Neurobehavioral Differences Between Mice Receiving Distinct Neuregulin Variants as Neonates; Impact on Sensitivity to MK-801

Neuregulin-1 (NRG1) is a well-recognized risk gene for schizophrenia and is often implicated in the neurodevelopmental hypothesis of this illness. Alternative splicing and proteolytic processing of the NRG1 gene produce more than 30 structural variants; however, the neuropathological roles of individual variants remain to be characterized. On the basis of the neurodevelopmental hypothesis of schizophrenia, we administered eNRG1 (0.1~1.0 μg/g), a core epidermal growth factor-like (EGF) domain common for all splicing NRG1 variants, to neonatal mice and compared their behavioral performance with mice challenged with a full mature form of type 1 NRG1 variant. During the neonatal stage, recombinant eNRG1 protein administrated from the periphery passed the blood-brain barrier and activated its receptor (ErbB4) in the brain. In adults, the mice receiving the highest dose exhibited lower locomotor activity and deficits in prepulse inhibition and tonedependent fear learning, although the hearing reduction of the eNRG1-treated mice may explain these behavioral deficits. Neonatal eNRG1 treatment also significantly potentiated MK-801-driven locomotor activity in an eNRG1 dose-dependent manner. In parallel eNRG1 treatment enhanced MK-801-driven c-Fos induction and decreased immunoreactivity for NMDA receptor subunits in adult brain. In contrast, mice that had been treated with the same molar dose of a full mature form of type 1 NRG1 as neonates did not exhibit hypersensitivity to MK-801. However, both animal models exhibited similar hypersensitivity to methamphetamine. Collectively, our findings suggest that aberrant peripheral NRG1 signals during neurodevelopment alter later behavioral traits and auditory functions in the NRG1 subtype-dependent manner.

Salivary pathogen and serum antibody to assess the progression of chronic periodontitis: a 24-mo prospective multicenter cohort study

BACKGROUND AND OBJECTIVE

A diagnosis of periodontitis progression is presently limited to clinical parameters such as attachment loss and radiographic imaging. The aim of this multicenter study was to monitor disease progression in patients with chronic periodontitis during a 24-mo follow-up program and to evaluate the amount of bacteria in saliva and corresponding IgG titers in serum for determining the diagnostic usefulness of each in indicating disease progression and stability.

MATERIAL AND METHODS

A total of 163 patients with chronic periodontitis who received trimonthly follow-up care were observed for 24 mo. The clinical parameters and salivary content of Porphyromonas gingivalis, Prevotella intermedia and Aggregatibacter actinomycetemcomitans were assessed using the modified Invader PLUS assay, and the corresponding serum IgG titers were measured using ELISA. The changes through 24 mo were analyzed using cut-off values calculated for each factor. One-way ANOVA or Fisher's exact test was used to perform between-group comparison for the data collected. Diagnostic values were calculated using Fisher's exact test.

RESULTS

Of the 124 individuals who completed the 24-mo monitoring phase, 62 exhibited periodontitis progression, whereas 62 demonstrated stable disease. Seven patients withdrew because of acute periodontal abscess. The ratio of P. gingivalis to total bacteria and the combination of P. gingivalis counts and IgG titers against P. gingivalis were significantly related to the progression of periodontitis. The combination of P. gingivalis ratio and P. gingivalis IgG titers was significantly associated with the progression of periodontitis (p = 0.001, sensitivity = 0.339, specificity = 0.790).

CONCLUSIONS

It is suggested that the combination of P. gingivalis ratio in saliva and serum IgG titers against P. gingivalis may be associated with the progression of periodontitis.

High-Resolution C-Arm CT and Metal Artifact Reduction Software: A Novel Imaging Modality for Analyzing Aneurysms Treated with Stent-Assisted Coil Embolization

BACKGROUND AND PURPOSE

Combination of high-resolution C-arm CT and novel metal artifact reduction software may contribute to the assessment of aneurysms treated with stent-assisted coil embolization. This study aimed to evaluate the efficacy of a novel Metal Artifact Reduction prototype software combined with the currently available high spatial-resolution C-arm CT prototype implementation by using an experimental aneurysm model treated with stent-assisted coil embolization.

MATERIALS AND METHODS

Eight experimental aneurysms were created in 6 swine. Coil embolization of each aneurysm was performed by using a stent-assisted technique. High-resolution C-arm CT with intra-arterial contrast injection was performed immediately after the treatment. The obtained images were processed with Metal Artifact Reduction. Five neurointerventional specialists reviewed the image quality before and after Metal Artifact Reduction. Observational and quantitative analyses (via image analysis software) were performed.

RESULTS

Every aneurysm was successfully created and treated with stent-assisted coil embolization. Before Metal Artifact Reduction, coil loops protruding through the stent lumen were not visualized due to the prominent metal artifacts produced by the coils. These became visible after Metal Artifact Reduction processing. Contrast filling in the residual aneurysm was also visualized after Metal Artifact Reduction in every aneurysm. Both the observational (P < .0001) and quantitative (P < .001) analyses showed significant reduction of the metal artifacts after application of the Metal Artifact Reduction prototype software.

CONCLUSIONS

The combination of high-resolution C-arm CT and Metal Artifact Reduction enables differentiation of the coil mass, stent, and contrast material on the same image by significantly reducing the metal artifacts produced by the platinum coils. This novel image technique may improve the assessment of aneurysms treated with stent-assisted coil embolization.

Outbreak of extended-spectrum β-lactamase-producing Escherichia coli transmitted through breast milk sharing in a neonatal intensive care unit

BACKGROUND

Routine surveillance in a neonatal intensive care unit (NICU) showed an increased detection of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-E. coli) in August 2012, following nearly a year without detection.

AIM

To describe the investigation and interventions by a hospital infection control team of an outbreak of ESBL-E. coli in a NICU.

METHODS

Six neonates with positive cultures of ESBL-E. coli (five with respiratory colonization, one with a urinary tract infection), control infants who were negative for ESBL-E. coli during the study period, and mothers who donated their breast milk were included. A case-control study was performed to identify possible risk factors for positive ESBL-E. coli cultures and molecular typing of isolated strains by pulsed-field gel electrophoresis.

FINDINGS

The odds ratio for ESBL-E. coli infection after receiving shared unpasteurized breast milk during the study period was 49.17 (95% confidence interval: 6.02-354.68; P < 0.05). The pulsed-field gel electrophoresis pattern showed that all strains were identical, and the same pathogen was detected in freshly expressed milk of a particular donor. After ceasing the breast milk sharing, the outbreak was successfully terminated.

CONCLUSION

This outbreak indicates that contamination of milk packs can result in transmission of a drug-resistant pathogen to newborn infants. Providers of human breast milk need to be aware of the necessity for low-temperature pasteurization and bacterial cultures, which should be conducted before and after freezing, before prescribing to infants.

Direct heating of a laser-imploded core by ultraintense laser-driven ions

A novel direct core heating fusion process is introduced, in which a preimploded core is predominantly heated by energetic ions driven by LFEX, an extremely energetic ultrashort pulse laser. Consequently, we have observed the D(d,n)^{3}He-reacted neutrons (DD beam-fusion neutrons) with the yield of 5×10^{8} n/4π sr. Examination of the beam-fusion neutrons verified that the ions directly collide with the core plasma. While the hot electrons heat the whole core volume, the energetic ions deposit their energies locally in the core, forming hot spots for fuel ignition. As evidenced in the spectrum, the process simultaneously excited thermal neutrons with the yield of 6×10^{7} n/4π sr, raising the local core temperature from 0.8 to 1.8 keV. A one-dimensional hydrocode STAR 1D explains the shell implosion dynamics including the beam fusion and thermal fusion initiated by fast deuterons and carbon ions. A two-dimensional collisional particle-in-cell code predicts the core heating due to resistive processes driven by hot electrons, and also the generation of fast ions, which could be an additional heating source when they reach the core. Since the core density is limited to 2 g/cm^{3} in the current experiment, neither hot electrons nor fast ions can efficiently deposit their energy and the neutron yield remains low. In future work, we will achieve the higher core density (>10 g/cm^{3}); then hot electrons could contribute more to the core heating via drag heating. Together with hot electrons, the ion contribution to fast ignition is indispensable for realizing high-gain fusion. By virtue of its core heating and ignition, the proposed scheme can potentially achieve high gain fusion.

Response measurement of single-crystal chemical vapor deposition diamond radiation detector for intense X-rays aiming at neutron bang-time and neutron burn-history measurement on an inertial confinement fusion with fast ignition

A neutron bang time and burn history monitor in inertial confinement fusion with fast ignition are necessary for plasma diagnostics. In the FIREX project, however, no detector attained those capabilities because high-intensity X-rays accompanied fast electrons used for plasma heating. To solve this problem, single-crystal CVD diamond was grown and fabricated into a radiation detector. The detector, which had excellent charge transportation property, was tested to obtain a response function for intense X-rays. The applicability for neutron bang time and burn history monitor was verified experimentally. Charge collection efficiency of 99.5% ± 0.8% and 97.1% ± 1.4% for holes and electrons were obtained using 5.486 MeV alpha particles. The drift velocity at electric field which saturates charge collection efficiency was 1.1 ± 0.4 × 10(7) cm/s and 1.0 ± 0.3 × 10(7) cm/s for holes and electrons. Fast response of several ns pulse width for intense X-ray was obtained at the GEKKO XII experiment, which is sufficiently fast for ToF measurements to obtain a neutron signal separately from X-rays. Based on these results, we confirmed that the single-crystal CVD diamond detector obtained neutron signal with good S/N under ion temperature 0.5-1 keV and neutron yield of more than 10(9) neutrons/shot.

3-T MRI safety assessments of magnetic dental attachments and castable magnetic alloys

OBJECTIVES

To assess the safety of different magnetic dental attachments during 3-T MRI according to the American Society for Testing and Materials F2182-09 and F2052-06e1 standard testing methods and to develop a method to determine MRI compatibility by measuring magnetically induced torque.

METHODS

The temperature elevations, magnetically induced forces and torques of a ferromagnetic stainless steel keeper, a coping comprising a keeper and a cast magnetic alloy coping were measured on MRI systems.

RESULTS

The coping comprising a keeper demonstrated the maximum temperature increase (1.42 °C) for the whole-body-averaged specific absorption rate and was calculated as 2.1 W kg⁻¹ with the saline phantom. All deflection angles exceeded 45°. The cast magnetic alloy coping had the greatest deflection force (0.33 N) during 3-T MRI and torque (1.015 mN m) during 0.3-T MRI.

CONCLUSIONS

The tested devices showed minimal radiofrequency (RF)-induced heating in a 3-T MR environment, but the cast magnetic alloy coping showed a magnetically induced deflection force and torque approximately eight times that of the keepers. For safety, magnetic dental attachments should be inspected before and after MRI and large prostheses containing cast magnetic alloy should be removed. Although magnetic dental attachments may pose no great risk of RF-induced heating or magnetically induced torque during 3-T MRI, their magnetically induced deflection forces tended to exceed acceptable limits. Therefore, the inspection of such devices before and after MRI is important for patient safety.

Species differences in the metabolism of ritobegron in vitro and assessment of potential interactions with transporters and cytochrome P450 enzymes

Ritobegron, a selective β3-adrenoceptor agonist, is the prodrug of the active compound, KUC-7322. We investigated species differences in its metabolism in vitro and the potential for drug-drug interactions with ritobegron. In rat, dog, monkey, and human liver microsomes, ritobegron was not metabolized by cytochrome P450 enzymes (CYPs). KUC-7322 was the only metabolite observed. Hydrolysis of ritobegron to KUC-7322 was likely catalyzed by carboxylesterases in human liver microsomes. The maximum velocity of the reaction (V(max))/Michaelis-Menten constant (K(m)) for hydrolysis of ritobegron to KUC-7322 was much higher in rat serum than those in other species. There were also species differences in the conjugation of KUC-7322. Sulfate conjugates of ritobegron were detected in all species, whereas glucuronide and glutathione conjugates of KUC-7322 were only observed in rat liver subcellular fractions. Ritobegron and KUC-7322 did not affect the CYP-mediated metabolism of probe substrates in human liver microsomes and organic anion transporter 1 (OAT1)-, OAT2-, OAT3-, organic cation transporter 2 (OCT-2)-, OCT3-, or organic cation/carnitine transporter 1 (OCTN1)-mediated uptake of probe substrates in S2 cells. Ritobegron, but not KUC-7322, inhibited P-glycoprotein-mediated digoxin transport in Caco-2 cells. Significant uptake of KUC-7322 was observed in OAT3-expressing S2 cells. Therefore, CYP-mediated drug-drug interactions are not likely when ritobegron is administered with CYP substrates or inhibitors. Ritobegron may increase the plasma concentrations of P-glycoprotein substrates, such as digoxin, and the plasma concentration of KUC-7322 may increase when it is administered in combination with OAT inhibitors such as probenecid.

Absorption, disposition, metabolism, and excretion of ritobegron (KUC-7483), a novel selective β3-adrenoceptor agonist, in rats

The pharmacokinetic profile of ritobegron, a novel, selective β3-adrenoceptor agonist, was investigated in rats. Ritobegron, an ethyl ester prodrug of the active compound KUC-7322, or KUC-7322 itself was orally administered (10 mg/kg). Ethyl esterification resulted in a 10-fold increase in the area under the plasma concentration-time curve (AUC(0-t)), as compared to KUC-7322. Following intravenous administration of KUC-7322 (1 mg/kg), total blood clearance was 1.36 L/h/kg, suggesting that intrinsic hepatic clearance is the rate-limiting step in KUC-7322 excretion. When ritobegron was orally administered (0.3, 1, 3, and 10 mg/kg), plasma concentrations of KUC-7322 rapidly increased and reached a maximum concentration (C(max)) at 0.25 to 0.31 h. KUC-7322 levels rapidly decreased, with a half-life (t 1/2) of 0.42 to 1.37 h thereafter. AUC(0-t) did not show a dose-dependent increase. The bioavailability of KUC-7322 was estimated to be 4%. Following oral administration of [14C]ritobegron (3 mg/kg), radioactivity concentrations in tissues rapidly increased and declined in parallel with changes in plasma concentration. In most of tissues, excluding the liver, kidney, urinary bladder, stomach and small intestine, radioactivity concentrations were lower than that in plasma. In plasma, bile, urine, and feces, KUC-7322 and its glucuronide, sulfate, and glutathione conjugates were detected. The glucuronide conjugate of KUC-7322 was the predominant metabolite in bile, plasma, and urine, and KUC-7322 was predominant in feces. Ritobegron was not detected in any of the samples. The cumulative excretion of radioactivity in urine and feces were 28.7% and 68.3% of the dose, respectively, up to 120 h after administration.

Photonuclear reaction based high-energy x-ray spectrometer to cover from 2 MeV to 20 MeV

A photonuclear-reaction-based hard x-ray spectrometer is developed to measure the number and energy spectrum of fast electrons generated by interactions between plasma and intense laser light. In this spectrometer, x-rays are converted to neutrons through photonuclear reactions, and the neutrons are counted with a bubble detector that is insensitive to x-rays. The spectrometer consists of a bundle of hard x-ray detectors that respond to different photon-energy ranges. Proof-of-principle experiment was performed on a linear accelerator facility. A quasi-monoenergetic electron bunch (Ne = 1.0 × 10(-6) C, Ee = 16 ± 0.32 MeV) was injected into a 5-mm-thick lead plate. Bremsstrahlung x-rays, which emanate from the lead plate, were measured with the spectrometer. The measured spectral shape and intensity agree fairly well with those computed with a Monte Carlo simulation code. The result shows that high-energy x-rays can be measured absolutely with a photon-counting accuracy of 50%-70% in the energy range from 2 MeV to 20 MeV with a spectral resolution (Δhν/hν) of about 15%. Quantum efficiency of this spectrometer was designed to be 10(-7), 10(-4), 10(-5), respectively, for 2-10, 11-15, and 15-25 MeV of photon energy ranges.

Development of multichannel low-energy neutron spectrometer

A multichannel low-energy neutron spectrometer for down-scattered neutron (DSN) measurements in inertial confinement fusion (ICF) experiments has been developed. Our compact-size 256-channel lithium-glass-scintillator-based spectrometer has been implemented and tested in ICF experiments with the GEKKO XII laser. We have performed time calibration of the 256-channel analog-to-digital convertor system used for DSN measurements via X-ray pulse signals. We have clearly observed the DD-primary fusion neutron signal and have successfully studied the detector's impulse response. Our detector is soon to be implemented in future ICF experiments.

Characterizing a fast-response, low-afterglow liquid scintillator for neutron time-of-flight diagnostics in fast ignition experiments

The characteristics of oxygen-enriched liquid scintillators with very low afterglow are investigated and optimized for application to a single-hit neutron spectrometer for fast ignition experiments. It is found that 1,2,4-trimethylbenzene has better characteristics as a liquid scintillator solvent than the conventional solvent, p-xylene. In addition, a benzophenon-doped BBQ liquid scintillator is shown to demonstrate very rapid time response, and therefore has potential for further use in neutron diagnostics with fast time resolution.

Plate presetting and arthroscopic reduction technique (PART) for treatment of distal radius fractures

BACKGROUND

Arthroscopy has been reported to be an efficient adjunct for the surgical treatment for distal radius fractures (DRF). However, performing wrist arthroscopy during palmar locking plate fixation seems to be troublesome. We have developed a surgical technique involving presetting of a palmar locking plate and an arthroscopic reduction technique (PART) of the fracture that can facilitate the procedure. This study is aimed to investigate the effectiveness of our technique in the treatment of DRF.

PATIENTS AND METHODS

249 fractures of the distal radius were treated by PART. 205 fractures in 200 patients were followed-up on average for 15 (12-60) months. There were 46 men and 154 women with an average age of 62 (16-85) years. According to the AO/ASIF fracture classification system there were 51 extra-articular fractures, and 154 intra-articular fractures. Scapholunate interosseous ligament injuries were classified according to Geissler and tears of the triangular fibrocartilage complex according to Abe. On arthroscopic inspection, residual intra-articular fragment dislocation after reduction under fluoroscopy was evaluated. Final evaluation included a radiological examination, measurements of wrist and forearm motion, grip strength, the Mayo modified wrist score (MMWS), and the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire.

RESULTS

On arthroscopic inspection, intraarticular dislocations were found to be residual in 22.7%, even if reduction seemed to have been achieved when viewed by fluoroscopy. Scapholunate interosseous ligament tears were recognized in 29.8%, and triangular fibrocartilage complex tears in 62.4%. The mean palmar tilt was 5.7 (-10 to 16)°, radial inclination 26.0 (18-31)°, and ulnar variance 0.1 (-2 to 5) mm. The mean extension of the wrist was 71 (50-85)°, and the mean flexion was 62 (40-79)°. The mean pronation of the forearm was 87.5 (70-90)°, and the mean supination was 89.1 (75-95)°. The mean grip strength was 90.0% (31-133%) of the opposite side. According to the MMWS there were 156 excellent, 47 good, and 2 fair results. The mean DASH score was 3.9.

CONCLUSIONS

The palmar locking plate in combination with arthroscopic reduction technique (PART) leads to good and excellent results. It can be recommended for all fractures of the distal radius needing operative treatment. Arthroscopic reduction of intra-articular fragments is superior to reduction under fluoroscopy. PART allows also the detection of intra-articular soft tissue lesions such as scapholunate ligament tears and injuries of the triangular fibrocartilage complex.

Denture wearing during sleep doubles the risk of pneumonia in the very elderly

Poor oral health and hygiene are increasingly recognized as major risk factors for pneumonia among the elderly. To identify modifiable oral health-related risk factors, we prospectively investigated associations between a constellation of oral health behaviors and incident pneumonia in the community-living very elderly (i.e., 85 years of age or older). At baseline, 524 randomly selected seniors (228 men and 296 women; mean age, 87.8 years) were examined for oral health status and oral hygiene behaviors as well as medical assessment, including blood chemistry analysis, and followed up annually until first hospitalization for or death from pneumonia. During a 3-year follow-up period, 48 events associated with pneumonia (20 deaths and 28 acute hospitalizations) were identified. Among 453 denture wearers, 186 (40.8%) who wore their dentures during sleep were at higher risk for pneumonia than those who removed their dentures at night (log rank P = 0.021). In a multivariate Cox model, both perceived swallowing difficulties and overnight denture wearing were independently associated with an approximately 2.3-fold higher risk of the incidence of pneumonia (for perceived swallowing difficulties, hazard ratio [HR], 2.31; and 95% confidence interval [CI], 1.11-4.82; and for denture wearing during sleep, HR, 2.38; and 95% CI, 1.25-4.56), which was comparable with the HR attributable to cognitive impairment (HR, 2.15; 95% CI, 1.06-4.34), history of stroke (HR, 2.46; 95% CI, 1.13-5.35), and respiratory disease (HR, 2.25; 95% CI, 1.20-4.23). In addition, those who wore dentures during sleep were more likely to have tongue and denture plaque, gum inflammation, positive culture for Candida albicans, and higher levels of circulating interleukin-6 as compared with their counterparts. This study provided empirical evidence that denture wearing during sleep is associated not only with oral inflammatory and microbial burden but also with incident pneumonia, suggesting potential implications of oral hygiene programs for pneumonia prevention in the community.