Coastal phytoplankton blooms expand and intensify in the 21st century.

Phytoplankton blooms in coastal oceans can be beneficial to coastal fisheries production and ecosystem function, but can also cause major environmental problems1,2-yet detailed characterizations of bloom incidence and distribution are not available worldwide. Here we map daily marine coastal algal blooms between 2003 and 2020 using global satellite observations at 1-km spatial resolution. We found that algal blooms occurred in 126 out of the 153 coastal countries examined. Globally, the spatial extent (+13.2%) and frequency (+59.2%) of blooms increased significantly (P < 0.05) over the study period, whereas blooms weakened in tropical and subtropical areas of the Northern Hemisphere. We documented the relationship between the bloom trends and ocean circulation, and identified the stimulatory effects of recent increases in sea surface temperature. Our compilation of daily mapped coastal phytoplankton blooms provides the basis for global assessments of bloom risks and benefits, and for the formulation or evaluation of management or policy actions.

Injury-related cell death and proteoglycan loss in articular cartilage: Numerical model combining necrosis, reactive oxygen species, and inflammatory cytokines.

Osteoarthritis (OA) is a common musculoskeletal disease that leads to deterioration of articular cartilage, joint pain, and decreased quality of life. When OA develops after a joint injury, it is designated as post-traumatic OA (PTOA). The etiology of PTOA remains poorly understood, but it is known that proteoglycan (PG) loss, cell dysfunction, and cell death in cartilage are among the first signs of the disease. These processes, influenced by biomechanical and inflammatory stimuli, disturb the normal cell-regulated balance between tissue synthesis and degeneration. Previous computational mechanobiological models have not explicitly incorporated the cell-mediated degradation mechanisms triggered by an injury that eventually can lead to tissue-level compositional changes. Here, we developed a 2-D mechanobiological finite element model to predict necrosis, apoptosis following excessive production of reactive oxygen species (ROS), and inflammatory cytokine (interleukin-1)-driven apoptosis in cartilage explant. The resulting PG loss over 30 days was simulated. Biomechanically triggered PG degeneration, associated with cell necrosis, excessive ROS production, and cell apoptosis, was predicted to be localized near a lesion, while interleukin-1 diffusion-driven PG degeneration was manifested more globally. Interestingly, the model also showed proteolytic activity and PG biosynthesis closer to the levels of healthy tissue when pro-inflammatory cytokines were rapidly inhibited or cleared from the culture medium, leading to partial recovery of PG content. The numerical predictions of cell death and PG loss were supported by previous experimental findings. Furthermore, the simulated ROS and inflammation mechanisms had longer-lasting effects (over 3 days) on the PG content than localized necrosis. The mechanobiological model presented here may serve as a numerical tool for assessing early cartilage degeneration mechanisms and the efficacy of interventions to mitigate PTOA progression.

Accuracy of Volumetric Bone Mineral Density Measurement in Weight Bearing, Cone Beam Computed Tomography.

BACKGROUND: Weight bearing computed tomography (WBCT) utilizes cone beam CT technology to provide assessments of lower limb joint structures while they are functionally loaded. Grey-scale values indicative of X-ray attenuation that are output from cone beam CT are challenging to calibrate, and their use for bone mineral density (BMD) measurement remains debatable. To determine whether WBCT can be reliably used for cortical and trabecular BMD assessment, we sought to establish the accuracy of BMD measurements at the knee using modern WBCT by comparing them to measurements from conventional CT. METHODS: A hydroxyapatite phantom with three inserts of varying densities was used to systematically quantify signal uniformity and BMD accuracy across the acquisition volume. We evaluated BMD in vivo (n = 5, female) using synchronous and asynchronous calibration techniques in WBCT and CT. To account for variation in attenuation along the height (z-axis) of acquisition volumes, we tested a height-dependent calibration approach for both WBCT and CT images. RESULTS: Phantom BMD measurement error in WBCT was as high as 15.3% and consistently larger than CT (up to 5.6%). Phantom BMD measures made under synchronous conditions in WBCT improved measurement accuracy by up to 3% but introduced more variability in measured BMD. We found strong correlations (R = 0.96) as well as wide limits of agreement (-324 mgHA/cm3 to 183 mgHA/cm3) from Bland-Altman analysis between WBCT and CT measures in vivo that were not improved by height-dependent calibration. CONCLUSION: Whilst BMD accuracy from WBCT was found to be dependent on apparent density, accuracy was independent of the calibration technique (synchronous or asynchronous) and the location of the measurement site within the field of view. Overall, we found strong correlations between BMD measures from WBCT and CT and in vivo measures to be more accurate in trabecular bone regions. Importantly, WBCT can be used to distinguish between anatomically relevant differences in BMD, however future work is necessary to determine the repeatability and sensitivity of BMD measures in WBCT.

Evidence for massive and recurrent toxic blooms of Alexandrium catenella in the Alaskan Arctic.

Among the organisms that spread into and flourish in Arctic waters with rising temperatures and sea ice loss are toxic algae, a group of harmful algal bloom species that produce potent biotoxins. Alexandrium catenella, a cyst-forming dinoflagellate that causes paralytic shellfish poisoning worldwide, has been a significant threat to human health in southeastern Alaska for centuries. It is known to be transported into Arctic regions in waters transiting northward through the Bering Strait, yet there is little recognition of this organism as a human health concern north of the Strait. Here, we describe an exceptionally large A. catenella benthic cyst bed and hydrographic conditions across the Chukchi Sea that support germination and development of recurrent, locally originating and self-seeding blooms. Two prominent cyst accumulation zones result from deposition promoted by weak circulation. Cyst concentrations are among the highest reported globally for this species, and the cyst bed is at least 6× larger in area than any other. These extraordinary accumulations are attributed to repeated inputs from advected southern blooms and to localized cyst formation and deposition. Over the past two decades, warming has likely increased the magnitude of the germination flux twofold and advanced the timing of cell inoculation into the euphotic zone by 20 d. Conditions are also now favorable for bloom development in surface waters. The region is poised to support annually recurrent A. catenella blooms that are massive in scale, posing a significant and worrisome threat to public and ecosystem health in Alaskan Arctic communities where economies are subsistence based.

The Inflamma-type: a patient phenotype characterized by a dysregulated inflammatory response after lower extremity articular fracture.

Synovial fluid was collected from 113 patients who had suffered tibial plateau (n = 48), tibial plafond (n = 29), or rotational ankle fractures (n = 36). Concentrations of IL-1ß, IL-1RA, IL-6, IL-8, IL-10, and MMP-1, -3, and -13 were quantified using multiplex assays. A cluster analysis of synovial fluid biomarker concentrations was performed. Patient demographics, fracture type, Injury Severity Score (ISS), Charlson Comorbidity Index (CCI), and biomarker concentrations were compared between clusters. A subset of patients demonstrated a dysregulated inflammatory response after articular fracture including elevated pro-inflammatory cytokines and degradative enzymes previously linked to the development of post-traumatic osteoarthritis.

Intraoral Hirudotherapy for Venous Congestion following Free Flap Head and Neck Reconstruction: Novel Intraoral Technique.

Intraoral hirudotherapy is traditionally used for venous congestion following head and neck free flap reconstruction. Many institutions and healthcare teams have been reluctant to use intraoral leech therapy due to risks such as migration into the airway, increased infection from intraoral manipulation, and patient discomfort. Several protocols recommend blocking the path to the oropharynx via gauze or leaving a tracheotomy in place to protect the airway. This report pre-sents a novel technique for intraoral hirudotherapy that is safe and simple for treatment of free flap venous congestion. The base of a clear cup or a plastic lid is utilized, and the leech is attached onto the inside of the lid with 2 sutures near each end. Several cups with leeches attached are made at a time to reduce delay and difficulty of application by less experienced clinical staff. The leech is then applied onto the compromised flap and then simply removed once it has unlatched from the flap. This method allows the leech to be applied with ease by multiple members of the healthcare team, decreases the need for intraoral manipulation, and reduces the risk of migration into the aerodigestive tract. Future prospective studies are warranted to assess the efficacy of this technique.

Surgical Skill Can be Objectively Measured From Fluoroscopic Images Using a Novel Image-based Decision Error Analysis (IDEA) Score.

BACKGROUND: To advance orthopaedic surgical skills training and assessment, more rigorous and objective performance measures are needed. In hip fracture repair, the tip-apex distance is a commonly used summative performance metric with clear clinical relevance, but it does not capture the skill exercised during the process of achieving the final implant position. This study introduces and evaluates a novel Image-based Decision Error Analysis (IDEA) score that better captures performance during fluoroscopically-assisted wire navigation. QUESTIONS/PURPOSES: (1) Can wire navigation skill be objectively measured from a sequence of fluoroscopic images? (2) Are skill behaviors observed in a simulated environment also exhibited in the operating room? Additionally, we sought to define an objective skill metric that demonstrates improvement associated with accumulated surgical experience. METHODS: Performance was evaluated both on a hip fracture wire navigation simulator and in the operating room during actual fracture surgery. After examining fluoroscopic image sequences from 176 consecutive simulator trials (performed by 58 first-year orthopaedic residents) and 21 consecutive surgical procedures (performed by 19 different orthopaedic residents and one attending orthopaedic surgeon), three main categories of erroneous skill behavior were identified: off-target wire adjustments, out-of-plane wire adjustments, and off-target drilling. Skill behaviors were measured by comparing wire adjustments made between consecutive images against the goal of targeting the apex of the femoral head as part of our new IDEA scoring methodology. Decision error metrics (frequency, magnitude) were correlated with other measures (image count and tip-apex distance) to characterize factors related to surgical performance on both the simulator and in the operating room. An IDEA composite score integrating decision errors (off-target wire adjustments, out-of-plane wire adjustments, and off-target drilling) and the final tip-apex distance to produce a single metric of overall performance was created and compared with the number of hip wire navigation cases previously completed (such as surgeon experience levels). RESULTS: The IDEA methodology objectively analyzed 37,000 images from the simulator and 688 images from the operating room. The number of decision errors (7 ± 5 in the operating room and 4 ± 3 on the simulator) correlated with fluoroscopic image count (33 ± 14 in the operating room and 20 ± 11 on the simulator) in both the simulator and operating room environments (R2 = 0.76; p < 0.001 and R2 = 0.71; p < 0.001, respectively). Decision error counts did not correlate with the tip-apex distance (16 ± 4 mm in the operating room and 12 ± 5 mm on the simulator) for either the simulator or the operating room (R2 = 0.08; p = 0.15 and R2 = 0.03; p = 0.47, respectively), indicating that the tip-apex distance is independent of decision errors. The IDEA composite score correlated with surgical experience (R2 = 0.66; p < 0.001). CONCLUSION: The fluoroscopic images obtained in the course of placing a guide wire contain a rich amount of information related to surgical skill. This points the way to an objective measure of skill that also has potential as an educational tool for residents. Future studies should expand this analysis to the wide variety of procedures that rely on fluoroscopic images. CLINICAL RELEVANCE: This study has shown how resident skill development can be objectively assessed from fluoroscopic image sequences. The IDEA scoring provides a basis for evaluating the competence of a resident. The score can be used to assess skill at key timepoints throughout residency, such as when rotating onto/off of a new surgical service and before performing certain procedures in the operating room, or as a tool for debriefing/providing feedback after a procedure is completed.

Influence of subscapularis stiffness with glenosphere lateralization on physiological external rotation limits after reverse shoulder arthroplasty.

BACKGROUND: Repair of the subscapularis following reverse shoulder arthroplasty (RSA) remains a controversial topic among surgeons. Poor rotator cuff muscle quality is associated with increased musculotendinous stiffness, and the subsequent effect of compromised tissue repair on RSA functional outcomes remains unclear. The objective was to investigate the influence of subscapularis stiffness together with glenoid component lateralization on pre- and postimpingement joint mechanics during external rotation after RSA. METHODS: A validated finite element model incorporating the Zimmer Trabecular Metal reverse system was used. The deltoid and subscapularis tendon were tensioned and wrapped around the joint prior to controlled shoulder external rotation. Baseline subscapularis stiffness, determined from cadaveric testing, was varied to 80%, 120% and 140% of baseline, to simulate a range of pliability associated with fatty infiltration and fibrosis. We evaluated the effects of varying subscapularis stiffness and the corresponding variation in joint tension with varying glenosphere lateralization (2, 4, and 10 mm) on the torque required to externally rotate the shoulder and the impingement/subluxation risk. RESULTS: Prior to any impingement, the torques required to externally rotate the shoulder ranged from 22-47 Nm across the range of parameters studied, with the greatest torques required for the 10-mm glenosphere lateralization. The impact of increasing subscapularis stiffness on torque requirements was most pronounced at the 10-mm lateralization, as well. A 20% increase in subscapularis stiffness necessitated a 7%-14% increase in preimpingement torque, whereas a 40% stiffness increase was associated with a 12%-27% increase in torque. Torque was proportional to lateralization. When lateralization was increased from 2 to 4 mm, the preimpingement torque increased by 10%-13%, whereas a 10-mm lateralization necessitated a 35%-62% torque increase relative to 2 mm of lateralization. Increased subscapularis stiffness did not limit impingement-free range of motion or substantially decrease postimpingement subluxation in this model. DISCUSSION: Mechanical gains achieved through lateralization may be hindered by increased torque demands, especially when a stiffer subscapularis is repaired. As lateralization increases subscapularis tension, greater torque is required to externally rotate the shoulder. The torque required for external rotation has been reported between 15-50 Nm. Subscapularis repair with the simulated increases in stiffness requires relative increases in torque that the reconstructed shoulder may not be able to physically produce to rotate the glenohumeral joint, particularly at 10-mm lateralization. These results suggest that subscapularis repair may not be indicated in cases where a lateralized glenoid component is used and the subscapularis is compromised.

Determination of the relative contribution of the non-dissolved fraction of ZnO NP on membrane permeability and cytotoxicity.

Background: While the role of lysosomal membrane permeabilization (LMP) in NP-induced inflammatory responses has been recognized, the underlying mechanism of LMP is still unclear. The assumption has been that zinc oxide (ZnO)-induced LMP is due to Zn2+; however, little is known about the role of ZnO nanoparticles (NP) in toxicity.Methods: We examined the contribution of intact ZnO NP on membrane permeability using red blood cells (RBC) and undifferentiated THP-1 cells as models of particle-membrane interactions to simulate ZnO NP-lysosomal membrane interaction. The integrity of plasma membranes was evaluated by transmission electron microscopy (TEM) and confocal microscopy. ZnO NP dissolution was determined using ZnAF-2F, Zn2+ specific probe. The stability of ZnO NP inside the phagolysosomes of phagocytic cells, differentiated THP-1, alveolar macrophages, and bone marrow-derived macrophages, was determined.Results: ZnO NP caused significant hemolysis and cytotoxicity under conditions of negligible dissolution. Fully ionized Zn2SO4 caused slight hemolysis, while partially ionized ZnO induced significant hemolysis. Confocal microscopy and TEM images did not reveal membrane disruption in RBC and THP-1 cells, respectively. ZnO NP remained intact inside the phagolysosomes after a 4 h incubation with phagocytic cells.Conclusions: These studies demonstrate the ability of intact ZnO NP to induce membrane permeability and cytotoxicity without the contribution of dissolved Zn2+, suggesting that ZnO NP toxicity does not necessarily depend upon Zn2+. The stability of ZnO NP inside the phagolysosomes suggests that LMP is the result of the toxic effect of intact ZnO NP on phagolysosomal membranes.

Outcomes of free flap reconstructions with near-infrared spectroscopy (NIRS) monitoring: A systematic review.

BACKGROUND: Free flap failure or vascular compromise remains a dreadful complication of microvascular free tissue transfer. Near-infrared spectroscopy (NIRS) is a novel technique for free flap monitoring that has the propensity for early detection of vascular compromise when compared to the current gold standard, clinical monitoring (CM). The objective of this review is to evaluate the efficacy of a NIRS system in the postoperative monitoring of free flaps and its effect on flap salvage. METHODS: A comprehensive literature review was performed including English-language articles evaluating the use of NIRS in free flap monitoring. MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), OVID, and Web of Science were searched upto December 2017. RESULTS: A total of 590 articles were identified, and 10 articles were included for analysis. Overall, flaps with vascular compromise monitored with NIRS had a significantly higher salvage rate of 89% compared with a salvage rate of 50% in the flaps monitored by CM alone (p < .01). Partial loss occurred in 15% of the successful salvages in the NIRS group versus 80% with CM alone (p < .01). Detection of vascular compromise by NIRS preceded clinical signs on average by 82 ± 49 min. NIRS was accurate in detecting compromised flaps with a low false-positive and false-negative rate. CONCLUSION: Despite lack of robust data, NIRS has the potential to be an objective, accurate, and continuous postoperative free flap monitoring technique with a greater flap salvage rate than CM alone.

Using Time-Resolved Fluorescence Anisotropy of di-4-ANEPPDHQ and F2N12S to Analyze Lipid Packing Dynamics in Model Systems.

The fluorescence probes di-4-ANEPPDHQ and F2N12S have solvochromatic emission spectra and fluorescence lifetimes that are sensitive to order within the environment of lipid membranes. We show in this communication that the time-resolved fluorescence anisotropy of these probes, analyzed either by the wobble-in-a-cone model or by the model-independent order parameter S2, provides complementary information about dynamics and lipid packing in a variety of homogeneous lipid membranes systems.

Do Skills Acquired from Training with a Wire Navigation Simulator Transfer to a Mock Operating Room Environment?

BACKGROUND: Skills training and simulation play an increasingly important role in orthopaedic surgical education. The intent of simulation is to improve performance in the operating room (OR), a trait known as transfer validity. No prior studies have explored how simulator-based wire navigation training can transfer to higher-level tasks. Additionally, there is a lack of knowledge on the format in which wire navigation training should be deployed. QUESTIONS/PURPOSES: (1) Which training methods (didactic content, deliberate practice, or proficiency-based practice) lead to the greatest improvement in performing a wire navigation task? (2) Does a resident's performance using a wire navigation simulator correlate with his or her performance on a higher-level simulation task in a mock OR involving a C-arm, a radiopaque femur model, and a large soft tissue surrogate surrounding the femur? METHODS: Fifty-five residents from four different medical centers participated in this study over the course of 2 years. The residents were divided into three groups: traditional training (included first-year residents from the University of Iowa, University of Minnesota, and the Mayo Clinic), deliberate practice (included first-year residents from the University of Nebraska and the University of Minnesota), and proficiency training (included first-year residents from the University of Minnesota and the Mayo Clinic). Residents in each group received a didactic introduction covering the task of placing a wire to treat an intertrochanteric fracture, and this was considered traditional training. Deliberate practice involved training on a radiation-free simulator that provided specific feedback throughout the practice sessions. Proficiency training used the same simulator to train on specific components of wire navigation, like finding the correct starting point, to proficiency before moving to assessment. The wire navigation simulator uses a camera system to track the wire and provide computer-generated fluoroscopy. After training, task performance was assessed in a mock OR. Residents from each group were assessed in the mock OR based on their use of fluoroscopy, total time, and tip-apex distance. Correlation analysis was performed to examine the relationship between resident performance on the simulator and in the mock OR. RESULTS: Residents in the two simulation-based training groups had a lower tip-apex distance than those in the traditional training group (didactic training tip-apex distance: 24 ± 7 mm, 95% CI, 20-27; deliberate practice tip-apex distance: 16 ± 5 mm, 95% CI, 13-19, p = 0.001; proficiency training tip-apex distance: 15 ± 4 mm, 95% CI, 13-18, p < 0.001). Residents in the proficiency training group used more images than those in the other groups (didactic training: 22 ± 12 images, p = 0.041; deliberate practice: 19 ± 8 images; p = 0.012, proficiency training: 31 ± 14 images). In the two simulation-based training groups, resident performance on the simulator, that is, tip-apex distance, image use, and overall time, was correlated with performance in the mock OR (r-square = 0.15 [p = 0.030], 0.61 [p < 0.001], and 0.43 [p < 0.001], respectively). CONCLUSIONS: As residency programs are designing their curriculum to train wire navigation skills, emphasis should be placed on providing an environment that allows for deliberate practice with immediate feedback about their performance. Simulators such as the one presented in this study offer a safe environment for residents to learn this key skill. LEVEL OF EVIDENCE: Level II, therapeutic study.

Young children with type 1 diabetes can achieve glycemic targets without hypoglycemia: Results of a novel intensive diabetes management program.

BACKGROUND: Young children with type 1 diabetes (T1D) present unique challenges for intensive diabetes management. We describe an intensive diabetes program adapted for young children and compare glycemic control, anthropometry, dietary practices and insulin regimens before and after implementation. METHODS: Cross sectional data from children with T1D aged ≥0.5 to <7.0 years attending the John Hunter Children's Hospital (JHCH), Australia in 2004, 2010 and 2016 were compared. Outcome measures were glycemic control assessed by hemoglobin A1c (HbA1c ); severe hypoglycemia episodes; body mass index standard deviation scores (BMI-SDS); diabetes ketoacidosis (DKA) episodes; and insulin regimen-twice daily injections, multiple daily injections, or continuous subcutaneous insulin infusion. RESULTS: Mean HbA1c declined by 12 mmol/mol over the study period (P < .01). The proportion of children achieving a mean HbA1c < 58 mmol/mol increased significantly from 31% in 2004 to 64% in 2010 (P < .01), and from 64% in 2010 to 83% in 2016 (P = .04). The mean BMI-SDS was significantly lower in 2010 when compared with 2004 (P<.01); however, this trend plateaued between 2010 and 2016 (P = .97). Severe hypoglycemia and DKA occurred infrequently. The prevalence of overweight or obesity increased from 2010 to 2016 (P = .03). CONCLUSIONS: The JHCH intensive diabetes management program has resulted in 83% of young children in 2016 achieving target glycemia without an increase in severe hypoglycemia or DKA. Overweight remains a challenge in this population warranting action to reduce weight and protect these children from future obesity-related health risks.

Endocrine and metabolic consequences due to restrictive carbohydrate diets in children with type 1 diabetes: An illustrative case series.

Low carbohydrate diets for the management of type 1 diabetes have been popularised by social media. The promotion of a low carbohydrate diet in lay media is in contrast to published pediatric diabetes guidelines that endorse a balanced diet from a variety of foods for optimal growth and development in children with type 1 diabetes. This can be a source of conflict in clinical practice. We describe a series of 6 cases where adoption of a low carbohydrate diet in children impacted growth and cardiovascular risk factors with potential long-term sequelae. These cases support current clinical guidelines for children with diabetes that promote a diet where total energy intake is derived from balanced macronutrient sources.

Bloom termination of the toxic dinoflagellate Alexandrium catenella: Vertical migration behavior, sediment infiltration, and benthic cyst yield.

New resting cyst production is crucial for the survival of many microbial eukaryotes including phytoplankton that cause harmful algal blooms. Production in situ has previously been estimated through sediment trap deployments, but here was instead assessed through estimation of the total number of planktonic cells and new resting cysts produced by a localized, inshore bloom of Alexandrium catenella, a dinoflagellate that is a globally important cause of paralytic shellfish poisoning. Our approach utilizes high frequency, automated water monitoring, weekly observation of new cyst production, and pre- and post-bloom spatial surveys of total resting cyst abundance. Through this approach, new cyst recruitment within the study area was shown to account for at least 10.9% ± 2.6% (SE) of the bloom's decline, ∼ 5× greater than reported from comparable, sediment trap based studies. The observed distribution and timing of new cyst recruitment indicate that: (1) planozygotes, the immediate precursor to cysts in the life cycle, migrate nearer to the water surface than other planktonic stages and (2) encystment occurs after planozygote settlement on bottom sediments. Near surface localization by planozygotes explains the ephemerality of red surface water discoloration by A. catenella blooms, and also enhances the dispersal of new cysts. Following settlement, bioturbation and perhaps active swimming promote sediment infiltration by planozygotes, reducing the extent of cyst redistribution between blooms. The concerted nature of bloom sexual induction, especially in the context of an observed upper limit to A. catenella bloom intensities and heightened susceptibility of planozygotes to the parasite Amoebophrya, is also discussed.

Insights into the loss factors of phytoplankton blooms: The role of cell mortality in the decline of two inshore Alexandrium blooms.

While considerable effort has been devoted to understanding the factors regulating the development of phytoplankton blooms, the mechanisms leading to bloom decline and termination have received less attention. Grazing and sedimentation have been invoked as the main routes for the loss of phytoplankton biomass, and more recently, viral lysis, parasitism and programmed cell death (PCD) have been recognized as additional removal factors. Despite the importance of bloom declines to phytoplankton dynamics, the incidence and significance of various loss factors in regulating phytoplankton populations have not been widely characterized in natural blooms. To understand mechanisms controlling bloom decline, we studied two independent, inshore blooms of Alexandrium fundyense, paying special attention to cell mortality as a loss pathway. We observed increases in the number of dead cells with PCD features after the peak of both blooms, demonstrating a role for cell mortality in their terminations. In both blooms, sexual cyst formation appears to have been the dominant process leading to bloom termination, as both blooms were dominated by small-sized gamete cells near their peaks. Cell death and parasitism became more significant as sources of cell loss several days after the onset of bloom decline. Our findings show two distinct phases of bloom decline, characterized by sexual fusion as the initial dominant cell removal processes followed by elimination of remaining cells by cell death and parasitism.

Test-retest reliability of tibiofemoral joint space width measurements made using a low-dose standing CT scanner.

OBJECTIVE: To determine the test-retest reliability of knee joint space width (JSW) measurements made using standing CT (SCT) imaging. SUBJECTS AND METHODS: This prospective two-visit study included 50 knees from 30 subjects (66% female; mean ± SD age 58.2 ± 11.3 years; BMI 29.1 ± 5.6 kg/m2; 38% KL grade 0-1). Tibiofemoral geometry was obtained from bilateral, approximately 20° fixed-flexed SCT images acquired at visits 2 weeks apart. For each compartment, the total joint area was defined as the area with a JSW <10 mm. The summary measurements of interest were the percentage of the total joint area with a JSW less than 0.5-mm thresholds between 2.0 and 5.0 mm in each tibiofemoral compartment. Test-retest reliability of the summary JSW measurements was assessed by intraclass correlation coefficients (ICC 2,1) for the percentage area engaged at each threshold of JSW and root-mean-square errors (RMSE) were calculated to assess reproducibility. RESULTS: The ICCs were excellent for each threshold assessed, ranging from 0.95 to 0.97 for the lateral and 0.90 to 0.97 for the medial compartment. RMSE ranged from 1.1 to 7.2% for the lateral and from 3.1 to 9.1% for the medial compartment, with better reproducibility at smaller JSW thresholds. CONCLUSION: The knee joint positioning protocol used demonstrated high day-to-day reliability for SCT 3D tibiofemoral JSW summary measurements repeated 2 weeks apart. Low-dose SCT provides a great deal of information about the joint while maintaining high reliability, making it a suitable alternative to plain radiographs for evaluating JSW in people with knee OA.

Optimizing Arthroscopy for Osteochondral Lesions of the Talus: The Effect of Ankle Positions and Distraction During Anterior and Posterior Arthroscopy in a Cadaveric Model.

PURPOSE: To quantify arthroscopic accessibility of the talar dome with predefined ankle positions through anterior and posterior approaches. METHODS: Fourteen below-knee cadaver specimens underwent preoperative range of motion assessments. A 30° 2.7-mm arthroscopic camera was used to mark accessible areas at varying ankle positions. Accessible regions were quantified using a surface laser scanner and digital 3 × 3 grid. Statistical analyses were performed to detect differences in arthroscopic accessibility between different flexion angles and noninvasive distraction. RESULTS: The mean arthroscopic accessibility of the talus was 58.5% and 49.8% for the anterior and posterior approaches, respectively (P < .001). During anterior arthroscopy, accessibility increased with up to 30° of plantarflexion (P < .001). There were no significant differences in accessibility between flexion groups for the posterior approach. There was significantly greater central zone accessibility for anterior arthroscopy (87.7%) when compared with posterior arthroscopy (74.3%; P = .002). Arthroscopic accessibility increased with increasing ankle distraction for both the anterior and posterior approaches (parameter estimates ± standard error): anterior = 6.5% ± 1.3%/mm of distraction, P < .001; and posterior = 7.0% ± 2.8%/mm, P = .026. Frequency analysis showed that the posterior third of the talus was completely inaccessible in 7 out of 14 of ankles during anterior arthroscopy. The anterior third of the talus during posterior arthroscopy was inaccessible in 11 out of 14 ankles during posterior arthroscopy. CONCLUSIONS: Ankle plantarflexion up to 30° may be adequate for anterior arthroscopy for osteochondral lesions of the talus (OLTs). Noninvasive distraction also increases accessibility during both anterior and posterior arthroscopy. Anterior arthroscopy should be used for central third OLTs due to greater accessibility. CLINICAL RELEVANCE: Ankle positioning is an important consideration for anterior arthroscopy. Surgical approach used should match with the location of the OLTs.

The effect of glenoid component version and humeral polyethylene liner rotation on subluxation and impingement in reverse shoulder arthroplasty.

BACKGROUND: A previously validated finite element modeling approach was used to determine how changes in glenoid component version and polyethylene liner rotation within the humeral component affect the arm abduction angle at which impingement between the inferior glenoid and the polyethylene liner occurs as well as the amount of subluxation generated by that impingement. MATERIALS AND METHODS: Five glenoid component versions (5° anteversion; neutral; 5°, 10°, and 20° retroversion) and 7 polyethylene liner rotations (20° and 10° anterior; neutral; 10°, 20°, 30°, and 40° posterior) were considered, resulting in 35 different clinically representative models. The humerus was internally and externally rotated and extended and flexed, and the resulting impingement and subluxation were measured. To further analyze more global trends and to identify implantations least prone to subluxation, polyethylene liner rotation was additionally varied in coarser 30° increments across the entire 360° range. RESULTS: All subluxation caused by impingement occurred during external rotation and extension, and external rotation produced nearly 10-fold more subluxation than extension. Neutral glenoid component version was associated with the least amount of subluxation for all polyethylene liner rotations. Posteriorly rotated polyethylene liners, which place the thick inferior region of the component away from the scapula, produced the least amount of subluxation. The 90° and 120° posterior liner rotations produced no subluxation, whereas the 30° and 60° anterior liner rotations produced the greatest amount of subluxation. CONCLUSION: These results indicate that rotating modern radially asymmetric humeral polyethylene liners posteriorly can reduce the risk of subluxation leading to dislocation and increase external rotation range of motion.

Revisiting the gastric pull-up for pharyngoesophageal reconstruction: A systematic review and meta-analysis of mortality and morbidity.

Gastric pull-up (GPU) is among the oldest techniques for reconstructing the pharyngoesophageal junction following cancer resection. This review examines morbidity and mortality rates following GPU pharyngoesophageal junction reconstruction from 1959 until present: 77 studies, 2,705 patients. The odds of mortality, anastomotic complications, and other complications decreased by 37.2% (95%CI = 28.0-45.3%; P < 0.0001), 8.0% (95%CI = -2.1 to 17.1%; P = 0.12), 21.0% (95%CI 3.5-35.2%; P = 0.021) per decade respectively. J. Surg. Oncol. 2016;114:907-914. © 2016 Wiley Periodicals, Inc.