The identification of Mycobacterium marinum genes differentially expressed in macrophage phagosomes using promoter fusions to green fluorescent protein

Mycobacterium marinum, like Mycobacterium tuberculosis, is a slow-growing pathogenic mycobacteria that is able to survive and replicate in macrophages. Using the promoter-capture vector pFPV27, we have constructed a library of 200-1000 bp fragments of M. marinum genomic DNA inserted upstream of a promoterless green fluorescent protein (GFP) gene. Only those plasmids that contain an active promoter will express GFP. Macrophages were infected with this fusion library, and phagosomes containing fluorescent bacteria were isolated. Promoter constructs that were more active intracellularly were isolated with a fluorescence-activated cell sorter, and inserts were partially sequenced. The promoter fusions expressed intracellularly exhibited homology to mycobacterial genes encoding, among others, membrane proteins and biosynthetic enzymes. Intracellular expression of GFP was 2-20 times that of the same clones grown in media. Several promoter constructs were transformed into Mycobacterium smegmatis, Mycobacterium bovis BCG and Mycobacterium tuberculosis. These constructs were positive for GFP expression in all mycobacterial strains tested. Sorting fluorescent bacteria in phagosomes circumvents the problem of isolating a single clone from macrophages, which may contain a mixed bacterial population. This method has enabled us to isolate 12 M. marinum clones that contain promoter constructs differentially expressed in the macrophage.     

Sinus histiocytosis with massive lymphadenopathy: presentation as giant granuloma annulare and detection of human herpesvirus 6

The authors report a case of laparoscopic resection of a bladder diverticulum performed at the same time as endoscopic treatment of its presumed cause. Dissection of the diverticulum, particularly its neck, and dissection of diverticula of the ureter and vas deferens are facilitated by magnification of the video image. This approach is only indicated in particular anatomical sites (posterior). The results of this technique must be compared with those of conventional treatments.     

Capillary zone electrophoresis separation of tryptophan and its metabolites, including quinolinic acid

Capillary zone electrophoresis with UV absorbance detection was used to separate tryptophan and ten of its metabolites. Run buffers of pH 4.0-10.0 were evaluated for their effect on resolution; a pH 9.6 buffer was found to give optimum separation of all components. Ethylenediaminetetraacetic acid (EDTA), which prevents complexation of some analytes with polyvalent cations, was included in the run buffer to insure good peak shape and reproducible mobilities. The resulting method was used to detect the presence of quinolinic acid in a urine sample.     

Chondroma of the petrous bone. A contribution to differential skull base tumor diagnosis

INTRODUCTION: Cartilaginous tumors of the mid-face and the skull base are rare. CASE REPORT: For the first time, a case report of a chondroma of the base of the ear in a 56-year-old woman is presented. In 1974 the patient developed a facial nerve paralysis while she was pregnant. Twenty-two years later the patient developed persistent headache and CT studies of the head were obtained, which showed an extensive tumorous lesion located at the base of the ear. A tumor was resected through an otoneurosurgical approach. The histological examination showed a chondroma. CONCLUSIONS: Even the rare diagnosis of a chondroma should be considered for a differential diagnosis of skull base tumors.     

Lotka and Zipf: Paper dragons with fuzzy tails

A linear correlation exists between the Lotka frequency and Zipf rank distribution functions. Relatively good correlation coefficients were found, but slope constants are not consistent with theory. They show that information distributions are not homogeneous and cannot be completely described by two parameter functions.     

A Three-Dimensional Finite-Difference Solution of the External Response of an Aircraft to a Complex Transient EM Environment: Part II-Comparison of Predictions and Measurements

Experimental charge and current measurements have recently been performed on an aircraft when it was exposed to the transient electromagnetic field of an electromagnetic-pulse (EMP) simulator. These new data allow a test of the predictive capabilities of the three-dimensional finite-difference method for realistic aircraft aircraftsimulator-test problems. Comparisons made between measurements and predictions show that the three-dimensional finite-difference technique provides reasonably accurate predictions for the induced currents and charges on a complex object responding to an applied transient electromagnetic field in the presence of a lossy earth.