Is dual-energy absorptiometry accurate in the assessment of bone status of patients with chronic kidney disease?

Several patients with chronic kidney disease (CKD) have deteriorated bone status. Estimation of bone status using DXA has limitations especially in patients with CKD accompanying aortic calcifications. Quantitative CT and the trabecular bone score could be more accurate methods to estimate bone status for patients with CKD and vascular calcifications. INTRODUCTION: It remains unclear whether dual-energy absorptiometry (DXA) is appropriate for the assessment of bone status in patients with chronic kidney disease (CKD), a disease that impacts bone health. The aims of this study were to compare DXA and central quantitative computed tomography (cQCT) and to evaluate bone status in patients with pre-dialysis CKD. METHODS: This retrospective study included 363 healthy control subjects whose bone mineral density (BMD) was evaluated with DXA and 117 CKD patients whose BMD was evaluated using both cQCT and DXA. Diagnostic discordance was assessed between the lumbar spine (LS) and femur neck (FN) from DXA or between two modalities. The trabecular bone score (TBS) was extracted from DXA images. The volume of abdominal aortic calcification (AAC) was calculated using CT images from cQCT. RESULTS: Using LS DXA T-score, osteoporosis was less common in the CKD group than in controls. Patients with normal LS BMD using DXA were reclassified into osteopenia or osteoporosis using cQCT in CKD patients. Among discordant subjects between FN and LS in DXA, a higher BMD of LS was more common in CKD patients than in controls. CKD patients had lower TBS than controls despite having the same diagnosis using DXA. AAC volume negatively correlated with BMD from cQCT and with TBS but not with BMD from DXA. CONCLUSIONS: TBS and cQCT could accurately assess bone status in CKD patients since DXA may overestimate LS BMD, likely due to an increased AAC volume.

Low pulmonary function is related with a high risk of sarcopenia in community-dwelling older adults: the Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2011.

UNLABELLED: Sarcopenia is the age-related reduction of skeletal muscle mass in older individuals. Respiratory muscle strength may be related to skeletal muscle mass and, thus, the present study attempted to estimate the risk of sarcopenia relative to decreased pulmonary function. The present findings demonstrated that low pulmonary function was associated with low muscle mass in community-dwelling older adults. INTRODUCTION: Lean body mass is related to pulmonary function in patients with chronic obstructive pulmonary disease (COPD). However, the relationship between muscle mass and pulmonary function in healthy older adults has yet to be clarified. Thus, the present study investigated the association of pulmonary function with muscle mass in an older community-dwelling Korean population. METHODS: This study included 463 disease-free subjects over 65 years of age who underwent anthropometric measurements, laboratory tests, spirometry, and the estimation of appendicular skeletal muscle (ASM) mass in the 2008-2011 Korea National Health and Nutrition Examination Survey (KNHANES). Low muscle mass was defined as the value of ASM divided by height squared (ASM/height(2)) that was less than two standard deviations (SD) below the sex-specific mean of the young reference group. RESULTS: Forced expiratory volume in 1 s (FEV1[L]) and forced vital capacity (FVC[L]) were positively correlated with ASM/height(2) in males (p < 0.001 and p = 0.001, respectively) but not in females (p = 0.360 and p = 0.779, respectively). A univariate logistic regression analysis revealed that males with low FEV1 or FVC were more likely to have low muscle mass (odds ratio [OR] = 3.11, 95% confidence interval [CI] 1.62-5.99 for FEV1; OR = 1.99, 95% CI 1.13-3.53 for FVC); similar results were found for females, but the significance was lower (OR = 11.37, 95% CI 0.97-132.91 for FEV1; OR = 7.31, 95% CI 1.25-42.74 for FVC). After adjusting for age, smoking, and moderate physical activity, a low FEV1 value was associated with low muscle mass in both males (OR = 2.90, 95% CI 1.50-5.63) and females (OR = 9.15, 95% CI 1.53-54.77). CONCLUSIONS: Using nationally representative data from the 2008-2011 KNHANES, low pulmonary function was found to be associated with low muscle mass in community-dwelling older Korean adults.

Association between eNOS polymorphisms and risk of coronary artery disease in a Korean population: a meta-analysis.

Coronary artery disease (CAD), a multifactorial disease, is a common cause of mortality in humans. Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene (-786T>C, 4a4b, and 894G>T) have been previously associated with increased CAD risk. However, the sample size of this previous study was too small and limited to comprehensively define an association between eNOS polymorphisms and CAD; therefore, this analysis was duplicated with a larger population. The study was conducted on 559 patients with CAD and 574 healthy controls. Genetic DNA was extracted using the commercial G-DEX blood extraction kit and statistical analyses were performed on the GraphPad prism 4.0 and MedCalc 12.0 statistical software platforms. No single variant of the eNOS polymorphism was associated with CAD risk. The combination genotypes of eNOS -786TT/4a4b+4a4a [adjusted odds ratio (AOR) = 0.122; 95% confidence interval (CI): 0.042-0.358] and eNOS -786TC+CC/4b4b (AOR = 0.379; 95%CI: 0.147-0.979) were associated with decreased CAD incidence. Haplotype analysis revealed that the T-4a haplotype of eNOS -786T>C and 4a4b exerted a protective effect against CAD. The association between eNOS -786T>C and increased CAD risk was not replicated in this (larger) population. However, some combined genotypes showed a meaningful association with CAD risk.

The relationship between pulmonary function and bone mineral density in healthy nonsmoking women: the Korean National Health and Nutrition Examination Survey (KNHANES) 2010.

UNLABELLED: The aim of this study was to examine the association between pulmonary function and bone mineral density (BMD) in subjects who had never smoked. Pulmonary function was associated with BMD in premenopausal, but not postmenopausal, women. INTRODUCTION: It has been reported that low bone mass is common in patients with pulmonary disorders such as chronic obstructive pulmonary disease. However, in healthy nonsmoking women, the relationship between bone mass and pulmonary function has yet to be clarified. The object of this study was to determine whether pulmonary function is related to BMD in healthy nonsmoking women based on menopausal status. METHODS: This study was a cross-sectional study based on data obtained from the Korean National Health and Nutrition Examination Survey (KNHANES), a nationwide representative survey conducted by the Korean Ministry of Health and Welfare in 2010. This study included 456 subjects who had never smoked and analyzed data concerning pulmonary function and BMD. RESULTS: Functional vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were correlated with BMD at lumbar spine, femur neck (FN), and total hip in premenopausal women (p = 0.030, p = 0.003, p = 0.019, respectively, for FVC; p = 0.015, p = 0.006, p = 0.059, respectively, for FEV1). However, FVC and FEV1 were only correlated with BMD at FN in postmenopausal women (p = 0.003 for FVC; p = 0.006 for FEV1). Body mass index (BMI), FVC, and FEV1 were significantly related with BMD at FN, even after adjusting for age and other confounding factors (ß = 0.334, p < 0.001; ß = 0.145, p = 0.017; and ß = 0.129, p = 0.037, respectively) in premenopausal women. However, only age and BMI were correlated with BMD at FN (ß = -0.268, p = 0.001 and ß = 0.384, p > 0.001) in postmenopausal women after adjusting for confounding factors. CONCLUSIONS: Pulmonary function, including FVC and FEV1 are associated with BMD at FN in healthy nonsmoking premenopausal women but not in postmenopausal women.

Association between bone marrow lesions detected by magnetic resonance imaging and knee pain in community residents in Korea.

OBJECTIVE: To describe the frequency of bone marrow lesions (BMLs) detected by magnetic resonance imaging (MRI), and to examine the association of BMLs with knee pain severity in community residents in Korea. METHODS: Participants were randomly chosen from the population-based Hallym Aging Study, irrespective of whether they had knee osteoarthritis (OA) or pain. Demographic and knee pain data were obtained by questionnaire. Radiographic evaluations consisted of weight-bearing knee anteroposterior radiographs and 1.5-T MRI scans. MRI was performed in the dominant knees of subjects without knee pain and in the more symptomatic knees of subjects with knee pain. BMLs were graded according to the whole-organ MRI score. RESULTS: The mean age of the 358 study subjects was 71.8 years, and 34.5% of subjects had radiographically detected knee OA. The prevalences of BMLs and large BMLs in the tibiofemoral compartments were 80.3% and 40.4%, respectively. After adjusting for age, sex, and body mass index, total and medial compartment BML scores were significantly associated with the presence of knee pain, and the association was stronger as the summary score for BML increased. In proportional regression analysis, knee pain severity increased with BML severity in any compartment and in the medial compartment. CONCLUSION: BMLs detected by MRI were highly prevalent in this elderly Asian population. BMLs were significantly linked to knee pain, and BML severity correlated with knee pain severity. BMLs may be important surrogate targets for monitoring pain and structure modification in OA therapeutics.

Laser-driven proton acceleration enhancement by nanostructured foils.

Nanostructured thin plastic foils have been used to enhance the mechanism of laser-driven proton beam acceleration. In particular, the presence of a monolayer of polystyrene nanospheres on the target front side has drastically enhanced the absorption of the incident 100 TW laser beam, leading to a consequent increase in the maximum proton energy and beam charge. The cutoff energy increased by about 60% for the optimal spheres' diameter of 535 nm in comparison to the planar foil. The total number of protons with energies higher than 1 MeV was increased approximately 5 times. To our knowledge this is the first experimental demonstration of such advanced target geometry. Experimental results are interpreted and discussed by means of 2(1/2)-dimensional particle-in-cell simulations.

Clinical implication of (18)F-FDG PET/CT in carcinoma of unknown primary.

The value of (18)F-Fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in the detection of carcinoma of unknown primary (CUP) differs among the studies. This study aimed to evaluate the role of (18)F-FDG PET/CT in CUP. Fifty-one patients (19 women, 32 men) with metastasis confirmed by histopathology from an unknown primary tumor were included in this study. Patients received 370 MBq of (18)F-FDG intravenously, and PET/CT was performed at 60 minutes after injection. Primary tumor sites were detected in 5 of 51 patients (9.6%): in 2 patients with carcinoma of the lung, in 1 patient with carcinoma of the gallbladder, in 1 patient with carcinoma of the esophagus, and in 1 patient with carcinoma of the stomach. No primary tumor was discovered in the remaining 46 patients (90.4%) during the follow-up. The sensitivity, specificity, and accuracy of (18)F-FDG PET/CT were 100%, 80.4%, and 82.4%. The positive and negative predictive values were 35.7 and 100%, respectively. Based on the data presented, (18)F-FDG PET/CT has a clinical implicative value in detecting the primary tumor of CUP. PET/CT can be useful to rule out the possibility of detecting the primary tumor during the follow-up.

Prediction of survival and cancer recurrence using F-18 FDG PET/CT in patients with surgically resected early stage (Stage I and II) non-small cell lung cancer.

The aim of the current study was to investigate the prognostic value of SUV(max) in patients with completely resected early stage (stage I and II) NSCLC. A retrospective review identified 76 patients with surgically resected early (stage I and II) NSCLC who received F-18 FDG PET/CT at diagnosis of cancer. Survival analysis was conducted using Kaplan-Meier analysis, and survival curves stratified by age, sex, mediastinal lymph node involvement, SUV(max), and TNM staging were generated for estimation of overall survival and disease free survival (DFS). Independent predictive factors for survival were determined using Cox proportional hazard model. For overall survival, the median survival of the patients with tumor SUV(max)≤ 6.7 was 48.9 months and was significantly longer than the patients with tumor SUV(max)>6.7 (Log rank test, Χ²=18.01, p5.9. The median survival of the patients with tumor SUV(max)≤ 5.9 was 31.7 months (Log rank test, Χ²=16, p=0.0001). In conclusion, high FDG uptake measured by F-18 FDG PET/CT might have a prognostic value for overall survival and DFS in surgically resected early stage (stage I and II) NSCLC even after stratified by pathologic stages.

Galectin-3 stabilizes heterogeneous nuclear ribonucleoprotein Q to maintain proliferation of human colon cancer cells.

Comparative analysis of proteomes using 5-fluorouracil (5-FU)-resistant human colon cancer cell line revealed that decreased galectin-3 expression was significantly associated with retarded proliferation. However, in the presence of 5-FU proliferation rate of cells with suppressed galectin-3 expression did not differ from that of cells with normal galectin-3 expression, even galectin-3 suppression augmented apoptosis. Mechanism by which galectin-3 regulates cancer cell proliferation has been identified in immunoprecipitates of the anti-galectin-3 antibody. Heterogeneous nuclear ribonucleoprotein Q (hnRNP Q) was identified as a protein interacting with galectin-3. Interestingly, while galectin-3 protein was not affected by the hnRNP Q level, its suppression was accompanied by a decrease in hnRNP Q expression. The present study demonstrates that galectin-3 stabilizes hnRNP Q via complex formation, and reduction in the hnRNP Q level leads to slow proliferation and less susceptibility to 5-FU.

Prognostic stratification using F-18 FDG PET/CT in patients with advanced stage (stage III and IV) non-small cell lung cancer.

F-18 FDG PET could provide prognostic information in patients with advanced resectable NSCLC. In the current study, we investigated the prognostic implication of F-18 FDG PET after chemotherapy in patients with advanced stage III and IV NSCLC. A retrospective review identified 19 patients with advanced stage (stage III and IV) NSCLC who received F-18 FDG PET/CT at diagnosis of cancer and after chemotherapy. The visual response and changes of SUV max before and after treatment on survival was investigated using Kaplan-Meier and Cox proportional hazard regression analyses. The median follow-up time was overall 24.8 month (range, 9.4-59.8 month), for surviving patients 41 month (range, 34.1-59.8 month), and for deceased patients 16.6 month (range, 9.4-29.4 month). Overall survival after baseline F-18 FDG PET/CT at 1 year was 73.7% and at 2 year was 47.4%. Comparing patients with and without F-18 FDG PET/CT response, there was statistically significant difference in overall survival between the 2 groups (median survival time, responder, 29.4 month; non-responder, 14.2 month, Chi(2)=3.91, p=0.048). Also, using the %DeltaSUV(max) for the comparison, significant difference was existed in overall survival between 2 groups (Chi(2)=12.6, p=0.0004). When the tumor reveals more than 17.85% reduction of %DeltaSUV(max), the survival could be predicted (AUC, 0857; standard error, 0.0866; 95% confidence interval, 0.622-0.971; sensitivity, 75%; specificity, 100%; p=0.0001). With Cox proportional hazard model, %DeltaSUV(max) was determined to be a potent prognostic factor for survival (Chi(2), 12.09; p=0.0005). In conclusion, using the visual and quantitative analyses of F-18 FDG PET/CT, the responder to chemotherapy in advanced stage NSCLC patients had a better prognosis. Moreover, the potent predictor of prognosis in advanced stage NSCLC patients was %DeltaSUV(max).

The influence of diabetes on the relationship between N-terminal pro-B-type natriuretic peptide and body mass index.

This study evaluated the influence of diabetes on the relationship between N-terminal pro-B-type natriuretic peptide (NT-proBNP) and body mass index (BMI). Simultaneous NT-proBNP and echocardiographic Doppler examinations were performed in 1117 patients with dyspnoea undergoing cardiac catheterization. Patients were divided into BMI > or =25 kg/m2 (obese), 23-25 kg/m2 (overweight) and <23 kg/m2 (non-obese) groups. In the 803 non-diabetic patients, mean plasma NT-proBNP levels in non-obese, overweight and obese patients showed a significant negative correlation with BMI (862.3 +/- 228.8 pg/ml, 611.5 +/- 149.7 pg/ml, 278.3 +/- 172.5 pg/ml, respectively). In the 314 patients with diabetes, there was no correlation between BMI and NT-proBNP. This study demonstrated that obese patients had reduced concentrations of NT-proBNP compared with non-obese patients, despite having higher left ventricular filling pressures. NT-proBNP was not reduced in obese patients with diabetes. These results suggest that factors other than cardiac status impact on NT-proBNP concentration.

Incidence of cancer among patients with systemic sclerosis in Korea: results from a single centre.

OBJECTIVE: The aim of this study was to determine whether the incidence of cancer has increased among patients with systemic sclerosis (SSc) in Korea. METHODS: The study subjects consisted of 112 patients who had been consecutively evaluated for at least 6 months between 1990 and 2007. We retrospectively reviewed their medical records, investigated the incidence rate of cancer and compared it with that of the Korea National Cancer Centre database. RESULTS: Nine out of 112 patients developed cancer (four males and five females). The average age at diagnosis of cancer was 56.4 years and the mean disease duration was 8.9 years. The standardized incidence ratio (SIR) for SSc patients was 4.2 [95% confidence interval (CI) 2.3-6.1], 3.7 for women (95% CI 1.2-6.2) and 6.4 for men (95% CI 1.6-11.2). Lung cancer was the most common cancer (n = 4), followed by oesophagus (n = 1), stomach (n = 1), liver (n = 1), pancreas (n = 1), and squamous cell carcinoma of unknown origin (n = 1). All patients who developed lung cancer were female and non-small cell carcinoma in origin. The SIR of lung cancer in female patients was 23.0 (95% CI 6.0-40.0). Two out of four lung cancer patients had concomitant interstitial lung disease (ILD); all were non-smokers. Treatment agents, autoantibodies, smoking, and lung involvement were not significantly different between SSc patients with or without cancer. CONCLUSION: The SIR of cancer was significantly higher in SSc patients, and especially in those who were male, than in the general population. Lung cancer was the most common cancer. Active surveillance for the detection of cancer should be performed in all SSc patients.

Effects of oral magnesium supplementation on insulin sensitivity and blood pressure in normo-magnesemic nondiabetic overweight Korean adults.

BACKGROUND AND AIM: Little is known about the effect of magnesium on insulin sensitivity and BP in healthy individuals. Therefore, we investigated whether magnesium could improve insulin sensitivity and blood pressure (BP) in normo-magnesemic nondiabetic overweight adults. METHODS AND RESULTS: In a double-blinded, placebo-controlled, randomized trial, a total of 155 participants (BMI > or = 23 kg/m(2)) received either 12.3 mmol (300 mg) of elemental magnesium in the form of magnesium oxide (n=75) or placebo (n=80) each day for 12 weeks, constituting the intent-to-treat population. A repeated-measures ANOVA was used to evaluate the between-group changes in variables during the study. The baseline characteristics between the intervention and control groups were similar. There were no significant differences between the groups in the pattern of change of the homeostasis model assessment insulin resistance index, BP over time during the 12-week study. In subgroup analysis, magnesium supplementation (n=8, 27, and 24, respectively) lowered BP much more than placebo (n=16, 29, and 25, respectively) in those subjects whose systolic BP > or = 140 mmHg, diastolic BP 80-90 mmHg, and diastolic BP > or = 90 mmHg at the start of the study (P=0.016, 0.043, and 0.023, respectively); in comparison, those subjects whose initial BP reading was low at baseline did not show a change in BP. No significant adverse events related to magnesium supplementation were recorded. CONCLUSIONS: These results suggested that magnesium supplementation does not reduce BP and enhance insulin sensitivity in normo-magnesemic nondiabetic overweight people. However, it appears that magnesium supplementation may lower BP in healthy adults with higher BP.

Characterization of pulmonary lesions with low F-18 FDG uptake using double phase F-18 FDG PET/CT: comparison of visual and quantitative analyses.

Background of the present study was to assess the usefulness of double phase positron emission tomography/computed tomography (PET/CT) to differentiate malignant from benign pulmonary lesions with low fluorine-18 fluorodeoxyglucose (F-18 FDG) uptake. Of 218 consecutive patients who underwent double phase F-18 FDG PET/CT to evaluate pulmonary lesions found on CT, we retrospectively analyzed 30 who had focal pulmonary lesions with an SUV of <2.5. All patients underwent PET/CT of the thorax at two time points: scan 1 at 60 min and scan 2 at 120 min after the intravenous injection of 2.5 MBq F-18 FDG. The F-18 FDG PET/CT images were analyzed visually and quantitatively. Of 30 evaluated nodules, 13 (43%) proved to be malignant and 17 (57%) benign. The SUVmax1 (maximal SUV of early image), SUVmax2 (maximal SUV of delayed image), %DeltaSUVmax (percent change of maximal SUV), CR1 (contrast ratio of early image), and CR2 (contrast ratio of delayed image) of malignant pulmonary lesion were significantly higher than those of benign. However, %DeltaCR (percent change of contrast ratio) revealed no statistical differences. Among the quantitative indices, SUVmax1, SUVmax2, and CR2 were superior to the visual analysis for differentiation of malignant from benign pulmonary lesions. The SUVmax1, SUVmax2, and %DeltaSUVmax were superior to %DeltaCR for differentiation of malignant from benign pulmonary lesions. Based on the presented results, the quantitative indices except %DeltaCR were higher in malignant nodules than benign pulmonary nodules. However, the diagnostic performances were similar between visual and quantitative analyses. Further studies are needed to confirm these results and improve statistical accuracy. Key words: F-18 FDG, PET/CT, double phase, SUV.

Low rate of total hip replacement as reflected by a low prevalence of hip osteoarthritis in South Korea.

OBJECTIVE: We attempted to estimate the rate of total hip replacement (THR) using a national database and the prevalence of hip osteoarthritis (OA) from the reading of intravenous pyelograms (IVPs) in a Korean population. MATERIALS: Reimbursement records from all hospitals in South Korea were extracted from the Health Insurance Review Agency (HIRA) database. Records with both the procedure code corresponding to THR and containing the diagnosis code for hip OA were selected. We estimated the age- and sex-specific rates of THR from 2002 to 2006. Hip joints from 580 subjects older than 70 years old who underwent an IVP were assessed for the presence of OA. RESULTS: The rate of THR increased with age, reaching a peak over the age of 65-69 years, with the age-standardized risk ratios in women vs men of approximately 1.5. Although the rate of THR increased over the 5-year study period, it was significantly lower than that of total knee replacement (TKR) in Korean population (THR vs TKR 1:15.9). The prevalence of hip OA in the IVP cohort was 1.2% (1.7% for men and 0.7% for women). CONCLUSION: The rate of THR was significantly lower than that of TKR in Korean population. Hip OA prevalence among the IVP subjects was 1.2%. Further studies on factors that account for the low prevalence of hip OA among Asians need to be conducted.

Comparison of double phase Tc-99m MIBI and Tc-99m tetrofosmin scintimammography for characterization of breast lesions: Visual and quantitative analyses.

The aim of the current study was to compare the diagnostic reliability of visual and quantitative indices of double phase Tc-99m MIBI scintimammography (M-SMM) and Tc-99m Tetrofosmin scintimammography (TF-SMM) for detection of breast cancer. Double phase M-SMM and TF-SMM (early; 10 minutes, delayed; hour) were performed after injection of 925 MBq of radiotracers in 75 highly suspected breast cancer patients (malignant:49, benign:26). For visual analysis, five scoring methods were used. For quantitative analysis, early, delayed lesions to non-lesion ratios (L/Ns), and washout rate (%, WR) were calculated. When over grade of visual grade was used as cut-off value in the detection of primary breast cancer, M-SMM and TF-SMM showed similar diagnostic accuracies. The optimal quantitative indices of M-SMM for the detection of breast cancer were 2.06 for early L/N and 1.72 for delayed L/N. Those of TF-SMM were 3.13 for early, and 2.56 for delayed image. Visual and quantitative analyses showed similar results. However, delayed L/N of M-SMM was superior to that of TF-SMM for the detection of breast cancer. In conclusion, the double phase M-SMM and TF-SMM showed favorable diagnostic accuracy in differentiating benign from malignant breast lesions, visually and quantitatively. The optimal visual interpretation grades for the detection of primary breast cancer of double phase M-SMM and TF-SMM were grade and 5. The optimal quantitative indices of M-SMM for the detection of breast cancer were 2.06 for early L/N and 1.72 for delayed L/N. Those of TF-SMM were 3.13 for early, and 2.56 for delayed image.

RESPONSE OF DOSEMETERS IN FIELDS GENERATED BY LASER-ACCELERATED PROTONS.

In laser-driven acceleration, ultra-short and intense laser pulses are focussed on targets to generate beams of ionising radiation. One of the most important issues to be addressed is personal monitoring. While traditional dosemeters were designed primarily for measurements in continuous fields, dosemeters for laser laboratories must be capable of working in pulsed fields of pulse length below 1 ps, in a single-shot regime up to the repetition rate of 1 kHz. Responses of conventional dosemeters (films, polyallyldiglycol carbonate, electronic personal dosemeter) to proton bunches of up to 30 MeV energy produced by South Korean PW laser system at the Advanced Photonics Research Institute, Gwangju Institute of Science and Technology were studied, both by means of Monte Carlo simulations and experimentally.

Alterations in p53 and E2F-1 function common to immortalized chicken embryo fibroblasts.

A number of non-virally and non-chemically immortalized chicken embryo fibroblast (CEF) cells have been established recently in continuous cell culture. All immortal CEF cells tested showed common genetic alterations in the expression patterns of p53 and E2F-1 mRNA and protein which were down- and up-regulated, respectively. The biological effects of differentially regulated p53 and E2F-1 were determined by reporter gene transcriptional activity assays, DNA binding assays, and Northern blot analysis of the expression patterns of down-stream genes. In addition, expression of most of the cyclin genes was up-regulated in immortal CEF cells, which may be associated with the rapid cell division rates and serum-independent growth patterns seen in immortal CEF cells. The telomeric lengths and chromosome integrity were maintained in all immortal CEF cell lines without detectable telomerase activity. Although the functional inactivations of the p53 and Rb regulatory pathways are known to be common events for cellular immortalization, the genetic changes leading to alteration of p53 and E2F-1 function through transcriptional and post-transcriptional regulation seem to be unique in immortal CEF cells.

Inhibition of the EGF-induced activation of phospholipase C-gamma1 by a single chain antibody fragment.

Phospholipase C-gamma1(PLC-gamma1) is known to play an essential role in various cellular responses, such as proliferation and tumorigenesis, and PLC-gamma1-specific inhibitors are commonly employed to investigate the mechanism of the PLC-gamma1-mediated signaling pathway. In this study, we developed a single chain antibody fragment (scFv) as a blocker for PLC-gamma1 mediated signaling. scFv, designated F7-scFv, specifically bound to PLC-gamma1 with high affinity (K(d)=1.9x10(-8) M) in vitro. F7-scFv also bound to PLC-gamma1 in vivo and altered the distribution pattern of PLC-gamma1 from the cytoplasm to the intracellular aggregates, where F7-scFv was localized. Moreover, F7-scFv interrupted the EGF-induced translocation of PLC-gamma1 from the cytosol to the membrane ruffle and attenuated EGF-induced inositol phosphates generation and intracellular calcium mobilization. These results indicate that F7-scFv blocks EGF-induced PLC-gamma1 activation by causing sequestering of PLC-gamma1 into intracellular aggregates, and may therefore be useful in studies of the PLC-gamma1-mediated signaling pathway.