Genetic Heterogeneity in pbp Genes among Clinically Isolated Group B Streptococci with Reduced Penicillin Susceptibility▿

The recent emergence of group B streptococcal isolates exhibiting increased penicillin MICs at the Funabashi Municipal Medical Center and other hospitals in Japan prompted a comparative analysis of the penicillin-binding proteins (PBPs) from those strains with the PBPs from penicillin-susceptible strains comprising four neonatal invasive strains isolated from 1976 to 1988 and two recent isolates. The PBP sequences of the penicillin-susceptible strains were highly conserved, irrespective of their isolation date. Of six strains with reduced susceptibility to penicillin (penicillin MICs, 0.25 to 0.5 μg/ml), strains R1, R2, R5, and R6 shared a unique set of five amino acid substitutions, including V405A adjacent to the 402SSN404 motif in PBP 2X and one in PBP 2B. The remaining two strains, R3 and R4, shared several substitutions, including Q557E adjacent to the 552KSG554 motif in PBP 2X, in addition to the substitutions in PBP 2B, which are commonly found among penicillin-insusceptible strains. Strains R7 and R8, which had a penicillin MIC of 1 μg/ml, shared a unique set of eight amino acid substitutions (two in PBP 2X; two in PBP 2B, including G613R adjacent to the 614KTG616 motif; three in PBP 1A; and one in PBP 2A), and the Q557E substitution in PBP 2X was common to R3 and R4. The binding of Bocillin FL was reduced or not detected in some PBPs, including PBP 2X of penicillin-insusceptible strains, but no significant reduction in the level of pbp2x transcription was found in such strains. The results of phylogenetic comparative analyses imply the absence of epidemic penicillin-insusceptible strains, and several genetic lineages of penicillin-insusceptible strains have been independently emerging through the accumulation of mutations in their pbp genes, especially in pbp2x

Bridging to transplant and post-transplant maintenance therapy with FLT3 inhibitors in patients with relapsed or refractory FLT3 mutated acute myeloid leukemia

ABSTRACTObjectives and Methods This single-center retrospective study was performed to evaluate the safety and efficacy of FMS-like tyrosine kinase 3 (FLT3) inhibitors before and after allogeneic hematopoietic cell transplantation (HCT) in relapsed/refractory patients with FLT3-mutation positive acute myeloid leukemia (AML).Results Ten patients who met the eligibility criteria were included. Eight of them achieved hematological remission at HCT, within a median span of 79 days (range: 43–197). In post-HCT, patients started maintenance therapy (MT; median time-to-start 79 days, range: 43–197), and the median duration of MT was 390 days (range: 67–815). Grade 3 hematological adverse events (AEs) were found in two patients, and non-hematological AEs were found in five patients. Nine patients underwent either dose reduction, discontinuation of therapy, or a switch to another FLT3 inhibitor due to AEs. Disease relapse occurred in one patient during MT. At the time of the last follow-up, seven patients are alive and disease-free, while three have died due to infection or transplant complications.Conclusion In relapsed/refractory FLT3 mutation-positive AML, the use of FLT3 inhibitors can lead to high response rates and provide a safe bridge from HCT to MT. If sufficient attention is paid to safety, this therapy is expected to prevent disease relapse even with reduced dosages

A Case of Giant Squamous Cell Carcinoma of the Buttock Possibly Arose from Syringocystadenoma and Invaded to the Rectum

We report a rare case of giant squamous cell carcinoma of the buttock infiltrated to the rectum. The tumor may have arisen from syringocystadenoma papilliferum. Since there was no sign of metastasis, radical operation including rectal amputation was performed after successful neoadjuvant therapies. Afterwards, the patient has been alive free from disease for 15 months with no lymph node and distant organ metastasis

Predominance of methicillin-resistant Staphylococcus aureus SCCmec type II-CC5 and SCCmec type IV-CC1/CC8 among companion animal clinical isolates in Japan: Findings from phylogenetic comparison with human clinical isolates

Objectives: To characterise the genotypic profiles of methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates from companion animals and to investigate their association with those from humans in Japan.Methods: Non-duplicated MRSA clinical isolates recovered between July 2016 and January 2018 were analysed. The MRSA isolates were typed by polymerase chain reaction (PCR)-based open reading frame (ORF) typing (POT) scores, SCCmec types, multilocus sequence typing, and virulence gene profiles. Phylogenetic comparison of those isolates with previously described human isolates was performed.Results: Among 56 MRSA isolates (33 cats, 20 dogs and three rabbits), 26 isolates with a POT1 score of 93, SCCmec type II mostly belonged to CC5, including ST5. Twenty-six isolates with a POT1 score of 106, SCCmec type IV showed diversity of STs: 15 isolates belonged to CC8, mainly including ST8, and 11 isolates belonged to CC1, including ST1 and newly identified STs 4768, 4775, and 4779. Two cat isolates were ST8-SCCmec type IV possessing pvl/ACME-arcA, presumed to be the hypervirulent community-associated MRSA (CA-MRSA) clone USA300. Notably, all three rabbit isolates belonged to ST4768. The POT1 score 106 CA-MRSA isolates from animals and humans were divided into two large clusters of CC1 and CC8, where host species-specific sub-clusters were not identified within each cluster. A large cluster of POT1 score 93 healthcare-associated MRSA (HA-MRSA) isolates from animals and humans consisted of sub-clusters formed exclusively by the vast majority of human isolates and those formed by animal and human isolates.Conclusion: Companion animals could be potential reservoirs and vehicles for the transmission of CA-MRSA to humans, and could transmit companion animal-adaptive HA-MRSA lineages to humans as their second reservoirs.ArticleJournal of Global Antimicrobial Resistance 20 : 253-259(2020)journal articl

A coarse grained molecular dynamics study on the structure and stability of small-sized liposomes

<div><p>The dependence of geometric structure and thermal stability of liposomes on their component phospholipid molecules and distribution of molecules in the inner and the outer layers of the liposome is investigated by conducting molecular simulations in explicit water for the eight types of liposomes constructed from different phospholipids. Using molecular mechanics structure-relaxation based on the coarse grained (CG) model, stable structures of the solvated liposomes are obtained. In addition, the molecular dynamics (MD) simulations based on the CG model are carried out at 310 and 360 K for elucidating the change in structure of the solvated liposomes. The MD simulations reveal that liposomes having the same number of lipids (SNL) in both the inner and the outer layers keep their spherical structures even at 360 K. In particular, the SNLs composed of palmitoyloleoyl-phosphatidyl-ethanolamine1 or dimyristoylglycero-phosphatidyl-choline lipid exhibit a compact spherical shape. In contrast, liposomes having the same density of lipids in the inner and the outer layers cannot keep their spherical shapes at 360 K. The obtained results contribute toward developing novel liposomes with enhanced thermal stability.</p></div

Alteration of mitochondrial functions by lipid peroxidation and inhibition by biscoclaurine alkaloid

During investigation of the changes in mitochondrial function accompanying lipid peroxidation, it was found that a biscoclaurine alkaroid protected their functional changes. The results obtained were as follows: 1) Fe(2+) induces lipid peroxidation of isolated mitochondria, resulting in deterioration of oxidative phosphorylation. 2) This deterioration relates to alteration in ion compartmentation of the mitochondrial membrane and an increase in latent ATPase activity. 3) This deterioration by Fe(2+) in ion compartmentation of mitochondrial membrane is strongly protected by a biscoclaurine alkaloid, cepharanthine. 4) Cepharanthine also inhibits the mitochondrial. lipid peroxidation induced by Fe(2+). 5) The protective effect of cepharanthine against deterioration in mitochondrial functions caused by Fe(2+) depends on its inhibitive action on lipid peroxidation as well as on its membrane stabilizing action. 6) Cepharanthine inhibits the lipid peroxidation of soybean lecithine liposomes by (60)Co-irradiation. 7) The action of cepharanthine described above is common to head to head type of biscoclaurin alkaloids which have diether bonds

Interconnected porous hydroxyapatite ceramics for bone tissue engineering

Several porous calcium hydroxyapatite (HA) ceramics have been used clinically as bone substitutes, but most of them possessed few interpore connections, resulting in pathological fracture probably due to poor bone formation within the substitute. We recently developed a fully interconnected porous HA ceramic (IP-CHA) by adopting the ‘foam-gel’ technique. The IP-CHA had a three-dimensional structure with spherical pores of uniform size (average 150 μm, porosity 75%), which were interconnected by window-like holes (average diameter 40 μm), and also demonstrated adequate compression strength (10–12 MPa). In animal experiments, the IP-CHA showed superior osteoconduction, with the majority of pores filled with newly formed bone. The interconnected porous structure facilitates bone tissue engineering by allowing the introduction of mesenchymal cells, osteotropic agents such as bone morphogenetic protein or vasculature into the pores. Clinically, we have applied the IP-CHA to treat various bony defects in orthopaedic surgery, and radiographic examinations demonstrated that grafted IP-CHA gained radiopacity more quickly than the synthetic HA in clinical use previously. We review the accumulated data on bone tissue engineering using the novel scaffold and on clinical application in the orthopaedic field