Direct observation of imploded core heating via fast electrons with super-penetration scheme

Fast ignition (FI) is a promising approach for high-energy-gain inertial confinement fusion in the laboratory. To achieve ignition, the energy of a short-pulse laser is required to be delivered efficiently to the pre-compressed fuel core via a high-energy electron beam. Therefore, understanding the transport and energy deposition of this electron beam inside the pre-compressed core is the key for FI. Here we report on the direct observation of the electron beam transport and deposition in a compressed core through the stimulated Cu Kα emission in the super-penetration scheme. Simulations reproducing the experimental measurements indicate that, at the time of peak compression, about 1% of the short-pulse energy is coupled to a relatively low-density core with a radius of 70 μm. Analysis with the support of 2D particle-in-cell simulations uncovers the key factors improving this coupling efficiency. Our findings are of critical importance for optimizing FI experiments in a super-penetration scheme.

Band-dependent superconducting gap in SrFe2(As0.65P0.35)2 studied by angle-resolved photoemission spectroscopy

The isovalent-substituted iron pnictide compound SrFe₂(As_1−xP_x)₂ exhibits multiple evidence for nodal superconductivity via various experimental probes, such as the penetration depth, nuclear magnetic resonance and specific heat measurements. The direct identification of the nodal superconducting (SC) gap structure is challenging, partly because the presence of nodes is not protected by symmetry but instead caused by an accidental sign change of the order parameter, and also because of the three-dimensionality of the electronic structure. We have studied the SC gaps of SrFe₂(As_0.65P_0.35)₂ in three-dimensional momentum space by synchrotron and laser-based angle-resolved photoemission spectroscopy. The three hole Fermi surfaces (FSs) at the zone center have SC gaps with different magnitudes, whereas the SC gaps of the electron FSs at the zone corner are almost isotropic and k_z-independent. As a possible nodal SC gap structure, we propose that the SC gap of the outer hole FS changes sign around the Z-X [(0, 0, 2π) − (π, π, 2π)] direction.

A Pilot Study of Soluble Form of LOX-1 as a Novel Biomarker for Neonatal Hypoxic-Ischemic Encephalopathy

OBJECTIVE

To evaluate the soluble form of lectin-like oxidized low-density lipoprotein receptor-1 (sLOX-1) as a biomarker of severity staging and prognosis in neonatal hypoxic-ischemic encephalopathy (HIE).

STUDY DESIGN

We performed an observational study enrolling 27 infants with HIE and 45 control infants of gestational age ≥36 weeks and birth weight ≥1800 g. The HIE criteria were pH ≤7.0 or a base deficit ≥16 mmol/L within 60 minutes after birth, and a 10-minute Apgar score ≤5 or resuscitation time ≥10 minutes. HIE severity was evaluated using modified Sarnat staging. We measured plasma sLOX-1 level and assessed general and neurologic signs at discharge, and classified infants with no neurosensory impairments as intact survival.

RESULTS

sLOX-1 level within 6 hours after birth was correlated with the severity of HIE. sLOX-1 differentiated moderate-severe HIE (median, 1017 pg/mL; IQR, 553-1890 pg/mL) from mild HIE (median, 339 pg/mL; IQR, 288-595 pg/mL; P = .007). The sensitivity and specificity of the differentiation with a cutoff value of ≥550 pg/mL were 80.0% and 83.3%, respectively. In 19 infants with therapeutic hypothermia, a sLOX-1 cutoff value of <1000 pg/mL differentiated intact survival (median, 761 pg/mL; IQR, 533-1610 pg/mL) from death or neurosensory impairment (median, 1947 pg/mL; IQR, 1325-2506 pg/mL; P = .019) with 100% specificity and a positive predictive value.

CONCLUSION

sLOX-1 may be a useful biomarker of neonatal HIE for severity staging and outcome prediction. Further investigations will facilitate its clinical use.

First report on USA300 outbreak in a neonatal intensive care unit detected by polymerase chain reaction-based open reading frame typing in Japan

Outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) in the neonatal intensive care unit (NICU) have been reported worldwide. Some outbreaks were caused by USA300, which is a community-associated MRSA clone. In 2011, polymerase chain reaction-based open reading frame typing (POT) for the initial MRSA isolates from all inpatients was started at the Tokyo Metropolitan Children's Medical Center. From March 2014 to April 2015, a total of 131 MRSA strains were isolated, 104 of which were analyzed as healthcare-associated MRSA. Thirteen stains (12.5%) had a POT number of 106-9-93, which strongly suggested USA300; these included 6 from nasal swabs, 6 from blood cultures and 1 from subcutaneous pus. All the MRSA strains were isolated from patients in the NICU; were typed as sequence type 8, spa type t008, and staphylococcal cassette chromosome type mec IVa; and possessed the lukS-lukF and arginine catabolic mobile element-arcA gene. Pulsed-field gel electrophoresis of all the strains, with USA300-0114 as a reference, showed indistinguishable banding pattern. Based on these results, POT was useful in recognizing this first MRSA outbreak of USA300 in a Japanese NICU and was advantageous in terms of swiftness, less cost and monitoring change of the epidemic MRSA lineage.

Comparison of USA300 with non-USA300 methicillin-resistant Staphylococcus aureus in a neonatal intensive care unit

OBJECTIVES

Reports of USA300 methicillin-resistant Staphylococcus aureus (MRSA) strain were still scarce in neonatal intensive care units (NICUs) and the relationship of USA300 MRSA to clinical infections is still controversial. The primary outcome was the incidence of MRSA infections caused by the USA300 and non-USA300 strains at a NICU in Japan.

METHODS

This retrospective cohort study was conducted between November 2011 and October 2016 at Tokyo Metropolitan Children's Medical Center in Japan. All MRSA isolated after 48h of hospitalization were included for analysis by pulsed-field gel electrophoresis (PFGE) using the standard USA300 strain. Genes were tested for Panton-Valentine leukocidin (PVL) and arginine catabolic mobile element (ACME). A whole genome sequence was performed for representative isolates of USA300.

RESULTS

In total, 109 MRSA isolates were included for analysis. PFGE classified 34 and 75 isolates of USA300 and non-USA300 MRSA, respectively. Both PVL and ACME genes were detected in USA300 and non-USA300 strains at rate of 100% (34/34) and 5.3% (4/75), respectively (P<0.05). There was no statistically significant difference in the proportion of clinical diseases between USA- 300 and non-USA 300 strains.

CONCLUSIONS

Infants with USA300 MRSA infection did not differ significantly from those with non-USA300 MRSA infection.

Antimicrobial Stewardship Program in a Pediatric Intensive Care Unit

We conducted an antimicrobial stewardship program in a pediatric intensive care unit. An interrupted time-series analysis revealed a significant reduction in level and trend of days of therapy per 1000 patient-days for antipseudomonal agents. No increase in adverse patient outcomes was found.

Variable tibiofemoral articular contact stress in fixed-bearing total knee arthroplasties

BACKGROUND

Rotational allowance at the tibiofemoral joint would be required during deep flexion. However, the amount of flexion and rotation has not been investigated in modern total knee arthroplasty (TKA) designs. The present study aimed to determine the contact stress in five posterior-stabilized fixed-bearing TKA designs.

HYPOTHESIS

We hypothesized that the contact area and stresses at the tibiofemoral articular surfaces vary according to the type of implant design and tested condition.

MATERIALS AND METHODS

The contact area and mean and peak contact stresses at the tibiofemoral articular surfaces were determined when a compressive load of 1200N was applied to a NexGen LPS Flex, Scorpio NRG, Genesis II, PFC Sigma, and Foundation implant. Measurements were performed at 0° and 45° flexion with 0°, 5°, 10°, and 15° rotation, and at 90° and 135° flexion with 0, 5°, 10°, 15°, and 20° rotation.

RESULTS

The LPS Flex showed that the femoral component could not achieve 20° rotation at 135° flexion. The Scorpio NRG showed less than 20MPa of contact stress at all conditions. The Genesis II showed higher contact stress than 20MPa at 135° flexion with 20° rotation. The PFC Sigma showed that the femoral component could not achieve >10° rotation at any flexion angle. The Foundation showed more than 20MPa of contact stress at 90° flexion with 20° rotation and at 135° flexion with 10°, 15°, and 20° rotation.

DISCUSSION

Surgeons should be more aware of the variable contact conditions of the tibiofemoral articular surfaces in individual TKA designs.

LEVEL OF EVIDENCE

Level IV, basic science study.

Sibling visits and viral infection in the neonatal intensive care unit

BACKGROUND

Sibling visits to the neonatal intensive care unit (NICU) are a part of family-centered care, which is now being increasingly endorsed as a positive development in patient care. Sibling visits, however, pose a risk of viral infection, and hence many NICU in Japan impose strict limits on the practice. The aim of this study was therefore to assess whether sibling visits to the NICU are related to an increase in the nosocomial viral infection rate.

METHODS

This retrospective study was conducted between April 2012 and March 2017 at Tokyo Metropolitan Children's Medical Center in Japan. Sibling visits were implemented after screening for symptoms of viral illness. Symptomatic patients in the NICU were tested for common viruses on rapid antigen test and polymerase chain reaction. The number of sibling visits and the rate of nosocomial viral infections were examined on Spearman's correlation test.

RESULTS

The total number of sibling visits and rate of nosocomial viral infection in the NICU was 102 and 0.068 per 1,000 patient-days during the study period, respectively. The number of enterovirus, respiratory syncytial virus, human metapneumovirus, influenza virus A, and Herpes simplex virus infections was 3, 2, 1, 1, 1, and 1, respectively. No infections were identified after sibling visits. The number of sibling visits and the rate of nosocomial viral infections were not correlated (correlation coefficient, -0.1; P = 0.873).

CONCLUSION

Sibling visits to the NICU did not result in an increase in the nosocomial viral infection rate.

Sustained pediatric antimicrobial stewardship program with consultation to infectious diseases reduced carbapenem resistance and infection-related mortality

OBJECTIVE

The impact of pediatric antimicrobial stewardship programs (ASP) on antimicrobial resistance (AMR) remains largely unknown. This study aimed to evaluate the AMR for carbapenem of Gram-negative bacilli (GNB) and carbapenem use with infectious diseases consultation after the implementation of an ASP.

METHODS

This quasi-experimental study was conducted at Tokyo Metropolitan Children's Medical Center in Japan. The pre- and post-intervention periods were April 2010 to September 2011 and October 2011 to March 2017, respectively. The pre-intervention phase consisted of consultations with the infectious diseases service alone. The ASP was implemented during the post-intervention phase. The carbapenem resistance rates of GNB were calculated. The correlation between carbapenem resistance rates and carbapenem day of therapy (DOT) was examined. The outcome metrics were compared by average length of hospitalization, all-cause mortality, and infection-related mortality.

RESULTS

A positive correlation was observed between the carbapenem resistance rate in Pseudomonas aeruginosa and DOT (0.76, p=0.04). The carbapenem resistance rate in P. aeruginosa (p<0.01) and DOT (p<0.01) decreased significantly in the post-intervention period. The length of hospitalization (p<0.01) and infection-related mortality (p=0.05) decreased in the post-intervention period.

CONCLUSIONS

A sustained ASP with additional consultation with the infectious disease service reduced carbapenem use and resistance in P. aeruginosa, leading to favorable outcomes in terms of length of hospitalization and infection-related mortality.

A Case of Congenital Folliculitis Caused by Pseudomonas aeruginosa in a Preterm Neonate

Intrauterine infections are associated with life-threatening neonatal conditions such as sepsis, intracranial hemorrhage, and chronic lung disease. Herein we present a case of generalized congenital folliculitis caused by Pseudomonas aeruginosa in a preterm neonate of 27 weeks gestational age successfully treated with antibiotics. Folliculitis is an important manifestation of intrauterine P. aeruginosa infection, and prompt, effective treatment is crucial to ensuring a good prognosis.

Characterisation of osteophytes as an autologous bone graft source: An experimental study in vivo and in vitro

Objectives

Osteophytes are products of active endochondral and intramembranous ossification, and therefore could theoretically provide significant efficacy as bone grafts. In this study, we compared the bone mineralisation effectiveness of osteophytes and cancellous bone, including their effects on secretion of growth factors and anabolic effects on osteoblasts.

Methods

Osteophytes and cancellous bone obtained from human patients were transplanted onto the calvaria of severe combined immunodeficient mice, with Calcein administered intra-peritoneally for fluorescent labelling of bone mineralisation. Conditioned media were prepared using osteophytes and cancellous bone, and growth factor concentration and effects of each graft on proliferation, differentiation and migration of osteoblastic cells were assessed using enzyme-linked immunosorbent assays, MTS ((3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium)) assays, quantitative real-time polymerase chain reaction, and migration assays.

Results

After six weeks, the area of mineralisation was significantly higher for the transplanted osteophytes than for the cancellous bone (43803 μm₂, sd 14660 versus 9421 μm₂, sd 5032, p = 0.0184, one-way analysis of variance). Compared with cancellous bone, the conditioned medium prepared using osteophytes contained a significantly higher amounts of transforming growth factor (TGF)-β1 (471 pg/ml versus 333 pg/ml, p = 0.0001, Wilcoxon rank sum test), bone morphogenetic protein (BMP)-2 (47.75 pg/ml versus 32 pg/ml, p = 0.0214, Wilcoxon rank sum test) and insulin-like growth factor (IGF)-1 (314.5 pg/ml versus 191 pg/ml, p = 0.0418, Wilcoxon rank sum test). The stronger effects of osteophytes towards osteoblasts in terms of a higher proliferation rate, upregulation of gene expression of differentiation markers such as alpha-1 type-1 collagen and alkaline phosphate, and higher migration, compared with cancellous bone, was confirmed.

Conclusion

We provide evidence of favourable features of osteophytes for bone mineralisation through a direct effect on osteoblasts. The acceleration in metabolic activity of the osteophyte provides justification for future studies evaluating the clinical use of osteophytes as autologous bone grafts.

Cite this article: K. Ishihara, K. Okazaki, T. Akiyama, Y. Akasaki, Y. Nakashima. Characterisation of osteophytes as an autologous bone graft source: An experimental study in vivo and in vitro. Bone Joint Res 2017;6:73–81. DOI: 10.1302/2046-3758.62.BJR-2016-0199.R1.

Serous cystic neoplasm of the pancreas: a multinational study of 2622 patients under the auspices of the International Association of Pancreatology and European Pancreatic Club (European Study Group on Cystic Tumors of the Pancreas)

OBJECTIVES

Serous cystic neoplasm (SCN) is a cystic neoplasm of the pancreas whose natural history is poorly known. The purpose of the study was to attempt to describe the natural history of SCN, including the specific mortality.

DESIGN

Retrospective multinational study including SCN diagnosed between 1990 and 2014.

RESULTS

2622 patients were included. Seventy-four per cent were women, and median age at diagnosis was 58 years (16-99). Patients presented with non-specific abdominal pain (27%), pancreaticobiliary symptoms (9%), diabetes mellitus (5%), other symptoms (4%) and/or were asymptomatic (61%). Fifty-two per cent of patients were operated on during the first year after diagnosis (median size: 40 mm (2-200)), 9% had resection beyond 1 year of follow-up (3 years (1-20), size at diagnosis: 25 mm (4-140)) and 39% had no surgery (3.6 years (1-23), 25.5 mm (1-200)). Surgical indications were (not exclusive) uncertain diagnosis (60%), symptoms (23%), size increase (12%), large size (6%) and adjacent organ compression (5%). In patients followed beyond 1 year (n=1271), size increased in 37% (growth rate: 4 mm/year), was stable in 57% and decreased in 6%. Three serous cystadenocarcinomas were recorded. Postoperative mortality was 0.6% (n=10), and SCN's related mortality was 0.1% (n=1).

CONCLUSIONS

After a 3-year follow-up, clinical relevant symptoms occurred in a very small proportion of patients and size slowly increased in less than half. Surgical treatment should be proposed only for diagnosis remaining uncertain after complete workup, significant and related symptoms or exceptionally when exists concern with malignancy. This study supports an initial conservative management in the majority of patients with SCN.

TRIAL REGISTRATION NUMBER

IRB 00006477.

Correction of coronal alignment correlates with reconstruction of joint height in unicompartmental knee arthroplasty

OBJECTIVES

Because there have been no standard methods to determine pre-operatively the thickness of resection of the proximal tibia in unicompartmental knee arthroplasty (UKA), information about the relationship between the change of limb alignment and the joint line elevation would be useful for pre-operative planning. The purpose of this study was to clarify the correlation between the change of limb alignment and the change of joint line height at the medial compartment after UKA.

METHODS

A consecutive series of 42 medial UKAs was reviewed retrospectively. These patients were assessed radiographically both pre- and post-operatively with standing anteroposterior radiographs. The thickness of bone resection at the proximal tibia and the distal femur was measured radiographically. The relationship between the change of femorotibial angle (δFTA) and the change of joint line height, was analysed.

RESULTS

The mean pre- and post-operative FTA was 180.5° (172.2° to 184.8°) and 175.0° (168.5° to 178.9°), respectively. The mean δFTA was 5.5° (2.3° to 10.1°). The joint line elevation of the tibia (JLET) was 4.4 mm (2.1 to 7.8). The δFTA was correlated with the JLET (correlation coefficient 0.494, p = 0.0009).

CONCLUSIONS

This study indicated that there is a significant correlation between the change of limb alignment and joint line elevation. This observation suggests that it is possible to know the requirement of elevation of the joint line to obtain the desired correction of limb alignment, and to predict the requirement of bone resection of the proximal tibia pre-operatively. Cite this article: Bone Joint Res 2015;4:128-133.

Correction of coronal alignment correlates with reconstruction of joint height in unicompartmental knee arthroplasty

Objectives

Because there have been no standard methods to determine pre-operatively the thickness of resection of the proximal tibia in unicompartmental knee arthroplasty (UKA), information about the relationship between the change of limb alignment and the joint line elevation would be useful for pre-operative planning. The purpose of this study was to clarify the correlation between the change of limb alignment and the change of joint line height at the medial compartment after UKA.

Methods

A consecutive series of 42 medial UKAs was reviewed retrospectively. These patients were assessed radiographically both pre- and post-operatively with standing anteroposterior radiographs. The thickness of bone resection at the proximal tibia and the distal femur was measured radiographically. The relationship between the change of femorotibial angle (δFTA) and the change of joint line height, was analysed.

Results

The mean pre- and post-operative FTA was 180.5° (172.2° to 184.8°) and 175.0° (168.5° to 178.9°), respectively. The mean δFTA was 5.5° (2.3° to 10.1°). The joint line elevation of the tibia (JLET) was 4.4 mm (2.1 to 7.8). The δFTA was correlated with the JLET (correlation coefficient 0.494, p = 0.0009).

Conclusions

This study indicated that there is a significant correlation between the change of limb alignment and joint line elevation. This observation suggests that it is possible to know the requirement of elevation of the joint line to obtain the desired correction of limb alignment, and to predict the requirement of bone resection of the proximal tibia pre-operatively. Cite this article: Bone Joint Res 2015;4:128–133

Congenital dacryocystoceles controlled by nCPAP via nasal mask in a neonate

Congenital dacryocystocele is a relatively rare type of nasolacrimal duct obstruction that may induce respiratory distress during the early neonatal period. We encountered a case of bilateral congenital dacryocystoceles with intranasal cysts in a premature infant delivered at 34 weeks of gestation. The patient developed symptoms of respiratory failure immediately after birth, but no ophthalmologic symptoms. Treatment with nasal continuous positive airway pressure via a nasal mask, instead of a nasal prong, effectively relieved the symptoms. Early diagnosis and appropriate treatment are critical for infants with nasal obstruction.

Histidine-rich protein as a possible origin of free amino acids of stratum corneum

The origin of free amino acids and/or their metabolites of the stratum corneum was investigated by pulse-chase experiments using hairless mice. Two, 24, 48, and 72 hrs after the animals were pulse-chased with 3H-histidine or 3H-arginine, radioactivity was determined in the following three fractions of the epidermis: the 0.1 N HClO4 soluble, ethanol soluble fraction (Fr. I); the 0.1N NClO4 soluble, ethanol insoluble fraction (Fr. II); and the 0.1 N HClO4 insoluble, 8M urea soluble fraction (Fr. III). Radioactivity of the epidermal proteins was also determined in SDS-PAGE gels by the gel slicing method. At first, 3H-histidine and/or 3H-arginine were predominantly incorporated into Fr. III, especially into a certain epidermal protein which showed little mobility on SDS-PAGE. Subsequently, 3H, once incorporated into Fr. III, appeared to shift from Fr. III to Fr. II and, simultaneously, from the top band(s) to a band of 32,000 daltons. As a result of amino acid analysis, a protein of Fr. II was considered a histidine-rich protein corresponding to HRP-II of the new born rats of Ball et al. After 48 hrs, as the radioactivities of Fr. III and Fr. II decreased remarkably, Fr. I gradually increased in radioactivity. The major radioactive substances in Fr. I at 72 hrs were identified as 3H-histidine and 3H-urocanic acid when 3H-histidine was used as a tracer, and as 3H-arginine, 3H-ornithine, and 3H-citrulline in the case of 3H-arginine. The amino acid composition of the histidine-rich protein was very similar to that of the free amino acids of the stratum corneum in the hairless mouse, in which some amino acid metabolites were considered as their precursor amino acids. These results strongly suggest that the free amino acids and/or their metabolites of the stratum corneum might be the final products of a degradation of the histidine-rich protein.

Phosphorylation of Smad2/3 at the specific linker threonine residue indicates slow-cycling esophageal stem-like cells before re-entry to the cell cycle

The stem cell compartment in the esophageal epithelium is possibly located in the basal layer. We have identified significant expression of Smad2/3, phosphorylated at specific linker threonine residues (pSmad2/3L-Thr), in the epithelial cells of murine stomach and intestine, and have suggested that these cells are epithelial stem cells. In this study, we explore whether pSmad2/3L-Thr could serve as a biomarker for esophageal stem cells. We examined esophageal tissues from normal C57BL/6 mice and those with esophagitis. Double immunofluorescent staining of pSmad2/3L-Thr with Ki67, CDK4, p63, or CK14 was performed. After immunofluorescent staining, we stained the same sections with hematoxylin-eosin and observed these cells under a light microscope. We used the 5-bromo-2-deoxyuridine (BrdU) labeling assay to examine label retention of pSmad2/3L-Thr immunostaining-positive cells. We collected specimens 5, 10, 15 and 20 days after repeated BrdU administrations and observed double immunofluorescent staining of pSmad2/3L-Thr with BrdU. In the esophagus, pSmad2/3L-Thr immunostaining-positive cells were detected in the basal layer. These cells were detected between Ki67 immunostaining-positive cells, but they were not co-localized with Ki67. pSmad2/3L-Thr immunostaining-positive cells showed co-localization with CDK4, p63, and CK14. Under a light microscope, pSmad2/3L-Thr immunostaining-positive cells indicated undifferentiated morphological features. Until 20 days follow-up period, pSmad2/3L-Thr immunostaining-positive cells were co-localized with BrdU. pSmad2/3L-Thr immunostaining-positive cells significantly increased in the regeneration phase of esophagitis mucosae, as compared with control mice (esophagitis vs.

CONTROL

6.889 ± 0.676/cm vs. 4.293 ± 0.659/cm; P < 0.001). We have identified significant expression of pSmad2/3L-Thr in the specific epithelial cells of murine esophagi. We suggest that these cells are slow-cycling epithelial stem-like cells before re-entry to the cell cycle.