Adverse events in acute myocardial infarction patients: the DAPT Score for risk stratification in an Asian population

Background

Dual antiplatelet therapy (DAPT) is essential in mitigating adverse ischemic events after myocardial infarction (MI), and current guidelines have recommended the therapy to be administered for at least 1 year. Though prolonged DAPT helps to reduce ischemic events in high-risk patients, it can also increase the risk of significant bleeding. Risk stratification tools, such as the DAPT Score, can help to identify patients who are most or least likely to benefit from prolonged DAPT.

Purpose

To evaluate the performance of the DAPT Score as a predictor of major adverse cardiovascular events (MACE) in an Asian cohort who underwent percutaneous coronary intervention (PCI) for MI.

Methods

The analysis cohort consisted of 2086 MI patients (86% of primary PCI patients) who were admitted to Singaporean hospitals between 2012 and 2014. Demographic, clinical and therapeutic data regarding the index hospitalisation and 12-month follow-up period were collected. Patients were grouped according to their DAPT Score (high ischemic vs high bleeding risk) and DAPT duration (12 vs <12 months; Figure 1). The primary endpoint was MACE (all-cause mortality, recurrent MI and stroke). MACE as an outcome was evaluated using multivariable Cox regression adjusted for age, gender, ethnicity, smoking status, prior MI, PCI or coronary artery bypass graft, hypertension, dyslipidaemia, cerebrovascular disease, diabetes mellitus, family history of coronary artery disease, vein graft stent and type of MI at presentation.

Results

The overall incidence rate of MACE in this cohort was 12.3%. There was a significantly higher MACE rate in Group 2 patients compared to Group 1 patients (high ischemic risk and <12-month DAPT vs high ischemic risk and 12-month DAPT; hazard ratio: 1.37, 95% confidence interval: 1.02–1.83, P=0.038). No other significant differences in MACE rates were observed among the rest of the groups (Group 3: 1.44 [0.89–2.34]; Group 4: 1.15 [0.61–2.16], P>0.050). Furthermore, MACE was independently associated with diabetes, hypertension, prior MI and cerebrovascular disease (1.49 [1.10–2.02], 1.43 [1.00–2.05], 1.41 [1.01–1.98], 3.06 [2.15–4.37], respectively, P<0.050). Patients <65 years and males were found to be protected against MACE (0.71 [0.51–0.99], 0.72 [0.52–0.99], respectively, P<0.050). The overall bleeding rate was 2.2% (Group 1: 2.0%; Group 2: 1.7%; Group 3: 6.0%; Group 4: 0.7%).

Conclusions

The DAPT Score predicted MACE up to 12 months after PCI in MI patients with high ischemic risk and <12 months of DAPT. This highlights the importance of adequate duration of DAPT in high ischemic risk MI patients. Moreover, the elderly, female, diabetic, hypertensive and those with prior cerebrovascular disease or MI were at increased risk for MACE.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Medical Research Council - Health Services Research Grants (Ministry of Health, Singapore) CohortsCox regression for MACE

Prognostic significance of preoperative inflammatory response biomarkers in patients undergoing curative thoracoscopic esophagectomy for esophageal squamous cell carcinoma

BACKGROUND

Recent studies have revealed significant relationships between the lymphocyte-to-monocyte ratio (LMR), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) and survival in various cancers. The purpose of this study was to confirm whether the LMR, NLR, and PLR have prognostic values, independent of clinicopathological criteria, in patients undergoing curative resection for esophageal cancer.

METHODS

The LMR, NLR and PLR were calculated in 147 consecutive patients who underwent curative esophagectomy between January 2006 and December 2014. Receiver operating characteristics (ROC) curve analysis was conducted to identify the optimal cutoff values of each biomarkers.

RESULTS

In multivariate analysis for cancer-specific survival (CSS), pTNM stage (p < 0.0001) and low LMR (p = 0.0081) were selected as independent prognostic factor. Similarly, pTNM stage(p < 0.0001) and low LMR (p = 0.0225) were found to be independent prognostic factor for overall survival (OS). There was no significant relationship between LMR, NLR and PLR and survival in patients with stage I or II, however, significant relationships between LMR and CSS or OS were observed in patients with stage III esophageal cancer.

CONCLUSIONS

LMR can be used as a novel predictor of postoperative CSS and OS in patients with esophageal cancer and that it may be useful in identifying patients with a poor prognosis even after radical esophagectomy.

Effect of high-sensitivity C-reactive protein on the development of diabetes as demonstrated by pooled logistic-regression analysis of annual health-screening information from male Japanese workers

AIM

The aim of this study was to determine the relationship between the development of diabetes mellitus and high-sensitivity C-reactive protein (HsCRP) adjusted for various potential confounders.

METHODS

This 5-year prospective cohort study was conducted at a Japanese steel factory and involved male workers who had received annual health screenings between 2005 and 2010. The 7392 male participants were aged 19-75 years. The study endpoint, the development of diabetes mellitus, was defined as HbA(1c) greater or equal to 6.5% or the use of antidiabetic medication. The association between variables was investigated using pooled logistic regression adjusted for various covariates such as age, baseline body mass index (BMI) and increase in BMI from baseline, blood biochemistry, job schedule and job-related stress.

RESULTS

The incidence rate of diabetes development per 1000 person-years was 13.9. Multivariate analysis showed a significant relationship between the development of diabetes and elevated levels of baseline HsCRP and increases in levels from baseline. The Odds ratios for a 2.9-fold (±1 geometric standard deviation) increase in baseline HsCRP and increase in HsCRP level from baseline were 1.18 [95% confidence interval (CI): 1.03-1.34; P=0.018] and 1.21 (95% CI: 1.03-1.41; P=0.018), respectively.

CONCLUSION

The present study has indicated that HsCRP is an independent predictor for the development of diabetes in men, together with various confounders such as BMI, type of job schedule and job-related stress.

Proposal for a new clinical entity, IgG4-positive multiorgan lymphoproliferative syndrome: analysis of 64 cases of IgG4-related disorders

BACKGROUND

Mikulicz's disease (MD) has been considered as one manifestation of Sjögren's syndrome (SS). Recently, it has also been considered as an IgG(4)-related disorder.

OBJECTIVE

To determine the differences between IgG(4)-related disorders including MD and SS.

METHODS

A study was undertaken to investigate patients with MD and IgG(4)-related disorders registered in Japan and to set up provisional criteria for the new clinical entity IgG(4)-positive multiorgan lymphoproliferative syndrome (IgG(4)+MOLPS). The preliminary diagnostic criteria include raised serum levels of IgG(4) (>135 mg/dl) and infiltration of IgG(4)(+) plasma cells in the tissue (IgG(4)+/IgG+ plasma cells >50%) with fibrosis or sclerosis. The clinical features, laboratory data and pathologies of 64 patients with IgG(4)+MOLPS and 31 patients with typical SS were compared.

RESULTS

The incidence of xerostomia, xerophthalmia and arthralgia, rheumatoid factor and antinuclear, antiSS-A/Ro and antiSS-B/La antibodies was significantly lower in patients with IgG(4)+MOLPS than in those with typical SS. Allergic rhinitis and autoimmune pancreatitis were significantly more frequent and total IgG, IgG(2), IgG(4) and IgE levels were significantly increased in IgG(4)+MOLPS. Histological specimens from patients with IgG(4)+MOLPS revealed marked IgG(4)+ plasma cell infiltration. Many patients with IgG(4)+MOLPS had lymphocytic follicle formation, but lymphoepithelial lesions were rare. Few IgG(4)+ cells were seen in the tissue of patients with typical SS. Thirty-eight patients with IgG(4)+MOLPS treated with glucocorticoids showed marked clinical improvement.

CONCLUSION

Despite similarities in the involved organs, there are considerable clinical and pathological differences between IgG(4)+MOLPS and SS. Based on the clinical features and good response to glucocorticoids, we propose a new clinical entity: IgG(4)+MOLPS.

Molecular targets of glioma invasion

Glioblastoma multiforme is the most common and lethal primary malignant brain tumor. Although considerable progress has been made in technical proficiencies of surgical and radiation treatment for brain tumor patients, the impact of these advances on clinical outcome has been disappointing, with median survival time not exceeding 15 months. Over the last 30 years, no significant increase in survival of patients suffering from this disease has been achieved. A fundamental source of the management challenge presented in glioma patients is the insidious propensity of tumor invasion into distant brain tissue. Invasive tumor cells escape surgical removal and geographically dodge lethal radiation exposure and chemotherapy. Recent improved understanding of biochemical and molecular determinants of glioma cell invasion provide valuable insight into the underlying biological features of the disease, as well as illuminating possible new therapeutic targets. These findings are moving forward to translational research and clinical trials as novel antiglioma therapies.

A review of FGF18: Its expression, signaling pathways and possible functions during embryogenesis and post-natal development

FGF18 is a novel growth factor first reported in 1998. Current evidence suggests that FGF18 may play a prominent role in chondrogenesis and osteogenesis during skeletal development and growth. However, its function extends to many other biological processes. Although there remains much to be discovered and investigated on the functions and mechanisms of FGF18, it may play a role as a useful therapeutic target for various applications. The following review summarizes the current knowledge on FGF18 with special emphasis on its skeletal functions and highlights its potential areas for future research.

An immunohistochemical analysis of the temporal and spatial expression of growth factors FGF 1, 2 and 18, IGF 1 and 2, and TGFbeta1 during distraction osteogenesis

Distraction osteogenesis (DO) is a well established surgical technique that generates new bone by gradual distraction of two bony segments. In this study, we investigated the temporal and spatial profile of FGF 1, 2 and 18, IGF 1 and 2, and TGFbeta1 during distraction osteogenesis using immunohistochemistry. An osteotomy was performed on the right tibia of 13 white male New Zealand rabbits. After a delay of 7 days, distraction was started at a rate of 0.25 mm/12 hrs for 3 weeks which was followed by a 3 week period of consolidation. Immunohistochemical analysis was performed on a weekly interval to determine the expression of the growth factors. Staining of all growth factors was apparent at various levels in the centre and callus region in fibroblasts and chondrocyte cells. FGF2 however, showed continued high expression in osteoblasts. Within two weeks after the end of distraction all growth factors showed a reduction in expression except for FGF18 which maintained high levels of expression (up to 100% staining) throughout the distraction and consolidation phases. The study suggests that in comparison to the other investigated growth factors, FGF18 may play in important role throughout the entire process of distraction osteogenesis.

Chemosensitivity testing of ovarian cancer using the histoculture drug response assay: sensitivity to cisplatin and clinical response

Despite cytoreductive surgery and chemotherapy, the prognosis of advanced ovarian cancer is still poor. Predicting the chemosensitivity of tumors might improve the outcome. Therefore, we investigated the clinical value of the histoculture drug response assay for ovarian cancer. Tumor specimens were cultured for 7 days on collagen gel sponge in medium containing cisplatin, and the 50% inhibitory concentration was determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide assay. Then the in vitro sensitivity to cisplatin was compared with the clinical response and survival. Apoptosis of tumor cells was also investigated. Among 173 ovarian cancer patients, 164 were evaluable by the assay, and 29 patients had measurable lesions for which the clinical response could be determined. The 5-year survival rate was significantly higher in patients with chemosensitive tumors than in those with chemoresistant tumors when the cutoff value was set at a 50% inhibitory concentration of 25 microg/mL and the accuracy of the assay was 82.8% (24/29). As chemosensitivity to cisplatin became greater, the number of apoptotic cells also increased. This chemosensitivity assay may help predict the clinical response to cisplatin-based chemotherapy, thus improving the survival of ovarian cancer patients.

Chemosensitivity testing of ovarian cancer using the histoculture drug response assay: sensitivity to cisplatin and clinical response

Despite cytoreductive surgery and chemotherapy, the prognosis of advanced ovarian cancer is still poor. Predicting the chemosensitivity of tumors might improve the outcome. Therefore, we investigated the clinical value of the histoculture drug response assay for ovarian cancer. Tumor specimens were cultured for 7 days on collagen gel sponge in medium containing cisplatin, and the 50% inhibitory concentration was determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide assay. Then the in vitro sensitivity to cisplatin was compared with the clinical response and survival. Apoptosis of tumor cells was also investigated. Among 173 ovarian cancer patients, 164 were evaluable by the assay, and 29 patients had measurable lesions for which the clinical response could be determined. The 5-year survival rate was significantly higher in patients with chemosensitive tumors than in those with chemoresistant tumors when the cutoff value was set at a 50% inhibitory concentration of 25 μg/mL and the accuracy of the assay was 82.8% (24/29). As chemosensitivity to cisplatin became greater, the number of apoptotic cells also increased. This chemosensitivity assay may help predict the clinical response to cisplatin-based chemotherapy, thus improving the survival of ovarian cancer patients.

Complications of laparoscopic procedures after concentrated training in urological laparoscopy

PURPOSE

To increase the safety and efficiency of laparoscopic surgery clinical training programs have been developed to increase the skill and efficiency of urological trainees. We evaluated the impact of dedicated laparoscopy training on the rate and type of complications after trainees entered clinical practice.

MATERIALS AND METHODS

Data were obtained from 13 centers where laparoscopy was performed by a single surgeon with at least 12 months of training in urological laparoscopy before clinical practice. Data included training experience, laparoscopic procedures performed after commencing clinical practice and associated complications. Procedures were classified as easy, moderate and difficult.

RESULTS

During training each surgeon participated in a mean of 71 cases. In clinical practice a total of 738 laparoscopic cases were performed with the group reporting an overall complication rate of 11.9%. The rate was unchanged when the initial 20, 30 and 40 cases per surgeon were compared with all subsequent cases (12%, 11.9% and 12% versus 11.8 to 12%, respectively). The re-intervention rate was 1.1%. The complication rate increased with case difficulty. Overall and early complication rates attributable to laparoscopic technique in the initial 20, 30 and 40 cases were identical. The most common complications were neuropathy in 13 patients, urine leakage/urinoma in 9, transfusion in 7 and ileus in 5.

CONCLUSIONS

The complication rate of surgeons who completed at least 12 months of laparoscopy training did not differ according to initial versus subsequent surgical experience. Intensive training seems to decrease the impact of the learning curve for laparoscopy.

Effect of angiotensin type I-receptor blockade on left ventricular remodeling in pressure overload hypertrophy

BACKGROUND

The renin-angiotensin system is involved in cardiac remodeling. In contrast to the well-recognized salutary effects of angiotensin-converting enzyme inhibition, the value of angiotensin II type I (AT(1))-receptor blockade on left ventricular (LV) hypertrophy and dysfunction is controversial.

METHODS AND RESULTS

Descending thoracic aorta-banded and sham-operated guinea pigs were given either losartan (30 mg x kg(-1) x day(-1) intraperitoneally) or vehicle for 8 weeks (n = 7 in each group). LV end-diastolic and end-systolic dimensions and wall thicknesses were measured echocardiographically, and LV fractional shortening, relative wall thickness, and LV mass normalized by body weight were calculated. Isolated heart function (Langendorff perfusion) was studied 8 weeks after surgery, and LV performance was assessed by maximum LV pressure and +/-dP/dt normalized by LV mass. Eight weeks after banding guinea pigs developed concentric LV hypertrophy and had decreased maximum LV pressure and +/-dP/dt normalized by LV mass; LV end-diastolic dimension and LV fractional shortening were unchanged. In band-operated guinea pigs treatment with losartan had no significant effects on any of these measurements.

CONCLUSIONS

In guinea pigs with descending aortic banding, treatment with losartan for 8 weeks neither attenuates progression of pressure overload hypertrophy nor significantly improves impaired mass-normalized pressure-derived indices of LV contraction and relaxation.

Inhibitory effect of modified 5'-capped short RNA fragments on influenza virus RNA polymerase gene expression

We have shown previously that the 5'-capped short phosphodiester RNA fragments, Cap decoy, (Gm 12 nt) are potent inhibitors of influenza virus RNA polymerase gene expression. Here we investigate the modified capped RNA derivative containing phosphorothioate oligonucleotides (Cap decoy) as a potential influenza virus RNA polymerase inhibitor. The modified 5'-capped short phosphorothioate RNA fragments (Gms 12-15 nt) with the 5'-capped structure (m7GpppGm) were synthesized by T7 RNA polymerase. The 5'-capped short RNA fragments (Gms 12-15 nt) were encapsulated in liposome particulates and tested for their inhibitory effects on influenza virus RNA polymerase gene expression in the clone 76 cells. The 12-15 nt long Gms RNA fragments showed highly inhibitory effects. By contrast, the inhibitory effects of the 13 nt long short RNA fragments (Gm 13 nt) were considerably less in comparison with the 5'-capped short phosphorothioate RNA fragments (Gms 12-15 nt). In particular, the various Gms RNA chain lengths showed no significant differences in the inhibition of influenza virus RNA polymerase gene expression. Furthermore, the capped RNA with a phosphorothioate backbone was resistant to nuclease activity. These phosphorothioate RNA fragments exhibited higher inhibitory activity than the 5'-capped short RNA fragments (Gm 12 nt). These decoys may prove to be useful in anti-influenza virus therapeutics.

[Nontuberculous atypical mycobacterial infection with progressive pancytopenia in a patient with myelodysplastic syndrome]

We describe a patient with myelodysplastic syndrome (MDS) who developed disseminated infection due to nontuberculous mycobacteria (NTM). A 64-year-old man was admitted because of persistent fever that had been unresponsive to antibiotics. Bone marrow aspiration specimens showed myelodysplasia (RA), but the origin of the fever was unclear. Cytopenia worsened to a level that required transfusion of red blood cells and platelets. Repeated bone marrow examination revealed hypoplasia with hemophagocytosis. Several weeks later, photochromogenic NTM was isolated from bone marrow specimens, sputum and broncho-alveolar lavage (BAL) fluid which had been obtained on admission. Antituberculosis treatment with clarithromycin markedly improved the patient's general condition and hematological abnormalities. Three months after resolution of the NTM infection, the peripheral blood monocyte count increased, the fever recurred, and the patient suddenly died of myocardial infarction. Disseminated infection with NTM has gained attention as a frequent complication of AIDS, and NTM can also be one of the pathogens causing disseminated infection in patients with MDS. In the present case, infection with mycobacteria that normally would have been digested by macrophages and would not have caused disseminated infection in a healthy individual, was probably related to the clinical features including high fever, severe pancytopenia and hemophagocytosis.

MEK and p38MAPK inhibitors potentiate TNF-alpha induced apoptosis in U937 cells

BACKGROUND

TNF-alpha is one of the key inflammatory cytokines and it modulates various events through several pathways. U937 myelomonocytic leukemia cells are sensitive to TNF-alpha and about 20% of these cells undergo apoptosis within 6 hours after treatment. Co-treatment of these cells with actinomycin D or cycloheximide enhances TNF-alpha induced apoptosis, suggesting that some TNF-alpha-derived signals can augment apoptosis. We investigated whether mitosis-activating protein kinases (MAPKs) had an influence on TNF-alpha induced apoptosis.

MATERIALS AND METHODS

U937 cells were treated by TNF-alpha with or without MEK or p38MAPK inhibitors. Apoptosis was assessed morphologically by fluorescence microscopy and caspase-3 was studied by immunoblotting. Expression of apoptosis-inhibitory proteins was studied by RT-PCR whilst the activation of JNKs was investigated by detecting their phosphorylation.

RESULTS

TNF-alpha treatment induced apoptosis in about 23% of the cells, while pretreatment with a MEK inhibitor (PD98059) caused 69% of the cells to undergo apoptosis. The inhibition of p38MAPK by SB203580 scarcely enhanced apoptosis, although another p38MAPK inhibitor (PD169316) induced apoptosis in 37% of the cells. Simultaneous pretreatment of cells with PD98059 and PD169316 resulted in the highest level of TNF-alpha induced apoptosis and 90% of the cells underwent apoptosis after 6 hours. In cells pretreated with PD98059 plus PD169316, caspase-3 was completely cleaved at 6 hours and early induction of c-IAP2/HIAP 1 mRNA was not observed. JNKs showed rapid and extensive phosphorylation in these cells.

CONCLUSION

TNF-alpha induced apoptosis was potentiated by the inhibition of either MEK alone, or MEK plus p38MAPK, suggesting that the MAPK pathway may be a promising target for cancer therapy.

Differential alteration of cardiotonic effects of EMD 57033 and beta-adrenoceptor agonists in volume-overload rabbit ventricular myocytes

BACKGROUND

We investigated the effects of EMD 57033, a prototype Ca2+ sensitizer, and beta-adrenoceptor agonists in ventricular myocytes isolated from the volume-overload (V-O) heart failure model of the rabbit.

METHODS AND RESULTS

V-O cardiac hypertrophy was induced in rabbits by the formation of an arterio-venous shunt between the carotid artery and jugular vein 12 to 15 weeks after the operation. Ventricular myocytes were enzymically isolated from normal and V-O rabbit hearts. The myocyte was loaded with a fluorescence Ca2+ dye, indo-1, and Ca2+ transients, and cell lengths were measured simultaneously. V-O myocytes were significantly larger than control myocytes. Duration of Ca2+ transients and cell shortening was significantly longer in the V-O myocytes than in control myocytes. Effects of cardiotonic interventions, including EMD 57033, isoproterenol, and dobutamine, on Ca2+ transients and cell shortening in V-O myocytes were compared with those in control rabbit myocytes. Isoproterenol and dobutamine increased the systolic cell shortening and peak Ca2+ transients and abbreviated the duration of cell shortening and Ca2+ transients. These responses were markedly attenuated in V-O myocytes. By contrast, the response of cell shortening to EMD 57033 was unaltered, and the Ca2+ sensitizing effect of EMD 57033 was rather enhanced in V-O myocytes.

CONCLUSION

Our results indicate that the effectiveness of Ca2+ sensitizers is maintained in the V-O rabbit hypertrophy and heart failure model in contrast to the blunted response to beta-adrenoceptor agonists, which provides an insight on therapeutic strategy with Ca2+ sensitizers for the treatment of contractile dysfunction in congestive heart failure.

Alterations in the inotropic responses to forskolin and Ca2+ and reduced gene expressions of Ca2+-signaling proteins induced by chronic volume overload in rabbits

Volume overload results in eccentric cardiac hypertrophy, but it is still unknown how this mechanical overload modulates the inotropic response to exogenous Ca2+ or adenylyl cyclase stimulation. Inotropic responsiveness in vivo and the levels of gene expression of Ca2+ signaling proteins were studied in rabbit hearts hypertrophied as a result of volume overload at 4 and 12 weeks after arteriovenous shunt formation. In sham-operated control rabbits, left ventricular (LV)+dP/dt was augmented in response to graded doses of CaCl2. Dose-related changes of LV+dP/dt to CaCl2 were attenuated significantly in shunt rabbits with volume overload. Forskolin dose-dependently augmented LV+dP/dt in sham rabbits, which was also attenuated significantly in rabbits with volume overload. The mRNA levels of dihydropyridine receptor, Na+/Ca2+ exchanger, sarcoplasmic reticulum Ca2+-ATPase, and ryanodine receptor decreased significantly at 4 and 12 weeks in the volume-overload rabbits compared with the sham rabbits, but the mRNA levels of phospholamban and calsequestrin remained unchanged. Chronic volume overload alters contractile responsiveness to Ca2+ or adenylyl cyclase stimulation, and downregulation of steady state mRNA levels of Ca2+ signaling proteins might be, at least in part, related to this pathologic process.

[Disseminated MALT lymphoma associated with macroglobulinemia]

We report a case of disseminated MALT lymphoma with macroglobulinemia in an 80-year-old man who presented with a persistent fever. A radiograph of the chest showed infiltration of the left lung and pleural effusion of the right lung. The fluid contained numerous atypical lymphoid cells, which were positive for CD19, CD20, and HLA-DR, and negative for CD5 and CD10. Analysis of a pleural biopsy sample demonstrated no abnormality. A CT scan of the abdomen showed extensive thickening of the wall of the stomach adjacent to a peritoneal mass. Endoscopic examination disclosed antral ulceration. Histopathological examination of gastric samples revealed infiltration by centrocyte-like cells and lymphoepithelial lesions. Serum electrophoresis detected a macroglobulin peak at 34.5 g/l, and immunoelectrophoresis revealed an IgM kappa component. A bone marrow aspirate showed infiltration by the same lymphoid cells as those in the pleural fluid. A chromosome study of the lymphoid cells from both the bone marrow and pleural fluid showed a normal karyotype. The final diagnosis was MALT lymphoma involving the stomach, lungs and bone marrow. The patient did not consent to chemotherapy, and instead was given oral prednisolone. He died of respiratory distress one year and four months after diagnosis. Autopsy revealed wide dissemination of the tumor cells.

Effects of long-term treatment with nonselective endothelin receptor antagonist, TAK-044, on remodeling of cardiovascular system with sustained volume overload

To assess the role of endothelin-1 (ET-1) on cardiovascular remodeling, nonselective endothelin-receptor antagonist TAK-044 was administered for the long term to rabbits with or without arteriovenous (A-V) shunt formation. Six weeks after sham operation (n = 12) or carotid-jugular shunt formation (n = 21), TAK-044 (30 mg/day) or saline was infused subcutaneously using osmotic mini pumps for another 6 weeks. Twelve weeks after operation, left ventricular (LV) diameter was enlarged with the presence of an A-V shunt; however, the levels of LV diameter and arterial pressure or the postmortem weight of LVs of shunt rabbits were similar between saline and TAK-044 groups. A linear relation of the luminal diameter and the medial cross-sectional area of the left and right carotid arteries was similar between shunt + saline and shunt + TAK-044 groups. In saline groups, myocardial ET-1 levels were higher in shunt than in sham rabbits (217+/-22 vs. 136+/-19 pg/g tissue; p < 0.01 between rabbit groups) without changes in plasma ET-1 concentrations during saline infusion for 6 weeks. Differences in plasma ET-1 levels before and 6 weeks after the administration of TAK-044 were 0.32+/-0.78 and 0.16+/-0.28 pg/ml (NS between periods) in shunt and sham groups, respectively. In TAK-044 groups, myocardial ET-I levels 12 weeks after operation were similarly lower in both sham (105+/-7.4 pg/g tissue) and shunt rabbits (126+/-9.2 pg/g tissue) than in those with saline administration; however, the plasma ET-1 concentrations were increased significantly 6 weeks after TAK-044 administration by 5.0+/-0.6-fold and 3.5 +/-0.3-fold (p < 0.01) of the levels 6 weeks after operation in shunt and sham groups (NS between groups), respectively. Accordingly, myocardial but not plasma ET-1 levels were increased by a long-term burden of volume overload and were attenuated by a long-term administration of TAK-044 without altering drastically the hemodynamics or vascular remodeling. These results suggest that endogenous ET-1 does not play a major role in the compensatory stage of cardiovascular remodeling in the present volume-overload model.

[Effects of (+/-)-pindolol over increased extracellular 5-HT level induced by fluvoxamine: regional difference in effect among the raphe, dorsal hippocampus and prefrontal cortex as measured by in vivo microdialysis technique]

It is known that the somatodendritic 5-hydroxytryptamine (5-HT)1A autoreceptor works to regulate the action of 5-HT neurons leading to the release of 5-HT. Our present study has addressed the possibility that (+/-)-pindolol, which is a non-selective beta-adrenoceptor antagonist/somatodendritic 5-HT1A autoreceptor antagonist, might have the ability to enhance the level of extracellular 5-HT when used with selective serotonin reuptake inhibitor (SSRI; i.e., fluvoxamine). We have used freely moving rats to measure the extracellular level of 5-HT and dopamine (DA) in the raphe, dorsal hippocampus and prefrontal cortex using an in vivo microdialysis technique. Response power of (+/-)-pindolol (8 mg/kg, i.p.) to the rise in extracellular 5-HT level when used with fluvoxamine (60 mg/kg, i.p.) was significant in the raphe, dorsal hippocampus and prefrontal cortex, while the degree of augmentation was more significant in the prefrontal cortex than in the dorsal hippocampus. The extracellular level of DA when used with (+/-)-pindolol showed a tendency to decrease in the raphe while showing a tendency to increase in the dorsal hippocampus. However, no change occurred in the prefrontal cortex. This indicates that (+/-)-pindolol has the ability to block the somatodendritic 5-HT1A autoreceptors, thereby weakening the fluvoxamine-induced indirect action of the autoreceptors in the raphe. We have obtained positive result for the probability of pindolol augmentation in two regions--dorsal hippocampus and prefrontal cortex. This indicates that augmentation therapy by the combined use of fluvoxamine with 5-HT1A antagonist will be valid and effective.

Differential responses of Bcl-2 family genes to etoposide in chronic myeloid leukemia K562 cells

Etoposide is a potent anticancer agent that is used to treat various tumors. We have investigated the dose-dependent effect of etoposide on apoptosis using chronic myeloid leukemia K562 cells treated with low (5 microM) or high (100 microM) concentrations of the drug. At a low concentration, etoposide induced little apoptosis at 24 h, while about 20% of the cells showed apoptosis morphologically at a high concentration. Processing of caspase-3 was slightly detected from 12 h and became obvious at 24 h with 100 microM etoposide. Caspase-3-like protease activity was detected at 24 h with a high concentration. Moreover, these changes were accompanied by cleavage of poly ADP ribose polymerase (PARP). Changes of the mRNA levels of most apoptosis-regulating genes were not prominent at both concentrations, except for the rapid induction of c-IAP-2/HIAP-1 and the down-regulation of Bcl-X(L) by 100 microM etoposide. The downregulation of Bcl-X(L) protein occurred from 6 h, while Bax protein conversely showed a slight increase from 6 h. Taken together, the present findings show that the dose-dependent apoptotic effect of etoposide is based on a change in the balance between Bcl-X(L) and Bax, which precedes the activation of caspase-3.

Function for p300 and not CBP in the apoptotic response to DNA damage

The cellular response to ionizing radiation (IR) includes the induction of apoptosis. The p300/CBP proteins possess histone acetyltransferase activity and function as transcriptional coactivators of p53. We have prepared cells deficient in p300 or CBP to define the roles of these proteins in the cellular response to DNA damage. The present results demonstrate that p300, but not CBP, contributes to IR sensitivity of cells. The results also demonstrate that IR-induced apoptosis is impaired in the p300-, but not CBP-, deficient cells. These findings indicate that p300 functions in the apoptotic response to DNA damage.

Role for caspase-mediated cleavage of Rad51 in induction of apoptosis by DNA damage

We report here that the Rad51 recombinase is cleaved in mammalian cells during the induction of apoptosis by ionizing radiation (IR) exposure. The results demonstrate that IR induces Rad51 cleavage by a caspase-dependent mechanism. Further support for involvement of caspases is provided by the finding that IR-induced proteolysis of Rad51 is inhibited by Ac-DEVD-CHO. In vitro studies show that Rad51 is cleaved by caspase 3 at a DVLD/N site. Stable expression of a Rad51 mutant in which the aspartic acid residues were mutated to alanines (AVLA/N) confirmed that the DVLD/N site is responsible for the cleavage of Rad51 in IR-induced apoptosis. The functional significance of Rad51 proteolysis is supported by the finding that, unlike intact Rad51, the N- and C-terminal cleavage products fail to exhibit recombinase activity. In cells, overexpression of the Rad51(D-A) mutant had no effect on activation of caspase 3 but did abrogate in part the apoptotic response to IR exposure. We conclude that proteolytic inactivation of Rad51 by a caspase-mediated mechanism contributes to the cell death response induced by DNA damage.

Role for p300 in stabilization of p53 in the response to DNA damage

The nuclear p300/CBP proteins function as coactivators of gene transcription. Here, using cells deficient in p300 or CBP, we show that p300, and not CBP, is essential for ionizing radiation-induced accumulation of the p53 tumor suppressor and thereby p53-mediated growth arrest. The results demonstrate that deficiency of p300 results in increased degradation of p53. Our findings suggest that p300 contributes to the stabilization and transactivation function of p53 in the cellular response to DNA damage.

Inhibition of influenza virus RNA polymerase by 5'-capped short RNA fragments

We have demonstrated that 5'-capped short RNA fragments inhibit the expression of chloramphenicol acetyltransferase (CAT) in the murine 76 cell line, derived which expresses the genes for the RNA polymerases (PB1, PB2, and PA) and the nucleoprotein (NP) of influenza virus in response to treatment with dexamethasone. We have synthesized 5'-capped short RNA fragments (8-13 ntds long) with a 5'-capped structure (m7GpppGm) using T7 RNA polymerase. The 5'-capped short RNA fragments (8-13 ntds long) were encapsulated in liposomes and were tested for their inhibitory effect by a CAT-ELISA assay using the clone 76 cells. The RNA fragments that were 9-12 ntds long showed inhibitory effects. In particular, the 9 ntds long RNA fragment, was highly inhibitory. On the other hand, the inhibitory effect of the 13 ntds long RNA fragment was considerably decreased in comparison with the other short RNA fragments. The minimal RNA chain length required for priming activity was found to be 12 ntds long. Furthermore, the 5'-capped RNA fragments exhibited higher inhibitory activities than the antisense phosphorothioate oligonucleotide (PB2-AUG-as, 20 ntds long) complementary to the site of the PB2-AUG initiation codon. Liposome encapsulation protected the RNA fragments in serum-containing medium and substantially improved their cellular accumulation.

Activation of protein kinase C delta by the c-Abl tyrosine kinase in response to ionizing radiation

The c-Abl protein tyrosine kinase is activated by ionizing radiation (IR) and certain other DNA-damaging agents. The present studies demonstrate that c-Abl associates constitutively with protein kinase C delta (PKCdelta). The results show that the SH3 domain of c-Abl interacts directly with PKCdelta. c-Abl phosphorylates and activates PKCdelta in vitro. We also show that IR treatment of cells is associated with c-Abl-dependent phosphorylation of PKCdelta and translocation of PKCdelta to the nucleus. These findings support a functional interaction between c-Abl and PKCdelta in the cellular response to genotoxic stress.

Surrogate thrombopoietin

The extracellular domain of human c-Mpl, the receptor for thrombopoietin (TPO), was expressed as a chimeric protein with the interleukin-2 receptor alpha chain on the surface of murine B cell-line B300-19. BALB/c mice were immunized with cells expressing the chimeric protein. The IgG purified from the resulting immune serum immunoprecipitated human c-Mpl. The immune IgG supported proliferation of both stable transfectant Ba/F3 cells expressing whole c-Mpl molecules (c-Mpl-Ba/F3 No. 9) and UT7/TPO cells bearing naturally occurring c-Mpl, whereas it did not support the growth of the untransfected parental Ba/F3 cells. Cell growth was induced using 3 to 100 microg/ml of immune IgG in a dose-dependent manner, but this induction was decreased at doses higher than 100 microg/ml. Non-immune IgG did not affect cell growth of c-Mpl-Ba/F3 No. 9 cells. Although the Fab fragment of immune IgG also immunoprecipitated c-Mpl, it did not support cell growth at concentrations as high as 180 microg/ml, implying that the bivalent binding of receptors by antibodies is essential for cell proliferation. These results suggest that antibodies against human c-Mpl stimulate the proliferation and differentiation of megakaryocytes by their bivalent binding to receptors like TPO.

Specific inhibition of influenza virus RNA polymerase and nucleoprotein gene expression by circular dumbbell RNA/DNA chimeric oligonucleotides containing antisense phosphodiester oligonucleotides

We have designed a new class of oligonucleotides, 'dumbbell RNA/DNA chimeric oligonucleotides', consisting of a sense RNA sequence and its complementary antisense DNA sequence, with two hairpin loop structures. The reaction of the nicked (NDRDON) and circular (CDRDON) dumbbell RNA/ DNA chimeric oligonucleotides with RNase H gave the corresponding antisense phosphodiester oligodeoxynucleotide together with the sense RNA cleavage products. The liberated antisense phosphodiester oligodeoxynucleotide was bound to the target RNA, which gave RNA cleavage products by treatment with RNase H. The circular dumbbell RNA/DNA chimeric oligonucleotide showed more nuclease resistance than the linear antisense phosphodiester oligonucleotide (anti-ODN) and the nicked dumbbell RNA/DNA chimeric oligonucleotide. The CDRDON with four target sites (influenza virus A RNA polymerases (PB1, PB2, PA) and nucleoprotein (NP)) was synthesized and tested for inhibitory effects by a CAT-ELISA assay using the clone 76 cell line. The circular dumbbell DNA/ RNA chimeric oligonucleotide (CDRDON-PB2-as) containing an AUG initiation codon sequence as the target of PB2 showed highly inhibitory effects.

Regulation of Rad51 function by c-Abl in response to DNA damage

The Rad51 protein, a homolog of bacterial RecA, functions in DNA double-strand break repair and genetic recombination. Whereas Rad51 catalyzes ATP-dependent pairing and strand exchange between homologous DNA molecules, regulation of this function is unknown. The c-Abl tyrosine kinase is activated by ionizing radiation and certain other DNA-damaging agents. Here we demonstrate that c-Abl interacts constitutively with Rad51. We show that c-Abl phosphorylates Rad51 on Tyr-54 in vitro. The results also show that treatment of cells with ionizing radiation induces c-Abl-dependent phosphorylation of Rad51. Phosphorylation of Rad51 by c-Abl inhibits the binding of Rad51 to DNA and the function of Rad51 in ATP-dependent DNA strand exchange reactions. These findings represent the first demonstration that Rad51 is regulated by phosphorylation and support a functional role for c-Abl in regulating Rad51-dependent recombination in the response to DNA damage.

3-(13-Hydroxytridecyl)-1-[13-(3-pyridyl)tridecyl]pyridinium chloride (YM-53792), a novel inhibitor of NF-AT activation

A compound, YM-53792, was identified as an inhibitor of interleukin-2 (IL-2) gene promoter activity, using a Jurkat cell-based reporter system in which the luciferase gene is regulated by the IL-2 gene promoter. Production of IL-2, interleukin-4 (IL-4) and interleukin-5 (IL-5) from human peripheral blood mononuclear cells was suppressed by YM-53792 in a dose-dependent fashion. Since expression of these cytokine genes is known to be regulated by NF-AT, we examined whether the promoter activity created by multimerization of NF-AT elements was inhibited with YM-53792. YM-53792 inhibited this promoter activity, but not AP-1- and NF-kappaB-driven promoter activities nor SV40 enhancer/promoter activity. In addition, electrophoretic mobility shift assays did not detect NF-AT/DNA complexes when nuclear extract prepared from YM-53792-treated, PMA/A23187-stimulated Jurkat cells was used, whereas AP-1/DNA complexes were observed. These results suggest that YM-53792 specifically inhibits the activation of NF-AT.

Pro-apoptotic effect of the c-Abl tyrosine kinase in the cellular response to 1-beta-D-arabinofuranosylcytosine

Treatment of cells with the antimetabolite 1-beta-D-arabinofuranosylcytosine (ara-C) and other genotoxic agents is associated with activation of the c-Abl protein tyrosine kinase. The functional role of c-Abl in the response to DNA damage, however, remains unclear. The present studies demonstrate that cells expressing a dominant negative, kinase-inactive c-Abl (K-R) are resistant to killing by ara-C. The expression of c-Abl (K-R) blocked ara-C-induced apoptosis by a mechanism that is at least in part independent of the p53 tumor suppressor. Cells null for c-Abl also exhibited resistance to induction of apoptosis. These findings provide support for a pro-apoptotic function of c-Abl in the response to certain genotoxic drugs.

Inhibition of phosphatidylinositol 3-kinase by c-Abl in the genotoxic stress response

Activation of phosphatidylinositol (PI) 3-kinase by growth factors results in phosphorylation of phosphatidylinositol lipids at the D3 position. Although PI 3-kinase is essential to cell survival, little is known about mechanisms that negatively regulate this activity. Here we show that the c-Abl tyrosine kinase interacts directly with the p85 subunit of PI 3-kinase. Activation of c-Abl by ionizing radiation exposure is associated with c-Abl-dependent phosphorylation of PI 3-kinase. We also show that phosphorylation of p85 by c-Abl inhibits PI 3-kinase activity in vitro and in irradiated cells. These findings indicate that c-Abl negatively regulates PI 3-kinase in the stress response to DNA damage.

Role for E2F in DNA damage-induced entry of cells into S phase

Mammalian cells respond to ionizing radiation (IR) with transient cell cycle arrest and induction of apoptosis. Here we show that IR increases the expression of the E2F-1 transcription factor and the entry of cells into S phase. E2F-1 transactivation function is inhibited by cyclin A-kinase to ensure orderly progression through S phase. However, in contrast to proliferating cells, IR treatment results in down-regulation of cyclin A-kinase. Expression of a dominant negative form of the E2F heterodimeric partner DP-1 confirmed the involvement of E2F in IR-induced S-phase entry. These findings also support opposing signals involving the induction of E2F and the down-regulation of cyclin A-kinase in the IR response.

Specific inhibition of influenza virus RNA polymerase and nucleoprotein genes expression by liposomally endocapsulated antisense phosphorothioate oligonucleotides: penetration and localization of oligonucleotides in clone 76 cells

Liposomally encapsulated phosphorothioate oligonucleotides with four target sites (PB1, PB2, PA, and NP) were synthesized and tested for inhibitory effects by a CAT-ELISA assay using the clone 76 cell line. The liposomally encapsulated phosphorothioate oligonucleotides (S-ODNs) complementary to the sites of the PB2-AUG and PA-AUG initiation codons showed highly inhibitory effects. Displacement of the target AUG initiation codon sequence to the 3'-end, 5'-end, and/or center sites on the antisense phosphorothioate oligonucleotides was studied with regard to the inhibition of influenza virus RNA polymerases and NP. The antisense phosphorothioate oligonucleotide containing the AUG initiation codon at the center site of the oligonucleotide had the highest inhibitory effects. The liposomally encapsulated phosphorothioate oligonucleotides exhibited higher inhibitory activity than the free oligonucleotides. Observation of clone 76 cells treated with the endocapsulated antisense phosphodiester oligonucleotide, FITC-ODNs-PB2-T3, by a confocal laser scanning microscope, revealed diffuse fluorescence, apparently within the cytoplasm. Interestingly, the endocapsulated antisense phosphorothioate oligonucleotide, FITC-S-ODNs-PB2-T3 accumulated in the nuclear region of clone 76 cells. However, weak fluorescence was observed in the endosomes and in the cytoplasms of the clone 76 cells treated with the free antisense phosphorothioate oligonucleotides.

Herbimycin A down-regulates messages of cyclin D1 and c-myc during erythroid differentiation of K562 cells

The ansamycin antibiotic, herbimycin A, is a potent tyrosine kinase inhibitor, and induces the erythroid differentiation of bcr-abl-possessing K562 cells. The growth of K562 cells was cytostatically reduced to less than 50% of the control level at 48 h by 0.5 microgram/ml of herbimycin A treatment. A total of 12% and 53% of the treated cells were benzidine-positive at 24 h and 48 h, respectively. The percentage of cells in the S phase decreased rapidly from 60% to 15% after 12 h of treatment. The reduction of S phase cells persisted until 24 h, whereas the G1 population conversely increased. Then underphosphorylated retinoblastoma gene product increased from 6 h to 24 h, but returned to baseline at 48 h. Most cell cycle controlling genes were unchanged by herbimycin A treatment. However, both cyclin D1 and c-myc were prominently down-regulated in the early phase of treatment, corresponding to the decline of the S phase population. Cyclin D1 was initially down-regulated to an undetectable level at 6 h, although its expression recovered gradually from 12 h and returned to baseline at 24 h. c-myc was also down-regulated from 1 h to 6 h. These data suggest that signals originating from bcr-abl kinase are at least partly transduced through both c-myc and cyclin D1, and that herbimycin A-induced erythroid differentiation occurs during or after the cessation of growth due to interference with these signals.

Laparoscopic complications in markedly obese urologic patients (a multi-institutional review)

OBJECTIVES

Significant obesity is considered to be a relative contraindication to laparoscopic surgery. This study reviews the complications encountered in massively obese patients undergoing urologic laparoscopic surgery.

METHODS

Body mass index (BMI) was used as an objective index to indicate massive obesity. Eleven institutions compiled retrospective data on 125 patients having a BMI greater than 30. Procedures performed included 76 pelvic lymph node dissections, 14 nephrectomies, 7 bladder neck suspensions, and 28 miscellaneous procedures.

RESULTS

For the group as a whole, the mean BMI was 35.1 (range 30.1 to 57.2). Mean operative time was 202 minutes (range 60 to 480). Conversion to open surgery occurred in 15 of the 125 patients (12%). Complication rates (minor and major) were 22% (27 occurrences in 125 patients) intraoperatively and 26% (33 occurrences in 125 patients) postoperatively. The major complications included 2 trocar injuries to abdominal wall vessels, 1 bladder injury, 3 peripheral nerve injuries, 1 dysrhythmia, 1 deep vein thrombosis, 1 wound seroma, 1 nephrocutaneous fistula, 1 incisional hernia, and 1 death.

CONCLUSIONS

In this review, complication rates for urologic laparoscopic surgery on massively obese patients were higher than in the general population undergoing laparoscopic surgery (0.3% to 21%).

The PB1 subunit alone can catalyze cRNA synthesis, and the PA subunit in addition to the PB1 subunit is required for viral RNA synthesis in replication of the influenza virus genome

We indicated that the PB1 and PA subunits of RNA polymerase and nucleoprotein (NP) can support replication of the influenza virus genome as well as transcription to yield uncapped poly(A)(+)-RNA (Y. Nakagawa, N. Kimura, T. Toyoda, K. Mizumoto, A. Ishihama, K. Oda, and S. Nakada, J. Virol. 69:728-733, 1995). To analyze the functions of the PB1 and PA subunits in replication and transcription, YP1N clones in which the PB1 and NP genes can be expressed in response to dexamethasone were established. cRNA was transcribed from model viral RNA (vRNA), but vRNA synthesis from model cRNA was not detected in YP1N clones. Furthermore, poly(A)(+)-RNA directed from model vRNA was synthesized in YP1N clones. These results indicated that PB1 and NP can support the syntheses of cRNA and poly(A)(+)-RNA and that the PA subunit, in addition to that of PB1 and to NP, is required for vRNA synthesis. In summary, the PB1 subunit is involved in the catalytic activities of nucleotide elongation, and the PA subunit may act as an allosteric modulator and cause a conformational change from a cRNA-to a vRNA-synthesizing form of the PB1 subunit.

Quality of life and anxiety before and after lung cancer chemotherapy: relationship to patient's personality

The purpose of the study was to assess the quality of life (QOL) and anxiety in 50 inpatients with primary lung cancer and examine the influence of their personalities on the QOL assessment. We used a psychological personality test to evaluate the patient's personality, then followed the course of QOL and anxiety before and after chemotherapy. To measure QOL, we used Holmes's QOL checklist, and the State-Trait Anxiety Inventory was adopted to estimate the patient's anxiety. Eighty courses of chemotherapy were administered, and QOL evaluations were performed 235 times. By using factor analysis, the somatic, social and psychological factors were extracted which confirmed the reliability and validity of the QOL checklist. The psychological QOL score showed a correlation with A (Adult) and AC (Adapted Child) of the five ego states in the Egogram. Therefore, it is important to survey the patients' personalities in order to grasp their QOL accurately.

Immunoassay and immunohistology studies of chromogranin A as a neuroendocrine marker in patients with carcinoma of the prostate

OBJECTIVES

Neuroendocrine differentiation in carcinoma of the prostate is characterized by the expression of neuroendocrine cell products such as chromogranin A (CgA). We studied serum levels and tissue staining for CgA in prostate cancer to assess their clinical value.

METHODS

In 82 patients with prostate cancer, serum specimens were obtained at diagnosis and studied by both CgA and prostate-specific antigen (PSA) immunoassays. In 43 additional patients with prostate cancer, paraffin-embedded tissue from core biopsies or transurethral resections and serum samples were studied, respectively, by immunohistology and immunoassay for CgA.

RESULTS

In serum samples from the 82 patients in whom CgA and PSA levels were measured, 26 of 82 (32%) had an elevated CgA (greater than 200 ng/mL), and 36 of 82 (44%) had an elevated PSA (greater than 4.0 ng/mL). Of the patients with Stage D2 cancer, 11 of 18 (61%) had an elevated CgA and 6 of 18 (33%) had an elevated PSA. Four of 5 patients with local recurrence had an elevated CgA, but only 1 patient had an elevated PSA. Of the 43 patients in whom serum and tissue CgA studies were performed, 12 (28%) had elevated serum CgA, and 15 of the 43 (35%) had CgA staining in their prostate tissue. Of the 14 of these patients with D2 disease (distant metastases), 9 (64%) had elevated serum levels of CgA and 6 (43%) had positive staining in their prostate tissue. Of the 9 patients with Stage D2 disease and elevated serum CgA, 6 had a normal serum PSA.

CONCLUSIONS

Our studies complement those of others and indicate that CgA has potential as a clinically useful serum and tumor marker for prostate cancer. Serum CgA measurements can identify some patients with advanced disease who do not have elevated serum PSA. However, further studies in larger groups of patients are needed to define the clinical value of CgA as a marker for prostate cancer.

Inhibition of influenza virus RNA polymerase and nucleoprotein genes expression by unmodified, phosphorothioated, and liposomally encapsulated oligonucleotides

We have demonstrated that antisense phosphodiester (ODNs) and phosphorothioate oligonucleotides (S-ODNs) inhibit CAT (chloramphenicol acetyltransferase) protein expression in the clone 76 cell line, which is a derivative of the murine C127 cell line. This cell line expresses the influenza virus RNA polymerase and nucleoprotein (NP) genes in response to treatment with dexamethasone. Phosphodiester, phosphorothioate, and liposomally encapsulated oligonucleotides with four target sites (PB1, PB2, PA, and NP) were synthesized and tested for inhibitory effects by a CAT-ELISA assay using the clone 76 cell line. The ODNs and S-ODNs complementary to the sites of the PB2-AUG and PA-AUG initiation codons showed highly inhibitory effects. On the other hand, the inhibitory effect of the S-ODNs targeted to PB1 was considerably decreased in comparison with the other three target sites. Liposome encapsulation afforded oligomer protection in serum-containing medium and substantially improved cellular accumulation. The liposomal encapsulated oligonucleotides exhibited higher inhibitory activity than the free oligonucleotides. The activities of the unmodified oligonucleotides are effectively enhanced by using the liposomal carrier.

Molecular dissection of influenza virus RNA polymerase: PB1 subunit alone is able to catalyze RNA synthesis

Influenza virus RNA polymerase with the subunit structure PB1-PB2-PA is involved in both transcription and replication of the RNA genome. Enzyme reconstitution experiments indicated that all three P proteins are required for RNA synthesis in vitro (Kobayashi, et al. Virus Res 22, 235-245, 1992). Nuclear extracts of HeLa cells infected with three kinds of the recombinant vaccinia virus, each carrying one of the three P protein cDNAs, exhibited the activity of complete replication, that is, vRNA-sense RNA-directed and cRNA-sense RNA-directed RNA synthesis in the absence of primers. The nuclear extract from cells singly infected with the virus carrying PB1 cDNA exhibited a significant level of model v-sense RNA-directed RNA synthesis activity. Thus we conclude that PB1 is the catalytic subunit of influenza virus RNA polymerase and that under certain conditions, PB1 alone is able to catalyze RNA synthesis in vitro.