Proof-of-Principle Experiment for Testing Strong-Field Quantum Electrodynamics with Exotic Atoms: High Precision X-Ray Spectroscopy of Muonic Neon

To test bound-state quantum electrodynamics (BSQED) in the strong-field regime, we have performed high precision x-ray spectroscopy of the 5g-4f and 5f- 4d transitions (BSQED contribution of 2.4 and 5.2 eV, respectively) of muonic neon atoms in the low-pressure gas phase without bound electrons. Muonic atoms have been recently proposed as an alternative to few-electron high-Z ions for BSQED tests by focusing on circular Rydberg states where nuclear contributions are negligibly small. We determined the 5g_{9/2}- 4f_{7/2} transition energy to be 6297.08±0.04(stat)±0.13(syst)  eV using superconducting transition-edge sensor microcalorimeters (5.2-5.5 eV FWHM resolution), which agrees well with the most advanced BSQED theoretical prediction of 6297.26 eV.

DETECTION OF ELDER ABUSE IN JAPAN NOT COVERED BY THE ELDER ABUSE PREVENTION LAW IN COMPARISON WITH WHO DEFINITION

The Elder Abuse Prevention Law mainly defines “elder abuse” inflicted by caregivers. Elder abuse by non-caregivers is therefore rarely covered by the law. We investigated domestic elder abuse reported in Matsudo City, Chiba, Japan, to determine the number of domestic elder abuse cases excluded from legal protection but constituting elder abuse defined by WHO. From April 2017 to March 2020, the municipal elder protection services agency received 525 reports of domestic elder abuse. We studied the effective records of 497 of these cases. 299 cases were confirmed elder abuse cases defined by the law, with 198 excluded. However, 176 out of the 198 excluded cases constitute elder abuse defined by WHO. In these 176 cases, abuse was perpetrated by non-caregivers. Due to the current formation of the law, this abuse went undetected and unprotected. We think amendment of the law is required to protect these excluded cases.

NEED FOR SUPPORT FOR PERSONS WITH DISABILITIES IN ELDER ABUSE

Among the elder abuse cases reported to Matsudo City, Chiba Prefecture (population 487,091 as of April 1, 2017) from fiscal year (FY) 2017 to FY 2019. Of the 525 reported cases, 497 for which records could be judged to be accurate were included in the study. There were 119 cases (23.9%) in which the abusers were presumed to have a disability. Out of these 119 cases, the abusers of 86 (72.3%) cases were not involved with health and welfare policies for people with disabilities or such involvement had been suspended. If the abuser had received support in the field of health and welfare for the disabled or as a person in need at an early stage, the elder abuse might not have occurred. Support for people with disabilities and support for persons in financial need are required before they become abusers.

Deexcitation Dynamics of Muonic Atoms Revealed by High-Precision Spectroscopy of Electronic K X Rays

We observed electronic K x rays emitted from muonic iron atoms using superconducting transition-edge sensor microcalorimeters. The energy resolution of 5.2 eV in FWHM allowed us to observe the asymmetric broad profile of the electronic characteristic Kα and Kβ x rays together with the hypersatellite K^{h}α x rays around 6 keV. This signature reflects the time-dependent screening of the nuclear charge by the negative muon and the L-shell electrons, accompanied by electron side feeding. Assisted by a simulation, these data clearly reveal the electronic K- and L-shell hole production and their temporal evolution on the 10-20 fs scale during the muon cascade process.

N-(6-phenylpyridazin-3-yl)benzenesulfonamides as highly potent, brain-permeable, and orally active kynurenine monooxygenase inhibitors

Huntington's disease (HD) is one of the serious neurodegenerative diseases and no disease modifiers are available to date. The correction of unbalanced kynurenine pathway metabolites may be useful to treat disease progression and kynurenine monooxygenase (KMO) is considered an ideal drug target. A couple of KMO inhibitors have been reported, but their brain permeability was very poor. We found pyridazinylsulfonamide as a novel lead compound, and it was optimized to the brain-permeable and highly potent KMO inhibitor 12, which was equipotent with CHDI-340246 and superior to CHDI-340246 in terms of brain penetration. Compound 12 was effective in R6/2 mice (HD model mice), i.e. neuroprotective kynurenic acid was increased, whereas neurotoxic 3-hydroxykynurenine was suppressed. In addition, impaired cognitive function was improved. Therefore, the brain-permeable KMO inhibitor was considered to be a disease modifier for HD treatment.

Efforts for Construction of More Effective Prevention and More Inclusive Protection Systems in Matsudo City

Matsudo City is preparing to implement an ordinance so that 3 protective services for children, older persons, and people with disabilities can work together for efficient prevention. Supporting pregnant women is sometimes effective for prevention of future child abuse. Supporting people with disabilities is often prevention of future neglect caused by them. Supporting perpetrators and victims of domestic violence is effective to prevent future elder abuse by interruption of abusive behaviors. We expect to prevent abuses by affiliation of various protective and supportive services. According to the Elder Abuse Prevention Law, elder abuse is defined as those inflicted by caregivers. Therefore, there is a big problem that abuses by non-caregivers are excluded from the coverage of the law. We are currently investigating abuses by non-caregivers to clarify the proportion of excluded cases among those reported to Elder Protective Services. I would like to talk about preliminary result of our investigation.

Impaired p53/CEP-1 is associated with lifespan extension through an age-related imbalance in the energy metabolism of C. elegans

In the nematode Caenorhabditis elegans, the mammalian tumor suppressor p53 ortholog CEP-1 mediates the stress response, activates germ line apoptosis and regulates meiotic chromosome segregation. A reduction in its expression, which frequently occurs in mammalian cancer cells, extends lifespan and induces an adaptive response in C. elegans. However, these effects do not involve an increase in oxidative stress resistance. Here, we showed that intermittent exposure to hyperoxia, which induces oxidative stress resistance and lowers the production of ROS derived from mitochondrial respiration in C. elegans, slightly improved the lifespan extension of cep-1 mutant. Interestingly, ATP levels were increased without an increase in oxygen consumption in cep-1 mutant during aging. In the wild-type, lactate levels and consequentially the lactate/pyruvate ratio decreased during aging in adults. Furthermore, the expression levels of mitochondrial respiration-related sco-1, which is a target of p53/CEP-1, as well as those of gluconeogenesis regulation and mammalian sirtuin ortholog genes, were also increased in the aged and adaptive conditioned wild-type animals. In contrast, the lactate/pyruvate ratio increased in cells of the cep-1 mutant and was amplified by intermittent hyperoxia. These results suggest that impaired p53/CEP-1 leads to an imbalance in the age-related energy metabolic alteration between mitochondrial oxidative phosphorylation and aerobic glycolysis and plays an important role in the extension of both intact and adaptive lifespans.

Serum amyloid A, C-reactive protein and remnant-like lipoprotein particle cholesterol in type 2 diabetic patients with coronary heart disease

Background: Serum amyloid A (SAA) and C-reactive protein (CRP) have been suggested to be involved in the process of coronary heart disease (CHD) and to be potential markers and/or predictors of CHD. Remnant-like lipoprotein particles (RLPs), which are regarded as atherogenic remnant lipoprotein, are reported to be increased in type 2 diabetic patients. We assessed the association of CHD with SAA, CRP and RLP-cholesterol in type 2 diabetic patients.

Methods: One hundred and twenty-six diabetic patients without CHD and 41 patients with CHD were recruited from our hospital. Plasma SAA was measured by the latex agglutination nephelometric immunoassay. Plasma high-sensitivity CRP was measured by a latex immunoturbidity method. Plasma RLP-cholesterol was measured by an immunoabsorption enzyme method.

Results: The mean standard deviation values of RLP-cholesterol in patients with and without CHD were 0.22 (0.26) mmol/L and 0.15 (0.10) mmol/L, respectively ( P <0.05). Median (interquartile ranges) for SAA in patients with and without CHD were 7.4 (4.2-11.2) mg/L and 3.9 (2.2-5.9) mg/L, respectively ( P <0.001). Median (interquartile ranges) for CRP in patients with and without CHD was 1.14 (0.45-2.08) mg/L and 0.43 (0.19-1.25) mg/L, respectively ( P <0.001). For all patients, the Spearman rank correlation statistics for RLP-cholesterol compared with SAA and with CRP were 0.213 ( P <0.05) and 0.301 ( P <0.01), respectively.

Conclusion: These data suggest that SAA, CRP and RLP-cholesterol are increased in type 2 diabetic patients with CHD, and that the inflammatory proteins correlate with remnant lipoprotein.

Differential diagnosis of vertical root fractures using reconstructed three-dimensional models of bone defects

OBJECTIVES

The purpose of this study was to evaluate the accuracy of diagnosing vertical root fractures (VRFs) by comparing the volume of bone defects in VRFs with those in non-VRFs on reconstructed three-dimensional (3D) models (TDMs) using CBCT.

METHODS

32 maxillary pre-molars and anterior teeth with radiolucent areas were evaluated on pre-operative CBCT images. Of the 32 teeth, 16 had a fractured root (VRF group) and 16 had a non-fractured root (non-VRF group). The radiolucent area of each tooth was traced in each dimension [mesiodistal, buccolingual and horizontal (the apicoincisal aspect)] by two observers, and 3D images were reconstructed with the Amira(®) software (Visage Imaging Inc., Richmond, Australia). The volume, V, of the TDM was divided into the coronal side and the periapical side at the horizontal slice through the apical foramen, and v was defined as the volume of the coronal side. The values of v/V were calculated for all cases. The Mann-Whitney U test was used to compare values between the VRF group and the non-VRF group (p < 0.05). A receiver operating characteristic (ROC) curve was constructed to select the optimal cut-point.

RESULTS

There was a statistically significant difference in the value of v/V between the two groups (p < 0.05). With a cut-point derived from the ROC curve, and the sensitivity, specificity and accuracy of predicting the VRFs were 1.00, 0.75 and 0.88, respectively.

CONCLUSIONS

Lesions resulting from VRFs can be distinguished from those of non-VRFs on 3D CBCT images with a high degree of accuracy, based on their different 3D shapes.

Biophysical and biological meanings of healthspan from C. elegans cohort

Lifespan among individuals ranges widely in organisms from yeast to mammals, even in an isogenic cohort born in a nearly uniform environment. Needless to say, genetic and environmental factors are essential for aging and lifespan, but in addition, a third factor or the existence of a stochastic element must be reflected in aging and lifespan. An essential point is that lifespan or aging is an unpredictable phenomenon. The present study focuses on elucidating the biophysical and biological meanings of healthspan that latently indwells a stochastic nature. To perform this purpose, the nematode Caenorhabditis elegans served as a model animal. C. elegans fed a healthy food had an extended healthspan as compared to those fed a conventional diet. Then, utilizing this phenomenon, we clarified a mechanism of healthspan extension by measuring the single-worm ATP and estimating the ATP noise (or the variability of the ATP content) among individual worms and by quantitatively analyzing biodemographic data with the lifespan equation that was derived from a fluctuation theory.

Noise-driven onset time of biodemographic aging

The lifespan of each individual, even in an isogenic cohort and a uniform environment, is quite different. The genetic factors influencing the lifespan in humans as well as animal models are few. The balance is attributed to "chance" variations. In this study, we focus on a third factor, noise or chance variations, as well as on genetic and environmental factors and examine how biodemographic aging is related to stochastic fluctuations, or noise. To elucidate the third factor in relation to aging and lifespan, we employed the nematode Caenorhabditis elegans, which can provide an ideal system for analyzing the mathematical and biophysical models. An amplification of ATP noise was clearly evident from around the onset of biodemographic aging (t(0)) as if the t(0) was synchronized with or derived from the amplification of noise. Furthermore, the expression noise of the unc-54 gene, which encodes the myosin heavy chain, increased from around the t(0). In contrast, the noise of genes related to the mitochondrial respiratory chain was almost constant with aging. There is a high energy barrier between life and death. Here we propose that the transition from living to dying may be facilitated by noise amplification. The finite value (or non-zero) of t(0) is essential to the lifespan equation derived from the diffusion model.

Odontoblastic syncytium through electrical coupling in the human dental pulp

We have previously reported a dye-coupling network between odontoblasts (OBs). However, it is still unclear how the information detected by the odontoblasts is transmitted. The aim of this study was to characterize the odontoblastic syncytium electrophysiologically in the human dental pulp. Pulpal cells were freshly isolated from human premolars immediately after extraction. Under a light microscope, coupled or small clusters (3-20) of odontoblasts, each of which had a monopolar process (95-280 µm) and an oval cell body, were easily observed to be lined up in parallel. Cells were used for electrophysiological recording within 3 hrs in the dual patch-clamp configuration. Electrical couplings were found between odontoblasts (37/40 pairs). Voltage gating showed directional independence between pairs of odontoblasts. The time constant to a current decay increased with the number of clustered odontoblasts. Nine of 37 pairs isolated from young patients were electrically coupled, but could not be voltage-clamped. Transjunctional currents were blocked by octanol. These results suggest that odontoblasts form a syncytium that is directionally independent via symmetric gap junction channels in the odontoblastic layer. Young odontoblasts with a high electrical conductance to neighboring cells may be related to high potential of information transmission or calcification.

Initial fibroblast attachment to Erbium:YAG laser-irradiated dentine

AIMS

To evaluate the effects of Erbium (Er):YAG laser irradiation on the morphology of resected dentine surfaces, and to investigate fibroblast attachment to laser-irradiated dentine surfaces.

METHODOLOGY

Dentine blocks obtained from single-rooted human teeth were divided into the following groups after sterilization in an autoclave: (i) Laser group treated with Er:YAG laser irradiation (30 mJ per pulse, 10 pps, 60 s); (ii) L-MTAD group treated with laser irradiation as in (i) plus a mixture of doxycycline, tetracycline isomer and citric acid; (iii) RC-Prep group treated with EDTA gel or cream (RC-Prep) and (iv) Control group left untreated. After each treatment, the dentine blocks were incubated with NIH/3T3 fibroblasts cultured to subconfluency in Dulbecco's modified Eagle's medium supplemented with 10% foetal bovine serum and antibiotics. The number of attached cells amongst the groups was analysed statistically at the 5% significance level. The dentine surface morphologies and cell attachments were evaluated by counting assays, histological observations and scanning electron microscopy (SEM).

RESULTS

The number of attached cells was significantly higher (P < 0.05) in the Laser group than in the RC-Prep and Control groups at 16 h. Dendritic cell extension of the fibroblasts was only observed in the Laser group at 8 h by SEM. In the histological analyses, significantly more attached cells were found on the dentine surfaces treated with laser irradiation.

CONCLUSIONS

Er:YAG laser irradiation induced morphological alterations in dentine surfaces, which may improve the attachment of fibroblasts to dentine.

MEPE Activated by Furin Promotes Pulpal Cell Adhesion

Matrix extracellular phosphoglycoprotein (MEPE) is predominantly expressed in osteoblasts, osteocytes, and odontoblasts and plays key biological roles in bone and dentin metabolism. Post-translational modifications are essential for its activation. This study tested the hypothesis that MEPE is activated through proteolytic processing by furin in dental pulp. MEPE was present in three sizes, 1 full-length and 2 cleaved fragments; the cleavage site was 146R↓147. The proprotein convertase family, particularly furin, was a candidate enzyme. Introducing a substitution at the cleavage site inhibited hydrolysis, but there was no cleavage of MEPE expressed in furin-deficient LoVo cells. Therefore, furin is a strong candidate for the proteolytic cleavage of MEPE. The C-terminal cleavage product promoted cell adhesion via its RGD motif. These results indicate that proteolytic processing by furin may activate MEPE during its secretion from odontoblasts and may play important roles in dentinogenesis and pulpal homeostasis. Abbreviations: MEPE, matrix extracellular phosphoglycoprotein; PTM, post-translational modifications; OLC, odontoblast-lineage cells.

Periapical bone defects of root filled teeth with persistent lesions evaluated by cone-beam computed tomography

AIM

To evaluate and categorize the bone defects of root filled teeth with persistent periapical lesions by cone-beam computed tomography (CBCT).

METHODOLOGY

Slice images of 532 teeth with persistent periapical lesions were obtained by CBCT in 427 patients and were examined by two endodontists. The periapical lesions were categorized into five types according to the characteristics of the bone defect based on CBCT images. The prevalence of each type was determined and analysed statistically at a 5% significance level using logistic regression.

RESULTS

Of the 532 teeth analysed, 67% had buccal or labial bone plate defects (type II), 4% palatal or lingual bone plate defects (type III), 7%'through and through' defects (type IV) and 10% apical root protrusions from the bone plate (type V). Mandibular teeth had a significantly greater prevalence of type I lesions (P=0.0005) and a significantly lower prevalence for types IV (P=0.041), V (P=0.001), V-1 (P=0.015) and V-2 (P<0.001) as compared to maxillary teeth.

CONCLUSION

CBCT accurately identified the type of periapical bone defect in persistent lesions. Because 10% of the teeth had apical root protrusions, which could not be identified by periapical radiography, the diagnostic information obtained by CBCT was an essential component of the treatment planning process.

Interrelationships between mitochondrial fusion, energy metabolism and oxidative stress during development in Caenorhabditis elegans

Mitochondria are known to be dynamic structures with the energetically and enzymatically mediated processes of fusion and fission responsible for maintaining a constant flux. Mitochondria also play a role of reactive oxygen species production as a byproduct of energy metabolism. In the current study, interrelationships between mitochondrial fusion, energy metabolism and oxidative stress on development were explored using a fzo-1 mutant defective in the fusion process and a mev-1 mutant overproducing superoxide from mitochondrial electron transport complex II of Caenorhabditis elegans. While growth and development of both single mutants was slightly delayed relative to the wild type, the fzo-1;mev-1 double mutant experienced considerable delay. Oxygen sensitivity during larval development, superoxide production and carbonyl protein accumulation of the fzo-1 mutant were similar to wild type. fzo-1 animals had significantly lower metabolism than did N2 and mev-1. These data indicate that mitochondrial fusion can profoundly affect energy metabolism and development.

Incidence of accessory canals in Japanese anterior maxillary teeth following root canal filling ex vivo

AIM

To investigate the vertical and horizontal distribution and the incidence of accessory canals in Japanese maxillary anterior teeth following root filling.

METHODOLOGY

The study included maxillary teeth; 69 central incisors, 61 lateral incisors and 31 canines. After the canal systems had been dyed and root canal instrumentation had been carried out, all prepared canals were filled with gutta-percha without using sealer. Transparent specimens were then obtained and examined with a digital microscope for horizontal and vertical distributions of accessory canals.

RESULTS

The incidence of teeth with accessory canals in the apical 3 mm was 46%, 29% and 38% for the maxillary central incisors, lateral incisors and canines, respectively. The horizontal distribution was mainly buccal for central incisors, palatal for lateral incisors and distal and palatal for canines. There was a significant difference (P < 0.05) between the apical 3 mm and the rest of the root (16%, 20% and 19% for the maxillary central incisors, lateral incisors and canines, respectively) in terms of the presence of accessory canals.

CONCLUSIONS

A high percentage of accessory canals can be found in apical 3 mm of the root. The horizontal distribution of accessory canals differed amongst the tooth types studied.

Neuron-immune interactions in the sensitized thalamus induced by mustard oil application to rat molar pulp

We have reported that mustard oil application to the rat dental pulp induces neuronal activation in the thalamus. To address the mechanisms involved in the thalamic changes, we performed neuronal responsiveness recording, immunohistochemistry, and molecular biological analysis. After mustard oil application, neuronal responsiveness was increased in the mediodorsal nucleus. When MK801 (an N-methyl-D-aspartate receptor antagonist) was applied to the mediodorsal nucleus, the enhanced responsiveness was decreased. N-methyl-D-aspartate receptor 2D, glial fibrillary acidic protein, and antigen-presenting cell-related gene mRNAs in the contralateral thalamus were up-regulated at 10 minutes after mustard oil application, but were down-regulated within 10 minutes after the antagonist application. OX6-expressing microglia and glial fibrillary acidic protein-expressing astrocytes did not increase until 60 minutes after mustard oil application. These results suggested that the thalamic neurons play some roles in regulating the glial cell activation in the mediodorsal nucleus via N-methyl-D-aspartate receptor 2D during pulp inflammation-induced central sensitization.

Analyzing observed or hidden heterogeneity on survival and mortality in an isogenic C. elegans cohort

It is generally difficult to understand the rates of human mortality from biological and biophysical standpoints because there are no cohorts or genetic homogeneity; in addition, information is limited regarding the various causes of death, such as the types of accidents and diseases. Despite such complexity, Gompertz's rule is useful in humans. Thus, to characterize the rates of mortality from a demographic viewpoint, it would be interesting to research a single disease in one of the simplest organisms, the nematode C. elegans, which dies naturally under identically controlled circumstances without predators. Here, we report an example of the fact that heterogeneity on survival and mortality is observed through a single disease in a cohort of 100% genetically identical (isogenic) nematodes. Under the observed heterogeneity, we show that the diffusion theory, as a biophysical model, can precisely analyze the heterogeneity and conveniently estimate the degree of penetrance of a lifespan gene from the biodemographic data. In addition, we indicate that heterogeneity models are effective for the present heterogeneous data.

[Primary thyrotracheal anastomosis for subglottic stenosis with tracheostomy]

A case of 42-year-old man with postintubation subglottic stenosis underwent primary thyrotracheal anastomosis. Since trachea had been incised longitudinally for previous tracheostomy, tracheal resection came to be longer. Therefore, we had to anastomose the incised trachea with thyroid cartilage even after the suprahyoid release. After the operation, he suffered from the tracheal collapse at the incised portion of the trachea One week after intubation, tracheal patency was achieved. We recommend horizontal incision for tracheostomy in patient with subglottic stenosis, when the following surgical approach is considered.

Antigen-presenting cells in human radicular granulomas

Substantial numbers of dendritic cells have been detected in radicular granulomas. To test the hypothesis that local antigen presentation from dendritic cells to T-cells is involved critically in immunological responses within radicular granulomas, we compared characteristics of dendritic cells and macrophages by morphological and biological analyses. Under light microscopy, HLA-DR+ and CD68+ cells showed diverse profiles, including dendritic-shaped cells. Transmission electron microscopy revealed that HLA-DR+ dendritic cells, with long cytoplasmic processes and lacking distinct phagosomes, were concentrated in the lymphocyte-rich area. HLA-DR alpha-chain, CD83, and CD86 mRNAs from HLA-DR+ dendritic cells, and CD28 mRNA from CD28+ T-cells were up-regulated in lymphocyte-rich area. Scanning electron microscopy demonstrated that the density of gold particles on dendritic cells was higher than that on HLA-DR+ macrophages. These results suggest that dendritic cells in radicular granulomas are associated with local defense reactions as stronger antigen-presenting cells, as compared with macrophages.

Logistic regression equation to screen for vertical root fractures using periapical radiographs

OBJECTIVES

To develop a predictive equation to screen for vertical root fractures (VRFs) by numerically evaluating the shapes of radiolucent areas on the periapical radiographs of endodontically treated maxillary incisors and premolars.

METHODS

41 pre-operative periapical radiographs of maxillary incisors and premolars with radiolucent areas at root apices were used. Out of 41 teeth, 18 had a fractured root (VRF group) and 23 had a non-fractured root (non-VRF group). The periapical radiolucent area of each tooth was traced out by six examiners on a personal computer and two indices, "Complexity" and "Radial SD", were measured. For each index, the difference between the VRF and non-VRF groups and the interexaminer differences were analysed with two-way ANOVA at 5% significance level. Multiple logistic regression analysis was used to develop a predictive equation and the probability of VRF in all samples was calculated. A receiver operating characteristic (ROC) curve was constructed to select the optimal cut-point. Each sample was predicted as "VRF" or "non-VRF" with this cut-point.

RESULTS

For both "Complexity" and "Radial SD", the VRF group showed significantly greater values than the non-VRF group (P<0.05). With a cut-point derived from the ROC curve, sensitivity, specificity and efficiency of VRF were 0.68, 0.80 and 0.75, respectively.

CONCLUSIONS

VRF teeth have more complicated radiolucent areas compared with non-VRF teeth. By evaluating the shapes of radiolucent areas, a logistic regression equation to screen for VRF was calculated and this equation could contribute to the diagnosis of VRF.

Ex vivo evaluation of the ability of four different electronic apex locators to determine the working length in teeth with various foramen diameters

BACKGROUND

The aim of this ex vivo study was to evaluate the accuracy of four electronic apex locators (EALs) to determine the working length in teeth with various foramen diameters. Our previous study revealed that electronically measured canal length was influenced by the root canal diameter. It is not known whether foramen size would interfere with the reading accuracy of an EAL.

METHODS

A total of 36 extracted human lower single rooted premolar teeth were divided into four groups of nine teeth each. In groups A, B and C, the root canals were instrumented using #10-80, #10-100 and #10-120 K-files, and the tip of size #80, #100 and #120 K-files were permitted to pass through the apical foramen to a length of 1mm, respectively. In group D, the teeth were instrumented using #10-140 K-files and the tip of #140 K-file was permitted to pass through the apical foramen to a length of 5 mm. Thus, the average apical foramen diameters in groups A, B, C and D were approximately 0.82 mm, 1.02 mm, 1.22mm and 1.5 mm, respectively. The teeth were then mounted in 1% agar and four EALs were used: Root ZX, Foramatron D10, Apex NRG and Apit 7. For electronic measurement, sizes #10 and #80, #10 and #100, #10 and #120, and #10 and #140 K-files were used for groups A, B, C and D, respectively. During electronic measurement the canals were flushed with 6% sodium hypochlorite solution.

RESULTS

Three-way ANOVA and Bonferroni test showed that EAL, file size and foramen size all had a significant influence on the measurement error (P<0.0001), with all the interactions between these three factors being significant (P<0.0001).

CONCLUSIONS

The four EALs were unreliable to determine the working length of teeth with a wide apical foramen, when using a small size file. The Root ZX and Foramatron D10 showed significantly better scores than the other two EALs and may be more reliable to determine the working length of teeth with a wide apical foramen, if a tight-fit file is used.

[Aortic dissection associated with traumatic pericardial rupture]

We report a case of a 76-year-old man with traumatic aortic dissection complicated with cardiac herniation due to traumatic pericardial rupture. He was involved in an automobile crush and was transferred to our hospital. His vital signs were stable except for atrial fibrillation. Enhanced computed tomography (CT) showed aortic dissection on the descending aorta, multiple left rib fractures, substernal hematoma and shift of the heart toward the left chest cavity. We performed emergency operation. Through left thoracotomy, pericardial rupture was observed. Dacron graft replacement of the descending aorta and pericardial patch plasty were performed. He was discharged on the 24th postoperative day. Careful attention should be paid to aortic injury and pericardial rupture in the patient with severe blunt chest trauma.

Basic principle of the lifespan in the nematode C. elegans

We present a biophysical model based on the principles of fluctuation and regulation to explain the effect of stochastics on survival. The model is a good fit for the survivorship and mortality rates observed in the nematode Caenorhabditis elegans. A parameter included in the theory, which is called the fluctuation constant, correlates well with a change (or declining rate) of respiration with age, which we term the physiological decline rate. The square of the physiological decline rate is proportional to the reciprocal of the fluctuation constant as revealed in a diffusion equation. In addition, the maximum and mean life spans are proportional to the reciprocal of the decline rate. The framework involved in the fluctuation theory is compatible with the existence of a regulatory system such as that acting in the insulin/insulin-like growth factor-1 (IGF-1) signaling pathway during adulthood, and that sensing, switching, and memorizing the rate of mitochondrial respiration early in life.

Analysis of mismatched DNA by mismatch binding ligand (MBL)–Sepharose affinity chromatography

Mismatch binding molecules (MBLs), strongly and selectively bound to the mismatched base pair in duplex DNA, were immobilized on Sepharose. Three MBL-Sepharose columns were prepared with three MBLs, naphthyridine dimer (ND), naphthyridine-azaquinolone (NA), and aminonaphthyridine dimer (amND), which exhibited different binding profiles to the mismatched base pairs. These three MBL-Sepharose columns showed characteristic elution profiles for DNA duplexes containing mismatched base pairs. The ND-Sepharose column separated the G-G and G-A mismatched DNA from fully matched duplexes. The NA-Sepharose column separated the A-A and G-A mismatched DNA from other DNA duplexes. The amND-Sepharose column separated the C-C mismatched DNA. These chromatographic profiles were very consistent with the binding preference of each MBL. By changing the elution conditions from sodium hydroxide to sodium chloride, MBL-Sepharose columns were also able to separate the mismatched DNA that weakly bound to the MBL from fully matched DNA duplex. Figure MBL-Sepharose affinity chromatography successfully separates the mismatched duplex DNA from fully matched duplex.

Allele Specific C-Bulge Probes with One Unique Fluorescent Molecule Discriminate the Single Nucleotide Polymorphism in DNA

A combination of an allele specific C-bulge probe and the fluorescent molecule N,N'-bis(3-aminopropyl)-2,7-diamino-1,8-naphthyridine (DANP) that binds specifically to the C-bulge provides a method for single nucleotide polymorphism (SNP) typing with only one fluorescent molecule without covalent modification of the DNA probe. The allele specific C-bulge probe contains one additional cytosine and produces a C-bulge directly flanking the SNP site upon hybridization to the target DNA. The C-bulge is a scaffold to recruit and retain DANP directly neighboring the SNP site. The DANP fluorescent probe was selectively modulated by the flanking matched and mismatched base pairs. The mutation type could be discriminated by the modulated fluorescent intensity with respect to the allele specific C-bulge probes used for the assay.

Phase transformation behaviour and bending properties of hybrid nickel?titanium rotary endodontic instruments

AIM

To investigate the bending properties of hybrid rotary nickel-titanium endodontic instruments in relation to their transformation behaviour.

METHODOLOGY

Four types of nickel-titanium rotary endodontic instruments with different cross-sectional shapes (triangular-based and rectangular-based) and different heat treatment conditions (super-elastic type and hybrid type with shape memory effect) were selected to investigate bending properties and phase transformation behaviour. Bending load of the instruments was measured in a cantilever-bending test at 37 degrees C with the maximum deflection of 3.0 mm. A commercial rotary instrument, ProFile (PF; Dentsply Maillefer, Ballaigues, Switzerland) was used as a reference for the bending test. Phase transformation temperatures were calculated from the diagrams obtained from differential scanning calorimetry. Data were analysed by anova and Scheffe's test.

RESULTS

The bending load values of the hybrid type that had undergone additional heat treatment at the tip were significantly lower (P < 0.05) than those of the super-elastic type with no additional heat treatment. The bending load values of rectangular-based cross-sectional shaped instruments were significantly lower (P < 0.05) than those of triangular-based cross-sectional shaped instruments. Phase transformation temperatures (M(s) and A(f) points) of the hybrid type were significantly higher (P < 0.05) than the super-elastic type. The M(f) and A(s) points of the tip part were significantly higher (P < 0.05) than those of the whole part of the hybrid instrument.

CONCLUSIONS

Additional heat treatment of hybrid nickel-titanium instruments may be effective in increasing the flexibility of nickel-titanium rotary instruments.

Evidence for the existence of a soybean resistant protein that captures bile acid and stimulates its fecal excretion

Feeding HMF, an insoluble "high-molecular-weight fraction" from an industrial enzymatic digest of a soy protein isolate, increased the fecal excretion of bile acid concomitant with increased fecal nitrogen. An amino acid analysis revealed that this increased fecal nitrogen could be explained by an increase in the insoluble protein fraction. This suggests the existence of an indigestible protein or peptide that can be called a "resistant protein" in the feces. The presumed resistant protein was rich in hydrophobic amino acids and bound bile acid by hydrophobic interaction. The residual fraction of HMF obtained after in vitro pepsin and pancreatin digestion, showed higher in vitro bile acid-binding capacity and excreted more bile acid in vivo than HMF. Its amino acid composition was similar to that of the feces of rat fed with HMF. These results suggest that the fecal resistant protein with bile acid-binding ability could be derived from the indigestible fraction of HMF.

Effect of NOS inhibitor on cytokine and COX2 expression in rat pulpitis

Various kinds of chemical mediators are synthesized in the course of pulpitis; thus, control of their production would assist in inducing a reduction in pulpal inflammation. We hypothesized that nitric oxide (NO) would be an important mediator of pulpal inflammation. Pulpal inflammation was induced by the application of LPS in rat incisor pulp, and inducible nitric oxide synthase (iNOS) expression was evaluated by reverse-transcription/polymerase chain-reaction and immunohistochemical staining. After LPS application, iNOS mRNA was first detected after 3 hrs, peaked at 6 hrs, and decreased thereafter. iNOS-positive cells were macrophages and neutrophils. An NOS inhibitor caused drastic decreases in the expression of pro-inflammatory cytokines and COX2 mRNA, which was highly induced in the LPS-induced pulpitis. These results indicate that NO synthesis is related to the initiation of mediator production, and that its down-regulation should contribute to the prevention of pro-inflammatory mediator synthesis.

Age-related changes of mitochondrial structure and function in Caenorhabditis elegans

A number of observations have been made to examine the role that mitochrondrial energetics and superoxide anion production play in the aging of wild-type Caenorhabditis elegans. Ultrastructural analyses reveal the presence of swollen mitochondria, presumably produced by fusion events. Two key mitochondrial functions - the activity of two electron transport chain complexes and oxygen consumption - decreased as animals aged. Carbonylated proteins, one byproduct of oxidative stress, accumulated in mitochondria much more than in the cytoplasm. This is consistent with the notion that mitochondria are the primary source of endogenous reactive oxygen species. However, the level of mitochondrially generated superoxide anion did not change significantly during aging, suggesting that the accumulation of oxidative damage is not due to excessive production of superoxide anion in geriatric animals. In concert, these data support the notion that the mitochondrial function is an important aging determinant in wild-type C. elegans.