Cardiac allograft remodeling after heart transplantation is associated with increased graft vasculopathy and mortality

The aim of this study was to assess the patterns, predictors and outcomes of left ventricular remodeling after heart transplantation (HTX). Routine echocardiographic studies were performed and analyzed at 1 week, 1 year and 3-5 years after HTX in 134 recipients. At each study point the total cohort was divided into three subgroups based on determination of left ventricle mass and relative wall thickness: (1) NG-normal geometry (2) CR-concentric remodeling and (3) CH-concentric hypertrophy. Abnormal left ventricular geometry was found as early as 1 week after HTX in 85% of patients. Explosive mode of donor brain death was the most significant determinant of CH (OR 2.9, p = 0.01) at 1 week. CH at 1 week (OR 2.72, p = 0.01), increased body mass index (OR 1.1, p = 0.01) and cytomegalovirus viremia (OR - 4.06, p = 0.02) were predictors of CH at 1 year. CH of the cardiac allograft at 1 year was associated with increased mortality as compared to NG (RR 1.87, p = 0.03). CR (RR 1.73, p = 0.027) and CH (RR 2.04, p = 0.008) of the cardiac allograft at 1 year is associated with increased subsequent graft arteriosclerosis as compared to NG.

Is a 2-week steroid trial after initial negative investigation for malignancy useful in differentiating autoimmune pancreatitis from pancreatic cancer? A prospective outcome study

BACKGROUND

Autoimmune pancreatitis (AIP) is a peculiar type of chronic pancreatitis that responds dramatically to steroid therapy. To date, there are no worldwide consensus criteria for AIP. Different criteria with institutional preference (HISORt, revised Kim and the revised Japanese criteria) are being used to diagnose AIP, and there is controversy regarding the inclusion of steroid responsiveness in the diagnostic criteria. In contrast to the HISORt and revised Kim criteria, the revised Japanese criteria do not include steroid responsiveness as a diagnostic component.

AIMS

This study was performed to evaluate whether "a 2-week steroid trial and subsequent assessment of its response" is a useful diagnostic tool for the differentiation of AIP from pancreatic cancer. A further aim was to discover the surgical and clinical outcome for a patient who followed the treatment algorithm based on the steroid responsiveness.

PATIENTS AND METHODS

From January 2004 to June 2007, in the setting of clinically suspected AIP, 22 consecutive patients with atypical imaging for AIP, while not meeting the classic imaging criteria for pancreatic cancer, were challenged to undergo 2 weeks of steroid therapy (0.5 mg/kg of oral prednisolone per day). After the 2-week steroid trial, steroid responsiveness was assessed based on a marked improvement of narrowing of the main pancreatic duct and a reduction of the pancreatic mass. The steroid trial was continued in the case of positive steroid responsiveness, whereas surgical exploration was conducted in the case of negative steroid responsiveness. The final diagnosis was made by surgical exploration or long-term clinical and radiological follow-up.

RESULTS

All patients (n = 15) who responded to steroids were diagnosed as having AIP, whereas all patients (n = 7) who did not show a response to steroids were confirmed as having pancreatic cancer. Complete resection was possible in all (6/6; 100%), except one individual who refused surgery.

CONCLUSION

In the clinical setting of suspected AIP with the continued need for differentiation from pancreatic cancer due to atypical imaging for AIP, "a 2-week steroid trial and subsequent assessment of its response" may be helpful in confirming the diagnosis of AIP without negative consequences for resectable pancreatic cancer. However, a steroid trial should be performed carefully only by specialists in pancreatology.

Isolated acute cellular rejection of the liver after simultaneous liver and kidney transplantation: a case report

Simultaneous liver and kidney transplantation (SLKT) is now considered the treatment of choice for patients with concurrent end-stage liver and kidney diseases. Even though the early postoperative mortality rate following SLKT is reported to be high compared to that of liver transplantation alone, the liver graft from the same donor has been argued to induce better kidney graft acceptance as evidenced by a low rate of acute renal rejection episodes. There have been many reports of a low incidence of acute renal rejection following SLKT; however, only a few cases were proven by simultaneous biopsies. The authors experienced a case of biopsy-proven isolated acute cellular rejection of the liver graft following SLKT.

Aberrant promoter CpG island hypermethylation of the adenomatosis polyposis coli gene can serve as a good prognostic factor by affecting lymph node metastasis in squamous cell carcinoma of the esophagus

There has been no clear evidence demonstrating whether DNA hypermethylation can affect the prognosis of esophageal cancer. We collected tissue from 50 cases of squamous cell carcinoma of the esophagus and tested them for DNA hypermethylation using methylation-specific polymerase chain reaction. CpG island hypermethylations were observed in 10% for p16, 34% for RARbetaP2, 46% for adenomatosis polyposis coli (APC), 14% for RASSF1A, 84% for FHIT, and 8% for hMLH1. APC promoter hypermethylation was frequently found in patients without lymph node metastasis compared with those with lymph node metastasis (62.5% : 30.8%, P = 0.025). The number of metastatic lymph nodes were lower in patients with APC promoter hypermethylation (0.87 +/- 0.30 : 3.07 +/- 0.72, P = 0.008). Excluding operative mortalities and incomplete resections, 42 patients were analyzed for long-term outcome. During the mean follow-up period of 35 months, 17 developed recurrence and 14 died of cancer. Ten patients died of other causes. In univariable analysis, unmethylation of APC (P = 0.0015) and FHIT (P = 0.0044), as well as presence of lymph node metastasis (P = 0.0038), were risk factors for recurrence. In multivariable analysis, lymph nodes metastasis (P = 0.050) and unmethylation of APC promoter (P = 0.023) remained as significant risk factors. In conclusion, promoter hypermethylation of the APC gene is related to a lower number of metastatic lymph nodes and to superior prognosis in terms of recurrence, which suggests it might be involved in the process of lymph node metastasis in esophageal cancer.

Electrical characterization of ZnO single nanowire device for chemical sensor application

Vertically well-aligned high quality ZnO nanowires were grown on GaN epilayer on c-plane sapphire via a vapor-liquid-solid (VLS) process by introducing an Au thin film (3 nm) as a catalyst. ZnO single nanowire device was ingenuously fabricated by combining conventional optical lithography and high resolution electron beam lithography and its current-voltage characteristics were measured with doing the post process to acquire reproducible performance as a chemical gas sensor. And its temperature dependent current-voltage characteristics were measured to investigate temperature dependant electrical transport. The ZnO nanowire device showed slightly non-ohmic current-voltage characteristics which may be due to back-to-back configuration of the diodes with the insulating contact barriers and showed an relatively small activation energy of 0.2 eV. To test our device as a chemical sensor, the NO2 gas response was reported at the elevated temperature.

Endoscopic evaluation of significant gastrointestinal lesions in patients with iron deficiency with and without anaemia: a Korean Association for the Study of Intestinal Disease study

BACKGROUND

Although endoscopy is recommended for patients with iron deficiency anaemia, there is, currently, no consensus on the role of endoscopy for iron-deficient patients without anaemia. The goal of this study was to determine the prevalence of serious gastrointestinal (GI) lesions, identified by endoscopy in patients with iron deficiency and anaemia compared with patients with iron deficiency without anaemia.

METHODS

One thousand five hundred and eighteen patients with a ferritin value of <or=50 ng/mL and a total iron-binding capacity >or=300 mg/dL were retrospectively investigated using oesophagogastroduodenoscopy and colonoscopy between January 2005 and September 2006. The lesions identified were classified as clinically important according to standard predetermined criteria.

RESULTS

Among the 1518 cases, 749 patients had anaemia and 769 had normal haemoglobin levels. Clinically important lesions were identified in 24.6% of the patients with anaemia and in 22.8% of the patients without anaemia (P > 0.05). The frequency of lower GI tract lesions (13.6 vs 11.4%, P > 0.05) and upper GI tract lesions (11.9 vs 12.5%, P > 0.05) was similar in the comparisons between the two groups. However, the frequency of malignant GI lesions was higher in the patients with anaemia (5.1 vs 0.7%, P < 0.01). In addition, the patients without anaemia were significantly more likely to have early-stage neoplasia (adenoma, early gastric cancer and Dukes' A and B colon cancer) than were the patients with anaemia (98.4 vs 52.5%, P < 0.01).

CONCLUSION

The results of this study suggest that patients with iron deficiency should undergo endoscopic evaluation of the GI tract, irrespective of whether they have anaemia. The endoscopic evaluation of the GI tract in patients with iron deficiency without anaemia could provide an opportunity for the detection of early-stage neoplasia at a curable stage.

Apparatus and method for achieving reproducible measurements of diauxic lag length and anoxic net maximum specific growth rate

An apparatus for continuous growth of pure bacterial cultures under oxic conditions followed by a switch to anoxic batch conditions was designed. The application of this apparatus gave variability of measured parameters (diauxic lag length, anoxic net maximum specific growth rate) which were significantly lower than the variability of previously reported data. The improvement is attributed to more consistent nitrate reductase levels as a result of achieving steady state under oxic condition prior to switching to anoxic batch conditions.

Electrophysiological safety of sibutramine HCl

Sibutramine is known to induce cardiovascular side effects such as tachycardia, vasodilation, and hypertension. The present study was aimed to examine the effects of sibutramine on action potential of guinea pig papillary muscle, recombinant hERG currents (IhERG), and inward currents (INa and ICa) of rat ventricular myocytes. Sibutramine at 30 μg/mL induced a shortening of action potential duration (APD) of guinea pig papillary muscle; on average, APD30 and APD90 were shortened by 23% and 17% at a stimulation rate of 1 Hz, respectively. Sibutramine suppressed the following currents: IhERG (IC50:2.408 ± 0.5117 μg/mL), L-type Ca current (IC50:2.709 ± 0.4701 μg/mL), and Na current (IC50:7.718 ± 1.7368 μg/mL). Sibutramine blocked IhERG, ICa, and INa in a concentration-dependent manner. In conclusion, sibutramine exerted a shortening effect on APD in guinea pig papillary muscle through its more powerful blocking effects on ICa and INa rather than IhERG.

Phylogenetic analysis of swine influenza viruses recently isolated in Korea

Several influenza A viral subtypes were isolated from pigs during a severe outbreak of respiratory disease in Korea during 2005 and 2006. They included a classical swine H1N1 subtype, two swine-human-avian triple-recombinant H1N2 subtypes, and a swine-human-avian triple-recombinant H3N2 subtype. In the current study, genetic characterization to determine the probable origin of these recent isolates was carried out for the first time. Phylogenetic analysis indicated that all the recent Korean isolates of H1N1, H1N2, and H3N2 influenza are closely related to viruses from the United States. Serologic and genetic analysis indicated that the Korean H1N2 viral subtypes were introduced directly from the United States, and did not arise from recombination between Korean H1N1 and H3N2. We suggest that the H1N1, H1N2, and H3N2 viral subtypes that were isolated from the Korean swine population originated in North America, and that these viruses are currently circulating in the Korean swine population.

Auranofin promotes retinoic acid- or dihydroxyvitamin D3-mediated cell differentiation of promyelocytic leukaemia cells by increasing histone acetylation

BACKGROUND AND PURPOSE

To investigate the molecular mechanism for the effect of auranofin on the induction of cell differentiation, the cellular events associated with differentiation were analysed in acute promyelocytic leukaemia (APL) cells.

EXPERIMENTAL APPROACH

The APL blasts from leukaemia patients and NB4 cells were cotreated with auroanofin and all-trans-retinoic acid (ATRA) at suboptimal concentration. The HL-60 cells were treated with auroanofin and a subeffective dose of 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2 vit D3) in combination. The effect of auroanofin was investigated on histone acetylation at the promoter of differentiation-associated genes and expression of cell cycle regulators.

KEY RESULTS

Treatment with auroanofin and ATRA cooperatively induced granulocytic differentiation of fresh APL blasts isolated from patients and NB4 cells. The combined treatment also increased reorganization of nuclear PML bodies and histone acetylation at the promoter of the RARbeta2 gene. Auroanofin also promoted monocytic differentiation of the HL-60 cells triggered by subeffective concentration of 1,25(OH)2 vit D3. The combined treatment of auroanofin and 1,25(OH)2 vit D3 stimulated histone acetylation at p21 promoters and increased the accumulation of cells in the G0/G1 phase. Consistent with this, the expressions of p21, p27 and PTEN were increased and the levels of cyclin A, Cdk2 and Cdk4 were decreased. Furthermore, the hypophosphorylated form of pRb was markedly increased in cotreated cells.

CONCLUSIONS AND IMPLICATIONS

These findings indicate that auroanofin in combination with low doses of either ATRA or 1,25(OH)2 vit D3 promotes APL cell differentiation by enhancing histone acetylation and the expression of differentiation-associated genes.

Association of MCP-1 and CCR2 polymorphisms with the risk of late acute rejection after renal transplantation in Korean patients

Among the factors modulating transplant rejection, chemokines and their respective receptors deserve special attention. Increased expression of monocyte chemoattractant protein-1 (MCP-1) and its corresponding receptor (chemokine receptor-2, CCR2) has been implicated in renal transplant rejection. To determine the impact of the MCP-1-2518G and CCR2-64I genotypes on renal allograft function, 167 Korean patients who underwent transplantation over a 25-year period were evaluated. Genomic DNA was genotyped using polymerase chain reaction followed by restriction fragment length polymorphism analysis. Fifty-five (32.9%) patients were homozygous for the MCP-1-2518G polymorphism. Nine (5.4%) patients were homozygous for the CCR2-64I polymorphism. None of the investigated polymorphism showed a significant shift in long-term allograft survival. However, a significant increase was noted for the risk of late acute rejection in recipients who were homozygous for the MCP-1-2518G polymorphism (OR, 2.600; 95% CI, 1.125–6.012; P = 0.022). There was also an association between the MCP-1-2518G/G genotype and the number of late acute rejection episodes (P = 0.024). Although there was no difference in the incidence of rejection among recipients stratified by the CCR2-V64I genotype, recipients with the CCR2-V64I GG genotype in combination with the MCP-1-2518G/G genotype had a significantly higher risk of acute or late acute rejection among the receptor-ligand combinations (P = 0.006, P = 0.008, respectively). The MCP-1 variant may be a marker for risk of late acute rejection in Korean patients.

Optimal clustering of kinetic patterns on malignant breast lesions: comparison between K-means clustering and three-time-points method in dynamic contrast-enhanced MRI

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is useful for breast cancer diagnosis and treatment planning. Nevertheless, due to the multi-temporal nature of DCE-MRI data, the assessment of early stage breast cancer is a challenging task. In this study, we applied an unsupervised clustering approach and cluster validation technique to the analysis of malignant intral-tumoral kinetic curves in DCE-MRI. K-means cluster analysis was performed from real world malignant tumor cases and the data were transformed into an optimal number of reference patterns representative each cluster. The optimal number of clusters was estimated by a cluster validation index, which was calculated with the ratio of inter-class scatter to intra-class scatter. This technique then classifies tumor specific patterns from a given MRI data by measuring the vector distances from the reference pattern set, and compared the result from the k-means clustering with that from three-time-points (3TP) method, which represents a clinical standard protocol for analysis of tumor kinetics. The evaluation of twenty five cases indicates that optimal k-means clustering reflects partitioning intra-tumoral kinetic patterns better than the 3TP technique. This method will greatly enhance the capability of radiologists to identify and characterize internal kinetic heterogeneity and vascular change of a tumor in breast DCE-MRI.

Target-controlled propofol infusion for sedation in patients undergoing transrectal ultrasound-guided prostate biopsy

The efficacy and safety of the routine use of target-controlled infusion of propofol for the sedation of patients undergoing transrectal ultrasound-guided prostate biopsy were assessed. The optimal level of sedation was also evaluated. A total of 250 patients were randomized into five groups according to sedation level determined by the Observer's Assessment of Alertness/Sedation (OAA/S) scale. As the level of sedation was increased, the overall pain and discomfort score decreased and the satisfaction rate tended to increase, although hypoxia meant that intervention occurred more frequently at higher sedation levels. Target-controlled infusion of propofol provided safe and effective sedation during transrectal ultrasound-guided prostate biopsy, particularly if moderate sedation (OAA/S score of 3) was achieved. The effect-site concentration of propofol for this level of sedation was about 1.5 microg/ml.

Inhibition of VEGF blocks TGF-beta1 production through a PI3K/Akt signalling pathway

Vascular endothelial growth factor (VEGF) is a mediator of airway inflammation and remodelling in asthma. Transforming growth factor (TGF)-beta(1) plays pivotal roles in diverse biological processes, including tissue remodelling and repair in a number of chronic lung diseases. However, there are few studies elucidating the interactions between VEGF and TGF-beta(1) in allergic airway disease. A murine model of allergic airway disease was used to define the mechanism by which VEGF induces subepithelial fibrosis and to investigate a potential relationship between VEGF and TGF-beta(1) and the mechanisms by which VEGF signalling regulates TGF-beta(1) expression in allergic airway disease. The ovalbumin (OVA)-inhaled murine model revealed the following typical pathophysiological features of allergic airway disease in the lungs: increased numbers of inflammatory cells of the airways, airway hyperresponsiveness, increased peribronchial fibrosis, and increased levels of VEGF and TGF-beta(1). Administration of VEGF inhibitors reduced the pathophysiological signs of allergic airway disease and decreased the increased TGF-beta(1) levels and peribronchial fibrosis, including phosphoinositide 3-kinase (PI3K) activity after OVA inhalation. In addition, the increased TGF-beta(1) levels and collagen deposition after OVA inhalation were decreased by administration of PI3K inhibitors. These results suggest that inhibition of vascular endothelial growth factor attenuates peribronchial fibrosis, at least when mediated by regulation of transforming growth factor-beta(1) expression through phosphoinositide 3-kinase/Akt pathway in a murine model of allergic airway disease.

Detection and molecular characterization of calf diarrhoea bovine coronaviruses circulating in South Korea during 2004-2005

Although the widespread occurrence of calf diarrhoea (CD) bovine coronavirus (BCoV) infections have been reported in most cattle producing countries, only the genetic differences in the BCoVs from American and Canadian isolates and/or strains have been identified and compared. Hence, it is unclear if the BCoVs circulating in the other countries have distinct genetic characteristics. The aim of this study was to determine the prevalence and genetic diversity of CD BCoVs based on the deduced amino acid (aa) sequences of the spike (S) and haemagglutinin/esterase (HE) proteins in South Korea. RT-PCR and nested PCR using the primer pairs specific to the nucleocapsid gene, BCoVs detected the BCoVs in 56 (15.6%) of 359 diarrhoeic faecal samples. Phylogenetic analysis of the entire S gene indicated that 10 Korean CD BCoV strains clustered with other Korean BCoV strains with different clinical forms but were different from the American and Canadian BCoV strains. Moreover, the phylogenetic data of the aa sequences of the HE gene revealed all the Korean CD strains to be distinct from the other Korean BCoV strains with different clinical forms. These results suggest that the Korean BCoVs cause endemic infections in diarrhoeic calves in Jeonnam province and have taken a different evolutionary pathway from the BCoVs in other countries. Moreover, the different BCoV strains are circulating in the different clinical forms in South Korea. These results also suggest that vaccines against the BCoVs can be developed with each Korean BCoV in different clinical forms.

Prevalence, microbiology, and clinical characteristics of extended-spectrum beta-lactamase-producing Enterobacter spp., Serratia marcescens, Citrobacter freundii, and Morganella morganii in Korea

We examined the prevalence and characteristics of extended-spectrum beta-lactamase (ESBL)-producing clinical isolates among Enterobacter spp., Serratia marcescens, Citrobacter freundii, and Morganella morganii, and evaluated screening criteria, clinical characteristics and outcomes of infections caused by ESBL-producing organisms. Between January and June 2005, a total of 493 nonduplicate consecutive isolates were collected at Asan Medical Center, a 2,300-bed tertiary hospital in Seoul, Republic of Korea. Fifty isolates (10.1%) were positive for phenotypical ESBL-test. The positive rate of phenotypical ESBL-test in Enterobacter spp., S. marcescens, C. freundii, and M. morganii was 12.8%, 12.4%, 4.9%, and 0% respectively. SHV-12 (18 isolates), CTX-M-9 (17 isolates), and TEM-52 (five isolates) were the most prevalent ESBL types. The ESBL in 17 strains could not be identified. As an ESBL screening criterion, the cefepime MIC >or=1 microg/ml had the highest sensitivity (0.84) and specificity (0.87). Half of the ESBL-producing isolates (25/50) were judged as pathogens. Cholangitis (ten cases), and pneumonia (six cases) were the most common infections. The overall mortality was 12.0%.

Numerical experiments for bioclogging in porous media

A mathematical model was developed in this study based on the macroscopic approach to describe bioclogging process in saturated porous media. Bacterial attachment and growth along with formation of extracellular polymeric substances (EPS) from substrate has been incorporated into the model. The model was used to simulate column experimental data for permeability change from literature. Numerical experiments were performed to investigate the effect of biomass growth and attachment on the permeability and porosity. In addition, sensitivity analysis was carried out to examine the influences of key model parameters on the model behavior. The predictive model could successfully fit the experimental data. Simulation results illustrated that relative permeability and porosity of porous media can be altered by the biomass growth and attachment on the solid matrix. Results also indicated that EPS may play a significant role in bioclogging in porous media. Sensitivity analyses showed that permeability and porosity profiles were sensitive to parameters such as maximum utilization rate of substrate and yield coefficient. Even though the bioclogging model presented in this study is not comprehensive, it will help understand the change of porous medium properties due to biomass deposition and growth.

Comparison of functional results with navigation-assisted minimally invasive and conventional techniques in bilateral total knee arthroplasty

This study was undertaken to compare the clinical and radiological results achieved using navigation-assisted minimally invasive surgery (NA-MIS) and conventional (CON) techniques in 42 bilateral total knee arthroplasty (TKA) patients with a minimum follow-up of one year. Clinical evaluations were performed using range of motion (ROM), Hospital for Special Surgery (HSS) scores, and Western Ontario and McMaster University (WOMAC) scores (pain, functional, and total) at 3, 6 and 9 months and one year postoperatively. Patients' subjective preferences and radiological indices, including mechanical axis and coronal inclinations of the prostheses, were compared at one year postoperatively. NA-MIS TKA yielded better HSS and WOMAC total scores than CON TKA up to six months, and a better WOMAC pain score up to 9 months. However, these differences were not significant at one year postoperatively. ROM was comparable in both groups at all times, but more patients preferred the NA-MIS side to the CON side. Radiological results showed no differences in mean values between the two surgical groups, although the NA-MIS group contained fewer outliers than the CON group. In conclusion, NA-MIS TKA was associated with better clinical results up to 6 or 9 months after surgery, giving more accurate leg alignment than CON TKA.

Dual enteric and respiratory tropisms of winter dysentery bovine coronavirus in calves

Although winter dysentery (WD), which is caused by the bovine coronavirus (BCoV) is characterized by the sudden onset of diarrhea in many adult cattle in a herd, the pathogenesis of the WD-BCoV is not completely understood. In this study, colostrum-deprived calves were experimentally infected with a Korean WD-BCoV strain and examined for viremia, enteric and nasal virus shedding as well as for viral antigen expression and virus-associated lesions in the small and large intestines and the upper and lower respiratory tract from 1 to 8 days after an oral infection. The WD-BCoV-inoculated calves showed gradual villous atrophy in the small intestine and a gradual increase in the crypt depth of the large intestine. The WD-BCoV-infected animals showed epithelial damage in nasal turbinates, trachea and lungs, and interstitial pneumonia. The WD-BCoV antigen was detected in the epithelium of the small and large intestines, nasal turbinates, trachea and lungs. WD-BCoV RNA was detected in the serum from post-inoculation day 3. These results show that the WD-BCoV has dual tropism and induces pathological changes in both the digestive and respiratory tracts of calves. To our knowledge, this is the first detailed report of dual enteric and respiratory tropisms of WD-BCoV in calves. Comprehensive studies of the dual tissue pathogenesis of the BCoV might contribute to an increased understanding of similar pneumoenteric CoV infections in humans.

Pseudotumour in the bladder as a complication of total hip replacement: ultrasonography, CT and MR findings

We report a pseudotumour in the urinary bladder following total hip replacement with review of the literature. Pseudotumour in the urinary bladder as a late complication of total hip replacement is an extremely rare condition. In this case, cross-sectional imaging modalities including sonography, CT and MR showed a hypervascular polypoid mass in the urinary bladder and adjacent wall thickening with a band connecting between the mass and the acetabulum. Histopathological diagnosis confirmed acute and chronic inflammation with calcification.

Disinfection and oxidation of sewage effluent water using ozone and UV technologies

This study was aimed at exploring the reclamation of sewage treatment plant effluent water (SEW) as an alternative water resource. For the oxidation of SEW, an ozone-UV system, based on the results of the combined ozone/UV process performed in our previous study, was set up under practical conditions, including a series type, continuous mode, semi-pilot scale operation (1.5 m3/d). As a result, the serial contact of the ozone and UV reactors showed lower CODCr and TOC removal efficiencies. However, these were greatly enhanced by recycling the water flow of the ozone-UV system at 40Q, as a result of the improvements in the transferred ozone dose in the ozone reactor and the contact efficiency between photons and ozone in the UV reactor, which approached that achieved in the combined ozone/UV process. For the disinfection of SEW, carried out in a syringe-type batch reactor, the increase of instantaneous ozone demand (ozone ID) led to a higher inactivation efficiency, an increased UV transmittance due to ozonation, and an enhanced inactivation rate of E. coli in the UV reactor. Additionally, it was concluded that the ozone/UV process could overcome the limitations of the ozone alone and UV alone processes for the reclamation of sewage effluent water.

Central sensitization in thalamic nociceptive neurons induced by mustard oil application to rat molar tooth pulp

We have recently demonstrated that application of mustard oil (MO), a small-fiber excitant and inflammatory irritant, to the rat maxillary molar tooth pulp induces central sensitization that is reflected in changes in spontaneous activity, mechanoreceptive field (RF) size, mechanical activation threshold, and responses to graded mechanical stimuli applied to the neuronal RF in trigeminal brainstem subnucleus caudalis and subnucleus oralis. The aim of this study was to test whether central sensitization can be induced in nociceptive neurons of the posterior thalamus by MO application to the pulp. Single unit neuronal activity was recorded in the ventroposterior medial nucleus (VPM) or posterior nuclear group (PO) of the thalamus in anesthetized rats, and nociceptive neurons were classified as wide dynamic range (WDR) or nociceptive-specific (NS). MO application to the pulp was studied in 47 thalamic nociceptive neurons and found to excite over 50% of the 35 VPM neurons tested and to produce significant long-lasting (over 40 min) increases in spontaneous activity, cutaneous pinch RF size and responses to graded mechanical stimuli, and a decrease in threshold in the 29 NS neurons tested; a smaller but statistically significant increase in mean spontaneous firing rate and decrease in activation threshold occurred following MO in the six WDR neurons tested. Vehicle application to the pulp did not produce any significant changes in six VPM NS neurons tested. MO application to the pulp produced pronounced increases in spontaneous activity, pinch RF size, and responses to mechanical stimuli, and a decrease in threshold in three of the six PO neurons. In conclusion, application of the inflammatory irritant MO to the tooth pulp results in central sensitization of thalamic nociceptive neurons and this neuronal hyperexcitability likely contributes to the behavioral consequences of peripheral inflammation manifesting as pain referral, hyperalgesia and allodynia.

Myocardial enhancement pattern in patients with acute myocardial infarction on two-phase contrast-enhanced ECG-gated multidetector-row computed tomography

AIM

To evaluate the myocardial enhancement pattern of the left ventricle on two-phase contrast-enhanced electrocardiogram (ECG)-gated multidetector computed tomography (MDCT) images in patients with acute myocardial infarction (AMI).

METHODS

Two-phase contrast-enhanced ECG-gated MDCT examinations were performed in 16 patients with AMI. The presence, location and pattern of myocardial enhancement were evaluated. MDCT findings were compared with the catheter angiographic results.

RESULTS

Subendocardial (n = 9) or transmural (n = 6) area of early perfusion defects of the myocardium was detected in 15 of 16 patients (94%) on early-phase CT images. Variable delayed myocardial enhancement patterns on late-phase CT images were observed in 12 patients (75%): (1) subendocardial residual perfusion defect and subepicardial late enhancement (n = 6); (2) transmural late enhancement (n = 1); (3) isolated subendocardial late enhancement (n=1); and (4) isolated subendocardial residual perfusion defect (n = 2). On catheter angiography, 14 of 15 corresponding coronary arteries showed significant stenosis.

CONCLUSION

Variable abnormal myocardial enhancement pattern was seen on two-phase, contrast-enhanced ECG-gated MDCT in patients with AMI. Assessment of myocardial attenuation on CT angiography gives additional information of the location and extent of infarction.

Pancreatic carcinoid tumor with obstructive pancreatitis: multislice helical CT appearance: case report

Carcinoid tumor of the pancreas is rare. Moreover, obstructive pancreatitis secondary to a pancreatic carcinoid tumor is extremely rare. We report a case of pancreatic carcinoid tumor in a 50-year-old male who presented with pancreatitis. On multislice helical computed tomography, the main pancreatic duct was obstructed by a small round tumor, and the main pancreatic duct proximal to the tumor was dilated. The correlation between the main pancreatic duct and the tumor was well depicted on minimum intensity projection image. This is the first report of multislice helical computed tomorgraphic and minimum intensity projection image findings of a pancreatic carcinoid tumor presenting with pancreatitis.

JC polyomavirus reactivation is not associated with herpes zoster

Herpes zoster (HZ) is a neurocutaneous disease caused by Varicella-zoster virus (VZV) as a consequence of declined cell-mediated immunity, immune suppression and immunodeficiency. As reactivation of JC polyomavirus (JCPyV) might be linked with immunodeficiency or immunosuppressive therapy, the relationship between HZ and JCPyV reactivation was investigated. The incidence of JCPyV in urine samples from 102 patients with HZ and 100 healthy individuals from South Korea was determined by PCR. The incidence values for HZ patients and control individuals did not differ significantly (24.5% vs. 20.0%, respectively, P = 0.5391). When different age groups were monitored, the positivity values of 21.1%, 20.0%, and 30% were found for 20-39, 40-59 and over 60 year-old patients, respectively. In order to determine the genotype of JCPyV isolates, their VP1-large T antigen (VT)-intergenic region was PCR amplified, sequenced and analyzed. Three distinct types, namely 1, 2A and 7B were found in 8%, 24%, and 68% of were found among 25 isolates from HZ patients. Using phylogenetic analysis, the type 1 isolates were assigned to the 1C subtype. These results indicate that HZ does not play an important role in JCPyV reactivation and is not associated with JCPyV.

Benign Breast Diseases Associated With Cyclosporine Therapy in Renal Transplant Recipients

PURPOSE

Our aim was to correlate the radiologic characteristics of cyclosporine-induced benign breast diseases with clinical and pathologic findings.

MATERIALS AND METHODS

The clinical, mammographic, and ultrasonographic records of 33 female renal transplant recipients who received cyclosporine were retrospectively reviewed. Eleven patients had 46 breast masses on ultrasonography. We performed core needle biopsies on 20 masses and reviewed the pathologic findings.

RESULTS

Among 33 female renal transplant recipients, 11 (33%) had 46 benign breast lesions detected on ultrasonography. We performed core needle biopsies on 20 of the 46 masses. On pathologic examination, 12 were fibroadenomas, 6 showed fibrocystic changes, and 2 revealed dense fibrosis. Regardless of the final pathologic diagnosis, more than half of the lesions revealed severe lymphatic and venular swellings. Among 11 patients with breast lesions on ultrasonography, 10/11 (91%) showed multiplicity, and 7/11 (64%) bilaterality. Mammographically, patients with breast lesions revealed heterogeneous or extremely dense breast patterns, and 8 of 11 patients, circumscribed masses. Twenty-two patients without breast lesions showed scattered fibroglandular densities (n = 7), or heterogeneously dense (n = 11) or extremely dense (n = 4) breast patterns, and 3 of 22 patients showed vague or asymmetric densities that needed further evaluation.

CONCLUSION

The development of new breast lesions in patients after renal transplantation should suggest a diagnosis of cyclosporine-induced benign breast disease including fibroadenoma, fibrocystic changes, and dense fibrosis.

Global physiological understanding and metabolic engineering of microorganisms based on omics studies

Through metabolic engineering, scientists seek to modify the metabolic pathways of living organisms to facilitate optimized, efficient production of target biomolecules. During the past decade, we have seen notable improvements in biotechnology, many of which have been based on metabolically engineered microorganisms. Recent developments in the fields of functional genomics, transcriptomics, proteomics, and metabolomics have changed metabolic engineering strategies from the local pathway level to the whole system level. This article focuses on recent advances in the field of metabolic engineering, which have been powered by the combined approaches of the various "omics" that allow us to understand the microbial metabolism at a global scale and to develop more effectively redesigned metabolic pathways for the enhanced production of target bioproducts.

Atomic-scale phase coexistence and fluctuation at the quasi-one-dimensional metal-insulator transition

Scanning tunneling microscopy of a quasi-one-dimensional (1D) metal-insulator transition in an In nanowire array on the Si(111) surface reveals unprecedented details in the transition dynamics. The transition proceeds in microscopic first order, namely, through the domain-by-domain conversion at the nanoscale, from the metallic to the insulating phase or vice versa. The definition of domains and their effective transition temperatures (Tc) are strongly correlated with the distribution of defects. Below Tc, the condensation and the fluctuation of 1D charge density waves are observed within the isolated metallic domains, as well as at the domain boundaries. The appearance of such isolated condensates suggests a strong intrawire coupling: a manifestation of the 1D nature of the critical fluctuation, as well as the origin of the first-order transition.

Coptis japonica root extract induces apoptosis through caspase3 activation in SNU-668 human gastric cancer cells

Apoptosis-modulating approaches offer an attractive opportunity for therapeutic use for many tumors. We investigated the effects of the roots of Coptis japonica var. dissecta (Ranunculaceae) on human gastric cancer cells, SNU-668. The cytotoxicity of Coptis japonica at 100 microg/ml (methanol extract) by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was 13.89 +/- 1.91% of control value. Considering the features by 4,6-diamidino-2-phenylindole (DAPI) staining and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay, it was confirmed that the death of SNU-668 cells was due to apoptosis. In the apoptosis-regulating genes, BCL2 expression was diminished out, whereas BAX and CASP3 expressions were increased, compared with control. Furthermore, the activity of caspase3 was significantly increased by Coptis japonica treatment. These results suggest that Coptis japonica could induce apoptotic anticancer effect through caspase3 activation on SNU-668 human gastric cancer cells.

Integration of scanning probes and ion beams

We report the integration of a scanning force microscope with ion beams. The scanning probe images surface structures non-invasively and aligns the ion beam to regions of interest. The ion beam is transported through a hole in the scanning probe tip. Piezoresistive force sensors allow placement of micromachined cantilevers close to the ion beam lens. Scanning probe imaging and alignment is demonstrated in a vacuum chamber coupled to the ion beam line. Dot arrays are formed by ion implantation in resist layers on silicon samples with dot diameters limited by the hole size in the probe tips of a few hundred nm.

Small cell carcinoma of the colon: barium study and CT findings

Extrapulmonary small cell carcinoma is a rare neoplasm. It is an aggressive malignant tumour characterized by rapid local progression and early metastasis. We report a case of small cell carcinoma arising in the transverse colon in a 34-year-old man who presented with epigastric pain. On CT, a poorly enhancing bulky mass encircling the transverse colon with extensive regional lymph node metastases was observed. A segmental annular narrowing with thick interhaustral folds of the transverse colon was found by barium enema examination. This is the first report of barium study and CT findings of extrapulmonary small cell carcinoma of the colon.

Ultrasound findings of iodide mumps

Iodide mumps, swelling of salivary glands after contrast medium injection, is a rare adverse reaction. We present a case in a 73-year-old man with advanced gastric cancer. About 10 min after a CT scan performed with intravenous injection of 140 ml of the low osmolality contrast agent Ioxaglate (Hexabrix 320, Guerbet, France), he complained of progressive swelling of the submandibular area. Ultrasound showed diffuse swelling and internal low echoic thick septa in the submandibular glands bilaterally. Approximately 1 h afterwards, the swelling of his submandibular glands started to regress and returned to normal within a day.

Medium-term results of extracorporeal membrane oxygenation for severe acute lung injury after lung transplantation

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) has been used successfully for early, severe reperfusion injury after lung transplantation. The purposes of this study are to: (1) document the medium-term survival of patients treated with ECMO; and (2) assess the extent of recovery of their pulmonary function.

METHODS

We retrospectively reviewed charts of 172 patients having lung transplants at our institution from 1997 through 2002. The group included 16 patients (9% of total; 10 bilateral, 5 single, 1 living lobar) treated with ECMO for primary allograft failure after single or bilateral single-lung transplantation. Survival and bronchiolitis obliterans syndrome (BOS)-free survival rates were calculated. Pulmonary function was assessed at 2 months, 1 year and 2 years post-transplant.

RESULTS

Median hospital stay was 48 days for the ECMO group and 16 days for the overall group (p < 0.05). The 90-day survival was 60% in the ECMO group, and 90% in the overall group. The 2-year survival was 46% in the ECMO group, and 69% in the overall group. Mean forced expiratory volume in 1 second (FEV(1)) in the ECMO group at 1 year was 59 +/- 13% of predicted, and at 2 years 60 +/- 15% of predicted; it was not significantly different for the overall group.

CONCLUSIONS

Patients treated with ECMO for primary allograft failure after lung transplantation showed acceptable medium-term survival and pulmonary function.

Direct evidence of the charge ordered phase transition of indium nanowires on Si111

A controversial issue of the driving force for the phase transition of the one-dimensional (1D) metallic In wires on Si(111) is studied by low-temperature scanning tunneling microscopy and spectroscopy. The energy gap opening and the longitudinal charge ordering through charge transfer at the Fermi level are unambiguously observed. The vacancy defects induce a local charge ordering decoupled from a lattice distortion above T(c), and pin the phase of charge order below T(c). All these results below and above T(c) including the detailed features such as local fluctuations strongly support the 1D charge-density-wave mechanism for the phase transition.

HeartMate® VE LVAS design enhancements and its impact on device reliability1

OBJECTIVE

The HeartMate VE left ventricular assist system (LVAS) has supported more than 2300 patients and has been shown to be effective for bridge to cardiac transplantation and has demonstrated improved outcomes in survival as a destination therapy. Improvements in device durability are needed as bridge to transplant times increase and as we move into the era of LVAD as destination therapy. The purpose of this study is to determine if design enhancements to the HeartMate LVAS have improved device reliability and durability.

METHODS

A retrospective analysis of serious mechanical failures was performed in 1865 devices (1458 VE, 407 XVE). The analysis of data included devices used to support patients from September 1998 for bridge to transplantation and destination therapy. Serious mechanical failures were defined as inflow valve dysfunction, percutaneous lead breaks, diaphragm fractures or punctures, bearing failures, outflow graft erosion and pump disconnects.

RESULTS

Median device duration for the VE was 97 days (max 1206 days), and 85 days (max 517 days) for the XVE. A total of 134 serious mechanical failures occurred and included inflow valve dysfunction (5.3% VE, 2.4% XVE) (P = 0.853) percutaneous lead breaks (1.9% VE, 0% XVE) (P < 0.001) diaphragm fractures (0.1% VE, 0% XVE) (P = 0.134) outflow graft erosion (0.2% VE, 0% XVE) (P = 0.1096), pump disconnects (0.1% VE, 0% XVE) (P = 0.1336) and bearing failures (0.6% VE, 0.2% XVE) (P = 0.5538). Of the XVEs 97% were free of serious mechanical failures at 6 months and 82% at 1 year compared to 92 and 73% for the VE, respectively. The 6-month difference between the devices was statistically significant (P = 0.0063) and there was no statistically significant difference at 1 year (P = 0.1492).

CONCLUSIONS

Preliminary experience with the HeartMate XVE LVAS demonstrated a significant reduction in percutaneous lead breaks. Early trends indicate positive impact of recent design modifications on XVE performance. These design modifications may improve device durability and reliability, which is crucial as we enter the era of LVADs as an alternative to medical therapy.

Auranofin induces apoptosis and when combined with retinoic acid enhances differentiation of acute promyelocytic leukaemia cells in vitro

1. Acute promyelocytic leukaemia (APL) is characterized by a block in differentiation at the promyelocyte stage. Here, we describe the effects of auranofin (AF), a coordinated gold compound, on apoptosis and differentiation of APL cells. 2. Nucleosomal DNA fragmentation assay and Hoechst 33342 staining indicated that AF induced apoptosis in APL-derived NB4 cells at low concentrations (0.5-1.0 microm). The AF-induced apoptosis involved caspase-3 activation and specific cleavage of poly-ADP-ribose polymerase. 3. The AF-treated NB4 cells also produced reactive oxygen species (ROS) and cotreatment with N-acetyl-l-cysteine protected the NB4 cells from AF-induced apoptosis. 4. Expression of the CD11b cell surface marker and C/EBPepsilon was increased when the cells were treated for 4 days with 0.3 microm AF and a physiological concentration of all-trans retinoic acid (ATRA, 5 nm). Treatment with AF in combination with ATRA markedly increased the number of cells with differentiated features, such as lobed or multiple nuclei and numerous granules and vacuoles. At these low concentrations, neither AF nor ATRA alone induced significant cell differentiation. 5. These findings suggest not only that AF induces caspase-3-dependent apoptosis via a mechanism involving ROS, but also that the combined treatment with AF and ATRA induces differentiation of NB4 cells. Our results demonstrate a novel characteristic of AF from which an effective drug treatment of APL might be developed.

Hydrocele of the canal of Nuck in a girl: ultrasound and MR appearance

Hydrocele of the canal of Nuck is a rare condition in females. A small evagination of parietal peritoneum forms the canal of Nuck. Failure of complete obliteration of the canal results in either an indirect inguinal hernia or a hydrocele of the canal of Nuck. We present a case in a 7-year-old girl. On ultrasound, there was a comma-shaped cyst with the tail directed cranially toward the inguinal canal. The cyst had no internal echoes and demonstrated increased through transmission. Coronal and axial MR showed a thin walled cystic mass.

Novel electronic structure of inhomogeneous quantum wires on a Si surface

A one-dimensional system of Si(111)-(5 x 2)-Au is explored using scanning tunneling microscopy and spectroscopy. The chain of Si adatoms called bright protrusions (BP's) is found to be semiconducting with an evanescent state in the gap, which originates from adjoining metallic BP-free segments. A quantitative analysis shows that the evanescent state decays in inverse-Gaussian form, leading to an appearance of a parabolic BP chain, and scales to its chain length. Spatial decay of the state suggests a quadratic band bending and the existence of a Schottky-like potential barrier at the interface driven by charge transfer.

Three-dimensional reconstructed images using multidetector computed tomography in evaluation of the biliary tract

The recent development of multidetector computed tomography (MDCT) and the parallel escalation in the capabilities of the workstation allow the use of high-quality multiplanar and three-dimensional reconstruction images. As a noninvasive technique, MDCT dedicated to the biliary tract represents an alternative to magnetic resonance cholangiography. The usefulness of three-dimensional reconstructed images using MDCT in evaluating biliary tract abnormality is illustrated.

Deficits of Organizational Strategy and Visual Memory in Obsessive-Compulsive Disorder

This study was conducted to investigate the deficits of organizational strategy and visual memory in obsessive-compulsive disorder (OCD). Thirty OCD patients and 30 healthy controls aged 20-35 years participated. The Maudsley Obsessive-Compulsive Inventory, Beck Anxiety Inventory, Wechsler Adult Intelligence Scale, and Rey-Osterrieth Complex Figure (ROCF) test were administered to participants. The authors scored ROCF performances using the Boston Qualitative Scoring System. The OCD patients showed poorer planning ability and higher fragmentation than did healthy controls when copying the ROCF, and they showed even poorer performances in the immediate and delayed recall conditions. The authors found that the Organization score in the copy condition mediated the difference between the OCD group and the healthy group in immediate recall. The direct effect of diagnosis (OCD or healthy) on the immediate recall condition of the ROCF was also significant. This study indicates that people with OCD have poor memory function and organizational deficits.

Poly(oligonucleotide) conjugates: applications in assembling nanoparticles and in detecting DNA sequences

The chemistry of oligonucleotide-nanoparticle conjugates is described. Examples are provided to illustrate (i) the utility of oligonucleotide linkers in constructing ordered nanoparticle assemblies and (ii) applications of nanoparticles as reporters for nucleic acid hybridization.

Renal perfusion abnormality. Coded harmonic angio US with contrast agent

PURPOSE

Coded harmonic angio (CHA) US is a recently developed technique that can depict the effects of contrast agents. The purpose of this study was to determine the role of this technique in depicting the enhancement patterns of various renal perfusion abnormalities compared with dynamic CT.

MATERIAL AND METHODS

During a 6-month period, various renal lesions including renal cell carcinoma (n=12), transitional cell carcinoma (n=5), acute pyelonephritis (n=5), and renal trauma (n=2) were evaluated with CHA US using a microbubble contrast agent. US images were obtained before contrast administration and with a bolus injection of 4 g of microbubble contrast agent (300 mg/ml) every 10 s for 1 min and every minute for 5 min. The contrast enhancement patterns of various renal masses were compared with dynamic CT.

RESULTS

Of 12 renal cell carcinomas, 9 (75%) showed heterogeneous enhancement and the remaining 3 (25%) showed homogeneous enhancement. Enhancement of more than adjacent renal parenchyma was seen 16-252 s after injection. The duration of enhancement was 13-208 s (mean, 80 s). All transitional cell carcinomas showed peripheral enhancement. Enhancement was seen 22-270 s after injection. The duration of enhancement was 191-238 s (mean, 291 s). Five patients with acute pyelonephritis and 2 with renal trauma showed focal perfusion defects not shown on the pre-contrast examinations.

CONCLUSION

CHA US with microbubble contrast agent is an effective US technique for the evaluation of both tumor vascularity and renal perfusion abnormality.

Renal perfusion abnormality. Coded harmonic angio US with contrast agent

PURPOSE

Coded harmonic angio (CHA) US is a recently developed technique that can depict the effects of contrast agents. The purpose of this study was to determine the role of this technique in depicting the enhancement patterns of various renal perfusion abnormalities compared with dynamic CT.

MATERIAL AND METHODS

During a 6-month period, various renal lesions including renal cell carcinoma (n=12), transitional cell carcinoma (n=5), acute pyelonephritis (n=5), and renal trauma (n=2) were evaluated with CHA US using a microbubble contrast agent. US images were obtained before contrast administration and with a bolus injection of 4 g of microbubble contrast agent (300 mg/ml) every 10 s for 1 min and every minute for 5 min. The contrast enhancement patterns of various renal masses were compared with dynamic CT.

RESULTS

Of 12 renal cell carcinomas, 9 (75%) showed heterogeneous enhancement and the remaining 3 (25%) showed homogeneous enhancement. Enhancement of more than adjacent renal parenchyma was seen 16-252 s after injection. The duration of enhancement was 13-208 s (mean, 80 s). All transitional cell carcinomas showed peripheral enhancement. Enhancement was seen 22-270 s after injection. The duration of enhancement was 191-238 s (mean, 291 s). Five patients with acute pyelonephritis and 2 with renal trauma showed focal perfusion defects not shown on the pre-contrast examinations.

CONCLUSION

CHA US with microbubble contrast agent is an effective US technique for the evaluation of both tumor vascularity and renal perfusion abnormality.

Production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) by metabolically engineered Escherichia coli strains

Recombinant Escherichia coli strains harboring a plasmid containing a novel artificial polyhydroxyalkanoate (PHA) operon consisting of the Aeromonas PHA biosynthesis related genes and Ralstonia eutropha reductase gene were developed for the production of poly(3-hydroxybutyrate-co-hydroxyhexanoate) [P(3HB-co-3HHx)] from dodecanoic acid. By applying stepwise reduction of dissolved oxygen concentration (DOC) during the fermentation, the final dry cell weight, PHA concentration, and PHA content of 79 g/L, 21.5 g/L, and 27.2 wt %, respectively, were obtained in 40.8 h, which resulted in the PHA productivity of 0.53 (g/L)/h. The 3HHx fraction slowly increased during the fed-batch culture to reach a final value of 10.8 mol %. The 3HHx fraction in the copolymer could be increased by 3-fold when the Aeromonas hydrophila orf1 gene was coexpressed with the PHA biosynthesis genes.

The radiation hypersensitivity of cells at mitosis

PURPOSE

Mitotic cells are hypersensitive to ionizing radiation, exhibiting single-hit inactivation coefficients near to those of repair deficient cell lines and lymphocytes. To elucidate possible mechanisms for this hypersensitivity, the kinetics of oxygen radiosensitization, the proportion of indirect effect by OH radicals and the kinetics of radiation-induced DNA strand breakage in the chromatin of mitotic cells were investigated.

MATERIALS AND METHODS

Synchronized populations of >90% mitotic HT-29 cells were obtained by the mitotic shake-off method. Cells were irradiated at < or =4 degrees C with (137)Cs gamma-rays. Cellular oxygen concentration was varied by gassing cell suspensions prior to and during irradiation with mixtures of pure N(2) that contained 5% CO(2) and measured quantities of O(2). The indirect effect of OH radicals was investigated with the radical scavenger, DMSO. DNA strand breakage was measured by the comet assay.

RESULTS

Mitotic HT-29 cell inactivation is well described by a single-hit inactivation coefficient (alpha) of 1.14 +/- 0.06 Gy(-1). The oxygen enhancement ratio of mitotic cells (at 10% survival) was found to be approximately 2.0, significantly lower than the value of 2.8 measured for interphase (asynchronous) cells. More than 60% of mitotic cell killing was eliminated when the media contained 2 M DMSO, indicating that indirect effect is as important in the killing of mitotic cells as it is for interphase cells. The chromatin in mitotic cells was found to be ~2.8 times more sensitive to radiation-induced DNA single-strand breakage than the chromatin of interphase cells.

CONCLUSIONS

The alpha-inactivation coefficient of mitotic HT-29 cells was ~30 times larger than that of interphase cells. Mitotic cell chromatin appears to contain intrinsic DNA breaks that are not lethal. In addition, chromatin in mitotic cells was found to be more susceptible to radiation-induced DNA strand-breakage than the dispersed chromatin of interphase cells. How the enhanced production of these simple DNA lesions (that are usually reparable) translates into the lethal (non-reparable) events associated with alpha-inactivation is not known. The compaction/dispersion status of DNA throughout the cell cycle appears to be an important factor for determining intrinsic cell radiosensitivity and might be manipulated for radiotherapeutic advantage.

Degradation of IkappaBalpha in activated RAW264.7 cells is blocked by the phosphatidylinositol 3-kinase inhibitor LY294002

The mechanism by which lipopolysaccharide (LPS) or phorbol 12-myristate 13-acetate (PMA) induces production of proinflammatory cytokines in murine macrophages, and the role of phosphatidylinositol 3-kinase (PI3-kinase) have not been well investigated. Activation of nuclear factor kappaB (NF-kappaB) is initiated by the phosphorylation of the inhibitory subunit, IkappaB, which targets IkappaB for degradation and leads to the release of active NF-kappaB. In this study we demonstrate that 2-(4-morpholinyl)-8-phenylchromone (LY294002), which inhibits PI3-kinase, specifically inhibited degradation of IkappaBalpha in RAW264.7 cells stimulated with interferon-gamma (IFN-gamma) plus LPS or IFN-gamma plus PMA. To elucidate the importance of this activity in RAW264.7 cells, we examined tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6 production in the activated cells. Pretreatment of the cells with LY294002 resulted in the inhibition of TNF-alpha and IL-6 production in RAW264.7 cells stimulated with IFN-gamma plus LPS or IFN-gamma plus PMA. Furthermore, LY294002 inhibited the production of nitric oxide (NO) in RAW264.7 cells stimulated with IFN-gamma plus LPS or IFN-gamma plus PMA. LY294002 also inhibited inducible NO synthase (iNOS) mRNA expression in the activated RAW264.7 cells. In conclusion, the present results suggest that PI3-kinase is involved in the signal transduction pathway responsible for LPS- or PMA-mediated TNF-alpha and IL-6 production, and that LY294002 inhibits NO generation through blocking the degradation of IkappaBalpha in activated RAW264.7 cells.