Properties of a chicken lymphoblastoid cell line from Marek's disease tumor.

Properties of a chicken lymphoblastoid cell line (MSB-1) from a Marek's disease tumor were studied. The cell line grew well at 41 degrees C in medium RPMI-1640 supplemented with 10% bovine fetal serum and had a doubling time of 8-12 hours. Cells grown in stationary suspension culture did not attach to the vessel and had the morphology of typical lymphoblasts. At 37 degrees C, the cell line grew initially but ceased to divide after several subcultures. In the subcultures maintained for 48-72 hours, 1-2% of the cells produced Marek's disease virus (MDV)-specific intracellular and mambrane antigens and contained herpesvirus particles when examined by the electron microscope. Cocultivation of these cells with duck or chicken embryo fibroblast cultures resulted in transfer of infection and production of microplaques typical of MDV. Peripheral nerve lesions and lymphoid tumors characteristic of Marek's disease were caused by inoculation of susceptible chicks with MSB-1 cells or duck cells infected with strain BC-1 of MDV recovered from the MSB-1 cell line. No specific tumors were produced at the site of inoculation, and infection was readily transmitted to cagemates. Tumors were also produced in the skeletal muscles and seemed to be largely virus induced. MSB-1 cell line was free of C-type virus particles.     

Metformin improves skin flap survival through nitric oxide system

Background

Metformin has shown cardioprotective effects in experimental models of ischemia reperfusion, which is partially mediated through nitric oxide (NO) synthesis. We investigated the effects of metformin pretreatment in a rat model of random-pattern skin flap, and the probable role of NO system.

Materials and methods

In the first experiment, the rats received increasing doses of metformin (150, 200, and 300 mg/kg), 4 h before the procedure. Dorsal skin flaps with caudal pedicles were elevated at the midline and flap survival was measured 7 d after surgery. Pathologic review of the skin flap specimen was performed in a subset of animals. In the second experiment, for evaluation of the role of NO, an NO synthase inhibitor N-nitro-L-arginine methyl ester hydrochloride (L-NAME) was administered with and without the effective dose of metformin. In the next experiment, subtherapeutic dose of NO precursor, L-Arginine, was administered with and without subeffective dose of metformin.

Results

Metformin pretreatment at doses of 200 and 300 mg/kg significantly increased skin flap survival rate. However, administration of L-NAME abolished the protective effects of metformin. On the other hand, subtherapeutic dose of L-arginine augmented the effects of low-dose metformin and significantly increased skin flap survival. Skin flaps from those rats that received 300 mg/kg metformin pretreatment and those treated with subtherapeutic doses of L-arginine and metformin showed increased vasodilation compared with control group.

Conclusions

Metformin pretreatment can improve skin flap survival through an NO dependent pathway.     

Combined use of aortic dissection detection risk score and D-dimer in the diagnostic workup of suspected acute aortic dissection

Background

Acute aortic dissection (AD) represents a diagnostic conundrum. Validated algorithms are particularly needed to identify patients where AD could be ruled out without aortic imaging. We evaluated the diagnostic accuracy of a strategy combining the aortic dissection detection (ADD) risk score with D-dimer, a sensitive biomarker of AD.

Methods

Patients from two clinical centers with suspected AD were prospectively enrolled in a registry, from January 2008 to March 2013. The ADD risk score was calculated by retrospective blinded chart review. For D-dimer, a cutoff of 500 ng/ml was applied.

Results

AD was diagnosed in 233 of 1035 (22.5%) patients. The ADD risk score was 0 in 322 (31.1%), 1 in 508 (49.1%) and > 1 in 205 (19.8%) patients. The sensitivity and the failure rate of D-dimer were 100% and 0% in patients with ADD score 0, versus 97.5% (95% CI 91.4–99.6%) and 4.2% (95% CI 0.7–12.5%) in patients with ADD risk score > 1. In patients with ADD risk score ≤ 1, the sensitivity and the failure rate of D-dimer were 98.7% (95% CI 95.3–99.8%) and 0.8% (95% CI 0.1–2.6%). The diagnostic efficiency of D-dimer in patients with ADD risk score 0 and ≤ 1 was 8.9% (95% CI 7.2–10.7%) and 23.6% (95% CI 21.1–26.2%) respectively.

Conclusions

In a large cohort of patients with suspected AD, the presence of ADD risk score 0 or ≤ 1 combined with a negative D-dimer accurately and efficiently ruled out AD.     

Coronary artery disease is common in asymptomatic patients with signs of myocardial ischemia

BackgroundThe incidence of coronary artery disease (CAD) in totally asymptomatic patients with myocardial ischemia during stress testing is unknown.Methods54 patients with asymptomatic myocardial ischemia participated in the Swiss Interventional Study on Silent Ischemia type I (SWISSI I). Asymptomatic myocardial ischemia was verified by bicycle ergometry and stress imaging (echocardiography or scintigraphy). Findings from coronary angiographies in the course of the study constituted the main outcome.ResultsOf the 54 study participants, 29 patients (53.7%) underwent coronary angiography. CAD was found in 27 of 29 patients (93.1%). In those 27 patients with CAD, 9 patients (33.3%) suffered from single vessel disease, 9 patients (33.3%) from two vessel disease, and 9 patients (33.3%) from triple vessel disease. Two patients showed left main coronary artery stenosis.ConclusionThis study shows a high incidence of relevant CAD among totally asymptomatic patients with myocardial ischemia during stress testing. Previously healthy subjects with exercise-induced ST-segment depression at check-up examinations, even if asymptomatic, should have further diagnostic evaluation.     

Functional mitral stenosis: a rare complication of the Impella assist device

In patients with left ventricular output failure, the Impellaleft ventricular assist device increases total cardiac outputdespite a drop in output provided by the left ventricle itself.We present a patient with cardiogenic shock after myocardialinfarction in whom an Impella recover 2.5 was implanted. Correctplacement was ensured by fluoroscopy, pressure and current signalsdisplayed on the console of the system, and transthoracic echocardiography.On follow-up, the Impella device was dislocated with the shaftof the device lying on the anterior mitral leaflet causing afunctional mitral stenosis evident by an increased transmitraldiastolic flow gradient. After removing the device, the patients'haemodynamics improved within minutes. Other than a mild regurgitation,mitral valve was without pathological findings. Although infrequent,this case shows a possible complication of the Impella ventricularassist device and highlights the importance of periodical echocardiographicsurveillance, especially in patients who show a poor responseto therapy.     

The Glycoprotein B Genes of Marek's Disease Virus Serotypes 2 and 3: Identification and Expression by Recombinant Fowlpox Viruses

The nucleotide sequences of the glycoprotein B (gB) genes of Marek's disease virus (MDV) serotypes 2 and 3 were determined (gB-2 and gB-3, respectively). The genomic locations of these genes coincide with that of the gB gene of serotype 1 MDV (gB-1). Alignment with gB-1 (Ross et al., 1989, J. Gen. Virol. 70, 1789-1804) revealed predicted amino acid identities of 83 and 82% for gB-2 and gB-3, respectively. Excluding the predicted N-terminal signal sequences, 8 of 9 potential N-linked glycosylation sites and all 10 cysteine residues in gB-1 are conserved in both gB-2 and gB-3. In addition, the putative proteolytic cleavage sites for processing of precursors (gp100s) to gp60s and gp49s are conserved among the three gB homologs. Fowlpox virus (FPV) recombinants expressing either the gB-2 or the gB-3 gene were constructed. We detected expression of authentic gB-2 and gB-3 complexes in cells infected with these FPV recombinants. Digestion of immunoprecipitated gB-1 and gB-3 with endoglycosidases revealed that both gp60s are modified by the additions of O -glycans and complex carbohydrates after cleavage of gp100s, while gp100s and gp49s contain only high-mannose carbohydrates. We confirm that the size differences between gB-1 and gB-3 complexes are due to different carbohydrate modifications.