Formation of Sindbis Virus Capsid Protein in Mammalian Cell-Free Extracts Programmed with Viral Messenger RNA

Extracts from Krebs II ascites cells and rabbit reticulocytes effectively synthesize viral proteins with Sindbis viral mRNA isolated from Sindbis-infected BHK cells. The major product is identical to Sindbis capsid protein on the basis of its electrophoretic mobility in sodium dodecyl sulfate-acrylamide gels and two-dimensional tryptic-peptide fingerprints. Various amounts of several additional discrete polypeptides are formed, depending on the components of the cell-free extracts. One of these polypeptides may be a prematurely terminated part of the viral-capsid protein, while another is larger in molecular weight than capsid protein but contains the capsid tryptic peptides. Several of the proteins formed in vitro also are detected in extracts of Sindbis-infected BHK cells labeled with [(35)S]methionine.The three proteins found in Sindbis virions are postulated to originate by proteolytic cleavage from a larger molecular weight polypeptide precursor that is translated from a polycistronic mRNA presumed to contain a single site for initiation of protein synthesis. The two in vitro systems appear to translate this polycistronic viral mRNA to yield specific viral capsid although no evidence was found for post-translational proteolysis. Other mechanisms for production of the capsid protein in the cell-free extracts are considered, and some of these may function in the viral-infected cell where unusually large amounts of viral capsid proteins are frequently detected.     

Diesel exhaust particulates affect cell signaling,mucin profiles,and apoptosis in trachea explants of Balb/C mice

Particulate matter from diesel exhaust (DEP) has toxic properties and can activate intracellular signaling pathways and induce metabolic changes. This study was conducted to evaluate the activation of extracellular signal‐regulated kinase (ERK) and c‐Jun N‐terminal kinase (JNK) and to analyze the mucin profile (acid (AB⁺), neutral (PAS⁺), or mixed (AB/PAS⁺) mucus) and vacuolization (V) of tracheal explants after treatment with 50 or 100 μg/mL DEP for 30 or 60 min. Western blot analyses showed small increases in ERK1/2 and JNK phosphorylation after 30 min of 100 μg/mL DEP treatment compared with the control. An increase in JNK phosphorylation was observed after 60 min of treatment with 50 μg/mL DEP compared with the control. We did not observe any change in the level of ERK1/2 phosphorylation after treatment with 50 μg/mL DEP. Other groups of tracheas were subjected to histological sectioning and stained with periodic acid‐Schiff (PAS) reagent and Alcian Blue (AB). The stained tissue sections were then subjected to morphometric analysis. The results obtained were compared using ANOVA. Treatment with 50 μg/mL DEP for 30 min or 60 min showed a significant increase (p < 0.001) in the amount of acid mucus, a reduction in neutral mucus, a significant reduction in mixed mucus, and greater vacuolization. Our results suggest that compounds found in DEPs are able to activate acid mucus production and enhance vacuolization and cell signaling pathways, which can lead to airway diseases. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1297–1308, 2015.     

Human chronic lymphocytic leukemia B cells can escape DNA damage-induced apoptosis through the nonhomologous end-joining DNA repair pathway

Nonhomologous end-joining (NHEJ) DNA factors maintain genomic stability through their DNA double-strand break (DSB) repair and telomere-associated activities. Unrepaired or misrepaired DSBs can lead to apoptotic death or chromosomal damage. The B cells of some B-chronic lymphocytic leukemia (B-CLL) patients are resistant to radiation-induced apoptosis in vitro. We show here that the novel DNA-dependent protein kinase (DNA-PK) inhibitor, NU7026 (2-(morpholin-4-yl)-benzo[h]chomen-4-one), and the phosphatidylinositol 3 (PI-3) kinase inhibitor, wortmannin, restored sensitivity to DNA damage-induced apoptosis of otherwise resistant cells. These resistant malignant B cells also escaped DSB-induced apoptosis following exposure to etoposide or neocarzinostatin. We found that at 15 minutes after irradiation, the levels of NHEJ (as measured by an in vitro DSB end-ligation assay) and DNA-PK catalytic subunit (DNA-PKcs) activity were, respectively, 2-fold and 4-fold higher in radio-resistant than in radio-sensitive B-CLL cells or Epstein-Barr virus (EBV)-transformed B cells. Ku70/Ku80 heterodimer DNA end-binding activity was also 2- to 3-fold higher in the resistant B-CLL cell subset compared with the sensitive B-CLL cell subset. Our results provide the first evidence that overactivating the NHEJ DNA repair pathway impairs DNA damage-induced apoptosis in malignant B cells and that this may contribute to their resistance to current chemotherapy.     

Aggressive primary gastrointestinal lymphomas: review of 91 patients treated with the LNH-84 regimen. A study of the Groupe d'Etude des Lymphomes Agressifs.

PURPOSE: Patients with aggressive primary gastrointestinal lymphoma undergoing the LNH-84 chemotherapy regimen were analyzed to determine the efficacy of intensive combination chemotherapy, the role of surgical debulking in patients treated with combination chemotherapy, and the toxicity associated with each of these modalities. PATIENTS AND METHODS: Ninety-one patients with primary gastrointestinal lymphoma who participated in the prospective multicenter LNH-84 combination chemotherapy trial (total number of patients in trial, 737) were analyzed. These 91 patients included 69 (76%) with diffuse large cell, nine (10%) with diffuse mixed, and seven (8%) with small noncleaved cell lymphoma. Two patients (2%) had stage IE, 54 patients (59%) stage IIE, and 35 patients (38%) stage IV disease; all patients with stage IE, 22 with stage IIE, and 18 with stage IV disease had bulky (greater than or equal to 10 cm) tumors. Specific sites of gastrointestinal involvement included stomach (47%), small bowel (38%), ileocecum (14%), colon (11%), and rectum (7%). Although surgical resection was attempted in 71 patients (78%), only 28 (31%) had complete tumor excision. All patients received three or four cycles of ACVB (defined in text) induction therapy followed by sequential consolidation as previously described. RESULTS: Responses to treatment in the 91 patients included 71 (78%) complete remissions, six (7%) partial remissions, five (5%) nonresponses, and nine (10%) deaths. With a median follow-up of 3 years, 10 patients (14%) have had relapses; predicted 4-year disease-free survival of complete responders is 85% and predicted 4-year survival of the entire group is 62%. In patients with stage IE or IIE disease, the complete response, survival, and disease-free survival rates were similar in those who underwent complete surgical resection or incomplete or no surgical resection prior to the administration of combination chemotherapy. Prognostic factors predicting for survival in the 91 patients with primary gastrointestinal lymphoma were similar to those in the 646 other patients treated with the LNH-84 regimen. CONCLUSIONS: Patients with aggressive gastrointestinal lymphoma treated with intensive chemotherapy have outcomes and prognostic factors comparable to those of patients with similar-stage aggressive lymphoma without primary gastrointestinal involvement. Surgical resection prior to the administration of combination chemotherapy did not influence the complete response rate, survival rate, or disease-free survival rate in this small group of patients.     

Post-exercise hypotension following different resistance exercise protocols

Sport Sciences for Health - To investigate the hemodynamic responses, especially HPE following different resistance exercises RE protocols in young adult subjects. Eighty-nine men...