Differential expression and distribution of ezrin,radixin and moesin in human natural killer cells

Cytoskeleton plays a crucial role in natural killer cell function. In this study the expression and subcellular distribution of ezrin, radixin and moesin, a family of proteins that connect actin filaments to many membrane structures, were evaluated in human NK cells. The results showed that NK cells expressed all these proteins, while NK cell-deprived peripheral blood leukocytes and purified T lymphocytes did not express radixin. Only ezrin changed its distribution following IL-2 activation and all three ezrin, moesin and radixin were polarized on uropods of adherent natural killer cells. Ezrin and radixin co-localized with the perforin granules at the intimate sites of contact between NK and the target cells, while moesin remains uniformly distributed on the membrane of NK cells. Ezrin, radixin and perforin co-localization was undetected in non-lytic conjugates and inhibited by treatment with actin depolymerizing agents. These results suggest that ezrin and radixin may exert a role in NK activity, particularly in the trafficking of perforin granules to the NK/target cells contact site. Moreover, our data suggest that radixin may represent an additional biological marker of human NK cells and that this protein may hold a specific role in NK cell function.     

The carboxyl segment of the mumps virus V protein associates with Stat proteins in vitro via a tryptophan-rich motif

Viruses of the Paramyxovirinae, similar to other viruses, have evolved specific proteins that interdict IFN action as part of a general strategy to counteract host innate immunity. In many (but not all) cases, this interdiction is accompanied by a lowering of the intracellular levels of the STAT proteins. Among rubulaviruses, there is a notable variation in how they interfere with IFN action. Whereas SV41, SV5, and MuV all act by lowering Stat1, hPIV2 acts by lowering Stat2. Here, we show that the mumps and hPIV2 V proteins both form a complex with several Stat proteins in a mixed-extract assay. This suggests that the specific degradation of these Stat proteins is not determined by complex formation, but presumably at some later stage of the degradation pathway. V/Stat complex formation requires a specific carboxyl segment of V. However, a previously unrecognized trp-rich motif, rather than the Zn(++)-binding cys-cluster of this segment, appears to be required for V/Stat interaction. The C protein of Sendai (respiro-) virus, another P gene encoded protein, also forms a complex with Stat1, and prebinding of MuV V to Stat1 prevents the subsequent binding of SeV C. Our results suggest that rubulavirus V proteins may be related to both the C and the V proteins of respiroviruses.     

Perceptions of pediatric patients and guardians about prosthetic appliances

Forty patients that received prosthetic appliances as part of dental treatment were interviewed about satisfaction with the apparatus. The opinions of the guardians were also considered. The majority of children had complained about missing teeth, but even a greater percentage expressed satisfaction during wear of the prosthetic appliance. Among the guardians, only one of them expressed dissatisfaction with the appliance design. Rehabilitation plan should be discussed with children and guardians considering their perceptions and adequate indications for each case.     

High expressor paraoxonase PON1 gene promoter polymorphisms are associated with reduced risk of vascular disease in younger coronary patients

Human paraoxonase-1 is hypothesised to protect serum lipoproteins from oxidative stress. Decreased serum activity of paraoxonase-1 in animal models is associated with an increased risk of vascular disease and has been linked to the anti-oxidant capacity of the enzyme. Promoter polymorphisms of the human paraoxonase-1 gene strongly influence serum concentrations of the enzyme. The present study examined the hypothesis that promoter polymorphisms may be genetic risk factors for vascular disease in man. Genotypes arising from the promoter C(-907)G polymorphism were analysed in the ECTIM2 population. The global odds ratio for myocardial infarction, comparing the high expressor GG genotype to other genotypes, was 0.77 (0.61-0.97) (P=0.024). The association with the promoter genotype was more pronounced in the youngest age group (odds ratio 0.52 (0.31-0.87), P=0.012) and was progressively lost with age (respectively 50 years to <60 years, P=0.26; >60 years, P=0.45). There was no association between the promoter genotypes and serum lipids. The data are consistent with the high expressor promoter genotype being linked to reduced risk of myocardial infarction. The influence of the genotype may be compromised in older patients.     

Air trapping in heart-lung transplant recipients: variability of anatomic distribution and extent at sequential expiratory thin-section CT

PURPOSE: To evaluate the intrapatient reproducibility of the extent and anatomic distribution of air trapping at sequential expiratory thin-section computed tomographic (CT) examinations in heart-lung transplant recipients. MATERIALS AND METHODS: Nineteen heart-lung transplant recipients (eight with and 11 without bronchiolitis obliterans syndrome [BOS]) underwent three expiratory CT examinations within 1 hour. Residual volumes were measured at CT. Anatomic distribution and extent of air trapping were scored by two observers at two independent readings, and the reproducibility of observations was calculated for each feature. CT examination results were compared by using an analysis of variance that took into account interobserver and BOS and non-BOS effects. The Spearman rank correlation coefficient was calculated to test the association between variability of residual volumes and variability of the extent of air trapping. RESULTS: Residual volumes did not significantly differ between the three CT examinations (P =.556). Reproducibility values for findings of anatomic distribution of air trapping ranged from 84% to 95%, with a tendency toward improved reproducibility in patients without BOS. Mean reproducibility values for the extent of air trapping ranged from 97.1% to 97.7%, and no substantial difference in these values between patients with and those without BOS was observed. The Spearman rank coefficient for the correlation between variability of residual volumes and variability of extent of air trapping ranged from 0.382 to 0.568 (P =.105-.016). No interobserver effect was detected (P =.944). CONCLUSION: Anatomic distribution and extent are reproducible characteristics of air trapping. No substantial variability of air trapping occurs in functionally stable heart-lung transplant recipients.     

Comparison between low-dose and standard-dose multidetector CT in patients with suspected chronic sinusitis

OBJECTIVE: This study was designed to compare low- and standard-dose multidetector CT (MDCT) findings in patients with suspected chronic sinusitis. SUBJECTS AND METHODS. Fifty patients underwent MDCT at 10 and 150 effective mAs. The low-dose MDCT protocol delivered a radiation dose of 0.047 mSv in men and 0.051 mSv in women, whereas the standard-dose MDCT protocol delivered a radiation dose of 0.70 mSv in men and 0.76 mSv in women. Scans of the right and left sides of sinonasal cavities were reviewed by three radiologists, with each physician reviewing a scan twice over an interval of more than 2 weeks. The reviewers were asked to evaluate the scans for eight mucosal and two bone abnormalities. We calculated the number of discrepancies in observed abnormalities between pairs of reviewers, among all three reviewers, and between findings on scans acquired with the two radiation doses. RESULTS: The mean number of discrepancies in observed abnormalities on scans acquired with different radiation doses ranged from 0 to 5.2. Discrepancies between pairs of reviewers ranged from 1.0 to 12.8 for low-dose scans and from 1.0 to 13.0 for standard-dose scans. Discrepancies among all reviewers ranged from 1.0 to 10.3 for low-dose scans and from 1.0 to 8.7 for standard-dose scans. In analyzing cases of significant discrepancies in observations, we found greater variation between pairs of reviewers and among all three reviewers than between findings obtained with different dose levels. CONCLUSION: Dose reduction played a far less important role in discrepancies of detected abnormalities than did the human element of reviewer observation. Given this finding and the fact that low-dose MDCT delivers a radiation dose that is no higher than that delivered by a four-view radiographic examination, low-dose MDCT should be considered the imaging method of choice in patients with suspected chronic sinusitis.     

Noncanonical structural-functional organization of nucleoli in maturing oocytes of sea urchin Paracentrotus lividus

The dynamics of structural and functional organization of the nucleolus in the oocytes of P. lividus is described. At the late stages of oogenesis the nucleolus is composed of two main components, namely the peripheral zone (PZ) and the central zone (CZ) which are spatially separated. This two-component structure of the nucleolus is formed, at early stages of oogenesis, by stepwise segregation of the fibro-granular component and by its migration to the nucleolar periphery. Absence of morphologically distinct fibrillar centers and dense fibrillar component in nucleoli of both somatic cells and oocytes makes it possible to classify the nucleoli of P. lividus as 'noncanonical' type. Based on detailed morphological and cytochemical analysis the following molecular interpretation of nucleolar ultrastructure in oocytes of P. lividus is proposed: 1) the PZ, containing RNP-positive granules 15 nm in size, but lacking Ag-NOR proteins and BrU incorporation, can be considered a structural equivalent of the granular component of 'typical' nucleoli; 2) the CZ, which is the site of incorporation of RNA precursors, contains intranuclear DNA, RNP-fibers and accumulates Ag-NOR proteins, corresponds to both FC and DFC of 'typical' nucleoli; 3) nucleolar growth during oogenesis, leading to the 1000-fold increase of nucleolar volume, seems to be correlated with the stockpiling of nonfunctioning mature preribosomal particles which will be utilized during embryogenesis.     

Training with cognitive sequences improves syntactic comprehension in agrammatic aphasics

A major open question in cognitive neuroscience concerns the modularity of language: does human language rely, in part, on neural processes that are not language specific? Such reliance would predict that learning should transfer between non-linguistic and linguistic domains via this common neural basis. To test this prediction, we studied effects of non-linguistic cognitive sequence training on syntactic comprehension of six left-hemisphere damaged aphasic patients. Syntactic comprehension impairment was quantified before and after 10 weeks of training on a non-linguistic sequence processing task. This task used a transformational rule specifically corresponding to the transformation required for understanding a particular type of sentence referred to as relativised. Non-linguistic sequencing improved significantly with training (day effect: F(9,45)=3.7, <0.005). Moreover, a significant transfer of this improvement was observed for relativised, but not active nor passive sentences (pre-post x type interaction: F(2,10)=4.72, <0.05). The specificity of this transfer indicates that language relies partially on functional and neural processes that are not language specific.