment. Forest floor and mineral soil samples were collected from 26 study sites across the northeastern United States and analyzed by strong acid digestion. Foliage and bolewood was collected from 12 of the 26 sites and analyzed for total Mn and Ca. Our results show forest floor and mineral soil horizon Mn concentrations and Mn/Ca ratios were higher at Pennsylvania and New York sites than New Hampshire and Vermont sites. Using a modified isotope equation, enrichment factors (EF) for Mn/Ca ratios were calculated to be ~3.6 in the forest floor, upper and lower mineral soil horizons at sites in New York and Pennsylvania compared to reference sites in New Hampshire and Vermont. Foliar and bolewood Mn concentrations also decreased from Pennsylvania towards New Hampshire. Moreover, foliar and bolewood Mn concentrations were strongly correlated to forest floor, upper, and lower mineral soil Mn concentrations. It was hypothesized that internal cycling (uptake, throughfall, and litterfall) of Mn controls retention of enriched Mn in forests. Geologic influences from a lithologic gradient and soil pH gradient could also influence Mn enrichment in addition to Mn pollution. Ratios of Mn/Ca and other elemental ratios hold promise as geochemical tracers but require further development.

Forest floor decomposition, metal exchangeability, and metal bioaccumulation by exotic earthworms: Amynthas agrestis and Lumbricus rubellus.

Earthworms have the potential to reduce the retention of pollutant and plant essential metals in the forest floor (organic horizons) by decomposing organic matter and increasing exchangeability of metals. We conducted a laboratory experiment to investigate the effects of two exotic earthworms, Amynthas agrestis and Lumbricus rubellus, on forest floor decomposition, metal exchangeability, and metal bioaccumulation. Eighty-one pots containing homogenized forest floor material were incubated for 20, 40, or 80 days under three treatments: no earthworms, A. agrestis added, or L. rubellus added. For earthworm treatments, A. agrestis and L. rubellus were stocked at densities observed in previous field studies. Pots containing either A. agrestis or L. rubellus had lost more forest floor mass than the control plots after 40 and 80 days of incubation. Forest floor pots containing A. agrestis had significantly lower % C (16 ± 1.5 %) than control pots (21 ± 1.2 %) after 80 days. However, L. rubellus consumed more forest floor and C mass than A. agrestis, when evaluated on a per earthworm biomass basis. Exchangeable (0.1 M KCl + 0.01 M AcOH extractable) and stable (15 M HNO3+ 10 M HCl extractable) concentrations of Al, Ca, Cd, Cu, Mg, Mn, Pb, and Zn in forest floor material were measured. Stable concentrations and % exchangeable metals in forest floor material were similar among treatments. Although exchangeable metal concentrations varied significantly for most metals among treatments (except Mg and Zn), we conclude that earthworms did not increase or decrease the exchangeability of metals. However, earthworms bioaccumulated Cu, Cd, Zn, and Mg and had potentially hazardous tissue concentrations of Al and Pb. This was best illustrated by calculating bioaccumulation factors using exchangeable concentrations rather than total concentrations. Future research is needed to understand the effect of earthworms on metals in other soil types.

Differences in concentration of metal debris in blood, serum, and plasma samples of patients with metal-on-metal hip resurfacing arthroplasty.

BACKGROUND/AIMS: Cobalt and chromium are released from MOM hips and their precise nature (ions/particles) is not known. Their distribution in serum, plasma, and whole blood may help to determine their nature. METHODS: We measured cobalt and chromium concentrations in plasma, serum, and whole blood samples of patients with resurfacing MOM hips. RESULTS: We found that chromium concentration was highest in plasma, followed by serum and whole blood. Chromium and cobalt concentrations were higher in serum and plasma, compared to whole blood. CONCLUSION: We, therefore, suggest that in future cobalt and chromium concentrations shall be reported using plasma samples.