Mika Sasaki

Morphology and function of pulmonary surfactant inhibited by meconium

The pathophysiology of neonatal meconium aspiration syndrome (MAS) is related to mechanical obstruction of the airways and to chemical pneumonitis. It has also been suggested that meconium causes inhibition of surfactant function. To assess its in vitro effect on surfactant function and morphology, we used a pulsating bubble surfactometer to measure the dynamic surface tension of meconium-surfactant mixtures and observed their electron microscopic structures. The mixtures were prepared by adding serial dilutions of human meconium to various concentrations of Surfactant-TA(Surfacten™) that had been used for the prevention and treatment of neonatal respiratory distress syndrome. Inhibition of the surface tension-lowering properties of Surfactant-TA was caused by the addition of meconium and depended on the concentration of the surfactant; the inhibition could be overcome by increasing the surfactant concentration. When meconium was added to Surfactant-TA, the characteristic ultrastructural features of the latter, the loosely stacked layers, changed to a spherical lamellar structure and folded linear structures. These results suggest that meconium inhibits surfactant function by altering surfactant morphology. Our morphologic and functional findings support the new concept that surfactant inhibition may play a role in the pathophysiology of MAS.

Stable microbubble test for predicting the risk of respiratory distress syndrome: II. Prospective evaluation of the test on amniotic fluid and gastric aspirate

We determined prospectively if the stable microbubble (SM) test on gastric aspirate obtained at birth was as useful as that on amniotic fluid in predicting respiratory distress syndrome (RDS). One hundred and five paired samples of amniotic fluid obtained at delivery from 105 consecutive women with gestation of 35 weeks or less and gastric aspirates from their neonates obtained within 30 min of birth were studied. The SM test with the predefined cut-off value of less than 5 bubbles/mm2 for amniotic fluid and less than 10 bubbles/mm2 for gastric aspirate signified the risk of RDS with the positive predictive value of 100% and 96% and with the negative predictive value of 91% and 84%, respectively. We conclude that the SM test on both amniotic fluid and gastric aspirate obtained at birth is a rapid (<10 min), simple and reliable procedure for predicting neonates who will develop RDS. It may be used as a bedside test to define a population of neonates with surfactant deficiency in clinical trials of prophylactic surfactant therapy.

Efficacy and Safety of Azathioprine and 6-Mercaptopurine in Japanese Pediatric Patients with Ulcerative Colitis: A Survey of the Japanese Society for Pediatric Inflammatory Bowel Disease

Background and Aims: Azathioprine (AZA) and 6-mercaptopurine (6-MP) have recently been used in Japanese pediatric patients with ulcerative colitis. The aims of this study were to evaluate both the therapeutic efficacy and safety of AZA/6-MP in this group of patients. Methods: Fourteen members of the Japanese Society for Pediatric Inflammatory Bowel Disease reported 35 retrospective cases that received AZA/6-MP and were evaluated for adverse drug effects. In those who tolerated AZA/6-MP, disease activity and corticosteroid doses before and during the first 6 months of therapy were assessed. Results: AZA or 6-MP was safely used in 21 of 35 patients (60%) without adverse drug effects. The disease activity began to decrease from the first month of therapy and the maximum effect was achieved after 3 months. The mean daily prednisolone dose was decreased from 26.9 to 11.6 mg and dose reduction was achieved in 58% of patients after 6 months of therapy. Fourteen of the 35 patients (40%) experienced adverse drug effects, including leukopenia (n = 11), aplastic anemia (n = 1), pancreatitis (n = 1) and liver dysfunction (n = 1). Conclusions: The majority of Japanese children with ulcerative colitis tolerated AZA/6-MP and experienced favorable effects. However, 40% experienced adverse drug effects, mainly myelosuppression.

Characteristics of inflammatory bowel disease with an onset before eight years of age: A multicenter epidemiological survey in Japan

Pediatric inflammatory bowel disease (IBD) has not been rare in Japan since the 1990s. The present study attempted to define the epidemiological and clinical characteristics of early‐childhood IBD in Japan in comparison with results from Western countries.

Homologous and Heterologous Antibody Responses to Lipopolysaccharide after Enterohemorrhagic Escherichia coli Infection

To evaluate antibody responses against lipopolysaccharide (LPS: O157, O26, and O111) in enterohemorrhagic Escherichia coli (EHEC) infection, sera of 24 schoolchildren associated with the Morioka outbreak in 1997 and of 74 sporadic patients suspected of having EHEC infection were examined. Using a positive standard serum, quantitative evaluation of LPS antibodies by an enzyme‐linked immunosorbent assay (ELISA) was established. High levels of specific IgM and IgA antibodies against homologous E. coli LPS were present in the acute period and are characteristic of EHEC. This could be used for the serological diagnosis of EHEC infection, except for early infants and the elderly. In addition to the specific homologous response, multiple antibody responses against different serotypes other than those isolated were demonstrated in many cases by qualitative analysis using Western blotting.

Ethanol resistive microbubble test: A modification of the stable microbubble test used to predict respiratory distress syndrome

The stable microbubble (SM) test on gastric aspirate obtained at birth proved useful in identifying infants who would develop respiratory distress syndrome (RDS). This test involves only the count of stable microbubbles of ≤ 15 μm in diameter. Larger bubbles (> 15 μm in diameter) are not necessary for the test and may interfere with stable microbubble counting. The aims of the present study were to determine: (i) if larger bubbles could be selectively removed by adding ethanol, a potent bubble breaker; and (ii) if the predictive value of this modified test, the ethanol resistive microbubble (ERM) test, on the development of RDS was similar to that of the SM test. Varying amounts of different concentrations of ethanol‐water solutions were added to the top of the bubble crop generated by the SM test procedure, and the mean counts of stable microbubbles and larger bubbles in five regions were calculated. A volume of 10 μL of 47.5% ethanol was effective in defoaming larger bubbles generated by the SM test procedure without altering the stable microbubble counts. When concurrently performed on 43 samples of gastric aspirate obtained at birth from infants of less than 35 weeks gestation, the RDS predictive value of the ERM test was similar to that of the SM test. It was concluded that the ERM test may serve as an alternative to the SM test.

Epstein-Barr virus-positive malignant lymphoma of salivary gland developing in an infant with selective depletion of CD4-positive lymphocytes

Epstein – Barr virus (EBV) is identified as an etiological agent of African type of Burkitt’s lymphoma. Latent infection genes of EBV including EBV nuclear antigens (EBNAs) and latent membrane proteins (LMPs) are expressed in latently infected and immortalized B cells. EBV infection in immunosuppressed patients, such as human immunodeficiency virus (HIV)-infected patients or allograft recipients receiving long-term immunosuppressive therapy, leads to polyclonal B-cell proliferative disorders, frequently resulting in the development of monoclonal malignant lymphomas. These lymphomas are most often diffuse lymphomas of the B-cell type and contain EBV DNA. Salivary glands often develop chronic inflammatory lesions, sialadenitis, sometimes with the background of autoimmune conditions, and form the acquired mucosa-associated lymphoid tissue (MALT). Sialadenitis increases the risk of malignant lymphoma, and both low-grade B-cell lymphoma of MALT type and high-grade diffuse large B-cell lymphoma develop in salivary glands of sialadenitis patients [1,2]. In these cases, most of the lymphomas do not exhibit EBV genome [2]. Here, we report an infant showing the selective depletion of CD4-positive T-cells without HIV infection, who subsequently developed an EBV-positive diffuse B-cell lymphoma of left submandibular gland. A 3-month-old Japanese girl presented in December 2002 with a high fever of 388C and rubella-like skin eruptions. She was uneventful in her perinatal period. Laboratory examinations revealed a marked elevation of liver enzymes (AST, 489 IU/l; ALT 487 IU/l). The peripheral blood picture showed red

Peripheral Blood CD64 Levels Decrease in Crohn's Disease following Granulocyte and Monocyte Adsorptive Apheresis

Granulocyte and monocyte adsorptive apheresis (GMA) is reportedly useful as induction therapy for Crohn’s disease (CD). However, the effects of GMA on CD64 have not been well characterized. We report here our assessment of CD64 expression on neutrophils before and after treatment with GMA in two patients with CD. The severity of CD was assessed with the CD activity index (CDAI). The duration of each GMA session was 60 min at a flow rate of 30 ml/min as per protocol. CD64 expression on neutrophils was measured by analyzing whole blood with a FACScan flow cytometer. In case 1, CD64 levels after each session of GMA tended to decrease compared to pretreatment levels, whereas in case 2, CD64 levels dropped significantly after treatment. The CDAI decreased after GMA in both cases 1 and 2. A significant correlation was noted between CDAI scores and CD64 levels in both cases. In conclusion, GMA reduced blood CD64 levels, which would be an important factor for the decrease of CDAI scores.

Assessment of ATP8B1 Deficiency in Pediatric Patients With Cholestasis Using Peripheral Blood Monocyte-Derived Macrophages

Progressive familial intrahepatic cholestasis type 1 (PFIC1), a rare inherited recessive disease resulting from a genetic deficiency in ATP8B1, progresses to liver failure. Because of the difficulty of discriminating PFIC1 from other subtypes of PFIC based on its clinical and histological features and genome sequencing, an alternative method for diagnosing PFIC1 is desirable. Herein, we analyzed human peripheral blood monocyte-derived macrophages (HMDM) and found predominant expression of ATP8B1 in interleukin-10 (IL-10)-induced M2c, a subset of alternatively activated macrophages. SiRNA-mediated depletion of ATP8B1 in IL-10-treated HMDM markedly suppressed the expression of M2c-related surface markers and increased the side scatter (SSC) of M2c, likely via impairment of the IL-10/STAT3 signal transduction pathway. These phenotypic features were confirmed in IL-10-treated HMDM from four PFIC1 patients with disease-causing mutations in both alleles, but not in those from four patients with other subtypes of PFIC. This method identified three PFIC1 patients in a group of PFIC patients undiagnosed by genome sequencing, an identical diagnostic outcome to that achieved by analysis of liver specimens and in vitro mutagenesis studies. In conclusion, ATP8B1 deficiency caused incomplete polarization of HMDM into M2c. Phenotypic analysis of M2c helps to identify PFIC1 patients with no apparent disease-causing mutations in ATP8B1.