Ductus Arteriosus of Extremely Preterm Twins is More Resistant to Cyclooxygenase Inhibitors Than Those of Singletons.

Symptomatic patent ductus arteriosus (sPDA) is common among preterm infants, and can lead to several complications. This is particularly true for extremely preterm infants, as closure of the ductus arteriosus using cyclooxygenase inhibitors is often difficult. A recent study using a preterm sheep model showed that intimal thickening-required for anatomical closure of the ductus arteriosus-is less developed in twins than in singletons. Therefore, this study primarily aimed to prove that the ductus arteriosus of extremely preterm twins is more resistant to cyclooxygenase inhibitors than those of extremely preterm singletons. Its secondary aim was to assess whether the resistance against cyclooxygenase inhibitors differed according to chorionicity. In this retrospective case-control study, medical records of 162 extremely preterm infants (gestational age < 28 weeks) were reviewed, and the treatment course of sPDA was subsequently compared between singletons (n = 131) and twins (n = 31). The median indomethacin doses for sPDA and the necessity for surgical ligation were significantly higher in twins than in singletons (5 vs 2 [p < 0.001] and 42% vs 21% [p = 0.018], respectively). No significant differences in sPDA treatment, including the number of indomethacin doses and the necessity for surgical ligation, were observed between monochorionic diamniotic and dichorionic diamniotic twins. This study confirms that the ductus arteriosus of extremely preterm twins is more resistant to cyclooxygenase inhibitors than those of singletons. However, there was no significant difference in sPDA treatment by chorionicity.

Safety of Conservative Approach for Persistent Patent Ductus Arteriosus in Preterm Infants: Neurodevelopmental Outcomes at 5 Years of Age.

Patent ductus arteriosus (PDA) is a common problem among preterm infants. The standard of care for PDA has been to attempt to close the PDA by pharmacological treatment or surgical ligation. Recently, conservative approach for PDA (i.e., infants receive no treatment for PDA unless it is necessary for rescue) is gaining interest. However, when PDA is persisted under the conservative approach, there is a concern about the neurodevelopmental problems caused by decreased cerebral oxygenation. Our objective was to examine the risk of neurodevelopmental impairment in preterm infants, when PDA remained persistently open under conservative approach for PDA. We retrospectively analyzed data from the medical charts in 72 included infants (gestational age < 29 weeks, birth weight < 1,250 g). Under our conservative approach for PDA, we divided infants by their ductal patency: a closed ductus group (ductus closure within 14 days after birth, n = 52) and a persistent patent ductus arteriosus group (ductus closure after 14 days, n = 20). We compared the clinical parameters and neurodevelopmental outcomes assessed with the Kaufman Assessment Battery for Children (K-ABC) at 5 years of corrected age in two groups. Among the children who completed the K-ABC test, there were no significant differences in neurodevelopmental scores between a closed ductus group (n = 44) and a persistent patent ductus arteriosus group (n = 17). A conservative approach for PDA, even in the case of prolonged PDA, does not increase the risk of neurodevelopmental impairment at 5 years of corrected age in preterm infants.

Relationship Between Physical Fitness at the End of Preseason and the Inseason Game Performance in Japanese Female Professional Baseball Players.

Watanabe, Y, Yamada, Y, Yoshida, T, Matsui, T, Seo, K, Azuma, Y, Hiramoto, M, Miura, Y, Fukushima, H, Shimazu, A, Eto, T, Saotome, H, Kida, N, and Morihara, T. Relationship between physical fitness at the end of preseason and the inseason game performance in Japanese female professional baseball players. J Strength Cond Res 33(6): 1580-1588, 2019-This study examined anthropometric and fitness profiles of Japanese female professional baseball players and investigated the relationship between players' physical fitness and inseason game performance. Fifty-seven players who were registered in the Japan Women's Baseball League (JWBL) participated. Height, body mass, grip strength, back strength, knee extension and flexion strength, hamstring extensibility, vertical jump height, and horizontal jump distance were measured at preseason (February and March) in 2013. Game performance during the 2013 season (March-November) was obtained from official JWBL statistics. Vertical jump height showed significant positive correlations with individual performance records (e.g., total bases [r = 0.551], slugging percentage [r = 0.459], and stolen bases [r = 0.442]). Similar relationships were observed between horizontal jump distance and performance statistics in most cases. By contrast, grip, back, and lower-limb strength, as well as hamstring extensibility were not significantly correlated with game performance. Stepwise regression analysis selected vertical jump height as an independent variable, significantly correlating with several game performance measures (e.g., total bases: adjusted R = 0.257). Also, vertical jump height and body mass index were identified as independent variables significantly associated with stolen bases (adjusted R = 0.251). Maximal jump performance, rather than simple isometric muscle strength or flexibility, is a good performance test that can be used at the end of preseason to predict inseason batting and stolen base performance. Our findings demonstrate the importance of constructing preseason training programs to enhance lower-limb muscular power that is linked to successful inseason performance in female baseball players.

Successful maintenance of key physiological parameters in preterm lambs treated with ex vivo uterine environment therapy for a period of 1 week.

BACKGROUND: Extremely preterm infants born at the border of viability (22-24 weeks' gestation) have high rates of death and lasting disability. Ex vivo uterine environment therapy is an experimental neonatal intensive care strategy that provides gas exchange using parallel membranous oxygenators connected to the umbilical vessels, sparing the extremely preterm cardiopulmonary system from ventilation-derived injury. OBJECTIVE: In this study, we aimed to refine our ex vivo uterine environment therapy platform to eliminate fetal infection and inflammation, while simultaneously extending the duration of hemodynamically stable ex vivo uterine environment therapy to 1 week. STUDY DESIGN: Merino-cross ewes with timed, singleton pregnancies were surgically delivered at 112-115 days of gestation (term is ∼150 days) and adapted to ex vivo uterine environment therapy (treatment group; n = 6). Physiological variables were continuously monitored; humerus and femur length, ductus arteriosus directional flow, and patency were estimated with ultrasound; serial blood samples were collected for hematology and microbiology studies; weight was recorded at the end of the experiment. Control group animals (n = 7) were euthanized at 122 days of gestation and analyzed accordingly. Bacteremia was defined by positive blood culture. Infection and fetal inflammation was assessed with white blood cell counts (including differential leukocyte counts), plasma and lung proinflammatory cytokine measurements, and lung histopathology. RESULTS: Five of 6 fetuses in the treatment group completed the 1-week study period with key physiological parameters, blood counts remaining within normal ranges, and no bacteremia detected. There were no significant differences (P > .05) in arterial blood oxygen content or lactate levels between ex vivo uterine environment therapy and control groups at delivery. There was no significant difference (P > .05) in birthweight between control and ex vivo uterine environment groups. In the ex vivo uterine environment group, we observed growth of fetal humerus (P < .05) and femur (P < .001) over the course of the 7-day experimental period. There was no difference in airway or airspace morphology or consolidation between control and ex vivo uterine environment animals, and there was no increase in the number of lung cells staining positive for T-cell marker CD3+. CONCLUSION: Five preterm lambs were maintained in a physiologically stable condition for 1 week with significant growth and without clinically significant bacteremia or systemic inflammation. Although substantial further refinement is required, a life support platform based around ex vivo uterine environment therapy may provide an avenue to improve outcomes for extremely preterm infants.

Stable Control of Physiological Parameters, But Not Infection, in Preterm Lambs Maintained on Ex Vivo Uterine Environment Therapy.

Ex vivo uterine environment (EVE) therapy is an experimental neonatal intensive care strategy wherein gas exchange is performed by membranous oxygenators attached to the umbilical vessels. Our aim was to assess the ability of a newly refined EVE system to maintain key physiological parameters in preterm lambs within optimal ranges for 48 h. EVE group; n = 6: Preterm lambs were delivered under general anesthesia at 115 ± 2 days of gestational age. Animals were submerged in a bath of artificial amniotic fluid on EVE therapy for 48 h. Physiological parameters were monitored in real-time over the length of the experiment. Control group; n = 11: Ewes carrying a single fetus (115 ± 2 days of gestational age) underwent recovery surgery to allow placement of a fetal carotid artery catheter. Fetuses received an infusion of sterile saline only. After euthanasia, EVE and Control group fetuses underwent necroscopy to perform static pressure-volume curves and for sampling of lung and cord blood plasma for molecular analyses. Five out of six fetuses in the EVE group completed the study period with key physiological variables remaining within their respective reference ranges for the duration of the 48 h study. Bacteremia was identified in four out of five EVE fetuses, and was associated with a systemic inflammatory response. Using our refined EVE therapy platform, preterm lambs were maintained in a stable physiological condition for 48 h. These findings represent a significant advance over earlier work with this system; however, the identification of bacteremia and a fetal inflammatory response suggests that further refinement to the EVE therapy platform is required.

Brief mechanical ventilation causes differential epithelial repair along the airways of fetal, preterm lambs.

Mechanical ventilation of preterm lambs causes lung inflammation and injury to the airway epithelium, which is repaired by 15 days after ventilation. In mice, activated basal cells (p63+, KRT14+, KRT8+) initiate injury repair to the trachea, whereas club cells coordinate distal airway repair. In both human and sheep, basal cells line the pseudostratified airways to the distal bronchioles with club cells only present in terminal bronchioles. Mechanical ventilation causes airway epithelial injury that is repaired through basal cell activation in the fetal lung. Ewes at 123 ± 1 day gestational age had the head and chest of the fetus exteriorized and tracheostomy placed. With placental circulation intact, fetal lambs were mechanically ventilated with up to 15 ml/kg for 15 min with 95% N2/5% CO2 Fetal lambs were returned to the uterus for up to 24 h. The trachea, left mainstem bronchi, and peripheral lung were evaluated for epithelial injury and cellular response consistent with repair. Peripheral lung tissue had inflammation, pro-inflammatory cytokine production, epithelial growth factor receptor ligand upregulation, increased p63 expression, and proliferation of pro-SPB, TTF-1 positive club cells. In bronchi, KRT14 and KRT8 mRNA increased without increases in Notch pathway mRNA or proliferation. In trachea, mRNA increased for Notch ligands, SAM pointed domain-containing Ets transcription factor and mucin 5B, but not for basal cell markers. A brief period of mechanical ventilation causes differential epithelial activation between trachea, bronchi, and peripheral lung. The repair mechanisms identified in adult mice occur at different levels of airway branching in fetal sheep with basal and club cell activation.

Outside-in? Acute fetal systemic inflammation in very preterm chronically catheterized sheep fetuses is not driven by cells in the fetal blood.

BACKGROUND: The preterm birth syndrome (delivery before 37 weeks gestation) is a major contributor to the global burden of perinatal morbidity and death. The cause of preterm birth is complex, multifactorial, and likely dependent, at least in part, on the gestational age of the fetus. Intrauterine infection is frequent in preterm deliveries that occur at <32 weeks gestation; understanding how the fetus responds to proinflammatory insult will be an important step towards early preterm birth prevention. However, animal studies of infection and inflammation in prematurity commonly use older fetuses that possess comparatively mature immune systems. OBJECTIVE: Aiming to characterize acute fetal responses to microbial agonist at a clinically relevant gestation, we used 92-day-old fetuses (62% of term) to develop a chronically catheterized sheep model of very preterm pregnancy. We hypothesized that any acute fetal systemic inflammatory responses would be driven by signaling from the tissues exposed to Escherichia coli lipopolysaccharide that is introduced into the amniotic fluid. STUDY DESIGN: Eighteen ewes that were carrying a single fetus at 92 days of gestation had recovery surgery to place fetal tracheal, jugular, and intraamniotic catheters. Animals were recovered for 24 hours before being administered either intraamniotic E coli lipopolysaccharide (n = 9) or sterile saline solution (n = 9). Samples were collected for 48 hours before euthanasia and necroscopy. Fetal inflammatory responses were characterized by microarray analysis, quantitative polymerase chain reaction, and enzyme-linked immunosorbent assay. RESULTS: Intraamniotic lipopolysaccharide reached the distal trachea within 2 hours. Lipopolysaccharide increased tracheal fluid interleukin-8 within 2 hours and generated a robust inflammatory response that was characterized by interleukin-6 signaling pathway activation and up-regulation of cell proliferation but no increases in inflammatory mediator expression in cord blood RNA. CONCLUSIONS: In very preterm sheep fetuses, lipopolysaccharide stimulates inflammation in the fetal lung and fetal skin and stimulates a systemic inflammatory response that is not generated by fetal blood cells. These data argue for amniotic fluid-exposed tissues that play a key role in driving acute fetal and intrauterine inflammatory responses.

Maternofetal pharmacokinetics and fetal lung responses in chronically catheterized sheep receiving constant, low-dose infusions of betamethasone phosphate.

BACKGROUND: Antenatal steroids are standard of care for cases of anticipated preterm labor to improve neonatal outcomes. However, steroids are potent drugs, and their use in pregnancy remains largely unoptimized. OBJECTIVE: The objective of the study was to measure the maternofetal pharmacokinetics of constant, low-dose intravenous betamethasone phosphate infusions and correlate these data with the transcriptional effect exerted by subclinical betamethasone exposures on the ovine fetal lung. STUDY DESIGN: Thirty-two ewes carrying a single fetus had surgery to catheterize fetal and maternal jugular veins at 116 days of gestation (term, 150 days). Animals were recovered for 2 days and then were randomized to receive 2 sequential maternal intravenous infusions of either (n = 4/group) of the following: 1) saline, 0.125, 0.04, or 0.0125 mg/kg betamethasone phosphate over 3 hours; or 2) saline, 0.25, 0.08, or 0.025 mg/kg betamethasone phosphate over 12 hours. Each infusion was separated by 2 days. Fetal lung tissue was collected for analysis using quantitative polymerase chain reaction and an ovine-specific microarray. Plasma betamethasone levels from time-course catheter samples were determined by mass spectrometry. Data were assessed for distribution, variance, and tested by an analysis of variance. RESULTS: Betamethasone was detectable (>1 ng/mL) in fetal plasma only in animals randomized to 0.125 mg/kg 3 hour or 0.250 mg/kg 12 hour infusions. Fetal betamethasone half-lives were 1.7-2.8 times greater than maternal values. At maximum concentration, fetal plasma betamethasone levels were approximately 10% of maternal levels. Compared with saline control, all animals, other than those receiving 0.0125 mg/kg 3 hour betamethasone phosphate infusions, had evidence of dose-dependent glucocorticoid transcriptional responses in the fetal lung. CONCLUSION: Constant maternal betamethasone infusions delivering substantially lower fetal and maternal betamethasone maximal concentrations than those achieved with current clinical treatment protocols were associated with dose-dependent changes in glucocorticoid-response markers in the fetal lung. Further studies to determine the minimally efficacious dose of steroids for improving outcomes in preterm infants should be viewed as a priority.

A Parallelized Pumpless Artificial Placenta System Significantly Prolonged Survival Time in a Preterm Lamb Model.

An artificial placenta (AP) is an arterio-venous extracorporeal life support system that is connected to the fetal circulation via the umbilical vasculature. Previously, we published an article describing a pumpless AP system with a small priming volume. We subsequently developed a parallelized system, hypothesizing that the reduced circuit resistance conveyed by this modification would enable healthy fetal survival time to be prolonged. We conducted experiments using a premature lamb model to test this hypothesis. As a result, the fetal survival period was significantly prolonged (60.4 ± 3.8 vs. 18.2 ± 3.2 h, P < 0.01), and circuit resistance and minimal blood lactate levels were significantly lower in the parallel circuit group, compared with our previous single circuit group. Fetal physiological parameters remained stable until the conclusion of the experiments. In summary, parallelization of the AP system was associated with reduced circuit resistance and lactate levels and allowed preterm lamb fetuses to survive for a significantly longer period when compared with previous studies.

Fluconazole treatment of intrauterine Candida albicans infection in fetal sheep.

BACKGROUND: Intrauterine Candida albicans infection causes severe fetal inflammatory responses and fetal injury in an ovine model. We hypothesized that intra-amniotic antifungal therapy with fluconazole would decrease the adverse fetal effects of intra-amniotic C. albicans in sheep. METHODS: Sheep received an intra-amniotic injection of 10(7) colony-forming units C. albicans. After 2 d, animals were then randomized to: (i) intra-amniotic and fetal intraperitoneal saline with delivery after 24 h (3 d C. albicans group); (ii) intra-amniotic and fetal intraperitoneal injections of fluconazole with delivery after either 24 h (3 d C. albicans plus 1 d fluconazole group) or 72 h (5 d C. albicans plus 3 d fluconazole group). Controls received intra-amniotic injections of saline followed by intra-amniotic and fetal intraperitoneal fluconazole injections. RESULTS: Intra-amniotic C. albicans caused severe fetal inflammatory responses characterized by decreases in lymphocytes and platelets, an increase in posterior mediastinal lymph node weight and proinflammatory mRNA responses in the fetal lung, liver, and spleen. Fluconazole treatment temporarily decreased the pulmonary and chorioamnion inflammatory responses. CONCLUSION: The severe fetal inflammatory responses caused by intra-amniotic C. albicans infection were transiently decreased with fluconazole. A timely fetal delivery of antimicrobial agents may prevent fetal injury associated with intrauterine infection.

Diagnosis and Treatment of a Preterm Infant With Inoperable Congenital Hepatoblastoma--A Case Report.

Reports of hepatoblastoma (HB) in preterm infants are quite rare. Herein, we report the clinical management of a preterm infant with inoperable congenital HB. A female fetus that had been diagnosed with a large liver tumor consistent with hemangioma was delivered by emergency cesarean section at 33 weeks of gestation because of fetal distress. Effective antitumor therapy could not be performed, resulting in rapid deterioration and death. The postmortem histopathologic analysis confirmed the tumor as a HB. This report demonstrates the difficulties inherent in both the image diagnosis of HB and in providing efficacious treatments for preterm infants with HB.

Maternal intravenous administration of azithromycin results in significant fetal uptake in a sheep model of second trimester pregnancy.

Treatment of intrauterine infection is likely key to preventing a significant proportion of preterm deliveries before 32 weeks of gestation. Azithromycin (AZ) may be an effective antimicrobial in pregnancy; however, few gestation age-approriate data are available to inform the design of AZ-based treatment regimens in early pregnancy. We aimed to determine whether a single intra-amniotic AZ dose or repeated maternal intravenous (i.v.) AZ doses would safely yield therapeutic levels of AZ in an 80-day-gestation (term is 150 days) ovine fetus. Fifty sheep carrying single pregnancies at 80 days gestation were randomized to receive either: (i) a single intra-amniotic AZ administration or (ii) maternal intravenous AZ administration every 12 h. Amniotic fluid, maternal plasma, and fetal AZ concentrations were determined over a 5-day treatment regimen. Markers of liver injury and amniotic fluid inflammation were measured to assess fetal injury in response to drug exposure. A single intra-amniotic administration yielded significant AZ accumulation in the amniotic fluid and fetal lung. In contrast, repeated maternal intravenous administrations achieved high levels of AZ accumulation in the fetal lung and liver and a statistically significant increase in the fetal plasma drug concentration at 120 h. There was no evidence of fetal injury in response to drug exposure. These data suggest that (i) repeated maternal i.v. AZ dosing yields substantial fetal tissue uptake, although fetal plasma drug levels remain low; (ii) transfer of AZ from the amniotic fluid is less than transplacental transfer; and (iii) exposure to high concentrations of AZ did not elicit overt changes in fetal white blood cell counts, amniotic fluid monocyte chemoattractant protein 1 concentrations, or hepatotoxicity, all consistent with an absence of fetal injury.

Maternal intravenous treatment with either azithromycin or solithromycin clears Ureaplasma parvum from the amniotic fluid in an ovine model of intrauterine infection.

Intrauterine infection with Ureaplasma spp. is strongly associated with preterm birth and adverse neonatal outcomes. We assessed whether combined intraamniotic (IA) and maternal intravenous (IV) treatment with one of two candidate antibiotics, azithromycin (AZ) or solithromycin (SOLI), would eradicate intrauterine Ureaplasma parvum infection in a sheep model of pregnancy. Sheep with singleton pregnancies received an IA injection of U. parvum serovar 3 at 85 days of gestational age (GA). At 120 days of GA, animals (n=5 to 8/group) received one of the following treatments: (i) maternal IV SOLI with a single IA injection of vehicle (IV SOLI only); (ii) maternal IV SOLI with a single IA injection of SOLI (IV+IA SOLI); (iii) maternal IV AZ and a single IA injection of vehicle (IV AZ only); (iv) maternal IV AZ and a single IA injection of AZ (IV+IA AZ); or (v) maternal IV and single IA injection of vehicle (control). Lambs were surgically delivered at 125 days of GA. Treatment efficacies were assessed by U. parvum culture, quantitative PCR, enzyme-linked immunosorbent assay, and histopathology. Amniotic fluid (AF) from all control animals contained culturable U. parvum. AF, lung, and chorioamnion from all AZ- or SOLI-treated animals (IV only or IV plus IA) were negative for culturable U. parvum. Relative to the results for the control, the levels of expression of interleukin 1ß (IL-1ß), IL-6, IL-8, and monocyte chemoattractant protein 2 (MCP-2) in fetal skin were significantly decreased in the IV SOLI-only group, the MCP-1 protein concentration in the amniotic fluid was significantly increased in the IV+IA SOLI group, and there was no significant difference in the histological inflammation scoring of lung or chorioamnion among the five groups. In the present study, treatment with either AZ or SOLI (IV only or IV+IA) effectively eradicated macrolide-sensitive U. parvum from the AF. There was no discernible difference in antibiotic therapy efficacy between IV-only and IV+IA treatment regimens relative to the results for the control.

Repeated maternal intramuscular or intraamniotic erythromycin incompletely resolves intrauterine Ureaplasma parvum infection in a sheep model of pregnancy.

OBJECTIVE: Ureaplasma spp are the most commonly isolated microorganisms in association with preterm birth. Maternal erythromycin administration is a standard treatment for preterm prelabor rupture of membranes. There is little evidence of its effectiveness in eradicating Ureaplasma spp from the intrauterine cavity and fetus. We used a sheep model of intrauterine Ureaplasma spp infection to investigate the efficacy of repeated maternal intramuscular and intraamniotic erythromycin treatment to eradicate such an infection. STUDY DESIGN: Thirty ewes with singleton pregnancies received an intraamniotic injection of 10(7) color change units of erythromycin-sensitive Ureaplasma parvum serovar 3 at 55 days' gestation. At 116 days' gestation, 28 ewes with viable fetuses were randomized to receive (1) intraamniotic and maternal intramuscular saline solution treatment (n = 8), (2) single intraamniotic and repeated maternal intramuscular erythromycin treatment (n = 10), or (3) single maternal intramuscular and repeated intraamniotic erythromycin treatment (n = 10). Fetuses were surgically delivered at 125 days' gestation. Treatment efficacy was assessed by culture, quantitative polymerase chain reaction, and histopathologic evaluation. RESULTS: Animals treated with intraamniotic erythromycin had significantly less viable U parvum serovar 3 in the amniotic fluid at delivery. However, neither combination of maternal intramuscular and intraamniotic erythromycin treatment successfully cleared U parvum serovar 3 from the amniotic fluid or fetal tissues. Three de novo erythromycin-resistant U parvum isolates were identified in erythromycin-treated animals. CONCLUSION: Erythromycin treatment, given both to the ewe and into the amniotic cavity, fails to eradicate intrauterine and fetal U parvum serovar 3 infection and may lead to development of erythromycin resistant U parvum.

Intrauterine Candida albicans infection elicits severe inflammation in fetal sheep.

BACKGROUND: Preventing preterm birth and subsequent adverse neonatal sequelae is among the greatest clinical challenges of our time. Recent studies suggest a role for Candida spp. in preterm birth and fetal injury, as a result of their colonization of either the vagina and/or the amniotic cavity. We hypothesized that intraamniotic Candida albicans would cause a vigorous, acute fetal inflammatory response. METHODS: Sheep carrying singleton pregnancies received single intraamniotic injections of either saline (control) or 10(7) colony-forming units C. albicans 1 or 2 d prior to surgical delivery and euthanasia at 124 ± 2 d gestation. RESULTS: Colonization of the amniotic cavity by C. albicans resulted in a modest inflammatory response at 1 d and florid inflammation at 2 d, characterized by fetal thrombocytopenia, lymphopenia, and significant increases of inflammatory cytokines/chemokines in the fetal membranes skin, lung, and the amniotic fluid. CONCLUSION: Acute colonization of the amniotic cavity by C. albicans causes severe intrauterine inflammation and fetal injury. C. albicans is a potent fetal pathogen that can contribute to adverse pregnancy outcomes.

Novel modification of an artificial placenta: pumpless arteriovenous extracorporeal life support in a premature lamb model.

BACKGROUND: Previous studies aimed at developing an artificial placenta have had limited success. We hypothesized that the introduction of a high-performance membranous oxygenator to a pumpless artificial placenta could prolong the survival time of premature lambs. METHODS: Immediately after delivery of the fetuses, the umbilical vessels were cannulated and connected to the pumpless artificial placenta. Both the fetuses and the circuit were submerged in a warm saline bath. RESULTS: Five fetuses survived for 18.2 ± 3.2 (mean ± SEM) h after attachment to the artificial placenta, which maintained fetal circulation. Circuit blood flow was positively correlated with mean arterial pressure and negatively correlated with blood lactate levels. Milrinone administration transiently decreased lactate levels, although dopamine administration unexpectedly induced a marked increase in the lactate levels despite an elevated arterial pressure and improved circuit blood flow. CONCLUSION: We prolonged the survival of fetal lambs using a high-performance membranous oxygenator with a small priming volume. The increased systemic resistance induced by vasoconstrictors may increase the circuit blood flow excessively, resulting in circulation failure in systemic organs; therefore, vasodilators may be more useful than vasoconstrictors for maintaining organ blood flow within this circuit.

Clinical and Bacteriologic Characteristics of Six Cases of Bifidobacterium breve Bacteremia Due to Probiotic Administration in the Neonatal Intensive Care Unit.

BACKGROUND: Bifidobacterium breve is widely used as a probiotic in preterm infants and children with congenital surgical conditions, however, some cases of probiotics-induced bacteremia have been reported recently. OBJECTIVES: To examine the clinical and bacteriologic features of Bifidobacterium breve bacteremia caused by a probiotic (BBG-01) in term and preterm infants. METHODS: We included 298 patients who were admitted to the neonatal intensive care unit of Miyagi Children's Hospital and were given BBG-01 as a probiotic within the period June 2014 to February 2019. We experienced six cases of B. breve bacteremia and assessed their features retrospectively. RESULTS: The incidence rate of B. breve bacteremia in our hospital was 2% (6/298), higher than reported previously. The median age at onset, corrected age, and weight of the patients was 8 days (range: 5-27 days), 35 weeks (range: 26-39 weeks), and 1,940 g (range: 369-2734 g), respectively. The bacteremia triggers were gastrointestinal perforations in two cases, food protein-induced enterocolitis syndrome in two cases, adhesive ileus in one case, ileal volvulus in one case, and aspiration pneumonia following esophageal atresia repair in one case. B. breve was detected on blood cultures after a median of 5 days 13 hours (range: 4 days 18 hours-9 days 13 hours). No patient demonstrated serious symptoms, such as septic shock. All patients received antibiotics and recovered without any sequelae. CONCLUSIONS: Ileus and intestinal mucosal damage, such as enteritis, can cause B. breve bacteremia. The incidence of B. breve bacteremia may be higher than reported previously and detection via culture may require a longer time than typically needed for more common bacteria. It is associated with a good prognosis.

A novel PHOX2B gene mutation in an extremely low birth weight infant with congenital central hypoventilation syndrome and variant Hirschsprung's disease.

Congenital central hypoventilation syndrome is a disorder of respiratory control caused by mutations in the paired-like homeobox 2B gene. Mutations in the paired-like homeobox 2B gene are also responsible for Hirschsprung's disease. Variant Hirschsprung's disease is a rarer disorder that does not meet the diagnostic criteria of Hirschsprung's disease, although severe functional bowel obstruction persists. We present a case of an extremely low birth weight infant with congenital central hypoventilation syndrome and variant Hirschsprung's disease. A male infant who was diagnosed to have fetal growth restriction and polyhydramnios was delivered by emergency cesarean section at 30 weeks and 3 days of gestational age due to non-reassuring fetal status. The birth weight was 979 g, and intensive care was started immediately following delivery. The patient exhibited refractory apnea and was diagnosed with congenital central hypoventilation syndrome by genetic testing of the paired-like homeobox 2B gene. The patient also exhibited refractory functional bowel obstruction and was diagnosed to have variant Hirschsprung's disease through pathological examination of his intestinal specimens. The patient grew slowly but surely with intensive care including mechanical ventilation and parenteral nutrition. However, the patient repeatedly suffered from sepsis and died of fungemia at 197 days of age. This is the first congenital central hypoventilation syndrome case that was accompanied with variant Hirschsprung's disease, and the paired-like homeobox 2B mutation detected in this case (NM_003924.3: c.441G > C; p.(Gln147His)) is novel. This case suggests that the paired-like homeobox 2B mutation causes not only congenital central hypoventilation syndrome and Hirschsprung's disease, but also variant Hirschsprung's disease in humans. It also highlights the extreme difficulty in treating premature infants with severe and prolonged functional bowel obstruction.

Antenatal Corticosteroid Exposure Disrupts Myelination in the Auditory Nerve of Preterm Sheep.

BACKGROUND: Antenatal corticosteroids (ACS) improve preterm neonatal outcomes. However, uncertainty remains regarding the safety of ACS exposure for the developing fetus, particularly its neurosensory development. OBJECTIVES: We investigated the effect of single and multiple ACS exposures on auditory nerve development in an ovine model of pregnancy. METHODS: Ewes with a single fetus (gestational age [GA] 100 days) received an intramuscular injection of 150 mg medroxyprogesterone-acetate, followed by intramuscular (i) betamethasone (0.5 mg/kg) on days 104, 111, and 118 GA; (ii) betamethasone on day 104 and saline on days 111 and 118 GA; or (iii) saline on days 104, 111, and 118 GA, with delivery on day 125 GA. Transmission electron microscope images of lamb auditory nerve preparations were digitally analyzed to determine auditory nerve morphology and myelination. RESULTS: Relative to the control, mean auditory nerve myelin area was significantly increased in the multiple-treatment group (p < 0.001), but not in the single-treatment group. Increased myelin thickness was significantly changed only in a subgroup analysis for those axons with myelin thickness greater than the median value (p < 0.001). Morphological assessments showed that the increased myelin area was due to an increased likelihood of decompacted areas (p = 0.005; OR = 2.14, 95% CI 1.26-3.63; 31.6 vs. 18.2% in controls) and irregular myelin deposition (p = 0.001; OR = 5.91, 95% CI 2.16-16.19; 49.0 vs. 16.8% in controls) in the myelin sheath. CONCLUSIONS: In preterm sheep, ACS exposure increased auditory nerve myelin area, potentially due to disruption of normal myelin deposition.