Comparisons of pulmonary and sinonasal lesions in patients with cystic fibrosis. Evaluation using computerized tomography

INTRODUCTION: Cystic fibrosis is a recessive genetic systemic exocrinopathy caused by a variety of mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR). The disease is characterized by alterations of the secretions, which become thickened and viscous. Both the paranasal sinuses and the lung parenchyma are involved in all cases. The aim of this study was to assess a correlation between the rhinosinusal and lung parenchyma changes in cystic fibrosis patients. MATERIAL AND METHODS: Eighteen patients (11 men and 7 women, age range: 8 to 22 years) were examined with chest HRCT and sinonasal low dose CT. Lung symptoms were found in all patients; 13 of them, also affected with rhinosinusal symptoms, had been examined with ENT and nasal endoscopy. The other 5 patients, without rhinosinusal symptoms and previously examined with ENT, were evaluated as control group. Chest CT was performed with the high-resolution technique, 2 mm slice thickness and 10 mm table feed. Rhinosinusal CT was performed with the low dose technique, acquiring contiguous 2-4 mm thickness coronal sections. The CT patterns were analyzed by two radiologists and scored as slight, medium and diffuse involvement of both districts. RESULTS: No statistically significant correlation between lung and sinonasal damage was found in our study. Parenchymal lung involvement appeared more severe than sinonasal involvement in 14/18 patients. The retention of secretions in the paranasal sinuses, even if limited, was demonstrated in all symptomatic and asymptomatic patients. CONCLUSIONS: The absence of correlation between pulmonary and sinonasal damage and more generally, the different severity of cystic fibrosis can be caused by different allele mutations of the cystic fibrosis transmembrane conductance regulator gene, the most frequent of which is Delta F-508.     

DMD-specific FISH probes are diagnostically useful in the detection of female carriers of DMD gene deletions

The challenge of Duchenne muscular dystrophy (DMD) carrier identification resides in the ability to identify the presence of a mutant gene over the background contributed by the normal allele. Current diagnosis of carrier status when a deletion has been identified in a proband is based on an analysis of a gene dosage. We present a diagnostic strategy that uses fluorescence in situ hybridization (FISH) to detect female carriers with major deletions in the dystrophin gene. We screened a human X-chromosome-derived genomic library with a full-length dystrophin cDNA and isolated 15 dystrophin-specific cosmids that contain DMD gene exons. Six cosmids were further tested as FISH probes in control individuals and subsequently applied on chromosomes from eight males with DMD and known deletions and on samples from three female carriers. As expected, X chromosomes in normal females displayed four signals, two for the DMD-specific probe and two for the X-chromosome centromeric probe. Hybridization on chromosomal spreads from carriers of deletions revealed only one signal from the DMD-specific probe and two from the control centromeric probe. Males carrying deletions showed no DMD-specific signal for the deleted exons tested. Our data indicate that FISH could represent an alternative method for the detection of female carriers with DMD gene deletions.     

Selective phosphorylation of adult tau isoforms in mature hippocampal neurons exposed to fibrillar A beta

How senile plaques and neurofibrillary tangles are linked represents a major gap in our understanding of the pathophysiology of Alzheimer's disease. We characterized a hippocampal neuronal culture system in which tau undergoes maturation in vivo; rat neurons maintained in culture for more than 3 weeks replicated the splicing and phosphorylation changes that tau undergoes upon maturation in situ. Using this model system, we induced an Alzheimer-like neuritic dystrophy following the application of fibrillar beta-amyloid. The dystrophy consisted of focal distortions and swellings within the neurites and an altered phosphorylation of the adult tau isoforms. Fibrillar beta-amyloid induced the concomitant activation of MAP kinase and GSK3 beta. The aberrant activation of several signaling pathways may lead to the abnormal phosphorylation of tau and neuritic degeneration.     

The inactivated plasmid inititator protein RepC/RepC* may have a regulatory role

During replication of the plasmid pT181, the initiator protein RepC is modified by the addition of an oligodeoxynucleotide, giving rise to a new form, RepC*. Here we show that during in vitro replication, RepC* is radioactively labeled, suggesting that the source of the RepC* oligodeoxynucleotide is the newly synthesized pT181 DNA. The RepC/RepC* heterodimer retains its ability to bind the pT181 double-strand origin and, therefore, it may act as a competitive inhibitor of the RepC homodimer during replication.     

Semi-Markov models with an application to power-plant reliabilityanalysis

Systems with, (1) a finite number of states, and (2) random holding times in each state, are often modeled using semi-Markov processes. For general holding-time distributions, closed formulas for transition probabilities and average availability are usually not available. Recursion procedures are derived to approximate these quantities for arbitrarily distributed holding-times; these recursion procedures are then used to fit the semi-Markov model with Weibull distributed holding-times to actual power-plant operating data. The results are compared to the more familiar Markov models; the semi-Markov model using Weibull holding-times fits the data remarkably well. In particular comparing the transition probabilities shows that the probability of the system being in the state of refitting converges more quickly to its limiting value as compared to convergence in the Markov model. This could be because the distribution of the holding-times in this state is rather unlike the exponential distribution. The more flexible semi-Markov model with Weibull holding-times describes more accurately the operating characteristics of power-plants, and produces a better fit to the actual operating data     

Source separation using a criterion based on second-orderstatistics

It is often assumed that blind separation of dynamically mixed sources cannot be done with second-order statistics. It is shown that separation of dynamically mixed sources indeed can be performed using second-order statistics only. A criterion based on second-order statistics for the purpose of separating crosswise mixtures is stated. The criterion is used in order to derive a gradient-based separation algorithm, as well as a Newton-type separation algorithm. The uniqueness of the solution representing the separation is also investigated. This reveals that (1) the channel system is parameter identifiable under weak conditions, and (2) if the sources have the same color, there exists at most two solutions. The local convergence behavior of the proposed algorithm is studied and reveals a sufficient condition for local convergence. Furthermore, the estimates of the channel system are shown to be consistent or to locally minimize the criterion     

Recovery of SDS-protein and DNA using commercial automated gel electrophoresis apparatus

Forty-seven children afflicted with acute leukemia were studied at the Tata Memorial Hospital Bombay to record the occurrence of oral manifestations prior to and during chemotherapy. Lymphadenopathy was the most frequent single finding suggestive of leukemia during head and neck examination. Gingival abnormalities, bleeding gums and oral mucosal pallor were the other findings on initial oral examination. Due to immunosuppression caused by the chemotherapy drugs oral mucosal ulcerations, uncontrolled herpes, candidiasis and pseudomoniasis were observed.