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A quasi-experimental study comparing the mixing and discard methods of laboratory specimen techniques in an adult acute care setting was conducted over a 30-month period. Primary end points were delta hemoglobin (Hgb) and transfusion rates. Secondary end points were redraws related to hemolysis and erroneous results, noting central venous access device (CVAD) type. Primary objectives included the comparison of hospital-acquired anemia and transfusion rates utilizing Hgb and venous sampling methods as part of a patient blood management (PBM) program. Secondary objectives tracked the type of CVAD used to acquire venous specimens and the impact on hemolysis rates or erroneous results. Considerations include exploring the benefits of utilizing the mixing method related to cost savings. In summary, the mixing versus discard method eliminates wasting blood to reduce hospital-acquired anemia as part of a PBM program. CVAD type did not influence hemolysis rates or impact erroneous results. The mixing method is easy to implement in any health care setting. Cost savings are feasible by elimination of external venous or arterial blood management protection devices. Removal of add-on devices supports standards by decreasing access points to reduce infection risk. Results, although inconclusive to superiority, demonstrated noninferiority and encouraged consideration of the mixing method for laboratory specimen collection., Competing Interests: Conflicts of interest:The authors report no conflicts of interest., (Copyright © 2024 Infusion Nurses Society.)

Objectives: Anticoagulation plays a key role in the management of children supported with extracorporeal membrane oxygenation. However, the ideal strategy for monitoring anticoagulation remains unclear. Our objective was to evaluate the utility of laboratory measures of anticoagulation in pediatric extracorporeal membrane oxygenation., Design: Retrospective cohort study., Setting: Quaternary care academic children's hospital., Patients: Children in a noncardiac PICU cannulated to extracorporeal membrane oxygenation in 2010-2016., Interventions: None., Measurements and Main Results: Demographic data, laboratory values, and heparin doses were extracted from the enterprise data warehouse. Primary diagnoses, indications for cannulation, hemorrhagic and thrombotic complications, and survival outcomes were abstracted from the local registry used for Extracorporeal Life Support Organization reporting. Statistical models accounting for repeated measures using generalized estimating equations were constructed to evaluate correlations between heparin doses and laboratory values; among laboratory values; and between heparin dose or laboratory values and clinical outcomes. One hundred thirty-three unique patients-78 neonates and 55 older patients-were included in the study. There was no significant association between antifactor Xa level, activated partial thromboplastin time, activated clotting time, or heparin dose with hemorrhage or thrombosis (odds ratio ≅ 1 for all associations). There was weak-to-moderate correlation between antifactor Xa, activated partial thromboplastin time, and activated clotting time in both neonates and older pediatric patients (R2 < 0.001 to 0.456). Heparin dose correlated poorly with laboratory measurements in both age groups (R2 = 0.010-0.063)., Conclusions: In children supported with extracorporeal membrane oxygenation, heparin dose correlates poorly with common laboratory measures of anticoagulation, and these laboratory measures correlate poorly with each other. Neither heparin dose nor laboratory measures correlate with hemorrhage or thrombosis. Further work is needed to identify better measures of anticoagulation in order to minimize morbidity and mortality associated with extracorporeal membrane oxygenation., Competing Interests: Dr. Thiagarajan’s institution received funding from Bristol Myers Squibb and Pfizer. He received funding from Advocate Children’s Hospital. Dr. Geva’s institution received funding from Eunice Kennedy Shriver National Institute of Child Health and Development and NIH through grant number K12HD047349. He received funding from the National Heart, Lung, and Blood Institute and NIH through grant number L40HL133929. The remaining authors have disclosed that they do not have any potential conflicts of interest. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The authors have no conflicts of interest to disclose., (Copyright © 2021 by the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies.)

Objective: This study evaluated HIV-1 antibody levels as predictors of cell-associated HIV-1 DNA levels in perinatally infected (PHIV) children with long-term viral suppression on antiretroviral therapy (ART)., Design: HIV-1 antibody and HIV-1 DNA levels were measured in blood specimens from 61 children and adolescents from the Pediatric HIV/AIDS Cohort Study: Adolescent Master Protocol. Twenty perinatally HIV-1-exposed, uninfected children studied through 2 years served as controls., Methods: HIV-1 IgG antibodies to six HIV-1 proteins were measured by quantitative ELISA; HIV-1 DNA levels were measured by droplet digital PCR., Results: Among 13 children with viral suppression at less than 1 year, antibodies to gp160 and gp41 were low but stable longitudinally; antibodies to p17, p24, and RT decreased, and antibodies to p31 were low or undetectable. Among 48 children with viral suppression between 1 and 5 years, antibody levels to all six HIV-1 proteins were higher than in children with earlier viral suppression and remained high over time. A receiver operator curve approach identified gp41 and gp160 as useful predictors of HIV-1 DNA less than 10 or less than 100 copies per million PBMC (cpm); C-statistics including all antibodies ranged from 0.75 to 0.77. An ensemble learning approach also identified gp41 and gp160 as important predictors of HIV-1 DNA less than 10 or less than 100 cpm; area under the curve estimates utilizing all HIV-1 antibodies ranged from 0.70 to 0.81., Conclusion: Quantitative HIV-1 gp41 and gp160 antibody levels may serve as rapid, inexpensive screening tools for low PBMC HIV-1 DNA levels in children with viral suppression on ART, facilitating inclusion into remission protocols.

Background: Mannitol is widely used in anesthesia and critical care medicine. Although its clinical effects were originally attributed to osmotic dehydration of brain cells, other mechanisms have also been proposed. Osmotic dehydration of astroglial cells is opposed by powerful volume-regulating mechanisms that involve inward transport of electrolytes. These mechanisms have been studied previously by exposing cells to hypertonic saline gradients. Because of its potential clinical relevance, the volume response of astroglial cells exposed to hypertonic mannitol was investigated., Methods: Rat C6 glioma cells were cultured to confluence, and their volume behavior was observed by laser light scattering. After equilibration at physiologic temperature and pH, cells were abruptly exposed to hypertonic mannitol solutions. In separate experiments, C6 cells were exposed to hypertonic solutions containing radiolabeled mannitol, and its cellular uptake was determined., Results: Hypertonic mannitol exposure produced initial cell shrinkage followed by rapid volume recovery and rebound swelling. The rebound swelling was similar in magnitude to the initial maximal shrinkage. For +40 mOsm and +70 mOsm mannitol challenges, mean volume recovery was 184+/-31% and 227+/-62%, respectively (where full recovery to baseline volume = 100%). Rebound swelling was substantially inhibited by furosemide. When exposed to mannitol in varying concentrations, uptake was linear, ranging from 82+/-7 nmol/mg to 406+/-26 nmol/mg protein. After 5 min, estimated intracellular concentrations of mannitol were similar to extracellular concentrations., Conclusions: Unlike hypertonic saline, hypertonic mannitol exposure produces rebound cell swelling. Cellular penetration of mannitol appears to account for much of this phenomenon. The clinical implications of these observations remain to be determined.

Purpose: Rhabdomyosarcomas (RMS) are heterogeneous in their clinical presentation, histology, and cytogenetics. The growth of some RMS cells has been found to be regulated by the tyrosine kinase insulin-like growth factor (IGF) type I receptor. However, RMS cells exhibit variable sensitivity to inhibitors of tyrosine kinases and IGF receptors. Collectively, these heterogeneous features suggest that differences exist in the growth regulatory pathways of RMS. The objective of this study is to identify active tyrosine kinase signal transduction pathways in embryonal and alveolar RMS cells., Methods: RMS tumor samples and cell lines representing both embryonal and alveolar histologic subtypes have been analyzed by immunoprecipitation and immunoblotting techniques to characterize phosphotyrosyl protein patterns and to identify tyrosine phosphorylated proteins., Results: RMS cells can be characterized based on the patterns of phosphotyrosyl proteins, including the phosphorylation status of the catenin-like protein Cas1 and the signal adapter protein SHC, and the activation of IGF type I receptor signaling cascades including the formation of SHC-GRB2 signal protein complexes and MAP kinase activation., Conclusions: Rhabdomyosarcomas, especially the embryonal histologic subtype, are heterogeneous at the level of tyrosine kinase signal transduction. It will be important to characterize the growth regulatory pathways active in individual RMS tumors before targeting molecular therapies to this malignancy.

Cytochromes P450 comprise a remarkably diverse superfamily of heme-thiolate proteins critical in the metabolism of numerous endogenous ligands and xenobiotics. Among the myriad of P450 substrates are many compounds of toxicological and pharmacological significance. The precise complement of cytochrome P450 isoforms in any given tissue may therefore be an important determinant of susceptibility to chemical-mediated toxicity. We have used a histological approach to study the distribution of individual P450s in human and rabbit gastro-intestinal tissues. We have focused primarily on P450 enzymes of importance in the metabolism of carcinogens, namely CYP1A1, CYP1A2, CYP2E1, CYP3A4/3A5 and CYP4B1. Here we give an overview of the distribution of these enzymes in human and rabbit tissues and discuss the possible toxicological implications of the results. In addition we will discuss the value of archival human tissue specimens for histological analysis of P450 distribution.

Background: Hypertonic dehydration of the brain through administration of osmotic agents, either alone or in combination with "loop" diuretics, has been a mainstay in the treatment of increased intracranial pressure for decades. Controversy exists, however, as to the mechanism and long-term value of such therapy. Although many cell types possess volume regulatory mechanisms capable of opposing hypertonic dehydration, such behavior in the brain is poorly understood., Methods: As a model for the mammalian central nervous system, the real-time volume behavior of rat C6 glioma cells was observed by laser light scattering during hypertonic challenge. Cells were allowed to equilibrate in isotonic balanced salt solutions at physiologic pH and temperature, and then rapidly exposed to hypertonic solutions. Experiments were conducted in the presence and absence of sodium, chloride, and the loop diuretic bumetanide to assess their roles in volume regulation., Results: In response to acute, large (70 mOsm) hypertonic exposures, cells immediately shrank and then rapidly regulated their volume completely back to control within minutes. In the presence of the loop diuretic bumetanide, the volume regulatory process was significantly inhibited with only 54% recovery observed at concentrations of 10(-4) M. Volume regulation was also significantly inhibited by removal of extracellular sodium and chloride., Conclusions: Brain cells possess powerful, electrolyte-dependent and bumetanide-sensitive volume-regulatory mechanisms that directly oppose attempted osmotic shrinkage. These observations suggest a possible new mechanism for the clinically observed synergistic effects of loop and osmotic diuretics in reduction of brain volume.

Objective: To identify simple, contemporary predictors of both morbidity and mortality in pediatric patients with purpuric sepsis syndrome in order to provide a basis for future study of innovative interventions., Design: Retrospective study., Setting: An 18-bed multidisciplinary intensive care unit (ICU) in a large pediatric hospital., Patients: A total of 53 patients, ranging in age from 18 days to 17 yrs (mean 4.9 yrs) with either culture-proven meningococcal sepsis or the systemic inflammatory response syndrome with purpura, who were admitted to the ICU during the period from January 1, 1982 through March 15, 1992., Methods: A computerized database was constructed containing the characteristics of these patients at presentation, during the first 24 hrs of hospitalization, and on discharge. Single variables were screened for significance between "good" (intact survival) and "poor" (mortality or survival with significant morbidity) outcome groups. Those variables found to be most significant were then tested for sensitivity, specificity, and predictive value. The best predictors identified in this manner were then compared with the two most-cited prognosticating strategies as applied to these patients., Measurements and Main Results: Coagulopathy (defined as a partial thromboplastin time > 50 secs or serum fibrinogen concentration < 150 mg/dL [4.4 mumol/L]) at the referral site or on ICU admission was identified as an excellent predictor of poor outcome: sensitivity, specificity, positive and negative predictive values of a low serum fibrinogen value, being 81%, 95%, 93%, and 88%, and of prolonged partial thromboplastin time, being 95%, 90%, 86%, and 97%, respectively. Classical prognosticating strategies were found to be inadequately associated with mortality, yet comparable with coagulopathy in identifying patients destined for clinically important morbidity., Conclusions: We conclude that: a) outcome of pediatric patients with meningococcal sepsis or the systemic inflammatory response syndrome with purpura can be predicted rapidly, more easily, and with overall accuracy superior to classical prognostication strategies by the simple presence or absence of coagulopathy; b) when applied to a contemporary population, classical prognostication strategies lack value for prediction of mortality, yet remain valid for prediction of "poor outcome" (significant morbidity + mortality); c) when evaluating treatment strategies for such patients, the presence of serious coagulopathy may potentially be useful as an index of illness severity.