Digoxin dosing in the aged: new pharmacokinetic system versus Jellife and Koup methods

To evaluate three methods for digoxin dose adjustment in aged patients, we determined the plasma digoxin levels that would be attained in 87 aged patients with doses adjusted to the kidney function by means of three separate procedures. Mean patient age was: 79.0 +/- 6.3 years; creatinine clearance (Clc): 0.70 +/- 0.23 mL/Kg of lean body weight and minute; digoxinemia/dose ratio (RCpD): 0.421 +/- 0.237 Kg/L. The dose that would attain a digoxinemia of 1.2 ng/mL, calculating the elimination constant (K) and the volume of distribution (V) as linear functions of the Clc, so that K ranges between 0.173 and 0.462 days-1 and V between 4 and 10 L/Kg of lean body weight when the Clc varies from 0 to 110 mL/minute, was 2947 ng/Kg of lean body weight, coefficient of variation (CV): 25.2%. The digoxinemia that patients would have with this D, taking into account the individual RCpD, was 1.1 ng/mL, CV: 38.0%; with figures between 0.8 y 2.0 ng/mL and above 2.0 ng/mL in the 81.6% and the 0.0% of the patients (95% confidence intervals (95% CI): 72.2% to 88.4 and 0.0% to 4.6%), respectively. The precision and the bias were 0.43 and -0.06 ng/mL (95% CI: 0.38 to 0.48 and -0.16 to 0.03 ng/mL), respectively, and with this method the digoxinemia was not associated with the Clc. We concluded that the described method would lead to good results if digoxin has not been prescribed in order to control the cardiac frequency in the setting of auricular fibrilation.     

Soft-tissue angiomatosis in adulthood: a case in the forearm showing a prominent myxoid adipose tissue component mimicking liposarcoma

Soft-tissue angiomatosis is a rare condition characterized by diffuse proliferation of benign vascular structures, accompanied by mature adipose tissue, which affect a large segment of the body in a contiguous fashion. Most patients present in childhood or adolescence. We report a case of large soft-tissue angiomatosis, located in the left forearm of a 65-year-old man, which showed extensive intramuscular and intermuscular infiltration, and embracement of the radius and the main vascular and neural bundles of the forearm. Due to the deep location, large size, ill-defined limits and non-homogeneous composition with areas suggestive of an adipose component in the radiological examination, the lesion raised the possibility clinically of a liposarcoma. The myxoid adipose tissue component of the lesion, a feature previously undescribed, and the predominance of small, capillary-sized vessels were considered concordant with the clinical diagnosis. This presentation is rare. The features of the lesion made complete surgical excision impossible and amputation of the extremity was considered the best treatment. The main differential diagnoses include infiltrating lipoma, myxolipoma, angiomyxolipoma, angiolipoma, intramuscular angioma, liposarcoma and low-grade myxofibrosarcoma. In conclusion, angiomatosis might simulate liposarcoma, particularly if the mass is large, heterogeneous, myxoid and appears later in life.     

C3 promotes clearance of Klebsiella pneumoniae by A549 epithelial cells

The airway epithelium represents a primary site for contact between microbes and their hosts. To assess the role of complement in this event, we studied the interaction between the A549 cell line derived from human alveolar epithelial cells and a major nosocomial pathogen, Klebsiella pneumoniae, in the presence of serum. In vitro, we found that C3 opsonization of poorly encapsulated K. pneumoniae clinical isolates and an unencapsulated mutant enhanced dramatically bacterial internalization by A549 epithelial cells compared to highly encapsulated clinical isolates. Local complement components (either present in the human bronchoalveolar lavage or produced by A549 epithelial cells) were sufficient to opsonize K. pneumoniae. CD46 could competitively inhibit the internalization of K. pneumoniae by the epithelial cells, suggesting that CD46 is a receptor for the binding of complement-opsonized K. pneumoniae to these cells. We observed that poorly encapsulated strains appeared into the alveolar epithelial cells in vivo but that (by contrast) they were completely avirulent in a mouse model of pneumonia compared to the highly encapsulated strains. Our results show that bacterial opsonization by complement enhances the internalization of the avirulent microorganisms by nonphagocytic cells such as A549 epithelial cells and allows an efficient innate defense.     

Haplotype analysis of the BRCA2 9254delATCAT recurrent mutation in breast/ovarian cancer families from Spain

A frame-shift 9254del5 mutation was independently identified in 12 families, eleven of them with Spanish ancestors, in a BRCA2 screening performed in 841 breast and/or ovarian cancer families and in 339 women with breast cancer diagnosed before the age of 40 at different centers in France and Spain. We sought to analyze in detail the haplotype and founder effects of the 9254del5 and to estimate the time of origin of the mutation. Eight polymorphic microsatellite markers and two BRCA2 polymorphisms were used for the haplotype analyses. The markers were located flanking the BRCA2 gene spanning a region of 6.1 cM. Our results suggest that these families shared a common ancestry with BRCA2 9254del5, which is a founder mutation originating in the Northeast Spanish, with an estimated age of 92 (95% CI 56-141) generations.     

Comparative evaluation of the new version of the INNO-LiPA Mycobacteria and genotype Mycobacterium assays for identification of Mycobacterium species from MB/BacT liquid cultures artificially inoculated with Mycobacterial strains

The performance of two DNA line probe assays, a new version of INNO-LiPA Mycobacteria (Innogenetics, Ghent, Belgium) and the GenoType Mycobacterium (Hain Diagnostika, Nehren, Germany), were evaluated for identification of mycobacterial species isolated from liquid cultures. Both tests are based on a PCR technique and designed for simultaneous identification of different mycobacterial species by reverse hybridization and line probe technology. The INNO-LiPA Mycobacteria v2 targeting the 16S-23S rRNA gene spacer region was developed for the simultaneous identification of 16 different mycobacterial species. The GenoType Mycobacterium, which targets the 23S rRNA gene, allows simultaneous identification of 13 mycobacterial species. Both tests were evaluated on 110 mycobacterial strains belonging to 22 different mycobacterial species (20 reference strains, 83 clinical strains, and 4 Mycobacterium kansasii strains isolated from tap water) that were previously inoculated into MB/BacT bottles. The sensitivity of both methods, defined as the number of positive results obtained with the Mycobacterium genus probe together with an interpretable result on the number of samples tested was 110 of 110 (100%) for INNO-LiPA and 102 of 110 (92.7%) for GenoType. For samples with interpretable results, INNO-LiPA was able to correctly identify 109 of 110 samples (99.1%), whereas the GenoType correctly identified 100 of 102 samples (98.0%). Both tests were easy to perform, rapid, and reliable when applied to mycobacterial identification directly from MB/BacT bottles.     

Development of high‐sensitive enzyme immunoassays for gliadin quantification using the streptavidin‐biotin amplification system

Optimization of three enzyme immunoassays of very high sensitivity using three antiprolamin monoclonal antibodies (MAbs) (13B4, 11C4 and 12A1) is presented here. These MAbs are specific for those prolamins toxic for coeliac patients, as determined by immunoblotting analysis. Biotinylated MAbs were used in two of the assays. In a competitive ELISA, the binding of each biotinylated MAb to a gliadin‐coated solid phase was inhibited by gliadin in the fluid phase. The best result was obtained using the biotinylated MAbl3B4 (detection limit: 20 ng ml^?1). With regard to capture ELISA, we tested the performance of the three MAbs. In this sandwich ELISA, the MAb used for antigenic capture was the same as that used as secondary biotinylated antibody. The MAbl2Al had the best performance (detection limit: 1 ng ml^?1). The use of biotin‐labelled gliadin in a quantitative immunoassay with a detection limit of 5 ng ml^?1 is also reported. This assay involves an antigenic capture using the MAbl2Al followed by a competition between biotinylated and non‐biotinylated gliadin. We have found the use of the streptavidin‐biotin interaction as signal amplification system to be very useful. This technique, as far as we know, has not been previously reported for gliadin quantification.     

NADPH oxidase-mediated oxidative stress: genetic studies of the p22(phox) gene in hypertension

Increased vascular production of reactive oxygen species, especially superoxide anion, significantly contributes to the oxidative stress associated with hypertension. An enhanced superoxide production causes an increased inactivation of nitric oxide that diminishes nitric oxide bioavailability, thus contributing to endothelial dysfunction and hypertrophy of vascular cells. It has been shown that NADPH oxidases play a major role as the most important sources of superoxide anion in phagocytic and vascular cells. Several experimental observations have described an enhanced superoxide generation as a result of NADPH oxidase activation in hypertension. Although these enzymes respond to stimuli such as vasoactive factors, growth factors, and cytokines, recent data suggest a significant role of the genetic background in the modulation of the expression of its different components. Several polymorphisms have been identified in the promoter and in the coding region of CYBA, the gene that encodes the essential subunit of the NADPH oxidase p22phox, some of which seem to influence significantly the activity of these enzymes in the context of cardiovascular diseases. Among CYBA polymorphisms, genetic investigations have provided a novel marker, the -930(A/G) polymorphism, which determines the genetic susceptibility of hypertensive patients to oxidative stress.     

NK cells mediate increase of phagocytic activity but not of proinflammatory cytokine (interleukin-6 [IL-6], tumor necrosis factor alpha,and IL-12) production elicited in splenic macrophages by tilorone treatment of mice during acute systemic candidiasis

The participation of NK cells in the activation of splenic macrophages or in resistance to systemic candidiasis is still a matter of debate. We had previously reported that there is a correlation between natural killer cell activation and resistance to systemic candidiasis. In those experiments we had used tilorone to boost NK cell activity in mice. Here we show a mechanism elicited by tilorone in splenic macrophages which could explain their effect on mouse survival during acute disseminated Candida albicans infection. The results demonstrate that tilorone treatment elicits, by a direct effect, the production of proinflammatory cytokines (interleukin-6 [IL-6], tumor necrosis factor alpha [TNF-alpha], and IL-12) by splenic macrophages. In addition, it increases the capacity of splenic macrophages to phagocytize C. albicans through activation of NK cells. We also demonstrate that the presence of NK cells is essential for maintaining a basal level of phagocytic activity, which characterizes splenic macrophages of na?ve control mice. The results demonstrate that it is possible to identify two phenotypically and functionally peculiar cell populations among splenic macrophages: (i). cells of the "stimulator/secretor phenotype," which show high levels of major histocompatibility complex (MHC) class II surface expression, are poorly phagocytic, and synthesize the proinflammatory cytokines IL-6, TNF-alpha, and IL-12, and (ii). cells of the "phagocytic phenotype," which express low levels of MHC class II molecules, are highly phagocytic, and do not secrete proinflammatory cytokines.