Investigating the dynamics of collective behavior among pedestrians crossing roads: A multi-user virtual reality approach

The utility maximization theory, based on the rationality of human beings, has proven effective in modeling pedestrians' decision-making processes while crossing roads. However, there are still unexplained variations in crossing behavior, and deviations from the rational utility model frequently occur in real-life scenarios. This experimental study sheds new light on the presence of inter-individual interactions among pedestrians and the nature of collective behaviors during road crossings. The present study develops a multi-pedestrian virtual reality simulator specifically designed to investigate the impact of social interaction on pedestrians' eye-scanning patterns, perceived responses, crossing behaviors, and the associated crash risk. Our findings indicate that the collective behavior significantly influences pedestrians' behaviors by diverting their attention from essential eye-scanning patterns that reflect their cognitive processes. Pedestrians in pairs exhibit a higher tendency to fixate on each other, spend less time in the decision phase, walk at a slower pace during the crossing phase, and consequently face a higher degree of exposure to dangerous situations compared to when crossing alone. Encouraged by these findings on the effects of social interaction, we discuss preventive strategies to mitigate the negative impacts of collective behavior and foster pedestrians' safety awareness.

Risk factors for hospital-acquired infection during the SARS-CoV-2 pandemic

OBJECTIVE

To evaluate risk factors for hospital-acquired infection (HAI) in patients during the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic, including historical and concurrent cohorts.

DESIGN

Retrospective cohort.

SETTING

Three Missouri hospitals, data from 1^st January 2017 to 30^th September 2020.

PARTICIPANTS

Patients aged ≥18 years and admitted for ≥48 h.

METHODS

Univariate and multi-variate Cox proportional hazards models incorporating the competing risk of death were used to determine risk factors for HAI. A-priori sensitivity analyses were performed to assess the robustness of the urine-, blood- and respiratory-culture-based HAI definition.

RESULTS

The cohort included 254,792 admissions, with 7147 (2.8%) HAIs (1661 blood, 3407 urine, 2626 respiratory). Patients with SARS-CoV-2 had increased risk of HAI (adjusted hazards ratio 1.65, 95% confidence interval 1.38-1.96), and SARS-CoV-2 infection was one of the strongest risk factors for development of HAI. Other risk factors for HAI included certain admitting services, chronic comorbidities, intensive care unit stay during index admission, extremes of body mass index, hospital, and selected medications. Factors associated with lower risk of HAI included year of admission (declined over the course of the study), admitting service and medications. Risk factors for HAI were similar in sensitivity analyses restricted to patients with diagnostic codes for pneumonia/upper respiratory infection and urinary tract infection.

CONCLUSIONS

SARS-CoV-2 was associated with significantly increased risk of HAI.

Pedestrians safety perception and crossing behaviors in narrow urban streets: An experimental study using immersive virtual reality technology

Virtual reality (VR) technology emerges as a promising tool for investigating human perception and behavior in highly controlled, immersive, and risk-free environments. This study proposed to apply simulated VR technology to investigate the interactions between perceived crash risk and behavior patterns in a road crossing with changes in the safety-related environmental attributes. In the context of the 8-meter-wide segment in a residential block, 35 VR environments with variations of six environmental attributes were generated. Two hundred participants were recruited for the experiment. The measured behavioral outcomes were 1) waiting and reaction time in the decision phase before crossing and 2) crossing speed and gait variability in the crossing phase. Random effect regression and multi-level structural equation models were constructed to test the study hypotheses. The results demonstrated that environmental attributes, including barriers to visibility (coefficient = 0.446), geometric patterns (coefficient = -0.625), and pavement signs (coefficient = -0.502), were associated with the pedestrians' perceived risk, but the influence varied by street types. In addition, changes in the perceived threats to pedestrians were found to mediate the environment-crossing behavior relationship (coefficient of the indirect effect = 0.679). Those who perceive higher crash risk took longer to decide to start walking at a crosswalk and tended to walk in haste while crossing the road. Using VR technology, the present study addressed an inter-relationship between environmental characteristics, cognition, and crossing behavior, contributing to better knowledge on road safety interventions to reduce the risk of pedestrian-involved crashes.

An examination of the intersection environment associated with perceived crash risk among school-aged children: using street-level imagery and computer vision

While computer vision techniques and big data of street-level imagery are getting increasing attention, a "black-box" model of deep learning hinders the active application of these techniques to the field of traffic safety research. To address this issue, we presented a semantic scene labeling approach that leverages wide-coverage street-level imagery for the purpose of exploring the association between built environment characteristics and perceived crash risk at 533 intersections. The environmental attributes were measured at eye-level using scene segmentation and object detection algorithms, and they were classified as one of four intersection typologies using the k-means clustering method. Data on perceived crash risk were collected from a questionnaire conducted on 799 children 10 to 12 years old. Our results showed that environmental features derived from deep learning algorithms were significantly associated with perceived crash risk among school-aged children. The results have revealed that some of the intersection characteristics including the proportional area of sky and roadway were significantly associated with the perceived crash risk among school-aged children. In particular, road width had dominant influence on risk perception. The findings provide information useful to providing appropriate and proactive interventions that may reduce the risk of crashes at intersections.

Early development of de novo hepatocellular carcinoma after direct-acting agent therapy: Comparison with pegylated interferon-based therapy in chronic hepatitis C patients

Patients with chronic hepatitis C who achieve a sustained viral response after pegylated interferon therapy have a reduced risk of hepatocellular carcinoma, but the risk after treatment with direct-acting antivirals is unclear. We compared the rates of early development of hepatocellular carcinoma after direct-acting antivirals and after pegylated interferon therapy. We retrospectively analysed 785 patients with chronic hepatitis C who had no history of hepatocellular carcinoma (211 treated with pegylated interferon, 574 with direct-acting antivirals) and were followed up for at least 24 weeks after antiviral treatment. De novo hepatocellular carcinoma developed in 6 of 574 patients receiving direct-acting antivirals and in 1 of 211 patients receiving pegylated interferon. The cumulative incidence of early hepatocellular carcinoma development did not differ between the treatment groups either for the whole cohort (1.05% vs 0.47%, P = .298) or for those patients with Child-Pugh Class A cirrhosis (3.73% vs 2.94%, P = .827). Multivariate analysis indicated that alpha-fetoprotein level >9.5 ng/mL at the time of end-of-treatment response was the only independent risk factor for early development of hepatocellular carcinoma in all patients (P < .0001, hazard ratio 176.174, 95% confidence interval 10.768-2882.473) and in patients treated with direct-acting agents (P < .0001, hazard ratio 128.402, 95% confidence interval 8.417-1958.680). In conclusion, the rate of early development of hepatocellular carcinoma did not differ between patients treated with pegylated interferon and those treated with direct-acting antivirals and was associated with the serum alpha-fetoprotein level at the time of end-of-treatment response.

Dual-graft adult living donor liver transplantation with ABO-incompatible graft: short-term and long-term outcomes

ABO-incompatible (ABOi) dual-graft (DG) adult living donor liver transplantation (ALDLT) is not commonly performed due to its inherently intricate surgical technique and immunological complexity. Therefore, data are lacking on the short- and long-term clinical outcomes of ABOi DG ALDLT. We performed a retrospective study by reviewing the medical records of patients who underwent ABOi DG ALDLT between 2008 and 2014. Additionally, computed tomography volumetric analysis was conducted to assess the graft regeneration rate. The mean age of a total of 28 recipients was 50.2 ± 8.5 years, and the mean model for end-stage liver disease score was 12.2 ± 4.6. The 1-, 3-, and 5-year patient survival rate was 96.4% during the mean follow-up period of 57.0 ± 22.4 months. The 1-, 3-, and 5-year graft survival rate was 96.4%, 94.2%, and 92.0%, respectively, and no significant differences were observed between ABO-compatible (ABOc) and ABOi grafts (P = .145). The biliary complication rate showed no significant difference (P = .195) between ABOc and ABOi grafts. Regeneration rates of ABOi grafts were not significantly different from those of ABOc grafts. DG ALDLT with ABOi and ABOc graft combination seems to be a feasible option for expanding the donor pool without additional donor risks.

Living Donor Liver Transplantation for Patients Older Than Age 70 Years: A Single-Center Experience

Over the past two decades, the age of liver transplantation (LT) recipients has been increasing. We reviewed our experience with LT for patients aged ≥70 years (range: 70-78 years) and investigated the feasibility of performing LT, especially living donor LT (LDLT), for older patients. We retrospectively reviewed the medical records of 25 patients (15 LDLT recipients, 10 deceased donor LT recipients) aged ≥70 years who underwent LT from January 2000 to April 2016. Their perioperative morbidity rate was 28.0%, and the in-hospital mortality rate was 16.0%; these results were comparable to those of matched patients in their 60s (n = 73; morbidity, p = 0.726; mortality, p = 0.816). For patients in their 70s, the 1- and 5-year patient survival rates were 84.0% and 69.8%, and the 1- and 5-year graft survival rates were 83.5% and 75.1%, respectively. Comparisons of patient and graft survival rates between matched patients in their 60s and 70s showed no statistically significant differences (patient survival, p = 0.372; graft survival, p = 0.183). Our experience suggests that patients aged ≥70 years should not be excluded from LT, or even LDLT, based solely on age and implies that careful selection of recipients and donors as well as meticulous surgical technique are necessary for successful results.

Anti-adhesive effect of a thermosensitive poloxamer applied after the removal of nasal packing in endoscopic sinus surgery: a randomised multicentre clinical trial

OBJECTIVE

To compare the efficacies of a thermosensitive poloxamer (TPX) and Merogel in preventing adhesion applied after the removal of nasal packing in endoscopic sinus surgery as a non-inferiority trial.

DESIGN

Randomised, multicentre, single-blind, active-controlled, matched-pair study.

SETTING

Yonsei University Gangnam Severance Hospital, Korea University Guro Hospital.

PARTICIPANTS

A total of 70 patients were enroled and underwent endoscopic sinus surgeries. Four of the patients did not complete their follow-up. Analysis of the 66 enroled patients having completed postoperative assessment was performed. The severity of rhinosinusitis was graded with a Lund-McKay CT score, and only those with bilateral disease and a CT score difference ≤2 between sinuses were included.

MAIN OUTCOME MEASURES

An independent rhinologist from a third institution through a blinded assessment with digital photoendoscopy of the middle meati bilaterally taken postoperatively.

RESULTS

In the blinded assessment, thermosensitive poloxamer (anti-adhesion rate: 92%) was similar to Merogel (anti-adhesion rate: 89%). Evaluation of the presence and grade of adhesion, oedema, and infection in the middle meatus revealed no significant differences between the thermosensitive poloxamer group and the Merogel group at all postoperative periods.

CONCLUSION

Anti-adhesive effects of thermosensitive poloxamer are similar to those of Merogel. Therefore, thermosensitive poloxamer can be considered a safe alternative to Merogel for preventing adhesion in patients undergoing endoscopic sinus surgeries, and further evaluation of thermosensitive poloxamer as an anti-adhesive and primary packing material compared with the control using no packing is needed.

Low-voltage-driven pentacene thin-film transistors with cross-linked poly(4-vinylphenol)/high-k Bi55b3O15 hybrid dielectric for phototransistor

This paper describes the fabrication of pentacene thin-film transistors (TFTs) with an organic/inorganic hybrid gate dielectric, consisting of cross-linked poly(4-vinylphenol) (PVP) and Bi5Nb3O15. A 300-nm-thick Bi5Nb3O15 dielectric film, grown at room temperature, exhibits a high dielectric constant (high-k) value of 40 but has an undesirable interface with organic semiconductors (OSC). To form better interfaces with OSC, a cross-linked PVP dielectric was stacked on the Bi5Nb3O15 dielectric. It is shown that, with the introduction of a hybrid dielectric, our devices not only can be operated at a low voltage (- -5 V) but also have improved electrical characteristics and photoresponse, including a field-effect mobility of 0.72 cm2/V x s, current sub-threshold slopes of 0.29 V/decade, and a photoresponse of 4.84 at a gate bias V(G) = 0 V under 100 mW/cm2 AM 1.5 illumination.

The embryo lethality of Escherichia coli isolates and its relationship to the presence of virulence-associated genes

The aims of this study were to determine if the chicken embryo lethality assay and the presence of 9 virulence-associated genes of Escherichia coli were correlated and to discover which virulence genes contributed most to embryo lethality. We examined 58 E. coli strains isolated from visceral organs of chickens with colibacillosis for the presence of 9 virulence genes (fimC, tsh, fyuA, irp2, iucD, cvi/cva, iss, astA, and vat) by PCR. The gene FimC (type I fimbriae) was detected with the highest prevalence in 93.1% of the isolates, followed by iucD (67.24%), iss (58.62%), tsh (34.48%), cvi/cva (34.48%), fyuA (32.76%), astA (31.0%), irp2 (27.59%), and vat (17.24%). The embryo mortality ranged from 5 to 100%; however, most of the isolates were moderately or highly virulent. High positive correlations were observed between the presence of virulence genes and chicken embryo lethality. In addition, presence of the iucD (aerobactin) gene was the trait that best contributed to embryo mortality by using the multivariate model. These results suggest that expression frequency of these 9 virulence genes is associated with embryo mortality, and the gene that best predicted embryo mortality was iucD.

Pretreatment HBeAg level and an early decrease in HBeAg level predict virologic response to entecavir treatment for HBeAg-positive chronic hepatitis B

There are few reports on hepatitis B e antigen (HBeAg) titres during nucleos(t)ide analogues treatment. We investigated the changes in HBeAg levels in patients treated with entecavir and the usefulness of HBeAg quantification for predicting antiviral response. Ninety-five consecutive HBeAg-positive patients treated with entecavir for more than 48 weeks were enrolled. Serum levels of hepatitis B surface antigen (HBsAg), HBeAg and HBV DNA were assessed at 4-week intervals to week 24 and thereafter at 12-week intervals. Virologic response (Y1VR) was defined as an undetectable HBV DNA level at week 48 of therapy. During 48 weeks, HBeAg and HBV DNA level decreased significantly in a biphasic manner and HBsAg level tended to decease. Fifty-three patients (55.8%) attained Y1VR. Pretreatment HBeAg levels were significantly lower in the Y1VR group than in no Y1VR group. At week 4 and 12 of therapy, 25% and 41.4% of patients showed a decrease of HBeAg levels with >0.5 log(10) and >1.0 log(10) from baseline, respectively. These patients achieved more Y1VR than those with less decrease of HBeAg levels (97.7%vs 22.2% and 86.2%vs 29.3%, respectively). HBeAg level at week 12 had higher predictive values for Y1VR than HBV DNA level. Multivariate analysis revealed that a pretreatment HBeAg level of <360 PEIU/mL and the reduction in HBeAg level >1.0 log(10) at week 12 were associated with Y1VR. These results suggest that pretreatment HBeAg level and an early decrease in HBeAg level are useful measurements for predicting one-year virologic response during entecavir treatment.

Serum hepatitis B surface antigen levels in the natural history of chronic hepatitis B infection

BACKGROUND  The production of hepatitis B surface antigen (HBsAg) may evolve during long-lasting virus-host interactions in chronic hepatitis B (CHB). The impact of age on HBsAg production remains unclear. AIM  To determine the age-specific distribution patterns of HBsAg and related factors during the natural course of CHB infection. METHODS  Seven hundred and sixty-eight untreated HBsAg carriers were enrolled in the study. The parameters and distribution patterns of HBsAg were evaluated in relation to age and immune phases. RESULTS  The HBsAg levels were significantly lower in the HBeAg-negative stage, with the lowest levels in inactive carriers. The HBsAg tended to decrease from hepatitis to cirrhosis and to hepatocellular carcinoma, and from Child-Pugh class A to B and to C. Age and HBV DNA were independently associated with HBsAg levels. In HBeAg-positive patients, the HBsAg levels were distributed in a triphasic-like decline pattern by 2 logs across age strata. For HBeAg-negative patients, the titres in inactive carriers exhibited a 2-log reduction, but remained unchanged over age strata in patients with HBeAg-negative hepatitis. The ratios of HBsAg/HBV-DNA were highest, but steadily decreased with age in inactive carriers, whereas the levels remained largely unchanged over the entire age strata in patients with HBeAg-negative hepatitis. CONCLUSIONS  Age and HBV DNA levels are independent parameters of HBsAg levels. During the natural course of CHB infection, HBsAg levels decrease with age and disease progression, but the patterns are significantly different between the immune phases of CHB. This information may contribute to our understanding of the immunopathogenesis of chronic hepatitis B and management involving HBsAg quantification.

Characterization of Escherichia coli isolates from laying hens with colibacillosis on 2 commercial egg-producing farms in Korea

The present study reports on layer chickens with colibacillosis in 2 commercial egg-producing farms (referred to as farm A and farm B, which were managed by the same owner and were about 1 km apart) in the middle region of the Korean peninsula. The 2 flocks were infected at the initiation of egg laying. They were characterized by no previous clinical signs but sudden mortality (2.7-4.0%), with severe lesions of septicemia and fibrinous polyserositis. Escherichia coli was isolated from the lesions of the infected birds. Serotyping tests identified isolates that belonged to somatic groups O1 (12/17), O46 (2/17), O78 (1/17), and O84 (1/17) or that were unidentified (1/17). Thirteen of 17 E. coli isolates (76.4%) obtained from 11 birds in the 2 flocks showed similar pulsed-field gel electrophoresis patterns that were arbitrarily designated as pattern A. The isolates had high frequencies of putative virulence genes including 100% [fimC (type 1 fimbriae), iucD (aerobactin synthesis), and iss (increased serum survival)], 94.1% [cva/cvi (structural genes of colicin V operon) and vat (vacuolating autotransporter toxin)], 88.2% [irp2, iron-repressible protein (yersinia bactin) synthesis, and fyuA, ferric yersinia uptake], and 82.3% [tsh (temperature-sensitive hemagglutinin)]; astA (encoding a heat-stable cytotoxin associated with enteroaggregative E. coli) was not associated with the enteric disorder. These data suggest that all chickens with colibacillosis on farms A and B were likely infected by E. coli strains that are highly pathogenic in avian species.

Survival rate of H5N1 highly pathogenic avian influenza viruses at different temperatures

The survival rate of Korean H5N1 highly pathogenic avian influenza (HPAI) viruses was investigated at different temperatures under the laboratory conditions. The estimated survival days for a starting viral concentration of 10(6.5) 50% egg infectious dose/0.1 mL were 930, 1,042, and 3,213 d at 4 degrees C; 226, 232, and 293 d at 20 degrees C; and 51, 55, and 58 d at 30 degrees C for A/chicken/Korea/ES/03, A/chicken/Korea/IS/06, and A/chicken/Korea/Gimje/08 (Gimje/08) viruses, respectively. The stability of the Gimje/08 virus was statistically significant compared with the other 2 viruses except for the data between Gimje/08 and A/chicken/Korea/IS/06 virus at 30 degrees C. This result indicated that the survival rate of 3 Korean HPAI viruses is different at various temperatures, which might have partially influenced the large scale of HPAI outbreak in Korea in 2008.

The susceptibility of magpies to a highly pathogenic avian influenza virus subtype H5N1

Korean wild magpies (Pica pica sericea) were intranasally inoculated with highly pathogenic avian influenza (A/Chicken/Korea/ES/03 virus) (H5N1), which was classified as clade 2.5. We estimated viral replication, death after infection, and histology and immunohistochemistry. This species was highly susceptible to severe infection; 100% of birds died within 5 to 8 d. The virus was detected from oropharyngeal (1 to 5 d postinfection) and cloacal (3 to 5 d postinfection) swabs from infected magpies. At necropsy, the prominent lesions were coalescing necrosis of the pancreas with enlargement of livers and spleens. Microscopically, pancreas, brain, heart, adrenal gland, and kidney were most consistently affected with necrotic and inflammatory changes, and viral antigen was frequently demonstrated in the parenchyma of these organs. As a result, Korean wild magpies were very susceptible to avian influenza (H5N1) virus.

Development of a stabilizer for lyophilization of an attenuated duck viral hepatitis vaccine

The live attenuated vaccine against duck viral hepatitis currently available in Korea requires special freezers for storage and transportation with extra costs involved. The development of a lyophilization stabilizer for live attenuated duck viral hepatitis virus (DHV) vaccines, therefore, has been highly recommended for the wider application of the vaccines. Four conventional vaccine stabilizer formulations containing a disaccharide, such as lactose, trehalose, or sucrose, and new formulations containing sorbitol were tested for their efficacy in stabilizing a new attenuated DHV type 3 vaccine candidate under different storage temperatures, 4 and 37 degrees C. The vaccine virus and each stabilizer formulation were combined and submitted to lyophilization and the viability of the virus was measured in 7-d-old specific-pathogen-free chicken embryos by determining the 50% egg lethal dose. Stabilizer formulations containing 2, 4, or 8% sorbitol preserved the viability of the vaccine virus much better than the other stabilizer formulations and 2% sorbitol was the optimal concentration in a standard stabilizing buffer, phosphate glutamate gelatin (0.0038 M KH2PO4, 0.0071 M K2HPO4, 0.0049 M monosodium L-glutamate, and 0.5% gelatin). The results demonstrate that the stabilizer formulation containing 2% sorbitol and 0.5% gelatin can be used for convenient storage and transportation of live DHV vaccines.

Organic thin film transistor with poly(4-vinylbiphenyl) blended 6,13-bis(triisopropylsilylethynyl)pentacene on propyleneglycolmonomethyletheracetate dielectric surface

This paper presents the latest results in the use of soluble materials, such as organic semiconductors (OSCs) and gate-dielectrics, for simplified processing of organic thin film transistors (OTFTs). In this work, the fabrication of a solution-processed OTFT, with 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) and TIPS-pentacene mixed with poly(4-vinylbiphenyl) (PVBP) as the OSC, and propyleneglycolmonomethyletheracetate (PGMEA) as the gate-dielectric, is described. From electrical measurements, we observed exemplary I-V characteristics for these TFTs. Device performance characteristics have been obtained, including the charge carrier mobility (micro) of 1.47 x 10(-2) cm2Ns, threshold voltage (V(T)) of -11.36 V, current on/off ratio (I(ON/OFF)) of 1.08 x 10(4), sub-threshold swing (SS) of 2.13 V/decade for an OTFT with PVBP blended TIPS-pentacene and micro of 1.39 x 10(-4) cm2/Vs, V(T) of 0.7 V, I(ON/OFF) of 1.64 x 10(3), SS of 4.21 V/decade for an OTFT without polymer binder, individually.

CT features of lobular capillary hemangioma of the nasal cavity

BACKGROUND AND PURPOSE

Lobular capillary hemangioma is a benign capillary proliferation of unknown etiology. To our knowledge, no comprehensive review of imaging findings of LCHNC has been presented. Thus, we investigated characteristic CT features of LCHNC.

MATERIALS AND METHODS

This retrospective study included 6 patients (2 men and 4 women; age range, 30-65 years; mean age, 49.2 years) with histologically proved LCHNC. We evaluated the size, site of origin, attenuation on NECT, degree and pattern of enhancement, and bony changes.

RESULTS

The LCHNC lesion was 13.0-45.0 mm (average, 25.0 mm) in diameter. These lesions arose from the inferior turbinate in 5 (83.3%) patients and the anterior nasal septum in 1 (16.7%). Compared with the masticator muscles, the LCHNC lesion was hypoattenuating in 2 (33.3%) and isoattenuating on NECT in 4 (66.7%) patients. In 5 (83.3%) patients, the LCHNC lesion consisted of 2 distinct areas on CECT: a lobular intensely enhancing mass and an iso- or hypoattenuating cap of variable thickness around the intensely enhancing mass. Bony changes included erosion in 3 (50.0%) and displacement in 2 (33.3%) patients.

CONCLUSIONS

CT features of LCHNC consist of an intensely enhancing mass and an iso- or hypoattenuating cap on CECT. The inferior turbinate seems to be a common site of origin, and bony changes are not uncommon features of LCHNC. CT is useful not only in identifying the site of origin and assessing the extent but also in suggesting the nature of LCHNC.

A flexible amorphous Bi(5)Nb(3)O(15) film for the gate insulator of the low-voltage operating pentacene thin-film transistor fabricated at room temperature

The amorphous Bi(5)Nb(3)O(15) film grown at room temperature under an oxygen-plasma sputtering ambient (BNRT-O(2) film) has a hydrophobic surface with a surface energy of 35.6 mJ m(-2), which is close to that of the orthorhombic pentacene (38 mJ m(-2)), resulting in the formation of a good pentacene layer without the introduction of an additional polymer layer. This film was very flexible, maintaining a high capacitance of 145 nF cm(-2) during and after 10(5) bending cycles with a small curvature radius of 7.5 mm. This film was optically transparent. Furthermore, the flexible, pentacene-based, organic thin-film transistors (OTFTs) fabricated on the poly(ether sulfone) substrate at room temperature using a BNRT-O(2) film as a gate insulator exhibited a promising device performance with a high field effect mobility of 0.5 cm(2) V(-1) s(-1), an on/off current modulation of 10(5), and a small subthreshold slope of 0.2 V decade(-1) under a low operating voltage of -5 V. This device also maintained a high carrier mobility of 0.45 cm(2) V(-1 )s(-1) during the bending with a small curvature radius of 9 mm. Therefore, the BNRT-O(2) film is considered a promising material for the gate insulator of the flexible, pentacene-based OTFT.

Anomalous double peak structure in superconductor/ferromagnet tunneling density of states

We have experimentally investigated the density of states (DOS) in Nb/Ni (S/F) bilayers as a function of Ni thickness, d(F). Our thinnest samples show the usual DOS peak at +/- Delta(0), whereas intermediate-thickness samples have an anomalous "double-peak" structure. For thicker samples (d(F) > or =3.5 nm), we see an inverted DOS, which has previously only been reported in superconductor or weak-ferromagnet structures. We analyze the data using the self-consistent nonlinear Usadel equation and find that we are able to quantitatively fit the features at +/- Delta(0) -- in particular the thickness at which the inversion occurs -- only if we include a large amount of spin-orbit scattering in the model. Interestingly, we are unable to reproduce the subgap structure through the addition of any parameter(s). Therefore, the observed anomalous subgap structure represents new physics beyond that contained in the present Usadel theory.

Fluoroscopically guided percutaneous jejunostomy: outcomes in 25 consecutive patients

AIM

To assess the feasibility and safety of fluoroscopically guided percutaneous jejunostomy.

MATERIAL AND METHODS

Between May 1999 and August 2006 percutaneous jejunostomy was attempted in 25 patients. A 5 F vascular catheter (n=20) or a 7.5 F multifunctional coil catheter (n=5) was used to insufflate the jejunum. The distended jejunum was punctured using a 17 G needle (n=19) or a 21 G Chiba needle (n=6) with the inserted catheter as a target. A 12 or 14 F loop feeding tube was inserted after serial dilations. The technical success, complications, 30-day mortality, and in-dwelling period of the feeding tube placement were evaluated.

RESULTS

The technical success rate was 92% (23/25). Technical failures (n=2) resulted from the inability to insufflate the jejunum secondary to failure to pass the catheter through a malignant stricture at the oesophagojejunostomy site and thus subsequent puncture of the undistended jejunum failed, or failure to introduce the Neff catheter into the jejunum. Pericatheter leakage with pneumoperitoneum was a complication in three patients (12%) and was treated conservatively. The 30-day mortality was 13% (3/23); however, there was no evidence that these deaths were attributed to the procedure. Except for four patients who were lost to follow-up and two failed cases, 15 of the 19 jejunostomy catheters were removed because of patient death (n=12) or completion of treatment (n=3), with a mean and median in-dwelling period of 231 and 87 days, respectively.

CONCLUSIONS

Fluoroscopically guided percutaneous jejunostomy is a feasible procedure with a high technical success and a low complication rate. In addition to a 17 G needle, a 21 G needle can safely be used to puncture the jejunum.

Effects of Homologous and Heterologous Neuraminidase Vaccines in Chickens Against H5N1 Highly Pathogenic Avian Influenza

The 2004 Asian H5N1 epizootic outbreak indicates the urgent need for vaccines against highly pathogenic avian influenza (HPAI) virus. The manufacture of inactivated whole-virus vaccines from HPAI viruses by traditional methods is not feasible for safety reasons as well as technical issues. The low pathogenic avian influenza A/wild bird feces/CSM2/02 (H5N3) virus was used as a heterologous neuraminidase vaccine, and HPAI A/CK/Korea/ES/03 (H5N1) virus was used as a homologous neuraminidase vaccine. Protection efficacy of both vaccines was evaluated by clinical signs, mortality rates, and virus shedding from oropharynx and cloaca of vaccinated chickens after challenge with HPAI A/CK/Korea/ES/03 (H5N1) virus. One dose of 128 hemagglutinin (HA) homologous H5N1 vaccine induced 100% protection in mortality and prevented viral shedding completely after lethal dose virus challenge, whereas one dose of 64 HA unit of heterologous H5N3 vaccine only induced 50% protection in mortality, and it did not prevent viral shedding. However, two doses at a 3-wk interval of 64 HA unit of heterologous H5N3 vaccine as well as one dose of 1024 HA unit of heterologous H5N3 vaccine induced 100% survival rate and could prevent viral shedding completely. Furthermore, we could differentiate the sera of infected birds from those of vaccinated birds by indirect immunofluorescent antibody test. These results suggest that heterologous neuraminidase H5N3 vaccine could be a useful tool for the control of H5N1 HPAI epidemic in poultry.

Retroanastomotic hernia after gastrojejunostomy: US and CT findings with an emphasis on the whirl sign

BACKGROUND

We reviewed ultrasound (US) and computed tomographic (CT) findings of retroanastomotic hernia and established whether such findings are characteristic of retroanastomotic hernia in patients who have undergone gastrojejunostomy.

METHODS

During a recent 10-year period, we encountered 13 consecutive cases of retroanastomotic hernia. Of the patients involved, 11 underwent US, 10 underwent CT, and three underwent small bowel followthrough imaging. The US and CT scans were retrospectively reviewed to determine abnormal findings. Surgical proof was available in all cases.

RESULTS

The efferent loop was herniated through the defect created behind the anastomosis in 10 cases, the efferent and afferent loops in two cases, and the afferent loop in one case. Retroanastomotic hernia was prospectively suggested in 12 of these 13 cases. Among the 10 cases of efferent loop herniation, US and CT signs of retroanastomotic hernia included whirling of mesenteric vessels, jejunal loops, and mesentery in the periumbilical abdomen (10 of 10); mural thickening of herniated bowel loops (six of 10); dilatation of herniated bowel loops (four of 10); decreased peristalsis of herniated bowel loops on US (three of nine); and decreased contrast enhancement of herniated bowel loops on CT (one of seven). In one case, US and CT signs of retroanastomotic hernia of the afferent loop included its dilatation and whirling of a short length of afferent loop behind the anastomosis. In two cases, US and CT signs of retroanastomotic hernia of the afferent and efferent loops included findings of afferent and efferent loop herniations. Three of 13 cases had reversible bowel ischemia, and one had bowel necrosis.

CONCLUSION

Retroanastomotic hernia is an important condition, and the US and CT findings we have described might suggest its diagnosis.

Studies on the development of functional powder from citrus peel

The suitability of citrus peels, generated as a by-product of the juice industry, as a source of antioxidants was investigated. Citrus peel powder was prepared by lyophilizing 70% ethanol extract from citrus peels. Extraction was carried out at room temperature (20 degrees C) for 72 h. The extract was subjected to gamma-irradiation treatment (20 kGy). The aqueous solutions of citrus peel powder were examined for color characteristics and antioxidant potential in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, beta-carotene bleaching and nitrite scavenging activities. There were significant changes in Hunter color values due to irradiation. The a*- and b*-values decreased due to radiation treatment. DPPH radical scavenging, beta-carotene bleaching and nitrite scavenging activities were not affected by irradiation treatment. Nitrite scavenging activity was the highest in the extract at pH 1.2 followed by pH 4.2 and 6.0. These functional properties of the aqueous solution were found to be stable in heat treatment. It could significantly improve oxidative stability of lipids in fish meat system. Based on these results there may be opportunities to use citrus peel powder as a functional component in the food processing industry with gamma irradiation treatment improving its color characteristics without adversely influencing the functional properties.

A pilot study on accelerated sludge degradation by a high-concentration membrane bioreactor coupled with sludge pretreatment

A new sludge treatment process combining a high MLSS membrane bioreactor with sludge pretreatment techniques was studied in pilot-scale experiments. The membrane bioreactor (MBR) was adopted for high efficiency aerobic digestion. The combination of alkaline-ozone treatment of the mixed liquor in the MBR reactor accelerated the biodegradation process by enhancing biodegradability of the sludge. The hydraulic retention time (HRT) of the reactor was set as 3.1 days and the DO level was 1 mg/L on average. After 5 months of operation, the accumulative total solids reduction was more than 70%. Removal efficiency of volatile solids and non-volatile solids were 76% and 54%, respectively. It was found that a considerable portion of the non-volatile solids was dissolved into ions and then flushed out with the effluent. Also, about 41% and 28% of T-N and T-P in the raw sludge were removed although no biological nutrient removal process was adopted. The experiment was run smoothly without significant membrane fouling, even at the relatively high levels of MLSS concentration (11,000-25,000 mg/L). It is concluded that the newly proposed process can significantly increase the sludge reduction efficiency with much shorter retention times.

Acidic and hydrogen peroxide treatment of polyaluminum chloride (PACL) sludge from water treatment

The water treatment sludge including coagulants cannot be easily removed by conventional dewatering methods. The possibility of hydrogen peroxide (H2O2) oxidation as a pretreatment to enhance the dewaterability of polyaluminum chloride (PACl) sludge from water works was investigated. H2O2 treatment alone was not effective but H2O2 treatment under acidic condition significantly reduced both the cake water content and specific resistance to filtration (SRF), indicating the enhancement of dewaterability and filterability. The filterability after acid/H2O2 treatment was comparable to polymer conditioning and even more dewatered cake than polymer conditioning was produced. By H202 combined with sulfuric acid (H2SO4), leached iron caused Fenton's reaction, which showed a potential to significantly reduce the amount of solids mass and to produce more compact cake with higher filterability.

The Vulnerable Attachment Style Questionnaire (VASQ): an interview-based measure of attachment styles that predict depressive disorder

BACKGROUND

The Vulnerable Attachment Style Questionnaire (VASQ) was developed to provide a brief self-report tool to assess adult attachment style in relation to depression and validated against an existing investigator-based interview (Attachment Style Interview--ASI). This paper describes the development and scoring of the VASQ and its relationship to poor support and major depression.

METHOD

Items for the VASQ reflected behaviours, emotions and attitudes relating to attachment relationship style, drawn directly from the ASI. The VASQ was validated against the ASI for 262 community-based subjects. Test-retest was determined on 38 subjects.

RESULTS

Factor analysis derived two factors, labelled 'insecurity' and 'proximity-seeking'. The VASQ insecurity dimension had highest mean scores for those with interview-based Angry-dismissive and Fearful styles and was significantly correlated with degree of interview-based insecurity. The proximity-seeking VASQ scores had highest mean for those with Enmeshed interview attachment style and was uncorrelated with ASI insecurity. VASQ scores were highly correlated with a well-known self-report measure of insecure attachment (Relationship Questionnaire) and text-retest reliability of the VASQ was satisfactory. The total VASQ score and the insecurity subscale proved highly related to poor support and to depressive disorder. This was not the case for the proximity-seeking subscale.

CONCLUSION

The VASQ is a brief self-report measure that distinguishes individuals with attachment styles vulnerable for depressive disorder. The use of the measure for screening in research and clinical contexts is discussed.

Colonic epithelial cells are a major site of macrophage inflammatory protein 3alpha (MIP-3alpha) production in normal colon and inflammatory bowel disease

BACKGROUND AND AIM

Macrophage inflammatory protein 3alpha (MIP-3alpha) is a recently described lymphocyte directed C-C chemokine expressed predominately at extralymphoid sites, including the intestine. The aim of this study was to determine whether colonic epithelial cells produce MIP-3alpha and whether its expression is upregulated in inflammatory bowel disease.

METHODS AND RESULTS

We found that interleukin 1beta and tumour necrosis factor alpha dose dependently stimulated MIP-3alpha production in Caco-2 and HT-29 intestinal epithelial cells. In cytokine treated Caco-2 and HT-29 cells, a significant increase in MIP-3alpha protein production was observed after three hours and continued for at least 24 hours. Analysis of colonic tissues by quantitative real time polymerase chain reaction and ELISA revealed significantly elevated MIP-3alpha mRNA levels (7.9-fold; p<0.05) and protein levels (8.9-fold; p<0.05) in Crohn's disease compared with controls or ulcerative colitis. MIP-3alpha immunoreactivity in normal colon and inflammatory bowel disease was principally associated with crypt and surface epithelial cells. Moreover, MIP-3alpha protein levels were elevated in primary epithelial cells isolated from patients with inflammatory bowel disease.

CONCLUSIONS

These findings indicate that increased enterocyte MIP-3alpha production may play an important role in lymphocyte activation and recruitment to the colonic epithelium in Crohn's disease and ulcerative colitis.

Erythropoietin response is inadequate in cancer patients receiving chemotherapy

The level of serum erythropoietin (EPO) is inappropriately decreased in cancer patients and has been advocated as the main cause of their anemia. In cancer patients, chemotherapy results in a cumulative anemia severe enough to require transfusion. We investigated the changes in serum EPO, hemoglobin, ceruloplasmin, and copper levels in cancer patients receiving chemotherapy. There was a weak but significant inverse relationship between hemoglobin and log[EPO] (r = -0.41; P < .001). Observed/expected serum EPO ratios decline with repeated chemotherapy indicating inadequate EPO response for the degree of anemia. There was no difference in the severity of anemia and in the degree of EPO response between platinum- and non-platinum-treated patients. Ceruloplasmin, copper, and ferritin levels did not change during chemotherapy. Our results suggest that the EPO response is inadequate for the degree of anemia and justifies the use of recombinant human EPO in cancer patients receiving chemotherapy.

ZBP-89, Sp1, and nuclear factor-kappa B regulate epithelial neutrophil-activating peptide-78 gene expression in Caco-2 human colonic epithelial cells

We reported previously that human colonic epithelial cells produce the C-X-C chemokine epithelial neutrophil-activating peptide-78 (ENA-78) and that its expression is up-regulated in ulcerative colitis. The aim of this study was to investigate the transcriptional regulation of ENA-78 gene expression in Caco-2 intestinal epithelial cells. Reporter gene transfection and electrophoretic mobility shift assay studies demonstrated that cooperation between two regions of the ENA-78 promoter were required for maximal gene expression in interleukin-1beta-stimulated Caco-2 cells. Binding of activated p50/p65 nuclear factor-kappaB to nucleotides -82 to -91 was essential for interleukin-1beta-dependent gene transcription, whereas binding of constitutively expressed zinc-requiring nuclear factors to nucleotides -125 to -134 (site A) was required for basal gene expression. Scanning mutagenesis of site A demonstrated overlapping binding elements at this locus. One site (CTCCCCC) bound Sp1 and Sp3, and overexpression of Sp1 (but not Sp3) up-regulated basal ENA-78 transcription. Another site (CCCCTCCCCC) was found to bind the zinc finger nuclear factor ZBP-89, and overexpression of this protein significantly repressed ENA-78 reporter gene activity. This study demonstrates that ENA-78 gene expression in Caco-2 intestinal epithelial cells is subject to complex regulation involving the coordinate binding of ZBP-89, Sp1, and nuclear factor-kappaB to the ENA-78 promoter.

Observation of a fast-formed absorption grating and a slowly formed phase grating in undeveloped dichromated gelatin

Real-time diffraction efficiency is measured during hologram formation in undeveloped dichromated gelatin (DCG) film. The main features of real-time diffraction efficiency of undeveloped DCG reveal double peaks with increasing exposure time. Adopting the grating translation technique, we show that the first peak originates from the absorption grating and that the latter is related to the phase grating. To explain such complicated hologram-formation dynamics, we present a phenomenological model for mixed gratings associated with photoinduced refractive-index changes and absorption changes. We have compared the model results with the experimental results, which show good agreement.

A novel recombinant basic fibroblast growth factor and its secretion

Basic fibroblast growth factor (FGF-2) is a pleiotropic mitogen which plays an important role in cell growth, differentiation, migration, and survival in different cells and organ systems. Recently, several clinical applications for FGF-2 gene transfer are being evaluated in wound healing and collateral artery development to relieve myocardial and peripheral ischemia due to the ability of FGF-2 to regulate the growth and function of vascular cells. However, FGF-2 lacks a classical hydrophobic secretion signal peptide, the FGF-2 chimeras containing various signal sequences have been explored. In this study, a novel recombinant 4sFGF-2 was constructed by replacing nine residues from the amino-terminus of native FGF-2 (Met1 to Leu9) with eight amino acid residues of signal peptide of FGF-4 (Met1 to Ala8) to better increase the secretion level of FGF-2. When the recombinant FGF-2 gene, cloned into the expression vector with CMV promoter, was expressed in COS-7 cells, the recombinant 4sFGF-2 was highly secreted into the media. The secreted 4sFGF-2 showed the same biological activity as the native FGF-2 in the dose-response effects on DNA synthesis and cell growth of rat aortic smooth muscle cells (RASMCs) and NIH3T3 cells. The 4sFGF-2 also was able to activate MAPK as wild FGF-2 in RASMCs. These results indicate that a novel recombinant 4sFGF-2 may be useful as clinical applicability of angiogenic growth factor gene transfer.

Coupling of cAMP/PKA and MAPK signaling in neuronal cells is dependent on developmental stage

Neurite formation, an essential feature of neuronal development, is believed to involve participation of the ras-mitogen-activated protein kinase (MAPK) and cAMP-dependent protein kinase A (cAMP/PKA)-mediated signaling pathways. These pathways have been studied extensively in the rat pheochromocytoma cell line PC12, and current hypotheses suggest a single effector mechanism resulting from the convergence of cAMP/PKA and MAPK signaling. However, based on observations using a central neuronal progenitor cell line, AS583-8, there also exists evidence that the two signaling pathways may act independently resulting in neurites with differing dynamic features. In the present study, the upstream components of cAMP/PKA signaling were examined in AS583-8 cells as well as possible interactions with the MAPK pathway. We found that activation of PKA is both necessary and sufficient for the elaboration of rapidly forming processes, typical of the cAMP response. In addition, blockade of the MAPK pathway has no effect on the cAMP response, suggesting that activation of the cAMP/PKA pathway can stimulate neurite formation independent of the MAPK pathway. In order to evaluate which cell line model, PC12 vs AS583-8, best reflects the signaling features of developing central neurons, we examined interactions between cAMP/PKA and MAPK signaling in primary neuronal cultures from several brain regions. In immature cultures (1-day-old), at a point where the initiation of neurite formation is maximal, no interaction was observed. In more mature cultures (7 days old), where synaptic contacts have been established, we found a weak but reproducible activation of MAPK following stimulation of the cAMP/PKA pathway. These results suggest that cAMP/PKA and MAPK signaling act independently at the initiation of neuritogenesis but become coupled during later stages of neuronal development. Therefore, the interaction of the two pathways may be cell stage (younger vs older) specific and may participate in cellular functions that take place after initial neurite formation.

Effects of mixing intensity on tissue-engineered cartilage

Mechanical forces regulate the structure and function of many tissues in vivo; recent results indicate that the mechanical environment can decisively influence the development of engineered tissues cultured in vitro. To investigate the effects of the hydrodynamic environment on tissue-engineered cartilage, primary bovine calf chondrocytes were seeded on fibrous polyglycolic acid meshes and cultured in spinner flasks either statically or at one of nine different turbulent mixing intensities. In medium from unmixed flasks, CO(2) accumulated and O(2) was depleted, whereas in medium from mixed flasks the concentrations of both gases approached their equilibrium values. Relative to constructs exposed to nonmixed conditions, constructs exposed to mixing contained higher fractions of collagen, synthesized and released more GAG, but contained lower fractions of GAG. Across the wide range of mixing intensities investigated, the presence or absence of mixing, but not the intensity of the mixing, was the primary determinant of the GAG and collagen content in the constructs. The all-or-none nature of these responses may provide insight into the mechanism(s) by which engineered cartilage perceives changes in its hydrodynamic environment and responds by modifying extracellular matrix production and release. 2001 John Wiley & Sons, Inc.

CDNA cloning of chloroplast omega-3 fatty acid desaturase from Capsicum annuum and its expression upon wounding

A clone for a plastid omega-3 fatty acid desaturase (FAD) was isolated from a leaf cDNA library of hot pepper (Capsicum annuum L.). The nucleotide sequence of a 1,317 bp open reading frame in the CachFAD showed 80.9% homology with that of tobacco plant. It codes for a polypeptide of 438 amino acids with molecular mass of 50.5 kDa and a pI of 8.14. The CachFAD had a putative transit peptide for targeting the chloroplast. Genomic Southern hybridization indicated that it exists as small gene family. Northern hybridization revealed that its mRNA was present in leaves, but not in roots. Transcript levels in the leaves upon wounding increased rapidly to reach the first peak between 1-3 h, decreased thereafter and slightly increased at 24 h after wounding. The levels of linolenic acid (18:3) in wounded leaves also reached the first peak at 6 h, decreased thereafter and reached the second peak at 18 h. These results indicated that wounding not only enhanced the accumulation of the CachFAD mRNA but also increased the conversion of linoleic acid (18:2) to linolenic acid (18:3) in leaf lipids of hot pepper.

Intrathoracic migration of Steinmann pins

The migration of surgical wires and pins placed for repair of orthopedic injury is well recognized. Such migration usually follows a retrograde path and the wires protrude near their entry point into the native bone. Occasionally, the migration occurs in an antegrade manner and produces injury. We describe a case where three Steinmann pins placed for fixation of a humeral neck fracture migrated, one slipping backwards towards the humeral entry point and two pins migrating into the thorax.

Cloning of the histidine biosynthetic genes from Corynebacterium glutamicum: organization and analysis of the hisG and hisE genes

The physically linked hisG and hisE genes, encoding for ATP-phosphoribosyltransferase and phosphoribosyl-ATP-pyrophosphohydrolase were isolated from the Corynebacterium glutamicum gene library by complementation of Escherichia coli histidine auxotrophs. They are two of the nine genes that participate in the histidine biosynthetic pathway. Molecular genetics and sequencing analysis of the cloned 9-kb insert DNA showed that it carries the hisG and hisE genes. In combining this result with our previous report, we propose that all histidine biosynthetic genes are separated on the genome by three unlinked loci. The coding regions of the hisG and hisE genes are 279 and 87 amino acids in length with a predicted size of about 30 and 10 kDa, respectively. Computer analysis revealed that the amino acid sequences of the hisG and hisE gene products were similar to those of other bacteria.

Gap measurement by position-sensitive detectors

A system for measuring the gap in a proximity exposure tool of a plasma display panel (PDP) is developed that uses single or dual position-sensitive detectors (PSD's). The resolution of the gap distance is 0.5 mum, with a capture range of 500 mum. Signal processing is simple and fast and easy because analogous PSD's are used as the position sensors. One PSD is used to detect the position of the reference beam, which is reflected from the upper surface of the gap; the other PSD is used to detect the position of the signal beam, which is reflected from the lower surface of the gap. A charge-coupled-device sensor is also employed to monitor the reflected beams and the region of measurement. In the gap-measurement system that uses a single PSD, first the reference beam is incident upon the PSD and then the signal beam is incident upon the same PSD. Then the separation between the two beams is calculated from the position of the reference beam and from the average beam position.

HIV-1 Nef plays an essential role in two independent processes in CD4 down-regulation: dissociation of the CD4-p56(lck) complex and targeting of CD4 to lysosomes

Human immunodeficiency virus type 1 (HIV-1) Nef down-regulates CD4 by triggering rapid endocytosis of cell surface CD4. To better understand how Nef induces CD4 down-regulation, we generated a series of Nef mutants with small in-frame deletions in the coding region. Three classes of mutants were obtained. The first class produces neither CD4 down-regulation nor dissociation of the CD4-p56(lck) complex. The second class induces CD4 down-regulation in cells lacking p56(lck) expression, but not in cells with p56(lck);these mutants fail to dissociate CD4 from p56lck. These results show that Nef-mediated CD4 dissociation from p56(lck) is important for CD4 down-regulation. The third class of mutants is able to dissociate the CD4-p56(lck) complex but fails to down-regulate surface CD4; internalized CD4 molecules are recycled back to the cell surface. This result suggests that Nef diverts the CD4 recycling pathway to a degradative pathway. We also demonstrate that Nef associates with phosphatidylinositol-3-kinase (PI3K) activity, which is known to be involved in several aspects of membrane trafficking. However, Nef mutants that cause internalized CD4 to be recycled do not associate with PI3K activity; thus Nef-associated PI3K activity might be involved in the latter process of targeting CD4 to a degradative pathway. We conclude that HIV-1 Nef plays a critical role in multiple processes in CD4 down-regulation: (i) disrupting the CD4-p56(lck) complex on the cell surface to allow CD4 internalization and (ii) diverting the internalized CD4 to a lysosomal pathway for its degradation, likely through a PI3K activity.

Site-directed mutagenesis of a possible type 1 copper ligand of bilirubin oxidase; a Met467Gln mutant shows stellacyanin-like properties

In our previous paper, we reported a mutant of recombinant Myrothecium verrucaria bilirubin oxidase, in which the Met467 residue was replaced by Gly [Shimizu, A. et al. (1999) Biochemistry 38, 3034-3042]. This mutant displayed a remarkable reduction in enzymatic activity and an evident decrease in the intensity of the absorption band around 600 nm (type 1 charge transfer transition). In this study, we report the preparation of three Met467 mutants (Met467Gln, Met467His, and Met467Arg) and characterize their enzymatic activities, midpoint potentials, and absorption and ESR spectra. Met467His and Met467Arg show no enzymatic activity and a great reduction in the intensity of the absorption band around 600 nm. Furthermore, their ESR spectra show no type 1 copper signal, but only a type 2 copper signal; however, oxidation by ferricyanide caused the type 1 copper signal to appear. On the other hand, Met467Gln as expressed shows both type 1 and type 2 copper signals in its ESR spectrum, the type 1 copper atom parameters being very different from usual blue copper proteins but very similar to those of stellacyanin. The enzymatic activity of the Met467Gln mutant for bilirubin is quite low (0.3%), but the activity for potassium ferrocyanide is similar (130%) to that of the wild type enzyme. These results indicate that Met467 is important for characterizing the features of the type 1 copper of bilirubin oxidase.

Myrothecium verrucaria bilirubin oxidase and its mutants for potential copper ligands

Bilirubin oxidase (EC:1.3.3.5) purified from a culture medium of Myrothecium verrucaria MT-1 (authentic enzyme) catalyzes the oxidation of bilirubin to biliverdin in vitro and recombinant enzyme (wild type) was obtained by using an overexpression system of the bilirubin oxidase gene with Aspergillus oryzae harboring an expression vector. The absorption and ESR spectra showed that both bilirubin oxidases are multicopper oxidases containing type 1, type 2, and type 3 coppers similar to laccase, ascorbate oxidase, and ceruloplasmin. Site-directed mutagenesis has been performed for the possible ligands of each type of copper. In some mutants, Cys457 --> Val, Ala, His94 --> Val, and His134.136 --> Val, type 1 and type 2 copper centers were perturbed completely and the enzyme activity was completely lost. Differing from the holoenzyme, these mutants showed type 3 copper signals. However, the optical and magnetic properties characteristic of type 1 copper were retained even by mutating one of the type 1 copper ligands, i.e., a mutant, Met467 --> Gly, showed a weak but apparent enzyme activity. A double mutant His456.458 --> Val had only type 1 Cu, showing a blue band at 600 nm (epsilon = 1.6 x 10(3)) and an ESR signal with very narrow hyperfine splitting (A parallel = 7.2 x 10(-)3 cm-1). Since the type 2 and type 3 coppers are not present, the mutant did not show enzyme activity. These results strongly imply that the peculiar sequence in bilirubin oxidase, His456-Cys457-His458, forms an intramolecular electron-transfer pathway between the type 1 copper site and the trinuclear center composed of the type 2 and type 3 copper sites.

Increased MAPK activity and MKP-1 overexpression in human gastric adenocarcinoma

Mitogen-activated protein kinase (MAPK) has been known to play a critical role in the regulation of the carcinogenesis in human cancers. In an effort to understand the functional role of the MAPK in the carcinogenesis of human gastric tissues, we examined the changes of MAPK levels in human gastric adenocarcinoma. We found that increased MAPK activity was accompanied by overexpression of mitogen-activated protein kinase phosphatase-1 (MKP-1), suggesting that signaling pathways leading to the activation of MAPK and the induction of MKP-1 expression are associated with carcinogenesis of human gastric adenocarcinoma.

Beta-adrenergic and fibroblast growth factor receptors induce neuronal process outgrowth through different mechanisms

The mechanisms that initiate and direct neuronal process formation remain poorly understood. We have recently described a neuronal progenitor cell line, AS583-8.E4.22 (AS583-8) which undergoes neurite formation in response to beta2-adrenergic and basic fibroblast growth factor (bFGF) receptor activation [Kwon, J.H. et al., (1996) Eur. J. Neurosci., 8, 2042-2055]. In the present study, a comparison of these responses revealed that isoproterenol (ISO), a beta-adrenergic receptor agonist, induces multiple, highly branched processes within 30 min while bFGF induces fewer, unbranched processes within 24 h. In contrast to the ISO response, bFGF induces mitogen-activated protein kinase activation and c-fos expression in the cell line and results in neurite outgrowth that is dependent on new mRNA and protein synthesis. Two-dimensional isoelectric focusing-sodium dodecyl sulphate-polyacrylamide gel electrophoresis of cytoskeletal preparations revealed different patterns following ISO vs. bFGF exposure suggesting selective changes in protein expression and/or post-translational modifications. Immunoblot analysis of these preparations for beta-tubulin, tyrosinated alpha-tubulin and acetylated alpha-tubulin also revealed different patterns following each type of treatment. Follow-up confocal microscopy revealed that following ISO, the distribution of tyrosinated tubulin extends to the distal ends of processes whereas acetylated alpha-tubulin is diminished within distal ends. This pattern has been reported to be associated with enhanced microtubule dynamics, a state in which process outgrowth is facilitated. In contrast, following bFGF treatment the distributions of tyrosinated and acetylated alpha-tubulin were identical, a state associated with a diminution of microtubule dynamics. These results, a different time course of neurite formation, dependency on new gene expression and differential expression and cellular distribution of major cytoskeleton proteins suggest that neurite outgrowth induced by ISO vs. bFGF is mediated by two distinct intracellular effector mechanisms in AS583-8 cells. In addition, studies, using the differential distribution of post-translational modified alpha-tubulins in neurites of primary neuronal cultures as marker for the two distinct processes of neurite formation suggest, that similar mechanisms are present in vivo. Therefore, the AS583-8 cell line provides a useful model to study these signalling mechanisms that couple neurotransmitter and growth factor receptor activation to the cytoskeletal changes that mediate neurite formation.

Cloning of the histidine biosynthetic genes of Corynebacterium glutamicum: organization and sequencing analysis of the hisA, impA, and hisF gene cluster

The hisA and hisF genes of Corynebacterium glutamicum were cloned by transforming histidine auxotrophic Escherichia coli with the genomic DNA library. They are two of the eight genes that participate in the histidine biosynthetic pathway. Cloned DNA fragments containing the genes can also complement hisH and hisI auxotrophs of Escherichia coli, suggesting that the four genes are clustered in the genome. We determined the nucleotide sequences of the minimal fragment containing the hisA and hisF genes, which are separated by the impA gene. The coding regions of the hisA and hisF genes are 245 and 257 amino acids in length with a predicted size of about 26 and 27 kDa, respectively. These are in good agreement with the sizes of proteins expressed in E. coli. A high similarity was observed in comparison of nucleotide sequences of each protein between C. glutamicum and other species, as well as those between hisA and hisF genes of C. glutamicum.

Insulin activates Ras in the PC12 cell line

To address whether Ras can be activated by insulin in the PC12 cell line, proteins interacting with insulin receptor and IRS-1 molecules and their tyrosine phosphorylation were analyzed by immunoblotting following immunoprecipitation with antibodies. Tyrosine phosphorylation of the insulin receptor and IRS-1 was increased by insulin. Grb2 and Ras-GAP appeared in the immunoprecipitates by anti-insulin receptor and anti-IRS-1 from insulin-treated cells. In addition, PI 3-kinase was activated by insulin treatment in this cell line and Grb2, Ras-GAP, and MAP kinase were coprecipitated with Ras from both insulin-treated and NGF-treated cells. Analysis of MAP kinases from insulin-treated cells revealed that insulin, like NGF, increased tyrosine phosphorylation. However, activation of the MAP kinase by NGF lasted longer than activation by insulin. These results indicate that Ras can be activated by insulin in the PC12 cell line and that Ras activation is neither an accurate nor a plausible method of discriminating signals between proliferation and differentiation.