Study of the electron-doping mechanism in single-walled carbon nanotubes using dimethylbenzimidazole.

Single-walled carbon nanotubes (SWCNTs) exhibit p-type properties in air, necessitating electron doping using n-dopants (e.g., reducing agents) for the development of SWCNT-based electronic devices. Dimethylbenzimidazole (DMBI-H) derivatives serve as effective electron dopants, not only for SWCNTs, but also for various organic semiconducting materials. However, the doping reaction is still a subject of debate. In this study, the electron-doping reactions of ortho-methoxy-substituted DMBI-H for SWCNTs were analyzed in protic and aprotic solvents in the presence and absence of dioxygen (O2). The presence of O2 was found to cause the reduction of O2 on the SWCNT surface in the protic solvent, resulting in the production of DMBI cations and water through proton-coupled electron transfer (PCET) from the n-doped SWCNT and ethanol. This work elucidates the mechanism behind the air-stability of n-type SWCNTs.

Can radiological technologists serve as primary screeners of low-dose computed tomography for the diagnosis of lung cancer?

BACKGROUND: The Accreditation Council for Lung Cancer CT Screening of Japan established guidelines for the certification of Radiological Technologists in 2009. OBJECTIVE: To analyze the trends in examination pass rates of the Radiological Technologists and discuss the reasons. METHODS: The cohort comprised 1593 Radiological Technologists (as examinees) based on 10-year of data (with a total of 17 examination runs). First, the examinees' written test results were analyzed. Second, an abnormal finding detection test was conducted using >100 client PCs connected to a dedicated server containing low-dose lung cancer CT screening images of 60 cases. The passing scores were correct answer rate >60% and sensitivity (TP) of >90%, respectively. RESULTS: Overall, 1243 examinees passed with an overall rate of 78%. The average pass rate for the written test was 91%, whereas that for the abnormal findings detection test was 85%. There was a moderate correlation between the test pass rate and average years of clinical experience of the examinees for the abnormal findings detection test (R = 0.558), whereas no such correlation existed for the written test (R = 0.105). CONCLUSIONS: In order for accredited Radiological Technologists to serve as primary screeners of low-dose computed tomography, it is important to revise the educational system according to current standard practices.

Standardized less invasive living donor hemihepatectomy using the hybrid method through a short upper midline incision.

BACKGROUND: Recently, applications of less invasive liver surgery in living donor hepatectomy (LDH) have been reported. The objective of this study was to evaluate the safety and efficacy of a hybrid method with a midline incision for LDH. METHODS: Hemihepatectomy using the hybrid method was performed in the fifteen most recent among 150 living donors who underwent surgery between 1997 and August 2011. Six donors underwent right hemihepatectomy and 9 underwent left hemihepatectomy. An 8-cm subxiphoid midline incision was created for hand assistance during liver mobilization and graft extraction. After sufficient mobilization of the liver, the hand-assist/extraction incision was extended to 12 cm for the right hemihepatectomy and 10 cm for a left hemihepatectomy. Encircling the hepatic veins and hilar dissection were performed under direct vision. Parenchymal transection was performed with the liver hanging maneuver. Bile duct division was performed after visualizing the planned transection point by encircling the bile duct using a radiopaque marker filament under real-time C-arm cholangiography. RESULTS: All procedures were completed without any extra subcostal incision. All grafts were safely extracted through the 10-12-cm upper midline incision without mechanical injury. No donors required an allogeneic transfusion; all of them have returned to their preoperative activity levels. CONCLUSION: LDH by the hybrid method with a short upper midline incision is a safe procedure.

Wireless LAN security management with location detection capability in hospitals.

OBJECTIVES: In medical institutions, unauthorized access points and terminals obstruct the stable operation of a large-scale wireless local area network (LAN) system. By establishing a real-time monitoring method to detect such unauthorized wireless devices, we can improve the efficiency of security management. METHODS: We detected unauthorized wireless devices by using a centralized wireless LAN system and a location detection system at 370 access points at the University of Tokyo Hospital. By storing the detected radio signal strength and location information in a database, we evaluated the risk level from the detection history. We also evaluated the location detection performance in our hospital ward using Wi-Fi tags. RESULTS: The presence of electric waves outside the hospital and those emitted from portable game machines with wireless communication capability was confirmed from the detection result. The location detection performance showed an error margin of approximately 4 m in detection accuracy and approximately 5% in false detection. Therefore, it was effective to consider the radio signal strength as both an index of likelihood at the detection location and an index for the level of risk. CONCLUSIONS: We determined the location of wireless devices with high accuracy by filtering the detection results on the basis of radio signal strength and detection history. Results of this study showed that it would be effective to use the developed location database containing radio signal strength and detection history for security management of wireless LAN systems and more general-purpose location detection applications.

Effects of prolonged water washing of tissue samples fixed in formalin on histological staining.

The effects of prolonged water washing after fixation for 48 h in 10% (v/v) phosphate-buffered neutral formalin on the quality of representative histological staining methods were evaluated using samples of liver, kidney, spleen and thymus collected from three male Crl:CD(SD)(IGS) rats and one male beagle dog. Because door-to-door courier services in Japan prohibit handling formalin, our goal was to confirm that formalin fixed wet tissue samples could be stored in tap water rather than formalin during transportation of the samples without decreasing the quality of their staining or immunohistochemistry. Each tissue sample was allocated randomly to one of three groups: 12 min, 3 days and 7 days of washing in running tap water; samples then were routinely embedded in paraffin and sectioned. The sections were stained with hematoxylin and eosin, periodic acid-Schiff, azan, and the TdT-mediated dUTP-biotin nick end labeling (TUNEL) method. Immunohistochemical staining for Factor VIII, ED-1 and CD3 also was assessed. Prolonged water washing for up to 7 days did not affect the morphology or stainability by standard histological methods, or the intensity and frequency of positive reactions using the TUNEL method. Only immunohistochemical staining of Factor VIII was altered in both the rat and dog sections after 7 days of water washing. The intensity of positive reactions of Factor VIII immunohistochemistry after 7 days water washing was still strong enough to detect microscopically. Therefore, prolonged water washing for up to 7 days after formalin fixation does not have seriously detrimental effects on the quality and characteristics of paraffin sections stained by various methods, including immunohistochemistry.

Cerebellar ataxia in a patient receiving calcineurin inhibitors after living donor liver transplantation: a case report.

Neurological complications of calcineurin inhibitors are frequent problems after transplantation. Cerebellar ataxia with other neurological findings and an abnormal density area in the subcortical white matter are found by MRI in the brains of most patients with central nervous system complications caused by calcineurin inhibitors. Such neurological complications are not life-threatening, but have a negative impact on the quality of life. We describe a 58-year-old woman who developed cerebellar ataxia at 4 days after living donor liver transplantation. She walked with a swaying gait, and after walking for 5 minutes she was unable to stand. Her symptoms persisted after a change from tacrolimus to cyclosporine, but dose reduction of cyclosporine and addition of mycophenolate mofetil cured the ataxia. We diagnosed a case of cerebellar ataxia without leukoencephalopathy or other neurological symptoms, as a new complication of calcineurin inhibitor treatment. We concluded that careful attention should be paid to neurological complications of calcineurin inhibitors.

Impact of serum flecainide level on control of atrial fibrillation in a case treated with cardiac resynchronization therapy.

A 72-year-old male patient with dilated cardiomyopathy was treated with oral flecainide (100 mg/day) for persistent atrial fibrillation (AF) that could not be converted to sinus rhythm by electrical cardioversion. Initiation of flecainide treatment provided sinus rhythm without prolongation of QRS and QTc, bradycardia and first-degree atrioventricular block at a serum flecainide level of 438 ng/mL. Then, he received cardiac resynchronization therapy (CRT). Dose reduction to 50 mg/day because of stabilization of heart rate after CRT produced AF at a serum flecainide level of 270 ng/mL. Electrical cardioversion did not restore the AF to a sinus or pacing rhythm. Dose escalation of flecainide (to 100 mg/day) restored the pacing rhythm at a serum flecainide level of 401 ng/mL. This case suggests that in the Japanese population, serum flecainide level should be maintained at >300 ng/mL to control AF even after effective CRT.

Tissue factor expression as a possible determinant of thromboembolism in ovarian cancer.

Ovarian cancer, and clear cell carcinoma in particular, reportedly increases the risk of venous thromboembolism (VTE). However, the mechanisms remain unclear. Tissue factor (TF) supposedly represents a major factor in the procoagulant activities of cancer cells. The present study examined the involvement of TF expression in VTE for patients with ovarian cancer. Subjects comprised 32 consecutive patients (mean age 49.8 years) with histologically confirmed ovarian cancer. Presence of VTE was examined using a combination of clinical features, D-dimer levels and venous ultrasonography. Immunohistochemical analysis was used to evaluate TF expression into 4 degrees. Venous thromboembolism was identified in 10 of the 32 patients (31%), including five of the 11 patients with clear cell carcinoma. Tissue factor expression was detected in cancer tissues from 24 patients and displayed significant correlations with VTE development (P=0.0003), D-dimer concentration (P=0.003) and clear cell carcinoma (P<0.05). Multivariate analysis identified TF expression as an independent predictive factor of VTE development (P<0.05). Tissue factor (TF) expression is a possible determinant of VTE development in ovarian cancer. In particular, clear cell carcinoma may produce excessive levels of TF and is more likely to develop VTE.

Cloning and characterization of six highly similar endo-1,3-beta-glucanase genes in hexaploid wheat.

Pathogenesis-related (PR) proteins are often used as a marker of plant defense reactions. Some endo-1,3-beta-glucanase (Gns) genes encode proteins that belong to the PR protein family 2 (PR-2). Although the number of homologous family member genes is significantly greater in hexaploid wheat (Triticum aestivum L.) compared to other model plants, earlier studies did not evaluate the possible contribution of their homologs to hybridization signals in Northern blot analysis. In this study, we have examined whether routine transcriptional analyses of a PR gene is of high reliability or not by isolating six highly similar Gns genes (TaGlb2a, TaGlb2b, TaGlb2c, TaGlb2d, TaGlb2e, and TaGlb2f) and characterizing their expression patterns in detail. While TaGlb2b was shown to be a PR-2 gene, transcription of TaGlb2c and TaGlb2d was not induced upon infection with either powdery mildew (Erysiphe graminis) or head blight (Fusarium graminearum) pathogens; their transcripts were most abundant in healthy spikes (lemmas and in particular paleae). Therefore, in some cases, the conventional analyses do not necessarily provide accurate information on expression pattern of a PR gene in hexaploid wheat. This is also the first report of wheat genes that are specifically expressed in lemma/palea tissues of flowering spikelets.

Secretion of bacterial xenobiotic-degrading enzymes from transgenic plants by an apoplastic expressional system: an applicability for phytoremediation.

In search of an effective method for phytoremediation of wastewater contaminated with organic compounds, we investigated the application of an apoplastic expressional system that secretes useful bacterial enzymes from transgenic plants into hydroponic media through the addition of a targeting signal. We constructed transgenic Arabidopsis expressing the aromatic-cleaving extradiol dioxygenase (DbfB), which degrades 2,3-dihydroxybiphenyl (2,3-DHB), and transgenic tobacco expressing haloalkane dehalogenase (DhaA), which catalyzes hydrolytic dechlorination of 1-chlorobutane (1-CB). Although crude leaf extracts of transgenic plants expressing cytoplasm-targeted degradative enzymes showed higher activity than did those from transgenic plants expressing apoplast-targeted enzymes, the hydroponic media of the latter showed 23.2 times (DbfB) and 76.4 times (DhaA) higher activity than plants containing the cytoplasm-targeted enzymes. Addition of crystalline 2,3-DHB to 100 mL of the hydroponic medium of transgenic or wild-type seedlings revealed that only medium from the transgenic Arabidopsis expressing apoplast-targeted DbfB showed rapid ring cleavage of 2,3-DHB. Transgenic tobacco expressing apoplast-targeted DhaA also resulted in the accumulation of the dehalogenation product 1-butanol in the hydroponic medium and showed a higher tolerance to 1-CB than wild-type or transgenic plants expressing cytoplasm-targeted DhaA. These results demonstrate the usefulness of the apoplastic expression of bacterial recombinant proteins in phytoremediation.

Pattern of N gene-mediated systemic hypersensitive response and turnover of viral replicase protein in tobacco.

We examined the pattern of the N gene-mediated systemic hypersensitive response (HR), which was induced by tobacco mosaic virus upon temperature shift, and analyzed the distribution of the coat protein and the virus-encoded 126 kDa replicase protein (126 K protein) by immunoblot analysis. In the middle- and lower-positioned leaves, HR occurred in the advancing edge of the infected area, where we detected both the coat protein and the 126 K protein. In the areas between the main vein and the advancing edge of these leaves, we observed no HR and did not detect 126 K protein, though virus was present in these areas. In the upper-positioned mosaic leaves, patterns of the HR were different depending on the leaf age. In these mosaic leaves, the mechanism preventing the virus from invading dark green tissue seemed to be broken down in 8-14 days old leaves, and HR was observed only in the tissue just invaded by the virus, where we detected the 126 K protein. Those results suggested that the viral 126 K protein was present when the viral replication was taking place, and easily degraded when the amount of the virus was saturated in the cells.

Bayesian classification of myocardial excitation abnormality using magnetocardiogram maps for mass screening.

We propose a novel classification method based on the Bayes rule to utilize the magnetocardiogram (MCG) in noninvasive mass screening. The cardiac excitation is directly tracked by maps of the MCG field generated by myocardial excitation current through the excited wave front. To adopt the characteristics of the excited wave fronts as a parameter for the Bayes theorem, we developed a parameterization procedure that consists of a two-dimensional wavelet approximation and a cluster analysis of magnetic field maps. With the parameter determined by this procedure, the probability of a subject to belong to a disease group or to the normal group is estimated by the Bayes theorem. The subject is classified into the group of the highest probability. We applied the proposed method to ST-T period of MCG data of 6 old myocardial infarction (OMI) patients and 15 normal controls. The method showed sensitivity of 83%; specificity, 100%; positive predictive value, 100%; and negative predictive value, 94% in the classification of OMI patients and normal controls. The processing time is less than 5 seconds per one subject. It suggests a possible application of the proposed method in mass screening of abnormal MCG patterns.

Microstructure analysis of calcium phosphate formed in tendon.

The surface of soft tendon tissue has been modified using calcium phosphate in order for the tendon to directly connect with hard bone and reconstruct an injured ligament. Calcium phosphate was coated onto the tendon in a soaking process using alternating a CaCl(2) (200 mM) and a Na(2)HPO(4) (120 mM) solution. According to SEM/EDX observations, calcium phosphate was formed, not only on the tendon surface, but also inside the tendon tissue. When the tendon was treated with seven soaking cycles, calcium phosphate was detected between 0-500 microm from the tendon surface. According to TEM observations, the crystal morphology of calcium phosphate depends on the distance from the surface. Hydroxyapatite crystals were observed near the surface, while octa-calcium phosphate crystals could be observed further from the surface, thus at initial soaking. The crystals were formed on collagen fibrils in spaces between the collagen fibrils with the c-axes of the crystals aligned parallel with the collagen fibrils. This finding suggests Ca(2+) ions to interact with the tendon surface, most probably with the carboxyl functional groups of collagen, and subsequently forming nucleation centers for the crystals.

Noninvasive, direct visualization of macro-reentrant circuits by using magnetocardiograms: initiation and persistence of atrial flutter.

AIMS: We analysed the cardiac magnetic fields on the body surface to visualize electrical currents noninvasively during reentrant arrhythmias. METHODS AND RESULTS: Seven patients with counterclockwise atrial flutter (AFL) were studied during 17 episodes of AFL using 64-channel magnetocardiograms (MCGs) and electrophysiological study. Eight of the episodes were paroxysmal AFL, in which MCGs were recorded from the time of spontaneous onset to the time of termination. We constructed iso-magnetic field maps of the tangential components and produced MCG animations. With respect to AFL initiation, an atrial premature complex induced AFL. Prior to the initiation of AFL, atrial fibrillation (AF) transiently occurred. The cardiac magnetic fields revealed a single peak during sinus rhythm or with premature complexes but a disorganized pattern during AF. When AF transformed to AFL, the magnetic fields changed from a disorganized pattern to a single peak at first and then evolved to a circular pattern. During persistent AFL, the magnetic source moved in a counterclockwise circuit. CONCLUSION: MCG animation can be used to visualize the sequence in which a premature complex transforms sinus rhythm to AFL via AF. Our findings indicate that MCGs can be used to identify noninvasively the mechanisms responsible for atrial tachyarrhythmias.

[Calf flow reserve measured by venous-occlusion near-infrared spectroscopy: relationship to exercise tolerance].

OBJECTIVES: The correlations between calf flow reserve evaluated with venous-occlusion near-infrared spectroscopy, air plethysmography or skin laser Doppler flowmetry were investigated in patients with cardiovascular diseases. The relationships to exercise tolerance during upright bicycle exercise were also examined. METHODS: The calf flow reserve (blood flow after 5 min of arterial occlusion/basal blood flow) evaluated by the above three methods and peak oxygen uptake (peak VO2) on bicycle exercise were measured in 24 male patients (mean age 65.0 +/- 7.7 years, left ventricular ejection fraction 24-86%). RESULTS: There was a good correlation between flow reserve by near-infrared spectroscopy (8.0 +/- 3.8) and air plethysmography (7.9 +/- 3.1; r = 0.90). However, there was a weak correlation between flow reserve by near-infrared spectroscopy and skin laser Doppler flowmetry (3.4 +/- 1.7; r = 0.42). There was a good correlation between flow reserve by near-infrared spectroscopy and peak VO2 (r = 0.69), or flow reserve by air plethysmography and peak VO2 (r = 0.53). However, there was no significant correlation between flow reserve by skin laser Doppler flowmetry and peak VO2 (r = 0.18). CONCLUSIONS: Calf flow reserve evaluated by venous-occlusion near-infrared spectroscopy relates to the flow reserve in the muscle tissue and is minimally affected by the flow reserve in the skin. The flow reserve in the muscle tissue is related to exercise tolerance, but the flow reserve in the skin is not, in patients with cardiovascular diseases.

Endothelin-1 production is enhanced by rotenone, a mitochondrial complex I inhibitor, in cultured rat cardiomyocytes.

In chronic heart failure and acute myocardial infarction, the tissue level of endothelin (ET)-1 in the heart, as well as its plasma level, has been reported to increase markedly. There is, however, little information about what in these pathologic conditions leads to increased production of ET-1, and which type of cell in the heart produces ET-1. We examined the mRNA and peptide expression of ET-1 using cultured rat neonatal cardiomyocytes, in which mitochondrial dysfunction was induced by rotenone, a mitochondrial respiratory chain complex I inhibitor, because one of the common features in failing or ischemic hearts is an alteration in energy metabolism due to mitochondrial dysfunction. Rotenone increased glucose use by the culture cells within 12 h of addition without affecting cell viability, and depressed the mitochondrial membrane potential after 72 h, indicating the induction of mitochondrial dysfunction in cardiomyocytes. Rotenone induced significant increase in the expression level of mRNA for ET-1 within 1 h of addition. In accordance with this finding, immunoreactive ET-1 in culture medium increased 3 times after 24 h of incubation, suggesting active secretion of ET-1 from cultured cells treated with rotenone. Immunocytochemical analysis verified significant increase of ET-1 peptide in cardiomyocytes, confirming the production of ET-1 by cardiomyocytes. These results suggest that derangement of mitochondrial function in cardiomyocytes itself could lead to the increased production of ET-1 in cardiomyocytes, and that this mechanism may contribute to the increased production of ET-1 in failing and ischemic hearts.

Physiological and pathological cardiac hypertrophy induce different molecular phenotypes in the rat.

Pressure overload, such as hypertension, to the heart causes pathological cardiac hypertrophy, whereas chronic exercise causes physiological cardiac hypertrophy, which is defined as athletic heart. There are differences in cardiac properties between these two types of hypertrophy. We investigated whether mRNA expression of various cardiovascular regulating factors differs in rat hearts that are physiologically and pathologically hypertrophied, because we hypothesized that these two types of cardiac hypertrophy induce different molecular phenotypes. We used the spontaneously hypertensive rat (SHR group; 19 wk old) as a model of pathological hypertrophy and swim-trained rats (trained group; 19 wk old, swim training for 15 wk) as a model of physiological hypertrophy. We also used sedentary Wistar-Kyoto rats as the control group (19 wk old). Left ventricular mass index for body weight was significantly higher in SHR and trained groups than in the control group. Expression of brain natriuretic peptide, angiotensin-converting enzyme, and endothelin-1 mRNA in the heart was significantly higher in the SHR group than in control and trained groups. Expression of adrenomedullin mRNA in the heart was significantly lower in the trained group than in control and SHR groups. Expression of beta(1)-adrenergic receptor mRNA in the heart was significantly higher in SHR and trained groups than in the control group. Expression of beta(1)-adrenergic receptor kinase mRNA, which inhibits beta(1)-adrenergic receptor activity, in the heart was markedly higher in the SHR group than in control and trained groups. We demonstrated for the first time that the manner of mRNA expression of various cardiovascular regulating factors in the heart differs between physiological and pathological cardiac hypertrophy.

[A clinical study on patients detected Pasteurella multocida from sputum].

We reported ten cases, (four female and six male), whose sputum cultures positive for Pasteurella multocida from 1990 to 2000. In the past eleven years increasing numbers of cases have appeared in our hospital. The majority of the cases with P. multocida possessed some underlying pulmonary diseases (seven cases, 70%), inactive lung tuberculosis or bronchiectasis. There were compromised hosts such as high ages person, steroids dependent person and diabetes mellitus patients. P. multocida was almost susceptible to antibioticus (penicillin and cephalosporins), although some erythromycin resistant strains were identified. The cats' oral cavities in our two cases were cultured and P. multocida were isolated. In our survey the prevalence of this organism is as high as 85% in cats. Our data suggests that patients who are in the high infection risk category are easily infected to P. multocida.

Differential expression of adenylyl cyclases in the rat nephron.

BACKGROUND: Adenylyl cyclases (ACs) are a family of enzymes that catalyze the formation of the second-messenger cyclic adenosine 3',5'-monophosphate (cAMP). At least nine isoforms of AC have been cloned. These isoforms differ in their tissue distribution and basal activity. AC isoforms also differ in their capacity to be stimulated or inhibited by G protein alpha(i), alpha(s) and beta/gamma subunits, protein kinase C, and intracellular calcium. The distribution of ACs in the kidney is only partially known, although it is known that ACs play important roles in kidney signal transduction. Several receptors are known to couple to AC, but their linkage to individual AC isoforms in the kidney is not known. METHODS: This study investigated the tissue distribution of AC isoforms along the nephron of Wistar-Kyoto rats using reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry, and immunoblotting. RESULTS: While AC VI and IX mRNA were found in all nephron segments, there was no expression of AC VIII mRNA. ACs II through V and VII mRNA were variably found in specific nephron segments. mRNA for AC isoforms II, III, VI, VII, and IX were expressed in renal proximal tubules. All of the AC isoforms studied, except VIII, were found in glomeruli. Immunoblotting and immunohistochemistry confirmed the mRNA results. AC isoforms II, III, IV, and IX were expressed in luminal rather than in basolateral membranes. However, immunohistochemical studies were not feasible for the other isoforms that could be expressed in basolateral membranes. CONCLUSION: Knowledge of the distribution of ACs may help establish the linkage between receptors and specific AC isoforms and define their functions.