Ethics of Pediatric Surgical Innovation: Considerations, Controversies, and Pitfalls.

AbstractThe field of surgery has relied on innovation and creativity to improve patient care and propel the field forward. Historically, regulatory oversight of innovative approaches to surgery has been largely inconsistent, rendering surgeons relatively unrestricted creative latitude in the operating room; whether this has proven to be more beneficial or harmful is subject to debate. While innovation plays a crucial role in the advancement of surgical techniques, the potential drawbacks of unregulated innovation must be seriously considered, especially when treating vulnerable populations such as infants and children. This article provides an overview of the ethical aspects surrounding innovation in pediatric surgery, including discussion of relevant considerations, controversies, and pitfalls. The following includes a review of the current and past literature surrounding the topic. The purpose of this review is to heighten awareness of the ethical challenges that surgeons face when considering novel operative techniques on pediatric patients.

International Analgesia and Sedation Weaning and Withdrawal Practices in Critically Ill Adults: The Adult Iatrogenic Withdrawal Study in the ICU.

OBJECTIVES: Iatrogenic withdrawal syndrome (IWS) associated with opioid and sedative use for medical purposes has a reported high prevalence and associated morbidity. This study aimed to determine the prevalence, utilization, and characteristics of opioid and sedative weaning and IWS policies/protocols in the adult ICU population. DESIGN: International, multicenter, observational, point prevalence study. SETTING: Adult ICUs. PATIENTS: All patients aged 18 years and older in the ICU on the date of data collection who received parenteral opioids or sedatives in the previous 24 hours. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: ICUs selected 1 day for data collection between June 1 and September 30, 2021. Patient demographic data, opioid and sedative medication use, and weaning and IWS assessment data were collected for the previous 24 hours. The primary outcome was the proportion of patients weaned from opioids and sedatives using an institutional policy/protocol on the data collection day. There were 2,402 patients in 229 ICUs from 11 countries screened for opioid and sedative use; 1,506 (63%) patients received parenteral opioids, and/or sedatives in the previous 24 hours. There were 90 (39%) ICUs with a weaning policy/protocol which was used in 176 (12%) patients, and 23 (10%) ICUs with an IWS policy/protocol which was used in 9 (0.6%) patients. The weaning policy/protocol for 47 (52%) ICUs did not define when to initiate weaning, and the policy/protocol for 24 (27%) ICUs did not specify the degree of weaning. A weaning policy/protocol was used in 34% (176/521) and IWS policy/protocol in 9% (9/97) of patients admitted to an ICU with such a policy/protocol. Among 485 patients eligible for weaning policy/protocol utilization based on duration of opioid/sedative use initiation criterion within individual ICU policies/protocols 176 (36%) had it used, and among 54 patients on opioids and/or sedatives ≥ 72 hours, 9 (17%) had an IWS policy/protocol used by the data collection day. CONCLUSIONS: This international observational study found that a small proportion of ICUs use policies/protocols for opioid and sedative weaning or IWS, and even when these policies/protocols are in place, they are implemented in a small percentage of patients.

Subsurface Manure Injection Reduces Surface Transport of Antibiotic Resistance Genes but May Create Antibiotic Resistance Hotspots in Soils.

Compared to surface application, manure subsurface injection reduces surface runoff of nutrients, antibiotic resistant microorganisms, and emerging contaminants. Less is known regarding the impact of both manure application methods on surface transport of antibiotic resistance genes (ARGs) in manure-amended fields. We applied liquid dairy manure to field plots by surface application and subsurface injection and simulated rainfall on the first or seventh day following application. The ARG richness, relative abundance (normalized to 16s rRNA), and ARG profiles in soil and surface runoff were monitored using shotgun metagenomic sequencing. Within 1 day of manure application, compared to unamended soils, soils treated with manure had 32.5-70.5% greater ARG richness and higher relative abundances of sulfonamide (6.5-129%) and tetracycline (752-3766%) resistance genes (p ≤ 0.05). On day 7, soil ARG profiles in the surface-applied plots were similar to, whereas subsurface injection profiles were different from, that of the unamended soils. Forty-six days after manure application, the soil ARG profiles in manure injection slits were 37% more diverse than that of the unamended plots. The abundance of manure-associated ARGs were lower in surface runoff from manure subsurface injected plots and carried a lower resistome risk score in comparison to surface-applied plots. This study demonstrated, for the first time, that although manure subsurface injection reduces ARGs in the runoff, it can create potential long-term hotspots for elevated ARGs within injection slits.

K in an Urban World: New Contexts for Hydraulic Conductivity.

Hydraulic conductivity (K) is a key hydrologic parameter widely recognized to be difficult to estimate and constrain, with little consistent assessment in disturbed, urbanized soils. To estimate K, it is either measured, or simulated by pedotransfer functions, which relate K to easily measured soil properties. We measured K in urbanized soils by double-ring infiltrometer (K dring), near-saturated tension infiltrometry (K minidisk), and constant head borehole permeametry (K borehole), along with other soil properties across the major soil orders in 12 United States cities. We compared measured K with that predicted from the pedotransfer function, ROSETTA. We found that regardless of soil texture, K dring was consistently larger than K minidisk; with the latter having slightly less sample variance. K borehole was dependent upon specific subsurface conditions, and contrary to common expectations, did not always decrease with depth. Based on either soil textural class, or percent textural separates (sand, silt clay), ROSETTA did not accurately predict measured K for surface nor subsurface soils. We go on to discuss how K varies in urban landscapes, the role of measurement methods and artifacts in the perception of this metric, and implications for hydrologic modeling. Overall, we aim to inspire consistency and coherence when addressing K-related challenges in sustainable urban water management.

Hypoalbuminemia in children with cancer treated with chemotherapy.

BACKGROUND: Hypoalbuminemia is a well-recognized finding associated with cancer, but its prevalence and prognostic significance have not been well studied in children with cancer. OBJECTIVE: To determine the prevalence of hypoalbuminemia prior to starting chemotherapy in children with cancer and its association with relapse-free survival (RFS) and overall survival (OS). DESIGN/METHOD: We performed a single institution, IRB-approved, retrospective review of pediatric oncology patients diagnosed between 1998 and 2012. Five-year survival was estimated using the Kaplan-Meier method; groups were compared using Cox regression. RESULTS: We identified 659 pediatric patients with a first diagnosis of cancer and a serum albumin level prior to starting chemotherapy. Mean age was 8.6 years (SD = 5.8); 62% were male and 92% were non-Hispanic. Hypoalbuminemia prior to starting chemotherapy was present at least once in 302 (45.8%). The five-year RFS and OS of those with hypoalbuminemia and without hypoalbuminemia were not significantly different. However, patients with severe hypoalbuminemia (defined as a value 10% or more below the lower limit of normal) had inferior RFS and OS for patients with hematologic/lymphatic malignancies, and inferior RFS for patients with metstatic Ewing sarcoma. CONCLUSION: Hypoalbuminemia prior to starting chemotherapy in pediatric oncology patients is common (nearly half in this cohort). Severe hypoalbuminemia was associated with inferior 5-year RFS in some subgroups.

Repair of colonic neovaginal stenosis using a biological graft in a male-to-female transgender patient.

INTRODUCTION AND HYPOTHESIS: One in 2900 genotypical men report gender dysphoria, and many undergo gender confirmation surgery to match their physical phenotype to their identity. A variety of surgical techniques are used in male-to-female transgender patients, one of which is bowel vaginoplasty, and postoperative stenosis of the colonic neovagina is common. Extracellular matrix grafts have been used in vaginal reconstruction. with porcine urinary bladder matrix (UBM) acting as a scaffold for smooth-muscle tissue and matrix regeneration. The aim of this surgical video is to describe the use of a UBM biological graft in repair of introital stenosis due to recurrent granulation tissue in the colonic neovagina of a male-to-female transgender patient. METHODS: A 32-year-old male-to-female transgender patient with a history of rectosigmoid neovagina formation for genital gender confirmation surgery 12 months prior presented with genital granulation tissue and stenosis of her neovaginal introitus. Despite two surgical revisions, the patient developed recurrence of granulation tissue and obliteration of the neovaginal introitus, preventing sexual function of the neovagina. RESULTS: Reconstruction of the neovaginal introitus was performed using UBM. The patient noted improvement in comfort, hygiene, and quality of life following the procedure. This video describes our surgical technique and perioperative clinical findings. CONCLUSIONS: We report the novel use of UBM biological graft in the revision of a neovaginal introitus after former rectosigmoid vaginoplasty in a male-to-female transgender patient.

Linking ecosystem function and hydrologic regime to inform restoration of a forested peatland.

Drainage is a globally common disturbance in forested peatlands that impacts peat soils, forest communities, and associated ecosystem functions, calling for informed hydrologic restoration strategies. The Great Dismal Swamp (GDS), located in Virginia and North Carolina, U.S.A., has been altered since colonial times, particularly by extensive ditch networks installed to lower water levels and facilitate timber harvests. Consequently, peat decomposition rates have accelerated, and red maple has become the dominant tree species, reducing the historical mosaic of bald cypress, Atlantic white-cedar, and pocosin stands. Recent repair and installation of water control structures aim to control drainage and, in doing so, enhance forest community composition and preserve peat depths. To help inform these actions, we established five transects of 15 plots each (75 plots total) along a hydrologic gradient where we measured continuous water levels and ecosystem attributes, including peat depths, microtopography, and forest composition and structure. We found significant differences among transects, with wetter sites having thicker peat, lower red maple importance, greater tree density, and higher overall stand richness. Plot-level analyses comported with these trends, clearly grouping plots by transects (via nonmetric multidimensional scaling) and resulting in significant correlations between specific hydrologic metrics and ecosystem attributes. Our findings highlight hydrologic controls on soil carbon storage, forest structure, and maple dominance, with implications for large-scale hydrologic restoration at GDS and in other degraded forested peatlands more broadly.

DNA mutagenic activity and capacity for HIV-1 restriction of the cytidine deaminase APOBEC3G depend on whether DNA or RNA binds to tyrosine 315.

APOBEC3G (A3G) belongs to the AID/APOBEC protein family of cytidine deaminases (CDA) that bind to nucleic acids. A3G mutates the HIV genome by deamination of dC to dU, leading to accumulation of virus-inactivating mutations. Binding to cellular RNAs inhibits A3G binding to substrate single-stranded (ss) DNA and CDA activity. Bulk RNA and substrate ssDNA bind to the same three A3G tryptic peptides (amino acids 181-194, 314-320, and 345-374) that form parts of a continuously exposed protein surface extending from the catalytic domain in the C terminus of A3G to its N terminus. We show here that the A3G tyrosines 181 and 315 directly cross-linked ssDNA. Binding experiments showed that a Y315A mutation alone significantly reduced A3G binding to both ssDNA and RNA, whereas Y181A and Y182A mutations only moderately affected A3G nucleic acid binding. Consistent with these findings, the Y315A mutant exhibited little to no deaminase activity in an Escherichia coli DNA mutator reporter, whereas Y181A and Y182A mutants retained ∼50% of wild-type A3G activity. The Y315A mutant also showed a markedly reduced ability to assemble into viral particles and had reduced antiviral activity. In uninfected cells, the impaired RNA-binding capacity of Y315A was evident by a shift of A3G from high-molecular-mass ribonucleoprotein complexes to low-molecular-mass complexes. We conclude that Tyr-315 is essential for coordinating ssDNA interaction with or entry to the deaminase domain and hypothesize that RNA bound to Tyr-315 may be sufficient to competitively inhibit ssDNA deaminase-dependent antiviral activity.

Obesity and dental caries in childhood: trends in prevalence and socioeconomic inequalities-a multicohort population-wide data linkage study.

OBJECTIVES: To quantify levels of coexisting obesity and caries experience in children in Scotland, and any associated socioeconomic inequalities over the years 2011/2012-2017/2018. DESIGN: A multicohort population-wide data linkage study. SETTING: Local authority primary schools in Scotland. PATIENTS: 335 361 primary 1 (approximately 5 years old) schoolchildren in Scotland between 2011/2012 and 2017/2018. MAIN OUTCOME MEASURES: Prevalence and inequalities in coexisting caries and obesity. RESULTS: The prevalence of coexisting obesity and caries experience was 3.4% (n=11 494 of 335 361) and did not change over the 7 years. Children living in the 20% most deprived areas had more than sixfold greater odds of coexisting obesity and caries experience than children from the 20% least deprived areas (adjusted OR=6.63 (95% CI=6.16 to 7.14; p<0.001)). There was a large persistent socioeconomic gradient across the Scottish Index of Multiple Deprivation groups, with the Slope and Relative Indices of Inequality remaining unchanged over the 7 cohort years. CONCLUSIONS: Despite improvements in oral health in children in Scotland, the prevalence of coexisting obesity and caries experience has remained static, with large persistent inequalities. These conditions are likely to signal increased risk of chronic conditions including multimorbidity in adulthood and therefore early identification of children most at risk and timely intervention tackling common risk factors should be developed and evaluated.

Development of a High-Fidelity Benchtop Model for Simultaneous Flow, Pressure, and Imaging Assessment of Transarterial Embolization Procedures.

PURPOSE: The development of new endovascular technologies for transarterial embolization has relied on animal studies to validate efficacy before clinical trials are undertaken. Because embolizations in animals and patients are primarily conducted with fluoroscopy alone, local hemodynamic changes are not assessed during testing. However, such hemodynamic metrics could be important indicators of procedure efficacy that could support improved patient outcomes, such as via the determination of procedural endpoints. The purpose of this study is to create a high-fidelity benchtop system for multiparametric (i.e., hemodynamic and imaging) assessment of transarterial embolization procedures. METHODS: The benchtop system consists of a 3D printed, anatomically accurate vascular phantom; a flow loop with a cardiac output simulator; a high-speed video camera; and pressure transducers and flow meters. This system enabled us to vary the heart rate and blood pressure and to simulate clinically relevant hemodynamic states, such as healthy adult, aortic regurgitation, and hypovolemic shock. RESULTS: With our radiation-free angiography-mimetic imaging system, we could simultaneously assess gauge pressure and flow values during transarterial embolization. We demonstrated the feasibility of recapitulating the digital subtraction angiography workflow. Finally, we highlighted the utility of this system by characterizing the relationship between an imaging-based metric of procedural endpoint and intravascular flow. We also characterized hemodynamic changes associated with particle embolization within a branch of the hepatic artery and found them to be within reported patient data. CONCLUSION: Our benchtop vascular system was low-cost and reproduced transarterial embolization-related hemodynamic phenomena with high fidelity. We believe that this novel platform enables the characterization of patient physiology, novel catheterization devices, and techniques.

Evaluating neonicotinoid insecticide uptake by plants used as buffers and cover crops.

Runoff and drainage from fields planted with neonicotinoid-coated seeds often contain insecticides that adversely affect aquatic life and other non-target organisms. Management practices such as in-field cover cropping and edge-of-field buffer strips may reduce insecticide mobility, making it important to understand the ability of different plants used in these interventions to absorb neonicotinoids. In this greenhouse study we evaluated uptake of thiamethoxam, a commonly used neonicotinoid, in six plant species - crimson clover, fescue, oxeye sunflower, Maximillian sunflower, common milkweed, and butterfly milkweed - along with a native forb mixture and a native grass plus native forb mixture. All plants were irrigated with water containing 100 or 500 µg/L of thiamethoxam for 60 days, then plant tissues and soils were analyzed for thiamethoxam and its metabolite clothianidin. Crimson clover accumulated up to 50% of the applied thiamethoxam, which was significantly more than other plants and indicates this species may be a hyper-accumulator that can sequester thiamethoxam. In contrast, milkweed plants had relatively low neonicotinoid uptake (<0.5%), meaning that those species may not pose excessive risk to beneficial insects that feed on them. In all plants, accumulated masses of thiamethoxam and clothianidin were greater in above-ground tissues (leaves and stems) than in below-ground roots, with more accrual in leaves than stems. Plants treated with the higher thiamethoxam concentration retained proportionally more of the insecticides. Because thiamethoxam primarily accumulates in above-ground tissues, management strategies that include biomass removal may reduce the input of such insecticides into the environment.

Customized External Cranioplasty for Management of Syndrome of Trephined in Nonsurgical Candidates.

BACKGROUND: Craniectomies represent a lifesaving neurosurgical procedure for many severe neurological conditions, such as traumatic brain injury. Syndrome of trephined (SoT) is an important complication of decompressive craniectomy, and cranial reconstruction is the definitive treatment. However, many patients cannot undergo surgical intervention because of neurological status, healing of the primary surgical wound, or the presence of concurrent infection, which may prevent cranioplasty. OBJECTIVE: To offer a customized external cranioplasty option for managing skull deformities for patients who could not undergo surgical intervention for definitive cranioplasty. METHODS: We describe the design and clinical application of an external cranioplasty for a patient with a medical history of intractable epilepsy, for which she underwent multiple right cerebral resections with a large resultant skull defect and SoT. RESULTS: The patient had resolution of symptoms and restoration of a symmetrical skull contour with no complication at 17 months. CONCLUSION: Customized external cranioplasty can improve symptoms associated with SoT for patients who cannot undergo a definitive cranioplasty. In addition, inset monitoring options, such as electroencephalography or telemetric intracranial pressure sensors, could be incorporated in the future for comprehensive monitoring of the patient's neurological condition.

Child oral health and preventive dental service access among children with intellectual disabilities, autism and other educational additional support needs: A population-based record linkage cohort study.

OBJECTIVE: Inequalities in child oral health are a global challenge and the intersection of socioeconomic factors with educational additional support needs (ASN), including children with intellectual disabilities or autism, have thus far received limited attention in relatively small clinical studies. We aimed to address this evidence gap by investigating oral health and access to preventive dental services among children with ASN compared to the general child population. METHODS: Cohort study linking data from six Scotland-wide health and education databases compared: dental caries experience and tooth extraction via general anaesthetic; receipt of school-based dental inspection; access to primary care and hospital dental services; and access to the Childsmile national oral health improvement programme between children with a range of ASN (intellectual disabilities, autism, social and other) and their peers for the school years 2016/17-2018/19 (n = 166 781). RESULTS: Children with any ASN had higher rates of caries experience than those with no ASN, however, after adjustment for socioeconomic deprivation, sex, year, and school type only those with a social or other ASN remained at increased risk. Rates of tooth extraction under general anaesthesia in hospital were higher among children with intellectual disabilities (aRR = 1.67;95% CI = [1.16-2.37]). School-based dental inspection access improved for children with intellectual disability and/or autism from 2016/17 onwards, although higher rates of child refusal on the day were observed in these groups (no ASN refusal: 5.4%; intellectual disability: 35.8%; autism: 40.3%). Children with any ASN were less likely to attend primary dental-care regularly, and in those who attended, children with intellectual disability or autism were less likely than their peers to receive prevention (fluoride varnish, oral-hygiene instruction, or dietary advice). Childsmile nursery-supervised toothbrushing programme access among children with any ASN was similar to children with no ASN and children with intellectual disability (aRR = 1.27;95% CI = [1.12-1.45]) or autism (aRR = 1.32;95% CI = [1.19-1.45]) were more likely to receive support from Childsmile dental health support worker. CONCLUSIONS: We have identified inequalities in oral health and dental care for children with different ASN in Scotland with both a greater burden of disease among some groups and higher complexity of care; compounded by reduced and variable access to preventive dental services. Further efforts are needed to develop and improve preventive care pathways for children with ASN and integrate oral health to wider healthcare systems for these children to mitigate against oral health inequalities.

Soil organic matter can delay-but not eliminate-leaching of neonicotinoid insecticides.

Soil organic matter (SOM) retains and attenuates many contaminants; however, its interactions with neonicotinoid insecticides under field conditions remain poorly understood. The goal of this study was to determine if SOM influences the persistence or leaching of two neonicotinoid insecticides: thiamethoxam (TMX) and its transformation-product clothianidin (CLO). Thiamethoxam-coated soybean [Glycine max (L.) Merr.] was planted into a clay soil containing different soil organic carbon (SOC) concentrations. Leachate and soil samples were collected for 10 wk after planting and were analyzed for insecticide concentrations using liquid chromatography-tandem mass spectrometry. Single and multiple linear regressions were performed between SOC, leaching volumes, and measured insecticide concentrations, focusing on rainfall events near the beginning, middle, and end of the study. Correlations were also tested between SOC and cumulative mass of leached insecticides. Neither SOC nor per-event leachate volumes explained variability in TMX leaching or residual CLO concentrations in soils; however, by the conclusion of the study residual thiamethoxam concentrations in soil were negatively correlated with cumulative volume of leached water. Initially, the concentration and total mass of leached CLO were significantly and negatively correlated with SOC content; however, this effect faded with time. Leachate dynamics also affected CLO transport, with positive correlations between leachate volume and CLO concentration during the latter events. This analysis demonstrates that SOM can reduce peak loading of neonicotinoids but may not alter cumulative leaching over the entire growing season.

A spectrum of preferential flow alters solute mobility in soils.

Preferential flow reduces water residence times and allows rapid transport of pollutants such as organic contaminants. Thus, preferential flow is considered to reduce the influence of soil matrix-solute interactions during solute transport. While this claim may be true when rainfall directly follows solute application, forcing rapid chemical and physical disequilibrium, it has been perpetuated as a general feature of solute transport-regardless of the magnitude preferential flow. A small number of studies have alternatively shown that preferential transport of strongly sorbing solutes is reduced when solutes have time to diffuse and equilibrate within the soil matrix. Here we expand this inference by allowing solute sorption equilibrium to occur and exploring how physiochemical properties affect solute transport across a vast range of preferential flow. We applied deuterium-labeled rainfall to field plots containing manure spiked with eight common antibiotics with a range of affinity for the soil after 7 days of equilibration with the soil matrix and quantified preferential flow and solute transport using 48 soil pore water samplers spread along a hillslope. Based on > 700 measurements, our data showed that solute transport to lysimeters was similar-regardless of antibiotic affinity for soil-when preferential flow represented less than 15% of the total water flow. When preferential flow exceeded 15%, however, concentrations were higher for compounds with relatively low affinity for soil. We provide evidence that (1) bypassing water flow can select for compounds that are more easily released from the soil matrix, and (2) this phenomenon becomes more evident as the magnitude of preferential flow increases. We argue that considering the natural spectrum preferential flow as an explanatory variable to gauge the influence of soil matrix-solute interactions may improve parsimonious transport models.

Culturable antibiotic-resistant fecal coliform bacteria in soil and surface runoff after liquid dairy manure surface application and subsurface injection.

Land application of manure, while beneficial to soil health and plant growth, can lead to an overabundance of nutrients and introduction of emerging contaminants into agricultural fields. Compared with surface application of manure, subsurface injection has been shown to reduce nutrients and antibiotics in surface runoff. However, less is known about the influence of subsurface injection on the transport and persistence of antibiotic-resistant microorganisms. We simulated rainfall to field plots at two sites (one in Virginia and one in Pennsylvania) 1 or 7 d after liquid dairy manure surface and subsurface application (56 Mg ha-1 ) and monitored the abundance of culturable antibiotic-resistant fecal coliform bacteria (ARFCB) in surface runoff and soils for 45 d. We performed these tests at both sites in spring 2018 and repeated the test at the Virginia site in fall 2019. Manure subsurface injection, compared with surface application, resulted in less ARFCB in surface runoff, and this reduction was greater at Day 1 after application compared with Day 7. The reductions of ARFCB in surface runoff because of manure subsurface injection were 2.5-593 times at the Virginia site in spring 2018 and fall 2019 and 4-5 times at the Pennsylvania site in spring 2018. The ARFCB were only detectable in the 0-to-5-cm soil depth within 14 d of manure surface application but remained detectable in the injection slits of manure subsurface-injected plots even at Day 45. This study demonstrated that subsurface injection can significantly reduce surface runoff of ARFCB from manure-applied fields.

Coupling time-lapse ground penetrating radar surveys and infiltration experiments to characterize two types of non-uniform flow.

Understanding linkages between heterogeneous soil structures and non-uniform flow is fundamental for interpreting infiltration processes and improving hydrological simulations. Here, we utilized ground-penetrating radar (GPR) as a non-invasive technique to investigate those linkages and to complement current traditional methods that are labor-intensive, invasive, and non-repeatable. We combined time-lapse GPR surveys with different types of infiltration experiments to create three-dimensional (3D) diagrams of the wetting dynamics. We carried out the GPR surveys and validated them with in situ observations, independent measurements and field excavations at two experimental sites. Those sites were selected to represent different mechanisms that generate non-uniform flow: (1) preferential water infiltration initiated by tree trunk and root systems; and (2) lateral subsurface flow due to soil layering. Results revealed links between different types of soil heterogeneity and non-uniform flow. The first experimental site provided evidence of root-induced preferential flow paths along coarse roots, emphasizing the important role of coarse roots in facilitating preferential water movement through the subsurface. The second experimental site showed that water infiltrated through the restrictive layer mainly following the plant root system. The presented approach offers a non-invasive, repeatable and accurate way to detect non-uniform flow.

PhoP and OxyR transcriptional regulators contribute to Yersinia pestis virulence and survival within Galleria mellonella.

The virulence of Yersinia pestis KIM6+ was compared with multiple isolates of Yersinia pseudotuberculosis and Yersinia enterocolitica toward larvae of the greater wax moth Galleria mellonella. Although Y. pestis and Y. pseudotuberculosis were able to cause lethal infection in G. mellonella, these species appeared less virulent than the majority of Y. enterocolitica strains tested. Y. pestis survived primarily within hemocytes of G. mellonella, and induced a strong antibacterial peptide response that lasted for at least 3 days in surviving larvae. Immunization with dead bacteria to induce an antibacterial response led to increased survival of the larvae following infection. Mutant strains lacking the either phoP or oxyR, which were less resistant to antibacterial peptides and hydrogen peroxide respectively, were attenuated and restoration of the wild-type genes on plasmids restored virulence. Our results indicate that the Y. pseudotuberculosis-Y. pestis lineage is not as virulent toward G. mellonella as are the majority of Y. enterocolitica isolates. Further, we have shown that G. mellonella is a useful infection model for analyzing Y. pestis host-pathogen interactions, and antibacterial peptide resistance mediated by phoP and reactive oxygen defense mediated by oxyR are important for Y. pestis infection of this insect.

Utilizing Playdoh in the Classroom to Construct a 3D Model Depicting Cellular Movements and Tissue Remodeling during Human Gastrulation, Early Organogenesis, and Embryonic Folding.

In classroom studies of mammalian embryology, students must fully grasp the cellular and tissue remodeling needed to initiate gastrulation to ensure comprehension of forthcoming developmental processes such as tissue specification and organogenesis. However, quickly and completely communicating three-dimensional concepts such as gastrulation, neurulation, and embryonic folding through common two-dimensional tools such as PowerPoint is challenging for students because this method lacks the spatial orientation needed to fully understand development. Therefore, professors can utilize active learning approaches with 3D-modeling clay to aid students in visualizing developmental changes. 3D-modeling of the developmental processes focused on cell and tissue movements for the initiation of gastrulation and organogenesis is limited in published literature/videos. Therefore, this activity fills in the modeling gap by focusing on the detachment and movement of the epiblast cell through the primitive streak to generate the three germ layers, neural tube folding, cardiogenesis, and the anatomical position of the early brain and heart to drive embryonic folding. The usage of this hands-on learning tool will assist lecturers in preventing early gaps in knowledge while students first construct the model and allows for correction in misunderstandings by utilizing the complete model in discussions after construction.