[Development of a Method for Estimating the Time Point of Hair Contamination in Retort Pouch Foods].

DNA from hair that has undergone retort pouch sterilization shows considerably more fragmentation. Assessing the extent of DNA fragmentation using a PCR assay could therefore be applied to infer the sterilization history of a contaminated food sample. Such assessments could make it possible to determine whether a food sample had been contaminated by hair during the production process. To determine the extent of retort pouch sterilization, primers specific for the detection of human DNA were designed to give an amplification product of approx 500 bp. Hair was subjected to retort sterilization as a model of contamination, and PCR was performed using the extracted DNA as a template and the primer set for determining retort pouch sterilization. The results showed that no DNA amplification occurred in retort pouch samples, whereas amplification was observed in samples that were unheated, heated in hot water, or heated in a microwave oven. The present method was thus able to specifically detect thermal decomposition of DNA from hair that had undergone retort sterilization, and will be useful for determining whether hair discovered in a retort pouch was responsible for contamination.

Electronic State of Low-Rank Coals with Exchanged Sodium Cations.

Our previous experimental study showed that Na+-exchanged coal prepared from low-cost natural soda ash is an excellent catalyst for steam gasification of low-rank coals using fixed-bed quartz reactors. However, it is difficult to experimentally clarify the effect of Na ion exchange on low-rank coal. In order to investigate the influence of Na+ ions on low-rank coal, this study determined the electronic state between the Na+-exchanged coal model and raw coal model and compared them using RHF/6-311G* and B3LYP/6-31G*. The experiments revealed that Na ion exchange has a significant effect on low-rank coal gasification. The model structure of low-rank coal is considered to change significantly in terms of the electronic state before and after Na exchange even with a simple main molecular structure. Molecular models where H of COOH/OH was ion-exchanged with one, two, and three Na ions were developed, and quantum chemical calculations were performed. The results showed that when the number of Na+-exchanged sites is increased, the electron state on the coal molecule becomes more negatively charged in the case of the Na+-exchange coal model. It is presumed that this contributes to enhancing the reactivity of low-rank coal and water vapor. In addition, weak bonds in the Na+-exchanged coal molecule were examined by calculating the difference in the value of the Mulliken and Löwdin bond orders before and after Na+ exchange. The results showed that the increase in the number of exchanged Na+ in the low-rank coal molecule model increased the number of weak bonds in the molecule. It is presumed that this contributes to enhancing the decomposition of low-rank coal.

A Clinical Prospective Observational Cohort Study on the Prevalence and Primary Diagnostic Accuracy of Occult Vertebral Fractures in Aged Women with Acute Lower Back Pain Using Magnetic Resonance Imaging.

BACKGROUND: Elderly female patients complaints of acute low back pain (LBP) may involve vertebral fracture (VF), among which occult VF (OVF: early-stage VF without any morphological change) is often missed to be detected by primary X-ray examination. The current study aimed to investigate the prevalence of VF and OVF and the diagnostic accuracy of the initial X-ray in detecting OVF. METHOD: Subjects were elderly women (>70 years old) complaining of acute LBP with an accurate onset date. Subjects underwent lumbar X-ray, magnetic resonance imaging (MRI), and bone mineral density (BMD) measurement at their first visit. The distribution of radiological findings from X-ray and magnetic resonance imaging (MRI) as well as the calculation of the prevalence of VF and OVF are investigated. RESULTS: The prevalence of VF among elderly women with LBP was 76.5% and L1 was the most commonly injured level. Among VF cases, the prevalence of OVF was 33.3%. Furthermore, osteoporotic patients tend to show increased prevalence of VF (87.5%). The predictive values in detecting VF on the initial plain X-ray were as follows: sensitivity, 51.3%; specificity, 75.0%; and accuracy rate, 56.7%. CONCLUSIONS: Acute LBP patients may suffer vertebral injury with almost no morphologic change in X-ray, which can be detected using MRI.

Neurilemmoma of the Vagus Nerve in the Poststyloid Parapharyngeal Space.

We report a large vagal neurilemmoma in the poststyloid compartment of the parapharyngeal space. A 52-year-old man was referred to our hospital with a feeling of discomfort in the left upper neck. Computed tomography showed a 30mm x 30mm x 40mm mass with inhomogeneous internal enhancement in the left carotid space. Magnetic resonance imaging revealed a 30mm × 30mm × 40mm heterogeneous mass in the area of the bifurcation of the common carotid artery. We gave a provisional diagnosis of neurilemmoma or vagal paraganglioma in the parapharyngeal space preoperatively based on the results of physical examination and imaging. We selected a transcervical-transmandibular approach. Under general anaesthesia, a tumour originating from the vagus nerve was completely extirpated while protecting the internal and external carotid arteries. Although mild postvagotomy dysphagia and hoarseness were seem for 6 months postoperatively, symptoms resolved and the patient showed a satisfactory course without recurrence after 10 years. Histological examination of the excised specimen showed antoni A and antoni B pattern. Positive immunoreactivity for S-100 protein was identified, but negative results were obtained for neuron-specific enolase, chromogranin and neurofilament. The tumour was diagnosed as neurilemmoma of the vagus nerve.

Structure-based analysis of the molecular interactions between acyltransferase and acyl carrier protein in vicenistatin biosynthesis.

Acyltransferases (ATs) are key determinants of building block specificity in polyketide biosynthesis. Despite the importance of protein-protein interactions between AT and acyl carrier protein (ACP) during the acyltransfer reaction, the mechanism of ACP recognition by AT is not understood in detail. Herein, we report the crystal structure of AT VinK, which transfers a dipeptide group between two ACPs, VinL and VinP1LdACP, in vicenistatin biosynthesis. The isolated VinK structure showed a unique substrate-binding pocket for the dipeptide group linked to ACP. To gain greater insight into the mechanism of ACP recognition, we attempted to crystallize the VinK-ACP complexes. Because transient enzyme-ACP complexes are difficult to crystallize, we developed a covalent cross-linking strategy using a bifunctional maleimide reagent to trap the VinK-ACP complexes, allowing the determination of the crystal structure of the VinK-VinL complex. In the complex structure, Arg-153, Met-206, and Arg-299 of VinK interact with the negatively charged helix II region of VinL. The VinK-VinL complex structure allows, to our knowledge, the first visualization of the interaction between AT and ACP and provides detailed mechanistic insights into ACP recognition by AT.

The crystal structure of the adenylation enzyme VinN reveals a unique ß-amino acid recognition mechanism.

Adenylation enzymes play important roles in the biosynthesis and degradation of primary and secondary metabolites. Mechanistic insights into the recognition of α-amino acid substrates have been obtained for α-amino acid adenylation enzymes. The Asp residue is invariant and is essential for the stabilization of the α-amino group of the substrate. In contrast, the ß-amino acid recognition mechanism of adenylation enzymes is still unclear despite the importance of ß-amino acid activation for the biosynthesis of various natural products. Herein, we report the crystal structure of the stand-alone adenylation enzyme VinN, which specifically activates (2S,3S)-3-methylaspartate (3-MeAsp) in vicenistatin biosynthesis. VinN has an overall structure similar to that of other adenylation enzymes. The structure of the complex with 3-MeAsp revealed that a conserved Asp(230) residue is used in the recognition of the ß-amino group of 3-MeAsp similar to α-amino acid adenylation enzymes. A mutational analysis and structural comparison with α-amino acid adenylation enzymes showed that the substrate-binding pocket of VinN has a unique architecture to accommodate 3-MeAsp as a ß-amino acid substrate. Thus, the VinN structure allows the first visualization of the interaction of an adenylation enzyme with a ß-amino acid and provides new mechanistic insights into the selective recognition of ß-amino acids in this family of enzymes.

The crystal structure of the amidohydrolase VinJ shows a unique hydrophobic tunnel for its interaction with polyketide substrates.

VinJ is an amidohydrolase belonging to the serine peptidase family that catalyzes the hydrolysis of the terminal aminoacyl moiety of a polyketide intermediate during the biosynthesis of vicenistatin. Herein, we report the crystal structure of VinJ. VinJ possesses a unique hydrophobic tunnel for the recognition of the polyketide chain moiety of its substrate in the cap domain. Taken together with the results of phylogenetic analysis, our results suggest that VinJ represents a new amidohydrolase family that is different from the known α/ß hydrolase type serine peptidases.

A natural protecting group strategy to carry an amino acid starter unit in the biosynthesis of macrolactam polyketide antibiotics.

Macrolactam antibiotics are an important class of macrocyclic polyketides that contain a unique nitrogen-containing starter unit. In the present study, a set of starter biosynthetic enzymes in the macrolactam antibiotic vicenistatin was characterized. We found that the protection-deprotection strategy of the aminoacyl-ACP intermediate was critical in this system. On the basis of bioinformatics, the described pathway is also proposed as a common method for carrying amino acids in the biosynthesis of other macrolactam antibiotics.

Utility of diffusion-weighted images using fast asymmetric spin-echo sequences for detection of abscess formation in the head and neck region.

OBJECTIVE: The objective of this study was to evaluate the utility of new diffusion-weighted magnetic resonance images (DWI) using fast asymmetric spin-echo (FASE) sequences for the detection of abscess formation in patients with phlegmon in the oral and maxillofacial regions. METHODS: We compared diffusion-weighted images using FASE sequences with those using the gradient-echo type of echo-planar images (EPI) in 10 control volunteers and 10 patients with phlegmon in the oral and maxillofacial regions. RESULTS: Many kinds of tissues in the oral and maxillofacial regions were relatively well visualized in all subjects on FASE-DWI, but not well on EPI-DWI. Apparent diffusion coefficients calculated from FASE sequences in abscess areas of patients with phlegmon were significantly lower than those in abscess-free areas; however, apparent diffusion coefficients calculated from EPI were not significantly different due to prominent distortion in small sample size study. CONCLUSIONS: We could accurately recognize the presence of abscess formation within inflammatory tissue in 5 patients with phlegmon using FASE-DWI. As an additional magnetic resonance examination, FASE-DWI might be useful in the detection of abscess formation in the oral and maxillofacial regions.

The functional evaluation of salivary glands using dynamic MR sialography following citric acid stimulation: a preliminary study.

OBJECTIVE: We introduce a new technique for the functional evaluation of the salivary glands using continuous magnetic resonance (MR) sialography before and after citric acid stimulation. METHODS: In 10 volunteers, the time-dependent changes in the maximum area of the detectable parotid gland ducts on MR sialographic images taken every 30 seconds before and after citric acid stimulation were analyzed. The time period to the occurrence of the maximum duct area poststimulation was noted, and then the time for the area to return to its 50% value pre-citric acid stimulation was also observed. This new technique was clinically applied in 1 patient with an excessive supply impression of saliva and in 1 patient with a short supply impression with saliva. RESULTS: In all volunteers after citric acid stimulation, the maximum area of the detectable salivary gland ducts first increased and then decreased. A strong relationship was found between the maximum area of the detectable salivary gland ducts before citric acid stimulation and total saliva volume (Pearson r = 0.672, P = .031). Compared with all the volunteers, the ratio of change in the detectable ducts was the highest in the patient with an excessive supply impression of saliva, but lowest in the patient with a short supply impression with saliva. CONCLUSIONS: This initial study suggests that dynamic MR sialography allows for functional and morphological evaluation of the salivary glands. This technique appears to have many possible applications and further investigation in this field is necessary.

Hepatitis E virus transmission from wild boar meat.

We investigated a case of hepatitis E acquired after persons ate wild boar meat. Genotype 3 hepatitis E virus (HEV) RNA was detected in both patient serum and wild boar meat. These findings provided direct evidence of zoonotic foodborne transmission of HEV from a wild boar to a human.

Phenotypic switch from paracrine to autocrine role of hepatocyte growth factor in an androgen-independent human prostatic carcinoma cell line, CWR22R.

Support mechanisms involved in growth of androgen-independent prostate cancer are primarily unknown. Hepatocyte growth factor (HGF)/Met has been suggested to be one of them based primarily on immunohistochemical studies. We conducted a series of experiments to assess the role of the HGF/Met system in an androgen-dependent human prostate carcinoma, CWR22 and its androgen-independent derivative, CWR22R. We found that action of HGF changed from paracrine to autocrine in progression to androgen-independent state. CWR22 tumors did not express HGF but expressed Met, whereas prostate stromal cells expressed HGF at a high level. Growth of CWR22 was stimulated either by addition of HGF to the culture or by the presence of prostate stromal cells. On the other hand, CWR22R cells expressed both HGF and Met. Knockdown of Met expression by RNA interference method suppressed the growth of CWR22R cells. Our data suggest that HGF is intimately involved in growth of human prostate cancer and that progression from the androgen-dependent to the androgen-independent state is associated with an adaptive switch in support mechanism from paracrine to autocrine. Our data offer one mechanism to account for androgen-independent human cancer growth.

[A case of mandibular gingival cancer (T4) responding to concurrent chemoradiotherapy with TS-1].

We report here a patient with advanced oral cancer in which concurrent chemoradiotherapy with TS-1 was performed. The patient was an 82-year-old male who had a 41 x 22 mm tumor mass around the left lower gingiva, whose X-ray showed a bone resorption image reaching the mandibular canal. We carried out concurrent chemoradiotherapy with TS-1. After 4 weeks, severe side effects, i.e., stomatitis and diarrhea, force us to discontinue the treatment. However, the tumor had begun to shrink from the 2nd week of treatment, and had clinically disappeared by the 8th week. The histopathological examination also indicated a complete response (CR). Thus, this treatment was very effective and may be useful for advanced cases.

Array-enhanced coherence resonance and forced dynamics in coupled FitzHugh-Nagumo neurons with noise.

Nonlinear dynamics of coupled FitzHugh-Nagumo neurons subject to independent noise is analyzed. A kind of self-sustained global oscillation with almost synchronous firing is generated by array-enhanced coherence resonance. Further, forced dynamics of the self-sustained global oscillation stimulated by sinusoidal input is analyzed and classified as synchronized, quasiperiodic, and chaotic responses just like the forced oscillations in nerve membranes observed by in vitro experiments with squid giant axons. Possible physiological importance of such forced oscillations is also discussed.