Alligators in the abyss: The first experimental reptilian food fall in the deep ocean

The high respiration rates of the deep-sea benthos cannot be sustained by known carbon supply pathways alone. Here, we investigate moderately-sized reptilian food falls as a potential alternative carbon pathway. Specifically, three individual carcasses of Alligator mississippiensis were deployed along the continental slope of the northern Gulf of Mexico at depths of ~2000m in early 2019. We posit the tough hide of alligators would impeded scavengers by limiting access to soft tissues of the alligator fall. However, the scavengers began consuming the food fall 43 hours post-deployment for one individual (198.2cm, 29.7kg), and the carcass of another individual (175.3 cm, 19.5kg) was completely devoid of soft tissue at 51 days post-deployment. A third individual (172.7cm, 18.5kg) was missing completely after 8 days, with only the deployment harness and weight remaining drug 8 meters away, suggesting a large elasmobranch scavenger. Additionally, bones recovered post-deployment reveal the first observations of the bone-eating Osedax in the Gulf of Mexico and are confirmed here as new to science. The findings of this study indicate the quick and successful utilization of terrestrial and aquatic-based carbon food sources in the deep marine environment, though outcome variability may be high.

Fluid overload and outcomes in critically ill children: A single center prospective cohort study

OBJECTIVE

To prospectively evaluate the association between fluid overload (FO) and clinical outcomes, mortality, mechanical ventilation (MV), and duration and length of stay in a pediatric intensive care unit (PICU).

METHODS

Over a 12-month period, patients who were on MV for >24h or vasoactive support were prospectively included. Demographic and clinical data were recorded. Daily FO was calculated as [(fluid in-fluid out)/admission weight]×100%. Multivariate stepwise logistic regression analysis was used to determine predictors of survival.

RESULTS

224 patients were included; median age was 3.3 (IQR 0.7, 9.9) years, mortality was 15.6%. The median peak FO (PFO) was 12.5% (IQR 5, 25), PFO>10% was present in 55.8% of patients, and PFO>20% was present in 33%. The PFO in non-survivors was 17.8% (IQR 8, 30) and 11% (IQR 4, 23) in survivors (p=0.028). A survival analysis showed no association between PFO and mortality. A multivariate analysis identified vasoactive support, >3 organ failures and acute kidney injury (AKI) but not FO as independent risk factors for mortality. FO was associated with MV duration and PICU length of stay.

CONCLUSION

FO is frequent in a general PICU population, but PFO is not an independent risk factor for mortality. Future studies of FO should focus on patients with AKI and multiorgan failure for better classification of severity and potential interventions.

The clinical impact of humoral immunity in pediatric renal transplantation

The development of anti-donor humoral responses after transplantation associates with higher risks for acute rejection and 1-year graft survival in adults, but the influence of humoral immunity on transplant outcomes in children is not well understood. Here, we studied the evolution of humoral immunity in low-risk pediatric patients during the first 2 years after renal transplantation. Using data from 130 pediatric renal transplant patients randomized to steroid-free (SF) or steroid-based (SB) immunosuppression in the NIH-SNSO1 trial, we correlated the presence of serum anti-HLA antibodies to donor HLA antigens (donor-specific antibodies) and serum MHC class 1-related chain A (MICA) antibody with both clinical outcomes and histology identified on protocol biopsies at 0, 6, 12, and 24 months. We detected de novo antibodies after transplant in 24% (23% of SF group and 25% of SB group), most often after the first year. Overall, 22% developed anti-HLA antibodies, of which 6% were donor-specific antibodies, and 6% developed anti-MICA antibody. Presence of these antibodies de novo associated with significantly higher risks for acute rejection (P=0.02), chronic graft injury (P=0.02), and decline in graft function (P=0.02). In summary, antibodies to HLA and MICA antigens appear in approximately 25% of unsensitized pediatric patients, placing them at greater risk for acute and chronic rejection with accelerated loss of graft function. Avoiding steroids does not seem to modify this incidence. Whether serial assessments of these antibodies after transplant could guide individual tailoring of immunosuppression requires additional study.

A peripheral blood diagnostic test for acute rejection in renal transplantation

Monitoring of renal graft status through peripheral blood (PB) rather than invasive biopsy is important as it will lessen the risk of infection and other stresses, while reducing the costs of rejection diagnosis. Blood gene biomarker panels were discovered by microarrays at a single center and subsequently validated and cross-validated by QPCR in the NIH SNSO1 randomized study from 12 US pediatric transplant programs. A total of 367 unique human PB samples, each paired with a graft biopsy for centralized, blinded phenotype classification, were analyzed (115 acute rejection (AR), 180 stable and 72 other causes of graft injury). Of the differentially expressed genes by microarray, Q-PCR analysis of a five gene-set (DUSP1, PBEF1, PSEN1, MAPK9 and NKTR) classified AR with high accuracy. A logistic regression model was built on independent training-set (n = 47) and validated on independent test-set (n = 198)samples, discriminating AR from STA with 91% sensitivity and 94% specificity and AR from all other non-AR phenotypes with 91% sensitivity and 90% specificity. The 5-gene set can diagnose AR potentially avoiding the need for invasive renal biopsy. These data support the conduct of a prospective study to validate the clinical predictive utility of this diagnostic tool.

Subclinical inflammation and chronic renal allograft injury in a randomized trial on steroid avoidance in pediatric kidney transplantation

Steroid avoidance is safe and effective in children receiving kidney transplants in terms of graft function and survival, but the effects on allograft histology are unknown. In this multicenter trial, 130 pediatric renal transplant recipients were randomized to steroid-free (SF; n = 60) or steroid-based (SB; n = 70) immunosuppression, and underwent renal allograft biopsies at the time of graft dysfunction and per protocol at implantation and 6, 12 and 24 months after transplantation. Clinical follow-up was 3 years posttransplant. Subclinical acute rejection was present in 10.6% SF versus 11.3% SB biopsies at 6 months (p = 0.91), 0% SF versus 4.3% SB biopsies at 1 year (p = 0.21) and 0% versus 4.8% at 2 years (p = 0.20). Clinical acute rejection was present in 13.3% SF and 11.4% SB patients by 1 year (p = 0.74) and in 16.7% SF and 17.1% SB patients by 3 years (p = 0.94) after transplantation. The cumulative incidence of antibody-mediated rejection was 6.7% in SF and 2.9% in SB by 3 years after transplantation (p = 0.30). There was a significant increase in chronic histological damage over time (p < 0.001), without difference between SF and SB patients. Smaller recipient size and higher donor age were the main risk factors for chronic histological injury in posttransplant biopsies.

Complete steroid avoidance is effective and safe in children with renal transplants: a multicenter randomized trial with three-year follow-up

To determine whether steroid avoidance in pediatric kidney transplantation is safe and efficacious, a randomized, multicenter trial was performed in 12 pediatric kidney transplant centers. One hundred thirty children receiving primary kidney transplants were randomized to steroid-free (SF) or steroid-based (SB) immunosuppression, with concomitant tacrolimus, mycophenolate and standard dose daclizumab (SB group) or extended dose daclizumab (SF group). Follow-up was 3 years posttransplant. Standardized height Z-score change after 3 years follow-up was -0.99 ± 2.20 in SF versus -0.93 ± 1.11 in SB; p = 0.825. In subgroup analysis, recipients under 5 years of age showed improved linear growth with SF compared to SB treatment (change in standardized height Z-score at 3 years -0.43 ± 1.15 vs. -1.07 ± 1.14; p = 0.019). There were no differences in the rates of biopsy-proven acute rejection at 3 years after transplantation (16.7% in SF vs. 17.1% in SB; p = 0.94). Patient survival was 100% in both arms; graft survival was 95% in the SF and 90% in the SB arms (p = 0.30) at 3 years follow-up. Over the 3 year follow-up period, the SF group showed lower systolic BP (p = 0.017) and lower cholesterol levels (p = 0.034). In conclusion, complete steroid avoidance is safe and effective in unsensitized children receiving primary kidney transplants.

Correlation and clinical utility of pp65 antigenemia and quantitative polymerase chain reaction assays for detection of cytomegalovirus in pediatric renal transplant patients

qPCR and pp65 antigenemia assays are used to monitor CMV infection in renal transplant recipients, but correlation of assays in a pediatric population has not been evaluated. Paired CMV real-time qPCR and pp65 antigenemia tests from 882 blood samples collected from 115 pediatric renal transplant recipients were analyzed in this retrospective cohort study for the strength of association and clinical correlates. The assays correlated well in detecting infection (κ = 0.61). Higher qPCR values were demonstrated with increasing levels of antigenemia (p < 0.01). Discordant test results were associated with antiviral treatment (OR 4.33, p < 0.01) and low-level viremia, with odds of concordance increasing at higher qPCR values (OR 3.67, p < 0.01), and no discordance occurring above 8500 genomic equivalents/mL. Among discordant samples, neither test preceded the other in detecting initial infection or in returning to negative while on treatment. Only two cases of disease occurred during the two-yr study period. With strong agreement in the detection of CMV infection, either qPCR or pp65 antigenemia assays can be used effectively for monitoring pediatric renal transplant patients for both detection and resolution of infection.

Metabolic abnormalities, cardiovascular disease risk factors, and GFR decline in children with chronic kidney disease

BACKGROUND AND OBJECTIVES

Metabolic abnormalities and cardiovascular disease (CVD) risk factors have rarely been systematically assessed in children with chronic kidney disease (CKD). We examined the prevalence of various CKD sequelae across the GFR spectrum.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data were used from 586 children participating in the Chronic Kidney Disease in Children (CKiD) study (United States and Canada) with GFR measured by iohexol plasma disappearance. Laboratory values and CVD risk factors were compared across GFR categories and with an age-, gender-, and race-matched community sample.

RESULTS

CKiD participants were 62% male, 66% Caucasian, 23% African American, and 15% Hispanic with a median age of 11 years and a median GFR of 44 ml/min per 1.73 m(2). Compared with those with a GFR ≥ 50 ml/min per 1.73 m(2), having a GFR < 30 ml/min per 1.73 m(2) was associated with a three-fold higher risk of acidosis and growth failure and a four- to five-fold higher risk of anemia and elevated potassium and phosphate. Median GFR change was -4.3 ml/min per 1.73 m(2) and -1.5 ml/min per 1.73 m(2) per year in children with glomerular and nonglomerular diagnoses, respectively. Despite medication and access to nephrology care, uncontrolled systolic hypertension was present in 14%, and 16% had left ventricular hypertrophy. Children with CKD frequently were also shorter and had lower birth weight, on average, compared with norms.

CONCLUSIONS

Growth failure, metabolic abnormalities, and CVD risk factors are present at GFR >50 ml/min per 1.73 m(2) in children with CKD and, despite therapy, increase in prevalence two- to four-fold with decreasing GFR.

Sleep and fatigue symptoms in children and adolescents with CKD: a cross-sectional analysis from the chronic kidney disease in children (CKiD) study

BACKGROUND

Although symptoms of sleepiness and fatigue are common in adults with chronic kidney disease (CKD), little is known about the prevalence of these symptoms in children with CKD.

STUDY DESIGN

Cross-sectional analysis within a cohort study.

SETTING & PARTICIPANTS

We describe the frequency and severity of sleep problems and fatigue and assess the extent of their association with measured glomerular filtration rate (mGFR) and health-related quality of life (HRQOL) in 301 participants of the Chronic Kidney Disease in Children cohort.

OUTCOMES & MEASUREMENTS

Sleep and fatigue-related items from the Pediatric Quality of Life Inventory 4.0 Generic Scales and the CKD-related Symptoms List were used.

RESULTS

Median mGFR was 42.0 mL/min/1.73 m(2) (25th-75th percentiles, 31.2-53.2), and median age was 13.9 years (25th-75th percentiles, 10.8-16.2). Children with mGFR of 40-<50, 30-<40, or <30 mL/min/1.73 m(2) had 2.07 (95% CI, 1.05-4.09), 2.35 (95% CI, 1.17-4.72), and 2.59 (95% CI, 1.15-5.85) higher odds of having more severe parent reports of low energy than children with mGFR > or = 50 mL/min/1.73 m(2). Compared with participants with mGFR > or = 50 mL/min/1.73 m(2), those with mGFR < 30 mL/min/1.73 m(2) had 3.92 (95% CI, 1.37-11.17) higher odds of reporting more severe weakness, and those with mGFR of 40-<50 mL/min/1.73 m(2) had 2.95 (95% CI, 1.26-6.88) higher odds of falling asleep during the day. Low energy, trouble sleeping, and weakness were associated with lower HRQOL scores.

LIMITATIONS

Symptoms of sleep and fatigue represent the child's or parent's perception of symptom severity, whereas individual items can lead to imprecise measurements of sleep and fatigue.

CONCLUSIONS

Lower mGFR was associated with increased weakness, low energy, and daytime sleepiness. Furthermore, a strong association between trouble sleeping, low energy, and weakness with decreases in overall HRQOL was observed. Detection and treatment of poor sleep and fatigue may improve the development and HRQOL of children and adolescents with CKD.

Fluid overload and mortality in children receiving continuous renal replacement therapy: the prospective pediatric continuous renal replacement therapy registry

BACKGROUND

Critically ill children with hemodynamic instability and acute kidney injury often develop fluid overload. Continuous renal replacement therapy (CRRT) has emerged as a favored modality in the management of such children. This study investigated the association between fluid overload and mortality in children receiving CRRT.

STUDY DESIGN

Prospective observational study.

SETTING & PARTICIPANTS

297 children from 13 centers across the United States participating in the Prospective Pediatric CRRT Registry.

PREDICTOR

Fluid overload from intensive care unit (ICU) admission to CRRT initiation, defined as a percentage equal to (fluid in [L] - fluid out [L])/(ICU admit weight [kg]) x 100%.

OUTCOME & MEASUREMENTS

The primary outcome was survival to pediatric ICU discharge. Data were collected regarding demographics, CRRT parameters, underlying disease process, and severity of illness.

RESULTS

153 patients (51.5%) developed < 10% fluid overload, 51 patients (17.2%) developed 10%-20% fluid overload, and 93 patients (31.3%) developed > or = 20% fluid overload. Patients who developed > or = 20% fluid overload at CRRT initiation had significantly higher mortality (61/93; 65.6%) than those who had 10%-20% fluid overload (22/51; 43.1%) and those with < 10% fluid overload (45/153; 29.4%). The association between degree of fluid overload and mortality remained after adjusting for intergroup differences and severity of illness. The adjusted mortality OR was 1.03 (95% CI, 1.01-1.05), suggesting a 3% increase in mortality for each 1% increase in severity of fluid overload. When fluid overload was dichotomized to > or = 20% and < 20%, patients with > or = 20% fluid overload had an adjusted mortality OR of 8.5 (95% CI, 2.8-25.7).

LIMITATIONS

This was an observational study; interventions were not standardized. The relationship between fluid overload and mortality remains an association without definitive evidence of causality.

CONCLUSIONS

Critically ill children who develop greater fluid overload before initiation of CRRT experience higher mortality than those with less fluid overload. Further goal-directed research is required to accurately define optimal fluid overload thresholds for initiation of CRRT.

Racial differences in graft survival: a report from the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS)

Multiple studies have documented racial differences in graft survival in kidney transplant recipients. Although several studies in adult kidney transplant recipients have evaluated risk factors that might predispose to these differences, studies in pediatric patients are lacking. This study retrospectively analyzed data from the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) to identify racial differences in kidney transplant outcomes and evaluate factors that might contribute to those differences. The study was restricted to the first NAPRTCS registry-reported kidney transplant for pediatric patients (age < or =21 yr) whose race was reported as either black or white. Univariate graft survival analyses were performed using the log rank statistic. Relative hazard rates for the effect of race on graft failure were determined using proportional hazards models. Multivariate analyses were restricted to patients with >30 d of graft survival and were adjusted for initial diagnosis, donor source, presence of delayed graft function, era of transplantation, estimated GFR at 30 d after transplantation, and number of days hospitalized in the first month after transplantation. Graft survival was significantly lower in black transplant recipients at 3 yr (70.9 versus 83.3%) and 5 yr (59.9 versus 77.7%). After controlling for confounding factors, black recipients continued to have a higher risk for graft failure than white recipients (adjusted hazard rate 1.65; 95% confidence interval 1.46 to 1.86). Significant racial differences in kidney transplant outcomes exist among pediatric patients even after controlling for confounding factors.

What is the role for mycophenolate mofetil in pediatric renal transplantation?

Mycophenolate mofetil (MMF) has gained considerable popularity in pediatric renal transplantation. This popularity is largely a result of data from three large trials of MMF in adult cadaveric transplant patients who demonstrated a decreased rate of acute rejection episodes when treated with cyclosporin A (CsA), prednisone, and MMF compared with those receiving CsA, prednisone, and azathioprine (AZA) or placebo. However, the ability of MMF to reduce acute rejection appears to be limited to the first month post-transplant, and its effectiveness with microemulsion CsA or tacrolimus-based regimens has not been proven. In addition, there are currently no data that convincingly demonstrate that this agent improves graft survival, patient survival, graft function or protects against chronic rejection. Finally, there may be an increased risk for severe cytomegalovirus (CMV) disease and lymphoproliferative disorder with central nervous system involvement in patients treated with MMF. These data call into question the role of MMF in current immunosuppressive regimens.

Sequential analysis of the lipid profile of children post-renal transplantation

Persistent hyperlipidemia and hypercholesterolemia post-transplantation are risk factors for accelerated atherosclerosis. To evaluate the natural history of lipid abnormalities in children post-transplantation, this study utilized a cohort of 29 patients who were all treated with the same three- drug maintenance immunosuppression (cyclosporine, azathioprine, and prednisone) and whose dosing regimen was rigidly controlled. Fasting blood samples were taken monthly to determine lipid profiles measuring total cholesterol (CHOL), triglycerides (TG), high-density lipoprotein cholesterol (HDL), very low density lipoprotein cholesterol (VLDL), and levels of lipoprotein (a) (LP(a)). A mean value was determined for each of five time periods: 0-3 months, 3-6 months, 6-9 months, 9-12 months and 12-15 months post-transplant. A single specimen of fasting lipid profile was drawn from 21 non-immunosuppressed children attending an ambulatory pediatric clinic and used as control. Despite significant reductions in the cyclosporine and prednisone doses post-transplantation, significant reduction in any of the lipid parameters was only noted after the first year. Reductions in the HDL fraction and in the TG level were noted during the 12-15 month period, however the values obtained in the patient population were significantly elevated for CHOL, TG, LDL and VLDL compared to controls. This study, using a fixed protocol, suggests that the lipid profile should be measured at one year post-transplant in all transplant patients, and if subsequent follow-up continues to exhibit abnormally elevated levels of CHOL and LDL, interventional therapy should be considered.

Baking soda: a potentially fatal home remedy

We present a case of a six-week-old infant who developed life-threatening complications after unintentional sodium bicarbonate intoxication. Baking soda was being used by the mother as a home remedy to "help the baby burp." A review of the literature regarding the use (or misuse) of baking soda follows. Our patient, along with the other noted case reports, emphasizes the need for warnings on baking soda products whose labels recommend its use as an antacid. Poisonings must be high in the differential diagnosis of any patient, regardless of age, who presents with altered mental status or status epilepticus.