Experimental evaluation of the plunger technique: A method of cyclic manual aspiration thrombectomy for treatment of acute ischemic stroke.

BACKGROUND: Mechanical thrombectomy via direct aspiration is a rapid treatment for acute ischemic stroke. This method often results in the partial ingestion of the clot or "corking" of the catheter tip. Cyclic aspiration may take advantage of the mechanical properties of the clot, resulting in greater clot ingestion and overall procedure success. METHODS: An in vitro analysis was performed comparing static and cyclic (plunger technique) aspiration. Embolus analogs were used to create occlusions in a mock circulatory flow loop, and one aspiration attempt (first pass effect) using either a static or plunger technique was performed. The percent ingestion of each embolus analog was recorded for each trial. RESULTS: Static aspiration for 0% and 50% hematocrit embolus analogs resulted in ingestions of 12.8 ± 4.6% and 15.1 ± 10.0%, respectively, while plunger technique (cyclic) aspiration resulted in 15.8 ± 7.3% and 34.4 ± 19.5% ingestion. Complete ingestion was observed only with 50% hematocrit analogs, occurring in 30% of plunger and 10% of static cases. Statistical differences were determined between the two aspiration techniques for the 50% hematocrit samples, with the plunger technique yielding significantly more ingestion. In addition, the plunger technique was shown to maintain a negative vacuum pressure throughout the duration of cyclic plunging. CONCLUSIONS: The plunger technique for manual cyclic aspiration resulted in higher rates of complete ingestion and greater average % ingestions when compared to static aspiration. Increased clot ingestion can result in a higher rate of complete reperfusion during the first aspiration attempt, maximizing the number of patients with good clinical outcomes.

Impact of intravenous fluid administration on cardiac output and oxygenation during cardiopulmonary resuscitation.

BACKGROUND: The effect of intravenous fluid (IVF) administration during cardiopulmonary resuscitation (CPR) is an unexplored factor that may improve cardiac output (CO) during CPR. The aim of this study was to determine the effect of IVF administration on CO and oxygenation during CPR. METHODS: This experimental animal study was performed in a critical care animal laboratory. Twenty-two Landrace-Yorkshire female piglets weighing 27-37 kg were anesthetized, intubated, and placed on positive pressure ventilation. Irreversible cardiac arrest was induced with bupivacaine. CPR was performed with a LUCAS 3 mechanical compression device. Pigs were randomized into IVF or no-IVF groups. Pigs in the IVF group were given 20 mL/kg of Plasma-Lyte (Baxter International, Deerfield, IL USA), infused from 15 to 35 min of CPR. CPR was maintained for 50 min with serial measurements of CO obtained using ultrasound dilution technology and partial pressure of oxygen (PaO2). RESULTS: A mixed-effects repeated measures analysis of variance was used to compare within-group, and between-group mean changes in CO and PaO2 over time. CO and PaO2 for the piglets were measured at 10-min intervals during the 50 min of CPR. CO was greater in the IVF compared with the control group at all time points during and after the infusion of the IVF. Mean PaO2 decreased with time; however, at no time was there a significant difference in PaO2 between the IVF and control groups. CONCLUSIONS: Administration of IVF during CPR resulted in a significant increase in CO during CPR both during and after the IVF infusion. There was no statistically significant decrease in PaO2 between the IVF and control groups.

Peer Education and Peer Counselling for Health and Well-Being: A Review of Reviews.

Peer education and peer counselling for health and wellbeing have been recognized as complementary approaches to professional intervention for over 50 years, but it is relatively recently that research into effects has become adequate. Potentially, they have advantages in reaching where professionals cannot, but it has not been clear if that potential is fulfilled, although the measurement of effects is difficult. The present paper examines 58 narrative and systematic reviews and meta-analyses on the topic. In peer education, there were many reviews of sexual health and of HIV/AIDS interventions, followed by reviews of various medical conditions and in the context of prisons. More general reviews covered a wider field. In peer counselling, there were several reviews of breast-feeding and mental health. Many early reviews complained of the lack of evaluation; then, later reviews found knowledge gains but not behavior gains; then, still later reviews found both knowledge and behavior gains. Thus, peer education and counselling appear effective but only if organizational factors are well managed and the cultural context of the country respected. The implications for future practice, policy and research were outlined.

Mask wearing increases eye involvement during smiling: a facial EMG study.

The use of face masks has become ubiquitous. Although mask wearing is a convenient way to reduce the spread of disease, it is important to know how the mask affects our communication via facial expression. For example, when we are wearing the mask and meet a friend, are our facial expressions different compared to when we are not? We investigated the effect of face mask wearing on facial expression, including the area around the eyes. We measured surface electromyography from zygomaticus major, orbicularis oculi, and depressor anguli oris muscles, when people smiled and talked with or without a mask. Only the actions of the orbicularis oculi were facilitated by wearing the mask. We thus concluded that mask wearing may increase the recruitment of the eyes during smiling. In other words, we can express joy and happiness even when wearing a face mask.

Effect of positive end-expiratory pressure on additional passive ventilation generated by CPR compressions in a porcine model.

BACKGROUND: Compressions given during cardiopulmonary resuscitation generate small, ineffective passive ventilations through oscillating waves. Positive end-expiratory pressure increases the volume of these passive ventilations; however, its effect on passive ventilation is unknown. Our objective was to determine if increasing positive end-expiratory pressure during cardiopulmonary resuscitation increases passive ventilation generated by compressions to a clinically significant point. This study was conducted on 13 Landrace-Yorkshire pigs. After inducing cardiac arrest with bupivacaine, cardiopulmonary resuscitation was performed with a LUCAS 3.1. During cardiopulmonary resuscitation, pigs were ventilated at a positive end-expiratory pressure of 0, 5, 10, 15, 20 cmH2O (randomly determined) for 9 min. Using the NM3 respiratory monitoring device, expired minute ventilation and volumetric capnography were measured. Arterial blood gas was obtained for each positive end-expiratory pressure level to compare the effects of positive end-expiratory pressure on carbon dioxide. RESULTS: Increasing positive end-expiratory pressure from 0 to 20 cmH2O increased the mean (SEM) expired minute ventilation from 6.33 (0.04) to 7.33 (0.04) mL/min. With the 5-cmH2O incremental increases in positive end-expiratory pressure from 0 to 20 cmH2O, volumetric capnography increased from a mean (SEM) of 94.19 (0.78) to 115.18 (0.8) mL/min, except for 15 cmH2O, which showed greater carbon dioxide exhalation with volumetric capnography compared with 20 cmH2O. PCO2 declined significantly as positive end-expiratory pressure was increased from 0 to 20 cmH2O. CONCLUSIONS: When increasing positive end-expiratory pressure from 0 to 20, the contribution to overall ventilation from gas oscillations generated by the compressions became more significant, and may even lead to hypocapnia, especially when using positive end-expiratory pressures between 15 and 20.

Reducing Expectations for Antibiotics in Patients With Upper Respiratory Tract Infections: A Primary Care Randomized Controlled Trial.

PURPOSE: Many family practitioners prescribe antibiotics for patients with upper respiratory tract infections (URTIs) to meet patients' expectations. We evaluated the impact of providing brief tablet-based information about antibiotic treatment of URTIs on patients' expectations for antibiotics and on family practitioners' antibiotic-prescribing behavior. METHODS: We performed a 3-arm randomized controlled trial among patients presenting with URTIs at 2 urban family practices in Auckland, New Zealand, during winter 2018. Participants were randomly allocated to view a presentation about the futility of antibiotic treatment of URTIs, the adverse effects associated with antibiotics, or the benefits of healthy diet and exercise (active control), immediately before their consultation. Before and after viewing the presentations, participants used a Likert scale to rate the strength of their belief that antibiotics are effective for treating URTIs and of their desire to be prescribed an antibiotic. Patients reported whether an antibiotic had been prescribed, and pharmacy dispensing records were reviewed to determine whether an antibiotic was dispensed. RESULTS: Participants who viewed either the futility or the adverse effects presentation had greater reductions in their expectations to receive antibiotics than the control group. The mean reduction (95% CI) was 1.1 (0.8-1.3) for the futility group, 0.7 (0.4-0.9) for the adverse effects group, and 0.1 (0-0.3) for the control group (Cohen d = 0.7; P <.001). There was no significant difference among the 3 groups with regard to antibiotic prescribing (P = .84) or dispensing (P = .43). CONCLUSIONS: A brief tablet-based waiting room intervention significantly reduced participants' expectations about receiving antibiotics for URTI immediately before their family practitioner consultation. The intervention did not influence family practitioner prescribing behavior, however.

The effect of positive end-expiratory pressure on cardiac output and oxygen delivery during cardiopulmonary resuscitation.

BACKGROUND: Positive end-expiratory pressure (PEEP) is used to optimize oxygenation by preventing alveolar collapse. However, PEEP can potentially decrease cardiac output through cardiopulmonary interactions. The effect of PEEP on cardiac output during cardiopulmonary resuscitation (CPR) is not known. METHODS: This was a preclinical randomized, controlled, animal study conducted in an animal research facility on 25 Landrace-Yorkshire pigs. After inducing cardiac arrest, CPR was performed with LUCAS 3. During CPR, pigs were ventilated at a PEEP of 0, 5, 10, 15, 20 cmH2O (randomly determined via lottery) for 9 min. Cardiac output, obtained via ultrasound dilution, and PaO2 were measured, and oxygen delivery calculated for each PEEP. RESULTS: A mixed-effects repeated-measures analysis of variance was used to compare the baseline value adjusted mean cardiac output, PaO2, and oxygen delivery between PEEP groups. Least significant difference test was used to conduct pairwise comparisons between PEEP groups. To determine optimum PEEP, Gaussian mixture model was applied to the adjusted means of cardiac output and oxygen delivery. Increasing PEEP to 10 and higher resulted in significant declines in cardiac output. A PEEP of 15 and higher resulted in significant declines in oxygen delivery. As PEEP was increased from 0 to 20, PaO2 increased significantly. Gaussian mixture model identified the 0-5 PEEP group as providing optimal cardiac output and oxygen delivery, with PEEP of 5 providing the highest oxygen delivery. CONCLUSIONS: A PEEP of 0-5 resulted in the optimal oxygen delivery and cardiac output during CPR, with PEEP of 5 resulting in higher oxygen delivery, and a slightly lower, statistically insignificant cardiac output than PEEP of 0.

Antibiotic Degradation by Commensal Microbes Shields Pathogens.

The complex bacterial populations that constitute the gut microbiota can harbor antibiotic resistance genes (ARGs), including those encoding ß-lactamase enzymes (BLA), which degrade commonly prescribed antibiotics such as ampicillin. The prevalence of such genes in commensal bacteria has been increased in recent years by the wide use of antibiotics in human populations and in livestock. While transfer of ARGs between bacterial species has well-established dramatic public health implications, these genes can also function in trans within bacterial consortia, where antibiotic-resistant bacteria can provide antibiotic-sensitive neighbors with leaky protection from drugs, as shown both in vitro and in vivo, in models of lung and subcutaneous coinfection. However, whether the expression of ARGs by harmless commensal bacterial species can destroy antibiotics in the intestinal lumen and shield antibiotic-sensitive pathogens is unknown. To address this question, we colonized germfree or wild-type mice with a model intestinal commensal strain of Escherichia coli that produces either functional or defective BLA. Mice were subsequently infected with Listeria monocytogenes or Clostridioides difficile, followed by treatment with oral ampicillin. The production of functional BLA by commensal E. coli markedly reduced clearance of these pathogens and enhanced systemic dissemination during ampicillin treatment. Pathogen resistance was independent of ARG acquisition via horizontal gene transfer but instead relied on antibiotic degradation in the intestinal lumen by BLA. We conclude that commensal bacteria that have acquired ARGs can mediate shielding of pathogens from the bactericidal effects of antibiotics.

Impact of Antibiotic-Resistant Bacteria on Immune Activation and Clostridioides difficile Infection in the Mouse Intestine.

Antibiotic treatment of patients undergoing complex medical treatments can deplete commensal bacterial strains from the intestinal microbiota, thereby reducing colonization resistance against a wide range of antibiotic-resistant pathogens. Loss of colonization resistance can lead to marked expansion of vancomycin-resistant Enterococcus faecium (VRE), Klebsiella pneumoniae, and Escherichia coli in the intestinal lumen, predisposing patients to bloodstream invasion and sepsis. The impact of intestinal domination by these antibiotic-resistant pathogens on mucosal immune defenses and epithelial and mucin-mediated barrier integrity is unclear. We used a mouse model to study the impact of intestinal domination by antibiotic-resistant bacterial species and strains on the colonic mucosa. Intestinal colonization with K. pneumoniae, Proteus mirabilis, or Enterobacter cloacae promoted greater recruitment of neutrophils to the colonic mucosa. To test the hypothesis that the residual microbiota influences the severity of colitis caused by infection with Clostridioides difficile, we coinfected mice that were colonized with ampicillin-resistant bacteria with a virulent strain of C. difficile and monitored colonization and pathogenesis. Despite the compositional differences in the gut microbiota, the severity of C. difficile infection (CDI) and mortality did not differ significantly between mice colonized with different ampicillin-resistant bacterial species. Our results suggest that the virulence mechanisms enabling CDI and epithelial destruction outweigh the relatively minor impact of less-virulent antibiotic-resistant intestinal bacteria on the outcome of CDI.

Integrating Parents in Neonatal and Pediatric Research.

BACKGROUND: Parents and their infants are the beneficiaries of neonatal and pediatric research, but in the past they have been excluded from most stages of research projects. As a result, many projects may fail to produce the most worthwhile information for parents and families. Lately, veteran resource parents and patients have been increasingly integrated in research initiatives. METHODS: Benchmarking of neonatal and pediatric research initiatives where resource parents and/or ex neonatal patients have helped to optimize pediatric research. We review ways in which resource parents/patients can be involved in research, with examples and practical ideas of how to proceed. RESULTS: Resource parents/patients can be collaborators in research and be integrated in many steps: prioritizing research projects, designing trials, determining the outcomes of interest, ethics review, developing and improving consent procedures, collection and interpretation of data, participation in data safety monitoring committees, publication of results, and presentation to peer groups. Some of the strategies for integration of stakeholders in clinical research are more complex, may involve risk and require more training than others. CONCLUSION: We suggest that groups wanting to involve parents in their research endeavors start with simpler tasks that entail less risk and develop teams of resource parents who have differing interests and abilities. Quality control of programs is essential, such as frequently giving and obtaining feedback from resource parents/patients and researchers. In the future, integration of resource parents/patients into every step of clinical research will be essential to ensure that parent and family important outcomes are examined.

Enlisting commensal microbes to resist antibiotic-resistant pathogens.

The emergence of antibiotic-resistant bacterial pathogens is an all-too-common consequence of antibiotic use. Although antibiotic resistance among virulent bacterial pathogens is a growing concern, the highest levels of antibiotic resistance occur among less pathogenic but more common bacteria that are prevalent in healthcare settings. Patient-to-patient transmission of these antibiotic-resistant bacteria is a perpetual concern in hospitals. Many of these resistant microbes, such as vancomycin-resistant Enterococcus faecium and carbapenem-resistant Klebsiella pneumoniae, emerge from the intestinal lumen and invade the bloodstream of vulnerable patients, causing disseminated infection. These infections are associated with preceding antibiotic administration, which changes the intestinal microbiota and compromises resistance to colonization by antibiotic-resistant bacteria. Recent and ongoing studies are increasingly defining commensal bacterial species and the inhibitory mechanisms they use to prevent infection. The use of next-generation probiotics derived from the intestinal microbiota represents an alternative approach to prevention of infection by enriching colonization with protective commensal species, thereby reducing the density of antibiotic-resistant bacteria and also reducing patient-to-patient transmission of infection in healthcare settings.

Atherosclerotic Plaque Tissue: Noninvasive Quantitative Assessment of Characteristics with Software-aided Measurements from Conventional CT Angiography.

Purpose To (a) evaluate whether plaque tissue characteristics determined with conventional computed tomographic (CT) angiography could be quantitated at higher levels of accuracy by using image processing algorithms that take characteristics of the image formation process coupled with biologic insights on tissue distributions into account by comparing in vivo results and ex vivo histologic findings and (b) assess reader variability. Materials and Methods Thirty-one consecutive patients aged 43-85 years (average age, 64 years) known to have or suspected of having atherosclerosis who underwent CT angiography and were referred for endarterectomy were enrolled. Surgical specimens were evaluated with histopathologic examination to serve as standard of reference. Two readers used lumen boundary to determine scanner blur and then optimized component densities and subvoxel boundaries to best fit the observed image by using semiautomatic software. The accuracy of the resulting in vivo quantitation of calcification, lipid-rich necrotic core (LRNC), and matrix was assessed with statistical estimates of bias and linearity relative to ex vivo histologic findings. Reader variability was assessed with statistical estimates of repeatability and reproducibility. Results A total of 239 cross sections obtained with CT angiography and histologic examination were matched. Performance on held-out data showed low levels of bias and high Pearson correlation coefficients for calcification (-0.096 mm2 and 0.973, respectively), LRNC (1.26 mm2 and 0.856), and matrix (-2.44 mm2 and 0.885). Intrareader variability was low (repeatability coefficient ranged from 1.50 mm2 to 1.83 mm2 among tissue characteristics), as was interreader variability (reproducibility coefficient ranged from 2.09 mm2 to 4.43 mm2). Conclusion There was high correlation and low bias between the in vivo software image analysis and ex vivo histopathologic quantitative measures of atherosclerotic plaque tissue characteristics, as well as low reader variability. Software algorithms can mitigate the blurring and partial volume effects of routine CT angiography acquisitions to produce accurate quantification to enhance current clinical practice. Clinical trial registration no. NCT02143102 © RSNA, 2017 Online supplemental material is available for this article. An earlier incorrect version of this article appeared online. This article was corrected on September 15, 2017.

The Importance of Accurate Diagnosis of ME/CFS in Children and Adolescents: A Commentary.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic illness that causes a range of debilitating symptoms. While most research has focused on adults, the illness also presents in children and adolescents. Many physicians find it difficult to diagnose the illness. In this commentary paper, we discuss a range of salient themes that have emerged from our ongoing research into the prevalence of ME/CFS in children and adolescents. We discuss reasons why pediatric prevalence estimates vary widely in the literature, from almost 0% to as high as 3%. We argue that there is considerable misdiagnosis of pediatric cases and over-inflation of estimates of pediatric ME/CFS. Many children and teenagers with general fatigue and other medical complaints may meet loose diagnostic criteria for ME/CFS. We make recommendations for improving epidemiological research and identifying pediatric ME/CFS in clinical practice.

Inflammatory Monocytes Promote Perineural Invasion via CCL2-Mediated Recruitment and Cathepsin B Expression.

Perineural invasion (PNI) is an ominous event strongly linked to poor clinical outcome. Cells residing within peripheral nerves collaborate with cancer cells to enable PNI, but the contributing conditions within the tumor microenvironment are not well understood. Here, we show that CCR2-expressing inflammatory monocytes (IM) are preferentially recruited to sites of PNI, where they differentiate into macrophages and potentiate nerve invasion through a cathepsin B-mediated process. A series of adoptive transfer experiments with genetically engineered donors and recipients demonstrated that IM recruitment to nerves was driven by CCL2 released from Schwann cells at the site of PNI, but not CCL7, an alternate ligand for CCR2. Interruption of either CCL2-CCR2 signaling or cathepsin B function significantly impaired PNI in vivo Correlative studies in human specimens demonstrated that cathepsin B-producing macrophages were enriched in invaded nerves, which was associated with increased local tumor recurrence. These findings deepen our understanding of PNI pathogenesis and illuminate how PNI is driven in part by corruption of a nerve repair program. Further, they support the exploration of inhibiting IM recruitment and function as a targeted therapy for PNI. Cancer Res; 77(22); 6400-14. ©2017 AACR.

Innate Lymphocyte/Ly6C(hi) Monocyte Crosstalk Promotes Klebsiella Pneumoniae Clearance.

Increasing antibiotic resistance among bacterial pathogens has rendered some infections untreatable with available antibiotics. Klebsiella pneumoniae, a bacterial pathogen that has acquired high-level antibiotic resistance, is a common cause of pulmonary infections. Optimal clearance of K. pneumoniae from the host lung requires TNF and IL-17A. Herein, we demonstrate that inflammatory monocytes are rapidly recruited to the lungs of K. pneumoniae-infected mice and produce TNF, which markedly increases the frequency of IL-17-producing innate lymphoid cells. While pulmonary clearance of K. pneumoniae is preserved in neutrophil-depleted mice, monocyte depletion or TNF deficiency impairs IL-17A-dependent resolution of pneumonia. Monocyte-mediated bacterial uptake and killing is enhanced by ILC production of IL-17A, indicating that innate lymphocytes engage in a positive-feedback loop with monocytes that promotes clearance of pneumonia. Innate immune defense against a highly antibiotic-resistant bacterial pathogen depends on crosstalk between inflammatory monocytes and innate lymphocytes that is mediated by TNF and IL-17A.

TLR-7 activation enhances IL-22-mediated colonization resistance against vancomycin-resistant enterococcus.

Antibiotic administration can disrupt the intestinal microbiota and down-regulate innate immune defenses, compromising colonization resistance against orally acquired bacterial pathogens. Vancomycin-resistant Enterococcus faecium (VRE), a major cause of antibiotic-resistant infections in hospitalized patients, thrives in the intestine when colonization resistance is compromised, achieving extremely high densities that can lead to bloodstream invasion and sepsis. Viral infections, by mechanisms that remain incompletely defined, can stimulate resistance against invading bacterial pathogens. We report that murine norovirus infection correlates with reduced density of VRE in the intestinal tract of mice with antibiotic-induced loss of colonization resistance. Resiquimod (R848), a synthetic ligand for Toll-like receptor 7 (TLR-7) that stimulates antiviral innate immune defenses, restores expression of the antimicrobial peptide Reg3γ and reestablishes colonization resistance against VRE in antibiotic-treated mice. Orally administered R848 triggers TLR-7 on CD11c(+) dendritic cells, inducing interleukin-23 (IL-23) expression followed by a burst of IL-22 secretion by innate lymphoid cells, leading to Reg3γ expression and restoration of colonization resistance against VRE. Our findings reveal that an orally bioavailable TLR-7 ligand that stimulates innate antiviral immune pathways in the intestine restores colonization resistance against a highly antibiotic-resistant bacterial pathogen.

Hepatitis B Virus--Specific and Global T-Cell Dysfunction in Chronic Hepatitis B.

BACKGROUND & AIMS: T cells play a critical role in viral infection. We examined whether T-cell effector and regulatory responses can define clinical stages of chronic hepatitis B (CHB). METHODS: We enrolled 200 adults with CHB who participated in the National Institutes of Health-supported Hepatitis B Research Network from 2011 through 2013 and 20 uninfected individuals (controls). Peripheral blood lymphocytes from these subjects were analyzed for T-cell responses (proliferation and production of interferon gamma and interleukin 10) to overlapping hepatitis B virus (HBV) peptides (preS, S, preC, core, and reverse transcriptase), influenza matrix peptides, and lipopolysaccharide. T-cell expression of regulatory markers FOXP3, programmed death-1, and cytotoxic T lymphocyte-associated antigen-4 was examined by flow cytometry. Immune measures were compared with clinical parameters, including physician-defined immune-active, immune-tolerant, or inactive CHB phenotypes, in a blinded fashion. RESULTS: Compared with controls, patients with CHB had weak T-cell proliferative, interferon gamma, and interleukin 10 responses to HBV, with increased frequency of circulating FOXP3(+)CD127(-) regulatory T cells and CD4(+) T-cell expression of programmed death-1 and cytotoxic T lymphocyte-associated antigen-4. T-cell measures did not clearly distinguish between clinical CHB phenotypes, although the HBV core-specific T-cell response was weaker in hepatitis B e antigen (HBeAg)(+) than HBeAg(-) patients (percent responders: 3% vs 23%; P = .00008). Although in vitro blockade of programmed death-1 or cytotoxic T lymphocyte-associated antigen-4 increased T-cell responses to HBV, the effect was weaker in HBeAg(+) than HBeAg(-) patients. Furthermore, T-cell responses to influenza and lipopolysaccharide were weaker in CHB patients than controls. CONCLUSIONS: HBV persists with virus-specific and global T-cell dysfunction mediated by multiple regulatory mechanisms, including circulating HBeAg, but without distinct T-cell-based immune signatures for clinical phenotypes. These findings suggest additional T-cell-independent or regulatory mechanisms of CHB pathogenesis that warrant further investigation.

17α-Ethynylestradiol-3-sulfate treatment of severe blood loss in rats.

BACKGROUND: From 2001-2011, >80% of potentially survivable United States battlefield deaths were due to severe hemorrhage. We subjected male rats to acute severe blood loss, administered a single dose of 17α-ethynylestradiol-3-sulfate (EE-3-SO4) without resuscitative fluids, and measured survival and also mean arterial pressures (MAP). METHODS: After controlled removal of 60% circulating blood volume (10-11 mL) over approximately 45 min, rats received EE-3-SO4 at 0 (vehicle controls), 0.1, 0.3, 1.0, or 3.0 mg/kg in 40 µL/100 g BW saline intravenously. MAP was recorded for 40 min after drug administration and survival was recorded for 6 h. RESULTS: The dose response curve was bell shaped with optimum survival at 1 mg/kg EE-3-SO4. Median survival times of rats receiving 1 mg/kg (360 min) were approximately 6 times that of the control group (57 min): P = 0.0001. The number of animals alive at 6 h was 16 of 20 (80%) in the 1 mg/kg group versus 0 of 20 (0%) in the control group. Early increases in MAP correlated with longer survival times. CONCLUSIONS: Administration of a single dose of 1 mg/kg EE-3-SO4 in 0.4 mL/kg of saline after controlled severe hemorrhage increased survival in rats by 6-fold. Partial recovery of blood pressure values correlated with longer survival time. These results, coupled with similar findings in a companion study in minipigs, support the further product development of EE-3-SO4 for: (1) severe hemorrhage when standard resuscitative fluids are not available, and (2) situations in which prolonged transportation periods are required for definitive treatment of the injured.

Transfusion related morbidity in premature babies: Possible mechanisms and implications for practice.

Many premature babies, especially those with a low birth weight are given multiple transfusions during their first few weeks of life. The major serious complications of prematurity include bronchopulmonary dysplasia, with lesser incidences of retinopathy of prematurity, intraventricular haemorrhage, and necrotising enterocolitis. Many studies have shown correlations between the receipt of blood transfusions and the development of these conditions, but little is known of the underlying pathophysiology of this relationship. Recent studies are beginning to provide some answers. This review examines recent findings with regard to the influence of preparation and storage of paediatric packed red blood cell units on heme, iron, and oxidative status of the units and relates these to the ability of the premature baby to deal with these changes following the receipt of blood transfusions. Paediatric packed red blood cell units are a potential source of heme, redox active iron and free radicals, and this increases with storage age. Haemolysis of transfused red blood cells may add further iron and cell free haemoglobin to the recipient baby. Premature babies, particularly those with low birth weight and gestational age appear to have little reserve to cope with any additional iron, heme and/or oxidative load. The consequences of these events are discussed with regard to their contribution to the major complications of prematurity and a novel hypothesis regarding transfusion-related morbidity in premature babies is presented. The review concludes with a discussion of potential means of limiting transfusion related iron/heme and oxidative load through the preparation and storage of packed red blood cell units and through modifications in clinical practice.