Plastic bronchitis caused by Haemophilus influenzae.

Plastic bronchitis is characterized by sputum obstructing the bronchus and causing atelectasis. Bronchoscopic removal of the clogged bronchial cast is typically performed, but small-diameter bronchoscopes with narrow suction ports cannot achieve adequate suction. Suction using a bronchoscope as a guide sheath may be effective for treating plastic bronchitis in children.

A PEDIATRIC CASE OF DISSEMINATED BARTONELLA HENSELAE INFECTION ACCOMPANIED BY MULTIPLE INTRACRANIAL LESIONS.

We report a pediatric case of disseminated Bartonella henselae infection accompanied by multiple intracranial lesions. The patient developed multiple intracranial lesions despite treatment with azithromycin and gentamicin. After switching to rifampicin, the clinical symptoms of the patient improved. Given its good penetration into the central nervous system, rifampicin may be recommended for the treatment of B. henselae infection accompanied by intracranial lesions.

The possible association between epidemics of hand-foot-and-mouth disease and responsiveness to immunoglobulin therapy in Kawasaki disease.

Background: Enterovirus causing hand-foot-mouth disease (HFMD) has been reported to be associated with the development of Kawasaki disease (KD), whereas the involvement of enterovirus in the clinical course of KD is uncertain. The aim of this study is to investigate the association between the clinical course of KD and HFMD epidemics. Methods: This study included 108 patients who developed KD during HFMD epidemic seasons (July and August) from 2010 to 2014 and who were initially treated with high-dose intravenous immunoglobulin (IVIG). A mean of ≥5.0 HFMD patients reported weekly from each sentinel medical facility was considered to represent a large HFMD epidemic. We compared the clinical characteristics of KD patients in summers of years with and without large HFMD epidemics. Results: Large HFMD epidemics occurred in 2011 and 2013. The number of KD patients in summer was the highest in 2011. The proportion of patients with resistance to the IVIG therapy in summers of years with the large epidemics (14%) was significantly lower than that in summers of other years (31%, P = 0.030), whereas the proportion of patients with coronary artery abnormalities did not differ to a statistically significant extent. The development of KD during large HFMD epidemics was significantly associated with a lower risk of resistance to the IVIG therapy (incidence rate ratio 0.92, P = 0.049). Conclusion: Patients developing KD during large HFMD epidemic may have good responsiveness to IVIG. It is important to identify microbes from KD patients to predict responsiveness to IVIG therapy.

The optimal duration of antimicrobial therapy for lower respiratory tract infection in patients with neuromuscular disorders based on a clone library analysis of the bacterial 16S rRNA gene sequence.

OBJECTIVES: The aim of this study is to determine the optimal duration of antimicrobial therapy for lower respiratory tract infection (LRTI) in neuromuscular disorder (NMD) patients. METHODS: This prospective study included 13 episodes from 9 NMD patients hospitalized for bacterial LRTI. Sputum samples were collected from these patients during the three consecutive days after their admission. Bacterial cell counts and the proportion of the most predominant bacterium identified by a clone library analysis of the bacterial 16S rRNA gene sequence in the samples obtained before antimicrobial therapy were serially investigated. RESULTS: All episodes were initially treated with ampicillin/sulbactam. In 12 episodes with a therapeutic effect, the bacterial cell counts in the samples obtained on the third day of therapy were significantly lower than those before therapy (P = 0.0013). In most of these episodes, the most predominant bacterium in the sample obtained before therapy was undetectable by the third day of therapy. In the one patient without a therapeutic effect, neither the bacterial cell counts nor the proportion of the most predominant bacterium in the sample obtained before therapy decrease after therapy. CONCLUSION: Short-term antimicrobial therapy is sufficiently effective for LRTI in NMD patients if the initial therapy is effective.

Impact of High Flow Nasal Cannula Therapy on Oral Feeding in Very Low Birth Weight Infants with Chronic Lung Disease.

Previous studies on high-flow nasal cannula (HFNC) in very-low-birth-weight infants (VLBWIs) focused on comparing HFNC with nasal continuous positive airway pressure (nCPAP) to determine the usefulness of HFNC as a backup in the case of extubation failure and nasal trauma; however, the studies did not consider oral feeding. This retrospective case-control study aimed at elucidating whether HFNC could prevent the delay in feeding and achievement of full oral feeding in VLBWIs with chronic lung disease (CLD). Forty five VLBWIs were enrolled in this study: an HFNC group (n = 11) that was supported by HFNC at oral feeding initiation, and a non-HFNC group (n = 34) that could start oral feeding without HFNC. The gestational age and birth weight of the HFNC group were lower than those in the non-HFNC group. The median duration of exposure to oxygen and neonatal intensive care unit stay were comparable in both groups. The timings of oral feeding initiation and full oral feeding achievement in both groups were not significantly different: 35.3 (33.0 - 38.1) vs. 35.5 (33.7 - 42.4) weeks (P = 0.91) for the HFNC and 38.6 (34.4 - 42.3) vs. 36.7 (34.6 - 44.4) weeks postmenstrual age (P = 0.29) for the non-HFNC. Clinically significant aspiration pneumonia during the period of oral feeding was not observed in the HFNC group. Respiratory support by HFNC in VLBWIs with CLD might prevent oral feeding delay. Initiation of oral feeding of VLBWIs on HFNC might be safe and might accelerate the achievement of oral feeding milestones.

Seasonality in clinical courses of Kawasaki disease.

OBJECTIVE: Epidemics of Kawasaki disease (KD) are well known; however, the seasonal variation in the clinical course of KD is uncertain. The aim of this study was to investigate the seasonality in the clinical course of KD. METHODS: This study included 744 patients who were admitted to six hospitals in Kitakyushu City for KD from 2010 to 2014. We divided the patients into two groups according to the average monthly temperature (warm and cold periods) and compared the clinical courses of KD. RESULTS: The clinical courses of 715 patients who were initially treated with intravenous immunoglobulin (IVIG) were investigated. The proportion of patients with resistance to the initial IVIG therapy was significantly higher during the warm period than during the cold period (p=0.016). There was no seasonality in the proportion of patients with coronary artery abnormalities. CONCLUSION: Seasonality was observed in the response to IVIG therapy of patients with KD.

Effectiveness of an early switch from intravenous to oral antimicrobial therapy for lower respiratory tract infection in patients with severe motor intellectual disabilities.

An early switch from intravenous to oral antimicrobial therapy is useful for reducing the duration of the hospitalization in adult patients with community acquired-pneumonia, whereas the efficacy of switch therapy for pediatric patients with community acquired (CA)-lower respiratory tract infection (LRTI) is uncertain. The aim of this study is to investigate the efficacy of switch therapy for LRTI in patients with severe motor intellectual disabilities (SMID). This retrospective study was performed on 92 patients with SMID who were admitted to the Department of Pediatrics at the Hospital of University of Occupational and Environmental Health, Japan from April 1, 2010 to March 31, 2017 for the suspicion of bacterial LRTI and were initially treated with an intravenous antimicrobial agent. Clinical outcomes were compared between patients with switch therapy (Switch therapy group) and conventional intravenous antimicrobial therapy (No switch therapy group). Thirteen and 79 in patients with SMID belonged to Switch thrapy group and No switch therapy group, respectively. Length of hospital stay in Switch therapy group was significantly shorter than that in No switch therapy group (P = 0.002). In the patients undergoing switch therapy, there was no patient who required re-treatment and/or re-hospitalization. Switch therapy for LRTI was useful for the reduction of length of hospital stay without increasing risk of re-treatment and re-hospitalization in patients with SMID.

Glutathione S-transferase π complexes with and stimulates Na⁺,K⁺-ATPase.

Glutathione S-transferase (GST) was found to complex with the Na⁺,K⁺-ATPase as shown by binding assay using quartz crystal microbalance. The complexation was obstructed by the addition of antiserum to the α-subunit of the Na⁺,K⁺-ATPase, suggesting the specificity of complexation between GST and the Na⁺,K⁺-ATPase. Co-immunoprecipitation experiments, using the anti-α-subunit antiserum to precipitate the GST-Na⁺,K⁺-ATPase complex and then using antibodies specific to an isoform of GST to identify the co-precipitated proteins, revealed that GSTπ was complexed with the Na⁺,K⁺-ATPase. GST stimulated the Na⁺,K⁺-ATPase activity up to 1.4-fold. The level of stimulation exhibited a saturable dose-response relationship with the amount of GST added, although the level of stimulation varied depending on the content of GSTπ in the lots of GST received from supplier. The stimulation was also obtained when recombinant GSTπ was used, confirming the results. When GST was treated with reduced glutathione, GST activity was greatly stimulated, whereas the level of stimulation of the Na⁺,K⁺-ATPase activity was similar to that when untreated GST was added. When GST was treated with H2O2, GST activity was greatly diminished while the stimulation of the Na⁺,K⁺-ATPase activity was preserved. The results suggest that GSTπ complexes with the Na⁺,K⁺-ATPase and stimulates the latter independent of its GST activity.

Epigallocatechin-3-gallate is an inhibitor of Na+, K(+)-ATPase by favoring the E1 conformation.

Four catechins, epigallocatechin-3-gallate, epigallocatechin, epicatechin-3-gallate, and epicatechin, inhibited activity of the Na(+),K(+)-ATPase. The two galloyl-type catechins were more potent inhibitors, with IC(50) values of about 1 microM, than were the other two catechins. Inhibition by epigallocatechin-3-gallate was noncompetitive with respect to ATP. Epigallocatechin-3-gallate reduced the affinity of vanadate, shifted the equilibrium of E1P and E2P toward E(1)P, and reduced the rate of the E1P to E2P transition. Epigallocatechin-3-gallate potently inhibited membrane-embedded P-type ATPases (gastric H+, K(+)-ATPase and sarcoplasmic reticulum Ca(2+)-ATPase) as well as the Na(+),K(+)-ATPase, whereas soluble ATPases (bacterial F(1)-ATPase and myosin ATPase) were weakly inhibited. Solubilization of the Na(+),K(+)-ATPase with a nonionic detergent reduced sensitivity to epigallocatechin-3-gallate with an elevation of IC50 to 10 microM. These results suggest that epigallocatechin-3-gallate exerts its inhibitory effect through interaction with plasma membrane phospholipid.

Functional consequences of various leucine mutations in the M3/M4 loop of the Na+,K +-ATPase alpha-Subunit.

Leucines were mutated within the sequence L311 ILGYTWLE319 of the extracellular loop flanking the third (M3) and fourth (M4) transmembrane segments (M3/M4 loop) of the Torpedo Na+,K+-ATPase alpha-subunit. Replacement of Leu311 with Glu resulted in a considerable loss of Na+,K+-ATPase activity. Replacement of Leu313 with Glu shifted the equilibrium of E1P and E2P toward E1P and reduced the rate of the E1P to E2P transition. The reduction of the transition rate and stronger inhibition of Na+,K+-ATPase activity by Na+ at higher concentrations together suggest that there is interference of Na+ release on the extracellular side in the Leu313 mutant. Thus, Leu313 could be in the pathway of Na+ exit. Replacement of Leu318 with Glu yielded an enzyme with significantly reduced apparent affinity for both vanadate and K+, with an equilibrium shifted toward E2P and no alteration in the transition rate. The reduced vanadate affinity is due to the lower rate of production of vanadate-reactive [K+ (2)]E2 caused by inhibition of dephosphorylation through reduction of the K+ affinity of E2P. Thus, Leu318 may be a critical position in guiding external K+ to its binding site.

Methionine aminopeptidase II: A molecular chaperone for sarcoplasmic reticulum calcium ATPase.

The monoclonal antibody to the beta-subunit of H(+)/K(+)-ATPase (mAbHKbeta) cross-reacts with a protein that acts as a molecular chaperone for the structural maturation of sarcoplasmic reticulum (SR) Ca(2+)-ATPase. We partially purified a mAbHKbeta-reactive 65-kDa protein from Xenopus ovary. After in-gel digestion and peptide sequencing, the 65-kDa protein was identified as methionine aminopeptidase II (MetAP2). The effects of MetAP2 on SR Ca(2+)-ATPase expression were examined by injecting the cRNA for MetAP2 into Xenopus oocytes. Immunoprecipitation and pulse-chase experiments showed that MetAP2 was transiently associated with the nascent SR Ca(2+)-ATPase. Synthesis of functional SR Ca(2+)-ATPase was facilitated by MetAP2 and prevented by injecting an antibody specific for MetAP2. These results suggest that MetAP2 acts as a molecular chaperone for SR Ca(2+)-ATPase synthesis.

Fe(II)/Cu(I)-dependent P-type ATPase activity in the liver of Long-Evans cinnamon rats.

This study examined Fe(II)-dependent ATPase activity in OTG (octylthioglucoside) -treated microsomes isolated from Wistar and LEC rats. The ATPase activity of the liver OTG-microsomes from Wistar rats increased sharply in the 5-150 microM range of Fe(II) with a K0.5 value of 23.9+/-3.6 microM, while the activity of LEC rat liver microsomes increased with increasing Fe(II) up to 500 microM with a K0.5 value of 64.4+/-8.1 microM. The K0.5 values for Fe(II)-dependent ATPase activity of spleen OTG-microsomes were nearly identical at 59.3 microM in the Wistar rat and 63.7 microM in the LEC rats with a similar level of activity at each Fe(II) concentration in both strains of animals. These results indicated that there are two types of Fe(II)-dependent ATPase with different Fe(II) sensitivity, a high sensitive (H) and a low sensitive (L) type, and that the H-type activity was specific to the liver. The H-type activity was, however, deficient in the liver of LEC rats that accumulate copper and iron in hepatocytes as a result of mutations in the Wilson's disease protein (WNDP). On the basis of these results, together with the similarity in optimal conditions required for full activity of the enzyme, we conclude that the Fe(II)-dependent ATPase (H-type) and WNDP may be identical.

Involvement in K+ access of Leu318 at the extracellular domain flanking M3 and M4 of the Na+,K+-ATPase alpha-subunit.

The effect of point mutation in the sequence 316TWLE319, which occurs in the extracellular loop flanking the third (M3) and the fourth (M4) transmembrane segment (L3/4) of the Na+,K+-ATPase alpha-subunit, was examined. Mutation of Glu319 to Asp yielded an enzyme with full activity, whereas substituting Glu319 to Ala resulted in a severe loss of activity. A negative charge was introduced along the sequence, one residue at a time, from Thr316 to Leu318 (by E-scanning) in the mutant construct with Glu319 already mutated to Gln. The activity that had been reduced to 60% by the mutation of Glu319 to Gln was restored upon the introduction of a negative charge by E-scanning. When Leu318 was replaced by Glu in a series of scanning experiments, the K+ sensitivity of the ATPase activity was lowered. The lowering of K+ sensitivity was further demonstrated when a mutation of Leu318 to Glu was introduced into the wild-type enzyme. Furthermore, mutants with Leu318 to Gln, Arg, and Phe displayed lower K+ sensitivity similar to that of Leu318 to Glu mutant. Leu318 may be in access path for K+, and any substitution at this position may interfere with access of K+ from outside the cell.

Transient association of the sarcoplasmic reticulum Ca2+ ATPase with the Na+/K+-ATPase and H+/K+-ATPase beta-subunits during its biogenesis in Xenopus oocytes.

We examined the effect of the beta-subunits of the Na+/K+ and H+/K+ ATPases on the biogenesis of the sarcoplasmic reticulum (SR) Ca2+ ATPase in Xenopus oocytes. Oocytes were simultaneously injected with cRNAs for both the SR Ca2+ ATPase and the beta-subunit of the Na+/K+ or the H+/K+ ATPase. Immunoprecipitation with antiserum specific for the beta-subunit of the Na+/K+ or the H+/K+ ATPase yielded not only the respective beta-subunit but also the SR Ca2+ ATPase, indicating that the SR Ca2+ ATPase was associated with the beta-subunits of the Na+/K+ and the H+/K+ ATPases. Pulse-chase experiments revealed that the complex between the SR Ca2+ ATPase and the beta-subunit of the Na+/K+ ATPase was formed transiently and dissociated during the course of maturation. This is the first report that demonstrates the association of the SR Ca2+ ATPase with the beta-subunit of the Na+/K+ and H+/K+ ATPases.

Functional role of the N-terminus of Na(+),K(+)-ATPase alpha-subunit as an inactivation gate of palytoxin-induced pump channel.

The N-terminus of the Na(+),K(+)-ATPase alpha-subunit shows some homology to that of Shaker-B K(+) channels; the latter has been shown to mediate the N-type channel inactivation in a ball-and-chain mechanism. When the Torpedo Na(+),K(+)-ATPase is expressed in Xenopus oocytes and the pump is transformed into an ion channel with palytoxin (PTX), the channel exhibits a time-dependent inactivation gating at positive potentials. The inactivation gating is eliminated when the N-terminus is truncated by deleting the first 35 amino acids after the initial methionine. The inactivation gating is restored when a synthetic N-terminal peptide is applied to the truncated pumps at the intracellular surface. Truncated pumps generate no electrogenic current and exhibit an altered stoichiometry for active transport. Thus, the N-terminus of the alpha-subunit appears to act like an inactivation gate and performs a critical step in the Na(+),K(+)-ATPase pumping function.

Monomeric sarcoplasmic reticulum Ca(2+)-ATPase is functionally active.

cRNAs for wild type and a functionless mutant of sarcoplasmic reticulum (SR) Ca(2+)-ATPase were co-injected into Xenopus oocytes in various molar ratios. SR Ca(2+)-ATPase activity of the microsomal fraction prepared from the injected oocytes increased linearly with increasing amounts of wild type cRNA. This result suggests that monomers are functional units of membrane-bound SR Ca(2+)-ATPase.