Blue carbon sinks in South Africa and the need for restoration to enhance carbon sequestration.

Blue carbon ecosystems (mangroves, salt marshes, and seagrasses) contribute towards climate change mitigation because they are efficient at sequestering atmospheric CO2 into long-term total ecosystem carbon stocks. Destruction or disturbance therefore reduces sink capacity and leads to significant CO2 emissions. This study reports the first national estimates of: 1) total carbon storage, 2) CO2 emissions from anthropogenic activities, 3) the potential for restoration to enhance carbon sequestration for blue carbon ecosystems in South Africa. Mangrove ecosystems have the greatest carbon storage per unit area (253-534 Mg C ha-1), followed by salt marshes (100-199 Mg C ha-1) and seagrasses (45-144 Mg C ha-1). Salt marshes are the most extensive and contribute 67 % to the national carbon stock of 4000 Gg C. Since 1930, 6500 ha has been lost across all blue carbon ecosystems (26 % of the natural extent), equivalent to losing 1086 Gg C from the national carbon stock. Historic CO2 emissions were estimated at an average rate of 30,266 t CO2e yr-1. Despite losses, a total of 3998 ha could be restored to increase carbon sequestration and CO2 removals of 14,845 tCO2e.yr-1. Extractive activities have declined rapidly in recent decades, but abiotic pressures on estuarine ecosystems (flow modification, reduced water quality, and artificial breaching) have been increasing. There is an urgent need to quantify the potential impact of these pressures and include them in estuarine management and restoration plans. Blue carbon ecosystems cover a relatively small area in South Africa, but they are valued for their multiple ecosystem services that contribute towards climate change adaptation and biodiversity co-benefits. These ecosystems need to be included in national policies driving climate change response in the Agriculture, Forestry and Other Land-Use (AFOLU) sector, such as incorporating them into the wetland subcategory of the national GHG inventory.

Barcoding of estuarine macrophytes and phylogenetic diversity of estuaries along the South African coastline.

Plant DNA barcoding serves as an effective approach to building community phylogenies and increasing our understanding of the factors that determine plant community assemblages. The aims of the study were to (i) barcode macrophytes with high estuarine fidelity and (ii) to determine the phylogenetic diversity (PD) of selected South African estuaries for conservation prioritisation. Three DNA barcoding gene regions (rbcLa, matK, and trnH-psbA) were assessed, and community phylogenies were constructed for 270 estuaries. Generally, the matK barcode had the greatest discrimination success rate of 67.4% (parsimony informative sites = 418). Closely related species formed clades that also represent estuarine habitat types. Estuaries with high phylogenetic diversity along the southeast coast were associated with a combination of mangrove and salt marsh habitats. Species richness was strongly and significantly correlated with PD (r = 0.93; p < 0.000). Based on mean pairwise distance (MPD), more temperate estuaries (56) showed significant phylogenetic clustering compared to subtropical estuaries (24) (p < 0.05). Similarly, based on mean nearest taxon distance (MNTD), significant phylogenetic clustering was highest in temperate estuaries (50) compared to subtropical estuaries (12) (p < 0.05). This suggests that the coexistence of plant species in estuaries is structured by both biotic and abiotic interactions.

The outpatient total hip arthroplasty : a paradigm change.

AIMS: To examine incidence of complications associated with outpatient total hip arthroplasty (THA), and to see if medical comorbidities are associated with complications or extended length of stay. PATIENTS AND METHODS: From June 2013 to December 2016, 1279 patients underwent 1472 outpatient THAs at our free-standing ambulatory surgery centre. Records were reviewed to determine frequency of pre-operative medical comorbidities and post-operative need for overnight stay and complications which arose. RESULTS: In 87 procedures, the patient stayed overnight for 23-hour observation, with 39 for convenience reasons and 48 (3.3%) for medical observation, most frequently urinary retention (13), obstructive sleep apnoea (nine), emesis (four), hypoxia (four), and pain management (six). Five patients (0.3%) experienced major complications within 48 hours, including three transferred to an acute facility; there was one death. Overall complication rate requiring unplanned care was 2.2% (32/1472). One or more major comorbidities were present in 647 patients (44%), including previous coronary artery disease (CAD; 50), valvular disease (nine), arrhythmia (219), thromboembolism history (28), obstructive sleep apnoea (171), chronic obstructive pulmonary disease (COPD; 124), asthma (118), frequent urination or benign prostatic hypertrophy (BPH; 217), or mild chronic renal insufficiency (11). CONCLUSION: The presence of these comorbidities was not associated with medical or surgical complications. However, presence of one or more major comorbidity was associated with an increased risk of overnight observation. Specific comorbidities associated with increased risk were CAD, COPD, and frequent urination/BPH. Outpatient THA is safe for a large proportion of patients without the need for a standardised risk assessment score. Risk of complications is not associated with presence of medical comorbidities. Cite this article: Bone Joint J 2018;100-B(1 Supple A):31-5.

Natural nutrient enrichment and algal responses in near pristine micro-estuaries and micro-outlets.

Naturally-occurring pristine estuarine ecosystems are rare in modern environments due to anthropogenic encroachment. There are more than 100 outlets around the South African coast arising from streams flowing from small catchments close to the sea. Eight near natural systems were sampled seasonally over the period of a year to acquire baseline information on water quality and chlorophyll a status across a variety of algal guilds (benthic microalgae, phytoplankton and macroalgal cover). Albeit on a much smaller-scale, these systems represent natural surrogates of larger temporarily open/closed estuaries (TOCEs). Inorganic nutrients (ammonium, total oxidized nitrogen and soluble reactive phosphate), phytoplankton and microphytobenthos chlorophyll a, as well as macroagal percentage cover, were measured using standard methods. Algae showed a seasonal trend, with blooms of both micro- and macro-algae occurring during summer, with a dieback recorded in autumn. During summer, only one system had a phytoplankton peak in chlorophyll a above 20µgL-1, while the microphytobenthos concentrations in three of the systems were above 100mgm-2. Summer blooms of green filamentous macroalgae occurred in all four micro-outlets and in one micro-estuary. Using a linear mixed-effects modelling approach, significant drivers for algal growth related to temperature, nutrient conditions, light availability and water residence time, all of which are known to stimulate primary production. The results show that enrichment from natural sources display similar responses from primary producers to mesotrophic and/or eutrophic water bodies, with the exception that they revert to a natural state rather than continue into a degraded state as is the case in artificially enriched systems. This importantly demonstrates how larger temporarily/open closed estuaries, most of which are anthropogenically degraded, might have functioned under a former more balanced state. Some of these larger systems now respond to nutrient enrichment by exhibiting permanent cultural eutrophication.

Radiological Decision Aid to determine suitability for medial unicompartmental knee arthroplasty: development and preliminary validation.

AIMS: An evidence-based radiographic Decision Aid for meniscal-bearing unicompartmental knee arthroplasty (UKA) has been developed and this study investigates its performance at an independent centre. PATIENTS AND METHODS: Pre-operative radiographs, including stress views, from a consecutive cohort of 550 knees undergoing arthroplasty (UKA or total knee arthroplasty; TKA) by a single-surgeon were assessed. Suitability for UKA was determined using the Decision Aid, with the assessor blinded to treatment received, and compared with actual treatment received, which was determined by an experienced UKA surgeon based on history, examination, radiographic assessment including stress radiographs, and intra-operative assessment in line with the recommended indications as described in the literature. RESULTS: The sensitivity and specificity of the Decision Aid was 92% and 88%, respectively. Excluding knees where a clear pre-operative plan was made to perform TKA, i.e. patient request, the sensitivity was 93% and specificity 96%. The false-positive rate was low (2.4%) with all affected patients readily identifiable during joint inspection at surgery. In patients meeting Decision Aid criteria and receiving UKA, the five-year survival was 99% (95% confidence intervals (CI) 97 to 100). The false negatives (3.5%), who received UKA but did not meet the criteria, had significantly worse functional outcomes (flexion p < 0.001, American Knee Society Score - Functional p < 0.001, University of California Los Angeles score p = 0.04), and lower implant survival of 93.1% (95% CI 77.6 to 100). CONCLUSION: The radiographic Decision Aid safely and reliably identifies appropriate patients for meniscal-bearing UKA and achieves good results in this population. The widespread use of the Decision Aid should improve the results of UKA. Cite this article: Bone Joint J 2016;98-B(10 Suppl B):3-10.

Early outcomes of twin-peg mobile-bearing unicompartmental knee arthroplasty compared with primary total knee arthroplasty.

AIMS: Since redesign of the Oxford phase III mobile-bearing unicompartmental knee arthroplasty (UKA) femoral component to a twin-peg design, there has not been a direct comparison to total knee arthroplasty (TKA). Thus, we explored differences between the two cohorts. PATIENTS AND METHODS: A total of 168 patients (201 knees) underwent medial UKA with the Oxford Partial Knee Twin-Peg. These patients were compared with a randomly selected group of 177 patients (189 knees) with primary Vanguard TKA. Patient demographics, Knee Society (KS) scores and range of movement (ROM) were compared between the two cohorts. Additionally, revision, re-operation and manipulation under anaesthesia rates were analysed. RESULTS: The mean follow-up for UKA and TKA groups was 5.4 and 5.5 years, respectively. Six TKA (3.2%) versus three UKAs (1.5%) were revised which was not significant (p = 0.269). Manipulation was more frequent after TKA (16; 8.5%) versus none in the UKA group (p < 0.001). UKA patients had higher post-operative KS function scores versus TKA patients (78 versus 66, p < 0.001) with a trend toward greater improvement, but there was no difference in ROM and KS clinical improvement (p = 0.382 and 0.420, respectively). CONCLUSION: We found fewer manipulations, and higher functional outcomes for patients treated with medial mobile-bearing UKA compared with TKA. TKA had twice the revision rate as UKA although this did not reach statistical significance with the numbers available. Cite this article: Bone Joint J 2016;98-B(10 Suppl B):28-33.

Distribution of polychlorinated biphenyl residues in sediments and blue mussels (Mytilus galloprovincialis) from Port Elizabeth Harbour, South Africa.

Sediment and Mytilus galloprovincialis samples collected from the Port Elizabeth Harbour were analysed for six indicator PCB congeners to assess their contamination status. The concentrations of total PCBs in sediments and M. galloprovincialis ranged from 0.56 to 2.35 ng/g dry weight and 14.48 to 21.37 ng/g wet weight, respectively. Congeners 138 and 153 were dominant and accounted for an average of 29% and 24% of total PCBs in M. galloprovincialis; 32% and 30% in sediments, respectively. Sediments are home to a wide variety of aquatic life. None of the sediments analysed exceeded the PCB limits recommended the Canadian interim sediment quality guideline and the South African recommended sediment guidelines (21.6 ng/g). Both humans and aquatic life are sensitive to the toxic effects of PCBs.

Wetland plants as indicators of heavy metal contamination.

In this study metal accumulating abilities of three emergent macrophytes (Phragmites australis, Typha capensis and Spartina maritima) were investigated in the urbanised Swartkops Estuary. Plants and sediment samples were collected at seven sites along the banks of the main channel and in adjacent canals. Sediments and plant organs were analysed, by means of atomic absorption spectrometry, for four elements (Cd, Cu, Pb, and Zn). Metal concentrations in the sediments of adjacent canals were found to be substantially higher than those at sites along the banks of the estuary. These differences were reflected in the plant organs for Pb and Zn, but not for Cu and Cd. All three species exhibited significantly higher concentrations of metals in their roots. These species are therefore suitable for use as indicators of the presence and level of heavy metal contaminants in estuaries.

Partial two-stage exchange of the infected total hip replacement using disposable spacer moulds.

The common recommended treatment for infected total hip replacement is two-staged exchange including removal of all components. However, removal of well-fixed femoral stems can result in structural bone damage. We recently reported on an alternative treatment of partial two-stage exchange used in selected cases, in which a well-fixed femoral stem was left and only the acetabular component removed, the joint space was debrided thoroughly, an antibiotic-laden polymethylmethacrylate spacer was moulded using a bulb-type syringe and placed in the acetabulum, intravenous antibiotics were administered during the interval, and delayed re-implantation was performed. In 19 patients treated with this technique from January 2000 to January 2011, 89% were free of infection at a mean follow-up of four years (2 to 11). Since then, disposable silicone moulds have become available to fabricate spacers in separate femoral and head units. The head spacer mould, which incorporates various neck taper adapter options, greatly facilitates the technique of partial two-stage exchange. We report our early experience using disposable silicone head spacer moulds for partial two-stage exchange in seven patients with infected primary hip replacements.

Why knee replacements fail in 2013: patient, surgeon, or implant?

Previous studies of failure mechanisms leading to revision total knee replacement (TKR) performed between 1986 and 2000 determined that many failed early, with a disproportionate amount accounted for by infection and implant-associated factors including wear, loosening and instability. Since then, efforts have been made to improve implant performance and instruct surgeons in best practice. Recently our centre participated in a multi-centre evaluation of 844 revision TKRs from 2010 to 2011. The purpose was to report a detailed analysis of failure mechanisms over time and to see if failure modes have changed over the past 10 to 15 years. Aseptic loosening was the predominant mechanism of failure (31.2%), followed by instability (18.7%), infection (16.2%), polyethylene wear (10.0%), arthrofibrosis (6.9%) and malalignment (6.6%). The mean time to failure was 5.9 years (ten days to 31 years), 35.3% of all revisions occurred at less than two years, and 60.2% in the first five years. With improvements in implant and polyethylene manufacture, polyethylene wear is no longer a leading cause of failure. Early mechanisms of failure are primarily technical errors. In addition to improving implant longevity, industry and surgeons must work together to decrease these technical errors. All reports on failure of TKR contain patients with unexplained pain who not infrequently have unmet expectations. Surgeons must work to achieve realistic patient expectations pre-operatively, and therefore, improve patient satisfaction post-operatively.

Which total knee replacement implant should I pick? Correcting the pathology: the role of knee bearing designs.

Debate has raged over whether a cruciate retaining (CR) or a posterior stabilised (PS) total knee replacement (TKR) provides a better range of movement (ROM) for patients. Various sub-sets of CR design are frequently lumped together when comparing outcomes. Additionally, multiple factors have been proven to influence the rate of manipulation under anaesthetic (MUA) following TKR. The purpose of this study was to determine whether different CR bearing insert designs provide better ROM or different MUA rates. All primary TKRs performed by two surgeons between March 2006 and March 2009 were reviewed and 2449 CR-TKRs were identified. The same CR femoral component, instrumentation, and tibial base plate were consistently used. In 1334 TKRs a CR tibial insert with 3° posterior slope and no posterior lip was used (CR-S). In 803 there was an insert with no slope and a small posterior lip (CR-L) and in 312 knees the posterior cruciate ligament (PCL) was either resected or lax and a deep-dish, anterior stabilised insert was used (CR-AS). More CR-AS inserts were used in patients with less pre-operative ROM and greater pre-operative tibiofemoral deformity and flexion contracture (p < 0.05). The mean improvement in ROM was highest for the CR-AS inserts (5.9° (-40° to 55°) vs CR-S 3.1° (-45° to 70°) vs CR-L 3.0° (-45° to 65°); p = 0.004). There was a significantly higher MUA rate with the CR-S and CR-L inserts than CR-AS (Pearson rank 6.51; p = 0.04). Despite sacrificing or not substituting for the PCL, ROM improvement was highest, and the MUA rate was lowest in TKRs with a deep-dish, anterior-stabilised insert. Substitution for the posterior cruciate ligament (PCL) in the form of a PS design may not be necessary even when the PCL is deficient.

Metal-on-metal hip arthroplasty: going, going, gone... - affirms.

Metal-on-metal hip arthroplasty gained significant favor in the first decade of the millennium. However, the past several years have seen increasing reports of failure, pseudotumor and other adverse reactions. This study presents the results of a single center's 15-year experience with metal-on-metal total hip arthroplasty as strong evidence that metal-on-metal is going, going, gone.

The severity of autism is associated with toxic metal body burden and red blood cell glutathione levels.

This study investigated the relationship of children's autism symptoms with their toxic metal body burden and red blood cell (RBC) glutathione levels. In children ages 3-8 years, the severity of autism was assessed using four tools: ADOS, PDD-BI, ATEC, and SAS. Toxic metal body burden was assessed by measuring urinary excretion of toxic metals, both before and after oral dimercaptosuccinic acid (DMSA). Multiple positive correlations were found between the severity of autism and the urinary excretion of toxic metals. Variations in the severity of autism measurements could be explained, in part, by regression analyses of urinary excretion of toxic metals before and after DMSA and the level of RBC glutathione (adjusted R(2) of 0.22-0.45, P < .005 in all cases). This study demonstrates a significant positive association between the severity of autism and the relative body burden of toxic metals.

Discoloration in raw and processed fruits and vegetables.

Discoloration in fruits and vegetables is reviewed in relation to the chemical and biochemical causes of black, brown, red, yellow, and green discolorations. In raw materials, only a limited understanding has so far been achieved of the internal black and brown discolorations. The biochemical signaling pathways triggered by wounding or chilling-storage, the nature of the enzymes and reactive oxygen species involved, and the identity of the phenolic compounds oxidized are areas where further information is desirable. In processed materials, a greater comprehension is needed of the role of ascorbic acid reactions in the browning of fruits and "pinking" of Brassicaceous vegetables, and more information is desirable on the structure and properties of the discoloring pigments in many products. It is concluded that a greater knowledge of these areas, and of the naturally-occurring constituents that can accelerate or inhibit the causative reactions, would lead to the development of more efficient methods of controlling fruit and vegetable discolorations.

Analyses of toxic metals and essential minerals in the hair of Arizona children with autism and associated conditions, and their mothers.

The objective of this study was to assess the levels of 39 toxic metals and essential minerals in hair samples of children with autism spectrum disorders and their mothers compared to controls. Inductively coupled plasma-mass spectrometry was used to analyze the elemental content of the hair of children with autism spectrum disorders (n=51), a subset of their mothers (n=29), neurotypical children (n=40), and a subset of their mothers (n=25). All participants were recruited from Arizona. Iodine levels were 45% lower in the children with autism (p=0.005). Autistic children with pica had a 38% lower level of chromium (p=0.002). Autistic children with low muscle tone had very low levels of potassium (-66%, p=0.01) and high zinc (31%, p=0.01). The mothers of young children with autism had especially low levels of lithium (56% lower, p=0.005), and the young children (ages 3-6 yr) with autism also had low lithium (-30%, p=0.04). Low iodine levels are consistent with previous reports of abnormal thyroid function, which likely affected development of speech and cognitive skills. Low lithium in the mothers likely caused low levels of lithium in the young children, which could have affected their neurological and immunological development. Further investigations of iodine, lithium, and other elements are warranted.

High temperature reduction of metmyoglobin in aqueous muscle extracts.

Oxymyoglobin in aqueous extracts of fresh beef longissimus dorsi muscles was initially oxidised to metmyoglobin during heat treatments at temperatures in the range 50-70 °C. The metmyoglobin then underwent reduction to a red pigment that was shown spectrally to be identical to oxymyoglobin. The formation of oxymyoglobin involved a heat induced precipitate that when removed from the solution, allowed oxidation to metmyoglobin to occur. However, on re-addition of the precipitate further reduction to oxymyoglobin took place. Dialysis of the muscle extract prior to heating markedly inhibited the reduction but addition of NADH to the dialysate permitted further reduction. The precipitate plus NADH caused oxymyoglobin formation in the presence of metmyoglobin but neither the precipitate nor NADH alone induced this formation. It is concluded that the initial conversion of oxymyoglobin to metmyoglobin on heating fresh beef muscle extracts was reversible and that the reverse reaction depended on the presence of both NADH and a muscle protein.

Minimal 10-year results of a tapered cementless femoral component in total hip arthroplasty.

A series of 120 primary total hip arthroplasties with minimal 10-year follow-up, in which a cementless, proximal-to-distal, dual-tapered geometry femoral component was used, was reviewed. At a mean follow-up interval of 12.20 years, a mean Harris hip score improvement of 38 points was calculated. Three (2.5%) femoral components were revised secondary to aseptic loosening, yielding a 97.5% survivorship. Thigh pain was mild or absent in 96.6% of the cases. Distal femoral osteolysis was observed in <2% of cases. The Harris hip score improvement, low incidence of severe thigh pain, high survivorship, and low incidences of significant stress shielding and distal osteolysis suggest excellent long-term results with the use of this uncemented tapered design, adding credence to the design rationale and justifying its continued use.

Simultaneous bilateral total knee arthroplasties: who decides?

The purpose of the current retrospective review was to compare the results of 1498 patients having 1090 simultaneous bilateral total knee arthroplasties and 958 unilateral total knee arthroplasties in a 3-year period, focusing on perioperative complications, length of hospital stay, and discharge disposition. Gender, age, diagnosis, and weight were similar between the groups. Patients undergoing simultaneous bilateral total knee arthroplasties had statistically significant higher amounts of intraoperative blood loss, with more patients requiring blood transfusion, and a higher average number of units of blood transfused compared with patients undergoing unilateral total knee arthroplasty. Overall, a significantly higher incidence of gastrointestinal complications was reported in patients who had simultaneous bilateral knee arthroplasties compared with patients who had unilateral knee arthroplasty. Comparing age subgroups within the unilateral group revealed significantly higher incidences of pulmonary, neurologic, cardiac, and genitourinary complications among patients 80 years or older versus patients younger than 80 years. Patients having simultaneous bilateral arthroplasties who were 80 years or older had significantly higher incidences of pulmonary, neurologic, and cardiac complications than patients younger than 80 years in that same group. These results suggest that age, not procedure, has a more significant role in the perioperative morbidity of total knee arthroplasty. Based on the results from the current study and previous literature documenting patient preference, patient satisfaction, efficacy, and outcomes comparable with those of patients having unilateral total knee arthroplasty, the authors continue to offer patients the option of simultaneous bilateral total knee arthroplasties.

An algorithm for the posterior cruciate ligament in total knee arthroplasty.

The fate of the posterior cruciate ligament in primary total knee arthroplasty is controversial. An algorithmic approach is presented that is based on pathologic criteria for evaluating and treating patients with primary total knee arthroplasty that will aid in the posterior cruciate ligament decision-making process, producing more predictable procedures and outcomes. A consecutive series of the first 120 patients (171 knees) who had primary posterior cruciate-retaining arthroplasty and the first 120 patients (180 knees) who had primary posterior-stabilized arthroplasty with a minimum 5-year followup in which the Maxim Complete Total Knee System and the algorithmic approach were used were compared. No statistically significant differences in outcome between the groups were observed. Among the patients who had posterior cruciate-retaining arthroplasty, no revisions attributable to aseptic loosening have been reported at an average followup of 6.39 years. The average followup Knee Society total score was 162.16 points, with 91 (54.8%) knees having excellent outcome ratings. No revisions attributable to aseptic loosening have been reported among the patients who had posterior-stabilized arthroplasty at an average followup of 5.98 years. The average followup Knee Society total score was 158.05 points, with excellent outcome ratings reported in 96 (54.9%) knees. The use of a standardized algorithm has streamlined the treatment of patients having primary total knee arthroplasty, consistently providing excellent clinical results when either retaining or sacrificing the posterior cruciate ligament.