RESUMO
In isotropic environments, an Escherichia coli cell exhibits coordinated rotational switching of its flagellar motors, produced by fluctuations in the intracellular concentration of phosphorylated CheY (CheY-P) emanating from chemoreceptor signaling arrays. In this study, we show that these CheY-P fluctuations arise through modifications of chemoreceptors by two sensory adaptation enzymes: the methyltransferase CheR and the methylesterase CheB. A cell containing CheR, CheB, and the serine chemoreceptor Tsr exhibited motor synchrony, whereas a cell lacking CheR and CheB or containing enzymatically inactive forms did not. Tsr variants with different combinations of methylation-mimicking Q residues at the adaptation sites also failed to show coordinated motor switching in cells lacking CheR and CheB. Cells containing CheR, CheB, and Tsr [NDND], a variant in which the adaptation site residues are not substrates for CheR or CheB modifications, also lacked motor synchrony. TsrΔNWETF, which lacks a C-terminal pentapeptide-binding site for CheR and CheB, and the ribose-galactose receptor Trg, which natively lacks this motif, failed to produce coordinated motor switching, despite the presence of CheR and CheB. However, addition of the NWETF sequence to Trg enabled Trg-NWETF to produce motor synchrony, as the sole receptor type in cells containing CheR and CheB. Finally, CheBc, the catalytic domain of CheB, supported motor coordination in combination with CheR and Tsr. These results indicate that the coordination of motor switching requires CheR/CheB-mediated changes in receptor modification state. We conclude that the opposing receptor substrate-site preferences of CheR and CheB produce spontaneous blinking of the chemoreceptor array's output activity. IMPORTANCE Under steady-state conditions with no external stimuli, an Escherichia coli cell coordinately switches the rotational direction of its flagellar motors. Here, we demonstrate that the CheR and CheB enzymes of the chemoreceptor sensory adaptation system mediate this coordination. Stochastic fluctuations in receptor adaptation states trigger changes in signal output from the receptor array, and this array blinking generates fluctuations in CheY-P concentration that coordinate directional switching of the flagellar motors. Thus, in the absence of chemoeffector gradients, the sensory adaptation system controls run-tumble swimming of the cell, its optimal foraging strategy.
Assuntos
Proteínas de Escherichia coli , Escherichia coli , Escherichia coli/genética , Escherichia coli/metabolismo , Quimiotaxia , Proteínas de Bactérias/genética , Proteínas de Bactérias/química , Células Quimiorreceptoras , Proteínas de Escherichia coli/metabolismo , Proteínas Quimiotáticas Aceptoras de Metil/metabolismoRESUMO
BACKGROUND: Chronic lung disease (CLD) is a major neonatal pulmonary disorder associated with inflammation. Recent studies have shown that protein C anticoagulant pathways, such as those for protein C (PC), protein S (PS), and thrombomodulin (TM), could be useful indices for reflecting pulmonary injury. However, the involvement of these factors in preterm infants with very low birthweight (VLBW) who have developed CLD remains to be investigated. Here, we investigated whether PC pathway-related factors could predict the development of CLD in preterm infants with VLBW. METHODS: We collected plasma samples from 26 preterm infants with VLBW (13 each from those with and without CLD) at the time of birth and measured TM, PC, and PS levels in their plasmas. We analyzed prospectively the relationship between these factors in infants with and without CLD. RESULTS: There were significant differences in gestational age, birthweight, Apgar score (5 min), and duration of mechanical ventilation between the CLD and non-CLD groups. No significant differences in the PC and PS levels at birth were observed between the two groups, whereas the TM levels in the CLD group were significantly higher than those in the non-CLD group (P = 0.013). The TM levels correlated with gestational age and duration of mechanical ventilation. However, covariance analysis demonstrated that gestational age was significantly associated with TM levels, and consequently, development of CLD was not associated with TM level at birth. CONCLUSIONS: Thrombomodulin, PC, and PS levels at birth could not predict the development of CLD in preterm infants with VLBW.
Assuntos
Doenças do Prematuro , Pneumopatias , Doença Crônica , Humanos , Lactente , Recém-Nascido , Recém-Nascido Prematuro , Doenças do Prematuro/diagnóstico , Doenças do Prematuro/etiologia , Pneumopatias/etiologia , Estudos Prospectivos , Proteína C , TrombomodulinaRESUMO
The original article can be found online.
RESUMO
FliI and FliJ form the FliI6FliJ ATPase complex of the bacterial flagellar export apparatus, a member of the type III secretion system. The FliI6FliJ complex is structurally similar to the α3ß3γ complex of F1-ATPase. The FliH homodimer binds to FliI to connect the ATPase complex to the flagellar base, but the details are unknown. Here we report the structure of the homodimer of a C-terminal fragment of FliH (FliHC2) in complex with FliI. FliHC2 shows an unusually asymmetric homodimeric structure that markedly resembles the peripheral stalk of the A/V-type ATPases. The FliHC2-FliI hexamer model reveals that the C-terminal domains of the FliI ATPase face the cell membrane in a way similar to the F/A/V-type ATPases. We discuss the mechanism of flagellar ATPase complex formation and a common origin shared by the type III secretion system and the F/A/V-type ATPases.
Assuntos
Proteínas de Bactérias/química , ATPases Translocadoras de Prótons/química , Sistemas de Secreção Tipo III/química , Sequência de Aminoácidos , Substituição de Aminoácidos , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Flagelos/química , Flagelos/genética , Flagelos/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Domínios e Motivos de Interação entre Proteínas , Multimerização Proteica , Estrutura Quaternária de Proteína , ATPases Translocadoras de Prótons/genética , ATPases Translocadoras de Prótons/metabolismo , Salmonella typhimurium/genética , Salmonella typhimurium/metabolismo , Homologia de Sequência de Aminoácidos , Eletricidade Estática , Sistemas de Secreção Tipo III/genética , Sistemas de Secreção Tipo III/metabolismoRESUMO
BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is caused by complement overactivation, and its presentation and prognosis differ according to the underlying molecular defects. The aim of this study was to characterize the genetic backgrounds of aHUS patients in Japan and to elucidate the associations between their genetic backgrounds, clinical findings, and outcomes. METHODS: We conducted a nationwide epidemiological survey of clinically diagnosed aHUS patients and examined 118 patients enrolled from 1998 to 2016 in Japan. We screened variants of seven genes related to complement and coagulation, as well as positivity for anti-CFH antibodies, and assessed clinical manifestations, laboratory findings, and clinical course. RESULTS: The most frequent genetic abnormalities were in C3 (31%) and the frequency of CFH variants was relatively low (10%) compared to Western countries. The predominant variant in this cohort was C3 p.I1157T (23%), which was related to favorable outcomes despite frequent relapses. A total of 72% of patients received plasma therapy, while 42% were treated with eculizumab. The prognosis of Japanese aHUS patients was relatively favorable, with a total mortality rate of 5.4% and a renal mortality rate of 15%. CONCLUSIONS: The common occurrence of genotype C3, especially the p.I1157T variant was the characteristic of the genetic backgrounds of Japanese aHUS patients that differed from those of Caucasian patients. In addition, the favorable prognosis of patients with the unique C3 p.I1157T variant indicates that understanding the clinical characteristics of individual gene alterations is important for predicting prognosis and determining therapeutic strategies in aHUS.
Assuntos
Síndrome Hemolítico-Urêmica Atípica/genética , Patrimônio Genético , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Proteínas do Sistema Complemento , Feminino , Humanos , Lactente , Japão , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto JovemRESUMO
A soluble protein, FliJ, along with a membrane protein, FlhA, plays a role in the energy coupling mechanism for bacterial flagellar protein export. The water-soluble FliH(X)-FliI(6) ATPase ring complex allows FliJ to efficiently interact with FlhA. However, the FlhA binding site of FliJ remains unknown. Here, we carried out genetic analysis of a region formed by well-conserved residues-Gln38, Leu42, Tyr45, Tyr49, Phe72, Leu76, Ala79, and His83-of FliJ. A structural model of the FliI(6)-FliJ ring complex suggests that they extend out of the FliI(6) ring. Glutathione S-transferase (GST)-FliJ inhibited the motility of and flagellar protein export by both wild-type cells and a fliH-fliI flhB(P28T) bypass mutant. Pulldown assays revealed that the reduced export activity of the export apparatus results from the binding of GST-FliJ to FlhA. The F72A and L76A mutations of FliJ significantly reduced the binding affinity of FliJ for FlhA, thereby suppressing the inhibitory effect of GST-FliJ on the protein export. The F72A and L76A mutations were tolerated in the presence of FliH and FliI but considerably reduced motility in their absence. These two mutations affected neither the interaction with FliI nor the FliI ATPase activity. These results suggest that FliJ(F72A) and FliJ(L76A) require the support of FliH and FliI to exert their export function. Therefore, we propose that the well-conserved surface of FliJ is involved in the interaction with FlhA.
Assuntos
Proteínas de Bactérias/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Bactérias/química , Transporte Biológico , Escherichia coli/genética , Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica/fisiologia , Proteínas de Membrana/química , Modelos Moleculares , Mutação , Plasmídeos , Ligação Proteica , Conformação Proteica , Salmonella enterica/genética , Salmonella enterica/metabolismoRESUMO
Congenital cytomegalovirus (cCMV) infection is the most common congenital viral infection and is the leading non-genetic cause of sensorineural hearing loss and an important cause of neurodevelopmental disabilities. Auto auditory brainstem response (AABR) is a simple hearing test and used for the purpose of neonatal hearing screening, but can use it for early detection hard of hearing within the study age of the model. We experienced two case of asymptomatic CMV infection in which congenital and late-onset hearing loss were diagnosed early with AABR, and hearing loss improved with valganciclovir.
Assuntos
Infecções por Citomegalovirus , Perda Auditiva Neurossensorial , Humanos , Recém-Nascido , Infecções por Citomegalovirus/congênito , Infecções por Citomegalovirus/diagnóstico , Potenciais Evocados Auditivos do Tronco Encefálico , Perda Auditiva Neurossensorial/congênito , Perda Auditiva Neurossensorial/diagnóstico , Triagem Neonatal/efeitos adversos , ValganciclovirRESUMO
Phototherapy converts lipophilic unconjugated bilirubin to hydrophilic bilirubin photoisomers, such as lumirubin. We comparatively used a blue light-emitting diode (LED) and a green fluorescent lamp (FL) as light sources for phototherapy of hyperbilirubinemic preterm neonates with the aim of examining potential differences in urinary lumirubin excretion between these two wavelengths. Urinary lumirubin levels were measured using a fluorescence assay with blue light exposure in the presence of the unconjugated bilirubin-inducible fluorescent protein UnaG, and denoted as urinary UnaG-bound bilirubin (UUB)/creatinine (Cr) (µg/mg Cr). Preterm neonates born at ≤ 33 weeks gestational age and treated with phototherapy were subjected to this study. The maximum UUB/Cr level during phototherapy per device intensity was compared between neonates treated with the blue LED and the green FL. A total of 61 neonates were examined to determine the maximum UUB/Cr levels. The median of maximum UUB/Cr excretion per light intensity of each device (µg/mg Cr/µW/cm2/nm) was 0.83 for the blue LED and 1.29 for the green FL (p = 0.01). Green light was found to be more effective than blue one for bilirubin excretion via urinary lumirubin excretion. This is the first spectroscopic study to compare the efficacy of phototherapy at different wavelengths using fluorescence assay.
Assuntos
Icterícia Neonatal , Icterícia , Recém-Nascido , Humanos , Fototerapia/métodos , Icterícia Neonatal/terapia , Bilirrubina/metabolismoRESUMO
The bacterial flagellar proteins are translocated into the central channel of the flagellum by a specific protein-export apparatus for self-assembly at the distal growing end. FliH and FliI are soluble components of the export apparatus and form an FliH2-FliI heterotrimer in the cytoplasm. FliI is an ATPase and the FliH2-FliI complex delivers export substrates from the cytoplasm to an export gate made up of six integral membrane proteins of the export apparatus. In this study, an FliHC fragment consisting of residues 99-235 was co-purified with FliI and the FliHC2-FliI complex was crystallized. Crystals were obtained using the hanging-drop vapour-diffusion technique with PEG 400 as a precipitant. The crystals belonged to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a=133.7, b=147.3, c=164.2â Å, and diffracted to 3.0â Å resolution.
Assuntos
Proteínas de Bactérias/química , ATPases Translocadoras de Prótons/química , Salmonella typhimurium/enzimologia , Proteínas de Bactérias/isolamento & purificação , Sistemas de Secreção Bacterianos , Cristalização , Cristalografia por Raios X , ATPases Translocadoras de Prótons/isolamento & purificaçãoRESUMO
A 51-year-old man who underwent umbilical cord blood transplantation for acute lymphoblastic leukemia with a Philadelphia chromosome in April 2006 achieved complete remission. In June 2008, progressive renal dysfunction and melena emerged and the patient was diagnosed with B-cell-type malignant lymphoma. He presented with severe hypo-phosphate- mia(0. 1m g/dL)due to paraneoplastic syndrome, simultaneously. Because the development of tumor lysis syndrome followed by hyper-phophatemia was feared to occur after CHOP chemotherapy, we discontinued the adjustment of serum phosphorus. The serum phosphorus level was elevated to 11.6mg/dL after 3 days and decreased to 3. 8mg/dL after 5 days. We must be careful regarding hyper-phosphatemia and phosphorus adjustment even in patients with severe hypo-phosphatemia that is due to paraneoplastic syndrome.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Linfoma de Células B/tratamento farmacológico , Síndromes Paraneoplásicas/sangue , Fosfatos/sangue , Síndrome de Lise Tumoral/sangue , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Ciclofosfamida/efeitos adversos , Ciclofosfamida/uso terapêutico , Doxorrubicina/efeitos adversos , Doxorrubicina/uso terapêutico , Humanos , Masculino , Pessoa de Meia-Idade , Prednisona/efeitos adversos , Prednisona/uso terapêutico , Vincristina/efeitos adversos , Vincristina/uso terapêuticoRESUMO
3q27 chromosomal translocation involving the BCL6 gene is one of the most frequent forms of cytogenetic abnormality observed in B-cell lymphoma. We report a case with diffuse large B-cell lymphoma (DLBCL) presenting dual 3q27 translocations. The patient was a 71-year-old man who presented with swelling of multiple abdominal lymph nodes (LNs) and obstructive jaundice. LN biopsy exhibited dense proliferation of atypical large cells expressing CD20, MUM1/IRF4, BCL2, BCL6, and MYC, but not CD10. He was diagnosed with non-GCB/ABC type DLBCL and showed an initially good response to R-CHOP chemotherapy, but relapsed soon after the completion of therapy. Chromosomal analysis of the biopsied LN exhibited multiple abnormalities including t(3;14)(q27;q32) and t(3;22)(q27;q11). Fluorescence in situ hybridization (FISH) using BCL6 break-apart probes confirmed chromosomal breaks occurring on both BCL6 alleles. Molecular analysis revealed two independent rearrangements of BCL6, either with the IGH or the IGL gene. 3q27 breakpoints were located 1.2kb apart from each other within the first intron of BCL6, while the IGH and IGL breaks occurred at the 5' of IGHG2 and within IGLV3-1, respectively. The results suggest that biallelic BCL6 rearrangements might be a rare but recurrent genetic event in B-cell lymphoma.
Assuntos
Linfoma Difuso de Grandes Células B , Translocação Genética , Masculino , Humanos , Proteínas de Ligação a DNA/genética , Proteínas Proto-Oncogênicas c-bcl-6/genética , Hibridização in Situ Fluorescente , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/genéticaRESUMO
Lumirubin is the most prevalently excreted hydrophilic bilirubin photoisomer in phototherapy for neonatal jaundice caused by excess hydrophobic unconjugated bilirubin (ZZ-bilirubin). We developed a simple method to estimate the amount of lumirubin by monitoring the reverse photoisomerization of lumirubin to ZZ-bilirubin. Although lumirubin formation was long considered irreversible, exposure to blue light in the presence of the fluorescent protein UnaG, which binds specifically and tightly to ZZ-bilirubin, enables the reverse photoisomerization of lumirubin. This reaction was first detected using a fluorescence assay of neonatal urine sampled during phototherapy and purified lumirubin. The phenomenon of reverse photoisomerization of lumirubin was validated using liquid chromatography-mass spectrometry, which confirmed that lumirubin is reconverted to ZZ-bilirubin in the presence of UnaG. Analyses of 20 urine samples from 17 neonates revealed a significant correlation (correlation coefficient [r] = 0.978; 95% confidence interval 0.867-0.979; P < .001) between lumirubin and ZZ-bilirubin concentration before and after reverse photoisomerization. In general, the rate of photo-reconversion of lumirubin to ZZ-bilirubin is approximately 40%. In conclusion, we demonstrate here that lumirubin can be photo-reconverted to ZZ-bilirubin via exposure to blue light in the presence of UnaG. Utilizing this approach, urinary lumirubin levels can be estimated using an easy-to-perform fluorescence assay.
Assuntos
Icterícia Neonatal , Bilirrubina/metabolismo , Humanos , Recém-Nascido , Icterícia Neonatal/terapia , Luz , Espectrometria de Massas , Fototerapia/métodosRESUMO
To investigate the effectiveness and safety of GVHD prophylaxis using FK506 alone as a continuous infusion, 104 patients who underwent reduced-intensity cord blood transplantation were retrospectively reviewed. The respective incidence of acute GVHD was 25 grade 1(24. 1%), 19 grade2(18. 3%), 15 grade3(14. 4%), and 4 grade4(3. 8%), which are comparable to that in the literature. The incidences of grade 2 and greater acute GVHD were 32 out of 69(46. 4%)for those whose wholeblood concentration of FK506 werele ss than 13 ng/mL, whereas 6 out of 35(17. 1%)for those FK5 06 were greater than 13 ng/mL. The differenceies between above and below 13 ng/mL were statistically significant(p=0. 008). There were 19 cases(18. 3%)of renal dysfunction, although none required hemodialysis. There were only 4 patients who discontinued FK506, which further confirmed the safety of FK506 alone. Together with our previous report on the upper limit of FK506(17 ng/mL)and these results, we recommend the optimal serum concentration of FK506 to range from 13 to 17 ng/ mL.
Assuntos
Sangue Fetal/transplante , Doença Enxerto-Hospedeiro/prevenção & controle , Tacrolimo/uso terapêutico , Adulto , Idoso , Feminino , Doença Enxerto-Hospedeiro/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Tacrolimo/efeitos adversos , Tacrolimo/sangue , Adulto JovemAssuntos
Anti-Inflamatórios/administração & dosagem , Beclometasona/administração & dosagem , Transplante de Células-Tronco de Sangue do Cordão Umbilical , Gastroenteropatias , Doença Enxerto-Hospedeiro , Neoplasias Hematológicas , Doença Aguda , Adulto , Idoso , Idoso de 80 Anos ou mais , Aloenxertos , Feminino , Gastroenteropatias/tratamento farmacológico , Gastroenteropatias/mortalidade , Doença Enxerto-Hospedeiro/tratamento farmacológico , Doença Enxerto-Hospedeiro/mortalidade , Neoplasias Hematológicas/mortalidade , Neoplasias Hematológicas/terapia , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
We report a patient with hairy cell leukemia Japanese variant (HCL-Jv) that developed after radiotherapy for orbital adnexal MALT lymphoma. A 78-year-old man was diagnosed as having MALT lymphoma in the left conjunctiva in December 2003. The patient was treated by local radiotherapy and the tumor disappeared. Thereafter, he gradually developed leukocytosis and mild splenomegaly. In May 2009, the leukocyte count was 34,300 with 80% lymphoid cells. A diagnosis of HCL-Jv was made since the lymphoid cells showed a hairy morphology with round nuclei and indistinct nucleoli. These cells expressed CD11c, CD19, CD20, CD103 and showed weak reaction for tartrate-resistant acid phosphatase (TRAP). Bone marrow was infiltrated by atypical cells with an intrasinusoidal pattern. No treatment was needed as the patient was asymptomatic without anemia, thrombocytopenia or lymphadenopathy. Results of the immunoglobulin light chain expression and the heavy chain rearrangement in the tumor cells indicated that the two mature B-lymphoid neoplasms, MALT lymphoma and HCL-Jv, in this patient were derived from independent clones. This appears to be the first reported case of HCL-Jv associated with other lymphoid tumor. Further analysis is needed to clarify the risk of secondary malignancy in HCL-Jv.
Assuntos
Neoplasias da Túnica Conjuntiva/radioterapia , Leucemia de Células Pilosas/diagnóstico , Linfoma de Zona Marginal Tipo Células B/radioterapia , Segunda Neoplasia Primária , Idoso , Neoplasias da Túnica Conjuntiva/etiologia , Neoplasias da Túnica Conjuntiva/patologia , Humanos , Imunidade Celular , Leucemia de Células Pilosas/imunologia , Leucemia de Células Pilosas/patologia , Linfoma de Zona Marginal Tipo Células B/etiologia , Linfoma de Zona Marginal Tipo Células B/patologia , MasculinoRESUMO
In this study, we investigated the level of gut absorption following oral beclomethasone dipropionate (BDP) administration by measuring the blood concentration of its metabolites measured by LC-MS/MS using the HPLC method. Five patients who were administered BDP orally for gut GVHD were included. The blood concentrations of beclomethasone-17-monopropionate (17BMP), which is one of the active metabolites of BDP, were 618 approximately 1, 749 pg/mL in 4 of the studied 5 patients, which was comparable to that after inhalation of BDP; however, it was relatively higher in one patient (2,439+/-161 pg/mL). As the blood concentration of 17BMP in this study patient was higher compared with healthy volunteers administered a single oral BDP 4 mg, GVHD patients might have a higher concentration than healthy volunteers. Given that a higher grade of gut GVHD was associated with a higher blood level of 17BMP, BDP absorption might be associated with gut mucosal injury. Thus, the systemic adverse effect following oral BDP administration might not be negligible especially in gut GVHD patients.
Assuntos
Anti-Inflamatórios/sangue , Beclometasona/sangue , Doença Enxerto-Hospedeiro/sangue , Absorção Intestinal/efeitos dos fármacos , Enteropatias/sangue , Administração Oral , Adulto , Idoso , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/uso terapêutico , Beclometasona/administração & dosagem , Beclometasona/uso terapêutico , Feminino , Doença Enxerto-Hospedeiro/tratamento farmacológico , Doença Enxerto-Hospedeiro/imunologia , Humanos , Enteropatias/tratamento farmacológico , Enteropatias/imunologia , Masculino , Pessoa de Meia-IdadeRESUMO
Practicing pharmaceutical care is necessary to promote the appropriate use of medicines. In the practice of pharmaceutical care, monitoring the efficacy and safety of drugs from the pharmacists' point of view is an important role for clinical pharmacists and it is necessary to standardize clinical skills. We would like to introduce the monitoring skills of pharmacotherapy of clinical pharmacists by taking vancomycin injection and injectable anticancer drugs that have different monitoring points as examples.
Assuntos
Monitoramento de Medicamentos , Assistência Farmacêutica , Farmacêuticos , Antibacterianos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Competência Clínica , Esquema de Medicação , Humanos , Equipe de Assistência ao Paciente , Papel Profissional , Fatores de Risco , Vancomicina/administração & dosagem , Vancomicina/efeitos adversosRESUMO
[This corrects the article DOI: 10.1371/journal.pone.0124655.].
RESUMO
BACKGROUND: Chorioamnionitis, or infiltration of the chorioamnion by neutrophils, is a risk factor associated with the development of bronchopulmonary dysplasia. Increased neutrophil elastase levels are observed in the tracheal aspirates of these patients. AIMS: To examine the effects of early administration of the selective neutrophil elastase inhibitor sivelestat, which is used to treat acute lung injury in adults, on bronchopulmonary dysplasia in extremely premature infants. STUDY DESIGN: Retrospective cohort study. SUBJECTS: This study included extremely low-birth-weight infants born at a gestational age<28weeks. Patients were divided into groups based on the receipt of sivelestat. OUTCOME MEASURES: The primary outcome was the rate of bronchopulmonary dysplasia-free survival at a postmenstrual age of 36weeks, and the secondary outcomes included various clinically significant factors of neonatal mortality and morbidity and adverse events. RESULTS: Of the 1031 included neonates, 124 (12.0%) were treated with sivelestat. Significant differences between the groups were noted for gestational age, delivery method, fetal number, the frequency of chorioamnionitis, immunoglobulin M levels, and WBC counts. No differences were identified concerning the bronchopulmonary dysplasia-free survival rate at a postmenstrual age of 36weeks (adjusted odds ratio for sivelestat to control, 0.83; 95% confidence interval=0.53-1.30). Secondary outcomes did not significantly differ between the groups. CONCLUSIONS: In extremely premature infants, early sivelestat use was not associated with an improved rate of survival without bronchopulmonary dysplasia at a postmenstrual age of 36weeks.