Oxidative and Inflammatory Markers Are Higher in Full-Term Newborns Suffering Funisitis, and Higher Oxidative Markers Are Associated with Admission.

The aim of this study was to assess whether oxidative and inflammatory mediators in the cord blood of newborns with funisitis and chorioamnionitis can serve as indicators of their inflammatory status, and whether there is a positive association between higher mediator levels and an increased risk of admission to the neonatal intensive care unit (NICU). This study was conducted prospectively in a neonatology department of a university hospital. In total, 52 full-term newborns were evaluated, including 17 funisitis cases, 13 chorioamnionitis cases, and 22 control newborns without funisitis or chorioamnionitis. Cord blood samples were measured for oxidative stress and inflammatory status markers. The oxidative stress markers included the total nitric oxide (NO), total hydroperoxide (TH), biological antioxidant potential (BAP), and TH/BAP ratio, comprising the oxidative stress index (OSI). Inflammatory markers included interleukin (IL)-1b, IL-6, IL-8, IL-10, tumor necrosis factor alpha (TNFα), interferon γ (IFNγ), and complement component C5a. TH, OSI, IL-1b, IL-6, and IL-8 concentrations were higher in the funisitis group than in the chorioamnionitis and control groups. C5a was higher in the funisitis and chorioamnionitis groups than in the control group. Among all enrolled newborns, 14 were admitted to the NICU. Multiple logistic regression analysis showed that elevated umbilical cord blood levels of OSI and TH were associated with a higher risk of admission to the NICU (OSI: R = 2.3, 95% CI 1.26-4.29, p = 0.007 and TH: R = 1.02, 95%CI = 1.004-1.040, p = 0.015). In conclusion, OSI and TH in cord blood from full-term newborns can provide an index of inflammatory status, and higher levels are associated with the risk of admission to the NICU and, therefore, could serve as an early indicator of inflammatory conditions in newborns.

Standardization of phototherapy for neonatal hyperbilirubinemia using multiple-wavelength irradiance integration.

BACKGROUND: Phototherapy with radiation of 460-490 nm wavelengths provides the most potent therapeutic effect for neonatal jaundice. However, the efficacy of phototherapy has been estimated using single-wavelength detectors with sensitivity at approximately 460 nm. Cyclobilirubin formation capacity (CFC), which comprises the sum of the irradiance values from three wavelengths multiplied by their specific coefficients, has been proposed as an alternative marker to evaluate the efficacy of phototherapy. This study aimed to test whether two types of phototherapy devices with distinct spectral characteristics provide similar therapeutic effects on adjustment of device-to-patient distances to deliver similar CFCs. METHODS: Using a three-wavelength spectroradiometer, CFCs and footprints of the light-emitting diode and fluorescent tube devices were assessed. Having determined the device-specific distances that ensured similar CFCs, 32 newborn infants, requiring phototherapy for hyperbilirubinemia, were randomized into the light-emitting diode and fluorescent tube groups. The total serum bilirubin levels before and after phototherapy were assessed. RESULTS: The light-emitting diode and fluorescent tube devices had comparable CFCs at distances of 60 and 50 cm, respectively. Phototherapy reduced the total serum bilirubin levels from 18.1 to 14.6 mg/dL and from 19.1 to 15.1 mg/dL in the light-emitting diode and fluorescent tube groups, respectively. The two groups did not differ significantly with respect to the patients' clinical backgrounds, serum bilirubin levels, or changes before and after phototherapy. CONCLUSION: At similar CFCs, the two phototherapy devices reduced the total serum bilirubin levels by comparable amounts. Hence, determining CFCs may help predict phototherapy efficacy. This may ensure better safety and greater efficacy of the treatment for newborn infants.

Efficacy of inhaled nitric oxide in neonates with hypoxic respiratory failure and pulmonary hypertension: the Japanese experience.

OBJECTIVE: To analyze data from a registry of Japanese neonates with hypoxic respiratory failure associated with pulmonary hypertension (PH) to compare the effectiveness of inhaled nitric oxide (iNO) in neonates born <34 weeks vs. ≥34 weeks gestational age (GA). MATERIALS AND METHODS: iNO was administered according to approved Japanese product labeling. Study data were collected before iNO administration and at predefined intervals until discontinuation. RESULTS: A total of 1,114 neonates were included (n=431, <34 weeks GA; n=675, ≥34 weeks GA; n=8, missing age data). Mean decrease from baseline oxygenation index (OI) was similar in both age groups. OI reduction was more pronounced in the <34 weeks subgroups with baseline OI ≥25. Survival rates were similar in the <34 weeks GA and ≥34 weeks GA groups stratified by baseline OI (OI<15, 89% vs. 93%; 15≤OI<25, 85% vs. 91%; 25≤OI≤40, 73% vs. 79%; OI>40, 64% vs. 66%). CONCLUSION: iNO improved oxygenation in preterm neonates as effectively as in late preterm and term neonates, without negative impact on survival. If clinically significant PH is present, as measured by pulse oximetry or echocardiography, a therapeutic trial of iNO might be indicated for preterm neonates.

Endothelin receptor antagonist attenuates oxidative stress in a neonatal sepsis piglet model.

BACKGROUND: Oxidative stress (oxidant-antioxidant imbalance) plays an important role in the pathophysiology of neonatal sepsis. This study evaluated whether an antisense peptide endothelin receptor antagonist, ETR-P1/fl, could attenuate oxidative stress in a neonatal sepsis model. METHODS: A total of 18 3-d-old piglets were anesthetized and mechanically ventilated. Six piglets received cecal ligation and perforation (CLP group) for induction of sepsis. Six piglets also received continuous infusion (0.05 mg/kg/h) of ETR-P1/fl 30 min after CLP (ETR-P1/fl group). Six piglets received a sham operation. Serum total hydroperoxide (TH), biological antioxidant potentials (BAPs), oxidative stress index (OSI, calculated as TH/BAP), interleukin (IL)-6, serum glutamic oxaloacetic transaminase (GOT), and creatinine were measured before CLP and at 1, 3, and 6 h after CLP. RESULTS: CLP evoked a state of shock resulting in elevated TH, OSI, and IL-6 levels. ETR-P1/fl administration after CLP resulted in lower serum TH at 1 and 3 h after CLP, OSI at 1 and 3 h after CLP, IL-6 at 1 and 3 h after CLP, and GOT at 3 and 6 h after CLP as compared with the CLP group. CONCLUSION: ETR-P1/fl treatment significantly attenuated the elevation of serum oxidative stress markers (TH and OSI), IL-6, and GOT in a progressive neonatal sepsis CLP model.

Periventricular leukomalacia is decreasing in Japan.

Periventricular leukomalacia is recognized as the leading cause of cerebral palsy in preterm infants. To clarify the prevalence of periventricular leukomalacia and cerebral palsy in Japan, a nationwide survey was performed. The prevalence of periventricular leukomalacia in the group of surviving preterm infants of gestational ages less than 33 weeks born in 2007 was 2.7% (78/2883) on ultrasound diagnosis, and 3.3% (92/2824) on magnetic resonance imaging. The prevalence of cerebral palsy was 4.3% (125/2883) on clinical diagnosis. In our previous study, the prevalences of periventricular leukomalacia in 1990-1991, 1993-1994, 1996, and 1999 were 4.8%, 4.9%, 4.9%, and 5.3% on ultrasound, and 7.9%, 7.7%, 6.9%, and 7.3% on magnetic resonance imaging, respectively. The prevalence of periventricular leukomalacia has decreased significantly in Japan.

Brain atrophy caused by vitamin B12-deficient anemia in an infant.

Vitamin B12 deficiency in infants often presents with nonspecific hematological, gastrointestinal, and neurological manifestations. It is usually caused by inadequate intake, abnormal absorption, or congenital disorders of vitamin B12 metabolism, including transport disorders. We describe a vitamin B12-deficient infant with severe anemia who was breastfed. His mother had undiagnosed vitamin B12 deficiency having undergone total gastrectomy 18 years earlier. The infant developed normally after taking vitamin B12. It is important to suspect vitamin B12 deficiency in mothers who have undergone gastrectomy. Early diagnosis and treatment of vitamin B12 deficiency in infants is important and will help improve long-term prognosis.

Edaravone, a hydroxyl radical scavenger, ameliorates the severity of pulmonary hypertension in a porcine model of neonatal sepsis.

Systemic infection in the newborn (neonatal sepsis) is the most common cause of neonatal mortality. Neonatal sepsis is complicated by pulmonary hypertension. In this study, we analyzed the effect of edaravone, a free radical scavenger that is known to reduce the production of inflammatory mediators, such as tumor necrosis factor α (TNFα), on pulmonary hypertension. Experimental and sham groups were drawn from 19 three-day-old piglets; 5 underwent a modified procedure of cecal ligation and perforation (CLP) (CLP group), 8 underwent CLP followed 30 min later by edaravone intravenous administration (edaravone group), and 6 did not undergo CLP and did not receive edaravone (sham group). To evaluate the pulmonary blood pressure despite the sepsis-induced low cardiac output, mean arterial blood pressure (mABP), mean pulmonary arterial pressure (mPAP), and comparative pulmonary hypertension ratio (mPAP/mABP) were determined. Serum TNFα levels were measured before the procedure and at 1, 3, and 6 h after. The mPAP levels were higher in the CLP group at 9 h compared to the edaravone group. The mPAP/mABP ratio was lower in the edaravone and sham groups compared to the CLP group at 6 and 9 h. TNFα in the edaravone and sham groups were lower at 1 and 3 h compared to that in the CLP group. In all animals, mPAP/mABP at 6 h correlated with serum levels of TNFα at 1, 3, and 6 h. These findings suggest that edaravone ameliorates the severity of pulmonary hypertension in a neonatal sepsis model by reducing serum TNFα levels.

Oxidative stress after living related liver transplantation subsides with time in pediatric patients.

BACKGROUND: Oxidative stress has been suspected to influence graft survival and prognosis in pediatric recipients of living related liver transplantation (LRLT). PURPOSE: We determined the oxidative status of pediatric LRLT recipients during their regular outpatient follow-up visits, and looked for a relationship between oxidative status and post-liver transplantation (post-LTx) duration. PATIENTS: The study included 43 patients (20 males and 23 females) between the ages of 1.6 and 25.1 years (median 10.7 years) who had undergone LRLT from 5 months to 17.5 years (median 7 years) prior to the study, between the ages of 1.2 and 14.4 years (median 3.5 years). METHODS: Serum glutamic pyruvic transaminase (GPT), glutamic oxaloacetic transaminase (GOT), gamma-glutamyl transpeptidase (γ-GTP), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), direct bilirubin and choline-esterase were measured as part of the patients' regular follow-up visits. Serum total hydroperoxide (TH) and biological antioxidative potential (BAP) were measured using the free radical analytic system which requires 20 µl of serum and 10 min of processing time for each sample. Oxidative stress index (OSI) was calculated as the ratio of TH to BAP. RESULTS: Serum OSI correlated positively with serum levels of GOT, GPT, LDH, ALP, γ-GTP and direct bilirubin. Serum OSI, TH, LDH, ALP and GOT correlated negatively with post-LTx duration. Serum BAP correlated positively with post-LTx duration. Serum TH correlated positively with serum GOT and γ-GTP, but negatively with serum BAP. CONCLUSIONS: (1) The OSI, which can be calculated based on data acquired through a simple outpatient procedure, can serve as an index of our patients' laboratory results and oxidative status. (2) The LRLT recipients in our study were at risk for oxidative stress early in the post-operative period, but this risk subsided with time.

Pediatric patients receiving ABO-incompatible living related liver transplantation exhibit higher serum transforming growth factor-ß1, interferon-γ and interleukin-2 levels.

BACKGROUND: ABO-incompatible liver transplantation (LTx) is becoming more common in response to the paucity of liver allografts. Several studies have expressed concern about the effect of ABO compatibility on graft survival. PURPOSE: To evaluate the differences in serum cytokine levels between ABO-incompatible (ABO-i) and ABO-compatible (ABO-c; includes ABO-compatible and identical) pediatric LTx recipients during regular outpatient follow-up. Note that, in the field of organ transplantation, transplants are categorized as incompatible, compatible or identical; accordingly, these are the terms we use in the paper. MATERIALS AND METHODS: A clinical outpatient study measuring serum transforming growth factor (TGF)-ß1, interferon (IFN)-γ, interleukin (IL)-2 and IL-10 in 43 living related liver transplantation (LRLT) recipients, of whom 36 received ABO-c LRLT (34 were ABO-identical and 2 were non-identical) and 7 ABO-i LRLT. Serum glutamic pyruvic transaminase, glutamic oxaloacetic transaminase, gamma-glutamyl transpeptidase, alkaline phosphatase, lactate dehydrogenase and bilirubin were measured as part of the patients' regular follow-up visits. RESULTS: There were no differences between the ABO-c and ABO-i groups in terms of recipient's age [mean 12.6 vs. 11.1 years (y)], post-LTx duration (mean 7.3 vs. 7.3 y), donor's age (mean 35.5 vs. 34.6 y), body weight (28.9 ± 2.9 vs. 27.9 ± 6.9 kg), or gender (19 female and 17 male vs. 4 female and 3 male). Serum TGF-ß1, IFN-γ and IL-2 were significantly higher in the ABO-i group than in the ABO-c group. IL-10, however, did not differ between the two groups. There was a tendency toward higher γGTP levels in the ABO-i group, but this difference did not reach significance. CONCLUSION: ABO-incompatible LRLTx patients have higher serum TGF-ß1, IFN-γ and IL-2 levels as measured at regular outpatient visits. As a result, they face a higher risk of T-helper 1 cell polarization, which could make graft rejection more likely.

[Effectiveness of vigabatrin in west syndrome associated with tuberous sclerosis].

Vigabatrin (VGB) is one of the most effective anti-epileptic drugs for tonic spasms, those accompanied with tuberous sclerosis complex (TSC), but is not available in Japan. We treated 7 patients with West syndrome (WS) and TSC with VGB. In these patients, VGB treatment was started at 5-65 months of age. Six patients (86%) had complete cessation of tonic spasms. Of these, 3 patients had complete cessation within 24 hours after VGB treatment. The mean initial dosage of VGB was 36.2 mg x kg(-1) x day(-1), and the mean maintenance dosage was 38.4 mg x kg(-1) x day(-1). At the beginning of VGB treatment, 3 patients had hypsarrhythmia, 2 had focal discharge with generalization, and 2 had only focal discharge on electroencephalography. Hypsarrhythmia disappeared within 4-8 weeks after VGB treatment. Behavioral problems and sleep difficulty were observed in 6 patients. Visual field examination revealed no abnormalities in 3 patients. We hope that patients with WS and TSC can be treated with VGB as soon as possible in Japan.

Endothelin receptor antagonist attenuates inflammatory response and prolongs the survival time in a neonatal sepsis model.

PURPOSE: To evaluate effects of endothelin receptor antagonist ETR-P1/fl in a neonatal sepsis model. METHOD: Eighteen anesthetized and mechanically ventilated 3-day-old piglets were divided into three groups. Six piglets received cecal ligation and perforation (CLP group). Six piglets were administrated a continuous infusion of ETR-P1/fl (0.05 mg/kg/h), an antisense homology box-derived peptide with an endothelin A receptor antagonist effect, starting 30 min after CLP (ETR-P1/fl group). Six piglets acted as the sham group. Mean arterial pressure (MAP), heart rate, cardiac output, arterial blood gas, body temp (BT), serum nitrite and nitrate (NOx), tumor necrosis factor (TNF)-α, and high-mobility group box 1 (HMGB-1) were measured before CLP and at 1, 3, 6, and 9 h after CLP. RESULTS: Cecal ligation and perforation exposure evoked a state of shock and showed deteriorated cardiac output, pulmonary hypertension, decreased MAP, low oxygen saturation, and base excess (BE) with elevated TNF-α, NOx, and HMGB1. ETR-P1/fl administration resulted in higher MAP at 6 and 9 h after CLP, less negative BE, lower mean pulmonary arterial pressure (mPAP)/MAP ratio at 9 h after CLP, and lower TNF-α, NOx, and HMGB-1 compared to the CLP group. BT showed no differences between the groups. Survival time in the ETR-P1/fl group was longer than in the CLP group (18.9 ± 2.3 h vs. 9.0 ± 0.8 h, p < 0.01). CONCLUSIONS: ETR-P1/fl treatment significantly attenuated the elevation of NOx, TNF-α, and HMGB-1, which improved the systemic hypotension, pulmonary hypertension, and blood gases, thereby causing improvement of survival time in a progressive neonatal sepsis CLP model.

Cytokine profiles before and after exchange transfusion in a neonate with transient myeloproliferative disorder and hepatic fibrosis.

SUMMARY: To study the effect of exchange transfusion on cytokine profiles in a patient with transient myeloproliferative disorder and hepatic fibrosis in which cytokines were measured before and after exchange transfusion. A newborn female was diagnosed with Down syndrome phenotypically and on karyotyping. Laboratory data showed a high leukocyte count with blast cells in the peripheral blood and liver dysfunction. Exchange transfusion was performed on day 1. However, respiratory distress and multiorgan failure progressed, and she died after 16 days. Of the cytokines examined, transforming growth factor-beta1 and interleukin-7 were extremely high before exchange transfusion, and decreased after exchange transfusion.

Effect of polymyxin B-immobilized fiber hemoperfusion on respiratory impairment, hepatocellular dysfunction, and leucopenia in a neonatal sepsis model.

PURPOSE: Sepsis and septic shock remain a major source of morbidity and mortality in neonates despite advances in antimicrobials and aggressive supportive care. Our aim was to study the effects of polymyxin-B direct hemoperfusion (PMX-DHP) therapy on sepsis-induced respiratory impairment, liver dysfunction and leucopenia in a neonatal cecal ligation and perforation (CLP) model. METHODS: Fourteen anesthetized and mechanically ventilated 3-day-old piglets underwent CLP and an arteriovenous extracorporeal circuit from 3 h until 6 h post-CLP, with a PMX column in the PMX-DHP treated group (7 piglets). Changes in oxygen saturation, PCO(2), base excess, white blood cell (WBC) count, platelet count, hematocrit (Hct%), serum glutamate pyruvate transaminase (SGPT), and serum glutamic oxaloacetic transaminase were measured before CLP and at 1, 3 and 6 h after. RESULTS: At 6 h, the PMX-DHP group showed lower Hct%, and SGPT in comparison to the control group, but higher oxygen saturation and WBC count. No effects on the platelet count were found. The survival times of the PMX-DHP group were longer than in control. CONCLUSION: PMX-DHP therapy limited the respiratory impairment, liver dysfunction and leucopenia in a neonatal septic model, which resulted in an improvement of survival time.

Bilateral occipital cortical dysplasia and white matter T2 hyperintensity with mild non-specific myopathy: two sibling cases.

We report two heterosexual sibling cases of mild non-specific myopathy, with bilateral occipital cortical dysplasia and diffuse white matter hyperintensity on brain magnetic resonance imaging (MRI). The histological examination of the muscle in the elder sister revealed non-specific myopathic changes and no reductions of alpha-dystroglycan and laminin alpha2 expressions. The characteristic findings in the occipital lobe on brain MRI in both cases suggested cobblestone lissencephaly. Disrupted structure of the glia limitans and pial basement membrane complex, by a cause other than an alpha-dystroglycan and laminin alpha2 abnormality, may be the cause of the cortical dysplasia in the sibling cases.

Detection of congenital cytomegalovirus infection using umbilical cord blood samples in a screening survey.

Easy screening and accurate diagnosis of congenital cytomegalovirus (CMV) infection are needed to predict and treat complications. We report the clinical course of two neonates with congenital CMV infection confirmed by real-time polymerase chain reaction (PCR) for CMV DNA in umbilical cord blood. A total of 1,010 neonates born at Yonaha Clinic from July 2005 to March 2007 were investigated. Umbilical cord blood was collected at birth, and DNA was extracted to screen for CMV DNA by real-time PCR. Head MRI and a developmental test were conducted for two cases (0.2%) in which CMV DNA was detected. Neither case showed clear abnormalities at birth, and head CT conducted at 1 month after birth revealed no abnormalities. Auditory brainstem responses were normal at both 1 and 12 months after birth in both cases. Head MRI at 12 months showed abnormalities in both cases. For both cases, development tests conducted at 12 months revealed mild developmental delays, particularly in posture and movement areas, which might have been caused by congenital CMV infection.

Diclofenac enhances proinflammatory cytokine-induced nitric oxide production through NF-kappaB signaling in cultured astrocytes.

Recently, the number of reports of encephalitis/encephalopathy associated with influenza virus has increased. In addition, the use of a non-steroidal anti-inflammatory drug, diclofenac sodium (DCF), is associated with a significant increase in the mortality rate of influenza-associated encephalopathy. Activated astrocytes are a source of nitric oxide (NO), which is largely produced by inducible NO synthase (iNOS) in response to proinflammatory cytokines. Therefore, we investigated whether DCF enhances nitric oxide production in astrocytes stimulated with proinflammatory cytokines. We stimulated cultured rat astrocytes with three cytokines, interleukin-1beta, tumor necrosis factor-alpha and interferon-gamma, and then treated the astrocytes with DCF or acetaminophen (N-acetyl-p-aminophenol: APAP). iNOS and NO production in astrocyte cultures were induced by proinflammatory cytokines. The addition of DCF augmented NO production, but the addition of APAP did not. NF-kappaB inhibitors SN50 and MG132 inhibited iNOS gene expression in cytokine-stimulated astrocytes with or without DCF. Similarly, NF-kappaB p65 Stealth small interfering RNA suppressed iNOS gene expression in cytokine-stimulated astrocytes with or without DCF. LDH activity and DAPI staining showed that DCF induces cell damage in cytokine-stimulated astrocytes. An iNOS inhibitor, L-NMMA, inhibited the cytokine- and DCF-induced cell damage. In conclusion, this study demonstrates that iNOS and NO are induced in astrocyte cultures by proinflammatory cytokines. Addition of DCF further augments NO production. This effect is mediated via NF-kappaB signaling and leads to cell damage. The enhancement of DCF on NO production may explain the significant increase in the mortality rate of influenza-associated encephalopathy in patients treated with DCF.

High postnatal oxidative stress in neonatal cystic periventricular leukomalacia.

Oxidative stress plays an important role in cystic periventricular leukomalacia (PVL). We performed a case-control study of preterm infants delivered at <35 weeks of gestation between January 2003 and December 2006. Patients were stratified into three groups, according to age at which cysts were initially identified: 10 days old (early cystic PVL; n=10), >10 days old (late cystic PVL; n=12); and no cystic PVL (controls; n=22). Serum total hydroperoxide, biological antioxidant potential and oxidative stress index (calculated as total hydroperoxide/biological antioxidant potential) were measured within 3h after birth. Frequencies of preterm rupture of membrane and chorioamnionitis were significant higher in early cystic PVL than in late cystic PVL or controls. Duration of oxygen treatment and mechanical ventilation and frequency of apnea were significantly higher in late cystic PVL than in controls or early cystic PVL. Serum total hydroperoxide levels and oxidative stress index were significantly higher in early cystic PVL than in late cystic PVL or controls (p<0.05, respectively). Postnatal duration until cyst identification displayed a significant negative correlation with oxidative stress index and total hydroperoxide level (r=-0.497, p<0.05; r=-0.50, p<0.05, respectively). These findings suggest that early onset of cystic PVL might be due to either antenatal or intrapartum factors, but late onset might be due to postnatal factors. In the pathophysiology and therapy of cystic PVL, oxidative stress and onset timing appear crucial. This is the first study to reveal that neonates experiencing much more oxidative stress at birth show earlier onset of cystic PVL.

HapMap scanning of novel human minor histocompatibility antigens.

Minor histocompatibility antigens (mHags) are molecular targets of allo-immunity associated with hematopoietic stem cell transplantation (HSCT) and involved in graft-versus-host disease, but they also have beneficial antitumor activity. mHags are typically defined by host SNPs that are not shared by the donor and are immunologically recognized by cytotoxic T cells isolated from post-HSCT patients. However, the number of molecularly identified mHags is still too small to allow prospective studies of their clinical importance in transplantation medicine, mostly due to the lack of an efficient method for isolation. Here we show that when combined with conventional immunologic assays, the large data set from the International HapMap Project can be directly used for genetic mapping of novel mHags. Based on the immunologically determined mHag status in HapMap panels, a target mHag locus can be uniquely mapped through whole genome association scanning taking advantage of the unprecedented resolution and power obtained with more than 3 000 000 markers. The feasibility of our approach could be supported by extensive simulations and further confirmed by actually isolating 2 novel mHags as well as 1 previously identified example. The HapMap data set represents an invaluable resource for investigating human variation, with obvious applications in genetic mapping of clinically relevant human traits.

Pretreatment with low doses of erythropoietin ameliorates brain damage in periventricular leukomalacia by targeting late oligodendrocyte progenitors: a rat model.

BACKGROUND: One of the pathological hallmarks of periventricular leukomalacia (PVL) is the selective vulnerability of late oligodendrocyte progenitors (preoligodendrocytes; preOLs) to hypoxia-ischemia (H-I). It is unknown whether recombinant human erythropoietin (rhEPO) protects preOLs in vivo. OBJECTIVES: To develop a rat PVL model in which preOLs are selectively damaged and exhibit similar pathological changes to diffuse-type human PVL, various conditions of H-I were compared in P2-P7 rats (P2 = postnatal day 2). To evaluate the effect of rhEPO on oligoprotection (preOLs), rhEPO was administered to P3 PVL rats. METHODS: After counts of NG2-positive and O4-positive cells were performed in P2-P7 rats, right common carotid artery occlusion followed by 6% O(2) for 0-120 min was performed in P2-P4 rats. The mortality and histological alterations after hematoxylin/eosin staining and ED1 immunostaining were assessed 2 days after H-I. Various doses of rhEPO (1-30,000 U/kg i.p.) were administered to PVL rats 15 min before administration of 6% O(2). RESULTS: Double-positive cells for NG2 and O4 were detected from P2, and their number gradually increased until P7. Although right common carotid artery occlusion with 6% O(2) for 60 min resulted in a relatively high proportion of deaths in P2-P4 rats, typical histological changes in the PVL diffuse component were found in most surviving P3 animals. With 50-100 U/kg rhEPO, the histological damage was attenuated. CONCLUSIONS: Histological changes similar to those seen in the PVL diffuse component were induced by H-I in P3 rats, in which preOLs were gradually developing, and a low dose of rhEPO was effective in the treatment of brain damage induced by H-I.

A drop in gas temperature in the external part of the endotracheal tube is problematic during neonatal respiratory support.

During neonatal respiratory support, maintaining optimal humidity minimizes the risk of airway occlusion and chronic lung disease. With neonatal respiratory support using a heated humidifier,condensation following decreases in temperature within the unheated part of the inspiratory circuit represents a serious problem, due to the resulting drop in absolute humidity. Several reports describing the temperature/humidity gradient in the unheated inspiratory limb have excluded the endotracheal tube (ETT). The present study investigated the extent to which the temperature gradient in the ETT affects breathing gas conditioning in premature infants, who display tiny minute volumes. By measuring temperature/dew point at various sites along the inspiratory circuit, including inside the ETT, we evaluated the effects of temperature change in the ETT using an in vitro model of a micropremie on mechanical respirator care in an incubator. We confirmed significant moisture loss (absolute humidity loss; 7.5-10.1 mg/L) with decreasing gas temperature in the ETT external to the body, with subsequent drying of the gas (relative humidity drop, 10.7-22.3%) as temperature increased in the ETT inside the body. The present results suggest that temperature decreases in the ETT represent an important issue in the respiratory care of very premature infants.