Protection afforded by intranasal immunization with the neuraminidase-lacking mutant of influenza A virus in a ferret model

Protective efficacy of the intranasal immunization with the neuraminidase (NA)-deficient mutant of the influenza A virus was investigated in ferrets. Despite the highly attenuated replication in vivo, the mutant completely protected the animals against the wild type virus challenge. When challenge was done with antigenic drift variants, significant reductions in the viral titers, inflammatory cell counts, and protein concentrations were observed in the nasal washes of the immunized animals. The genetically engineered NA-deficient mutant also protected animals against the challenge and induced humoral immune response against the foreign protein that replaced the NA. We conclude that the NA as antigen is dispensable in the live attenuated influenza virus vaccine and that the NA-lacking mutant can be used as a virus vector.     

Vitellogenesis in two spathebothriidean cestodes

Vitellogenesis in two spathebothriidean tapeworms, dixenous adult Cyathocephalus truncatus and monoxenous progenetic Diplocotyle olrikii, has been examined using transmission electron microscopy and cytochemical staining with periodic acid-thiosemicarbazide-silver proteinate for glycogen. Each vitelline follicle consists of vitellocytes at various stages of development and one irregularly shaped interstitial cell. Projections of the interstitial cell enclose the vitellocytes and extend as a cytoplasmic sheath on the follicular periphery. An outer thin fibrous layer (= extracellular lamina) covers the cytoplasmic sheath in C. truncatus, but lacks in D. olrikii. Maturing and mature vitellocytes contain vitelline material in the form of single small shell globules that gradually fuse and give rise to the large shell globule clusters. Morphology of shell globule clusters differs slightly in both species. In addition, single lamellar granules are present in the cytoplasm of vitellocytes of C. truncatus, but not in D. olrikii. Both electron lucent and electron dense lipid droplets are present in the vitellocytes of C. truncatus, whereas only electron dense lipids occur in D. olrikii. A single lipid droplet turns up occasionally in the nuclei of some of the vitellocytes of C. truncatus. The ultrastructural features of vitellogenesis in spathebothriideans resemble those reported previously in lower cestodes, especially in pseudophyllideans.     

Alternatives for measuring endogenous adrenocortical activity in asthmatics treated with inhaled corticosteroids

We compared a 12-hour, hourly integrated plasma cortisol profile in asthmatics treated with a corticosteroids with a variety of modified methods based on less frequent blood sampling. Excellent agreement with the reference was observed for sampling at 10 p.m. and 8 a.m. (correlation coefficient of 0.97; 95 % confidence interval 0.97, 0.98); at 9 p.m. and 7 a.m. (r = 0. 95; 0. 94, 0.96); at 11 p.m. and 7 a.m. (r = 0.94; 0.93, 0.95); every 2 hours (r = 0. 96; 0.96, 0.97); and every 3 hours (r = 0. 91, 0.91, 0.93). The two-sample alternatives (10 p.m/8 a.m. and 9 p.m/7 a.m.) are accurate, as well as more convenient, economical, and practical.     

Early diagnosis in hypertrophic cardiomyopathy--case report

Disproportionate heart muscle enlargement compared with little or no chamber enlargement are characteristic for hypertrophic cardiomyopathy (HCM). The clinical course of HCM is highly variable. Many patients are asymptomatic or mildly symptomatic and may be relatives of patients with known disease. Unfortunately, the first clinical manifestation of the disease may be sudden death, frequently occurring in children and young adults, often during or after physical exertion. We present 2 cases of HCM who emphasize the variability of clinical and ECG modifications and underline the importance of routine echocardiography in patients with atypical cardiac symptoms in order to identify the disease and prevent high risk for sudden death.     

Risk of sudden death in patients with chronic renal failure and hemodialysis

Cardiovascular mortality in uremic patients treated by hemodialysis overrates ten times cardiovascular mortality in general population. Approximatively 40% of patients on iterative hemodialysis die from cardiac diseases, half of cases by sudden death. Several risk factors for sudden death are well known: QTc interval prolongation, decrease of RR interval <750 msec, decrease of heart rate variability, presence of late ventricular potentials (LVP), presence of high risk ventricular extrasystoles, decrease of ejection fraction (EF) <40 %, presence of left ventricular hypertrophy. Our study evaluated the above-mentioned risk factors for sudden death in patients with chronic renal failure on hemodialysis. We studied 37 patients, 22 males and 15 females, with mean age of 42 years old, without diabetes, heart failure and arrhythmias, without myocardial ischemia on ECG, being on hemodialysis (HD) programme for minimum 1 year (HD parameters are: 4 h x 3/week, qB = 300 ml/min, buffer = bicarbonate, Ca dialysate = 1.75 mmol/l, K dialysate = 2.1 mmol/l, conductivity = 135 mS). The patients were evaluated by echocardiography, standard and Holter ECG. Statistics evaluation was performed in SPSS v.9.0. Program. The results proved that 80% of patients on HD have risk factors for sudden death, which are closely related with age and hyperhydration. Statistics proved that presence of high-risk arrhythmias is connected with heart rate variability and prolongation of QTc interval (favored by HD). 50% of our patients have 2 to 4 risk factors for sudden death, which increase incidence of sudden death in patients on HD.     

The relationship between levels of PCBs and pesticides in human hair and blood: preliminary result

Human hair as a biologic measure of exposure to persistent organic pollutants (POPs) has some advantages over the more commonly used blood and adipose tissue samples. However, one of the primary limitations is the difficulty in distinguishing between exogenous and endogenous contamination. In addition, there are currently no standardized methods for hair sample collection, washing, and chemical analysis. There is also very limited information describing the correlation between levels of organic contaminants in hair and other body compartments. To explore levels of POPs in blood and hair, samples from 10 volunteers were collected and analyzed for select organochlorine pesticides and 57 individual polychlorinated biphenyl (PCB) congeners. We demonstrated that the method for analyzing organic contaminants in human hair was reliable and reproducible. Washing hair with shampoo decreased levels of PCBs, pesticides, and lipids by 25-33% on average and up to 62% for low-chlorinated congeners. The percentage of lipids and the levels of organochlorines in hair were higher than in serum. We found strong correlation (r = 0.8) between p,p -DDE (dichlorodiphenyldichloroethylene) levels in hair and blood and moderate correlations for the more persistent PCB congeners, but no correlations or weak correlations for other organochlorines. The present study provides preliminary evidence on the utility of hair analysis for POPs; however, further larger studies are recommended before hair analysis can be successfully applied in epidemiologic studies on POPs.     

The interaction of p53 with replication protein A mediates suppression of homologous recombination

The tumor suppressor protein p53 is emerging as a central regulator of homologous recombination (HR) processes and DNA replication. P53 may downregulate HR through multiple mechanisms including the reported associations with the Rad51 and Rad54 recombinases, and the BLM and WRN helicases. Here, we investigated whether the interaction of p53 with human replication protein A (RPA) is necessary for the regulation of HR. By employing a plasmid-based HR assay in p53-null H1299 lung carcinoma cells, we studied the HR-suppressing properties of a panel of p53 mutants, which varied in their ability to interact with RPA. Both wild-type p53 and a transactivation-deficient p53 mutant (L22Q/W23S) suppressed HR and prevented RPA binding to ssDNA in vitro and in vivo. Conversely, p53 mutations that specifically disrupt the RPA-binding domain, while not compromising p53 transactivation function (D48H/D49H and W53S/F54S), did not affect HR. Suppression of HR was also not seen with missense mutations in the p53 core domain (His175 and His273), which retained the ability to interact with RPA, suggesting that the disruption of additional binding interactions of p53, for example, with Rad51 or recombination intermediates, also impacts on HR. We hypothesize that sequestration of RPA by p53 at the sites of recombination is one means by which p53 can inhibit HR processes. Our data support and extend the previously formulated 'dual model' of p53's role as guardian of the genome.     

In vitro characterization of A-315675, a highly potent inhibitor of A and B strain influenza virus neuraminidases and influenza virus replication

A-315675 is a novel, pyrrolidine-based compound that was evaluated in this study for its ability to inhibit A and B strain influenza virus neuraminidases in enzyme assays and influenza virus replication in cell culture. A-315675 effectively inhibited influenza A N1, N2, and N9 and B strain neuraminidases with inhibitor constant (K(i)) values between 0.024 and 0.31 nM. These values were comparable to or lower than the K(i) values measured for oseltamivir carboxylate (GS4071), zanamivir, and BCX-1812, except for the N1 enzymes that were found to be the most sensitive to BCX-1812. The time-dependent inhibition of neuraminidase catalytic activity observed with A-315675 is likely due to its very low rate of dissociation from the active site of neuraminidase. The half times for dissociation of A-315675 from B/Memphis/3/89 and A/Tokyo/3/67 (H3N2) influenza virus neuraminidases of 10 to 12 h are significantly slower than the half times measured for oseltamivir carboxylate (33 to 60 min). A-315675 inhibited the replication of several laboratory strains of influenza virus in cell culture with potencies that were comparable or superior to those for oseltamivir carboxylate and BCX-1812, except for the A/H1N1 viruses that were found to be two- to fourfold more susceptible to BCX-1812. A-315675 and oseltamivir carboxylate exhibited comparable potencies against a panel of A/H1N1 and A/H3N2 influenza virus clinical isolates, but A-315675 was found to be significantly more potent than oseltamivir carboxylate against the B strain isolates. The favorable in vitro results relative to other clinically effective agents provide strong support for the further investigation of A-315675 as a potential therapy for influenza virus infections.     

Association of lipoprotein(a) excess with early vein graft occlusions in middle-aged men undergoing coronary artery bypass surgery

OBJECTIVE: To assess the relationship of lipoprotein(a) to early vein graft occlusions in patients after coronary artery bypass grafting. METHODS: We studied 102 male patients (mean age 52.3 +/- 8.6 years) with chest pain occurrence during the first year (mean time 5.3 +/- 3.0 months) after surgical myocardial revascularization. Graft patency was examined by electron-beam computed tomography (n = 102) and quantitative coronary angiography (n = 31). RESULTS: Patients were divided into 2 groups according to graft patency data: 66 (65%) with occlusions and 36 (35%) without occlusions at follow-up. No significant differences were found between the groups concerning age, smoking, family history of coronary heart disease, previous myocardial infarction, hypertension, serum lipids, and apolipoprotein B. Lipoprotein(a) level was significantly higher in patients with occluded grafts with a median (95% confidence intervals) of 24 mg/dL (17-42 mg/dL) versus 12 mg/dL (6-24 mg/dL) in patients with patent grafts, P <.01. More patients with nonoccluded grafts were taking statins postoperatively: 42% versus 18% of patients with occluded grafts, P <.05. The sensitivity and specificity of electron-beam computed tomography in revealing vein graft occlusion was close to 100%. CONCLUSION: There is an association between high lipoprotein(a) level and vein graft occlusions in middle-aged men during the first year after coronary artery bypass grafting. Use of statins is associated with a lower rate of vein graft occlusion. Electron-beam tomography could be useful for assessing graft occlusions.