In vitro inhibition of the growth of Gardnerella vaginalis by bacteriocins produced by strains of Pseudomonas aeruginosa

BACKGROUND: Pseudomonas aeruginosa with inhibitory capacity in vitro was studied on Gardnerella vaginalis strains. METHODS: Antimicrobial activity was demonstrated by inhibitory halos of bacterial growth on solid media by two methods: crossed streak and agar well diffusion. The inhibitory activity of this substance produced by P. aeruginosa was characterized as bacteriocin by: activity spectrum sensitivity proteolytic enzyme, chloroform, heat, pH, ultraviolet, irradiation effect and molecular weight. RESULTS: Four strains of P. aeruginosa producers of bacteriocins were chosen for this study and contacted with 40 strains of G. vaginalis. The producing strain D inhibited 70% of these G. vaginalis strains. The strains B and C inhibited 55% and 52.5%, respectively. The 3 strains presented a wide rank of action but the strain A had effect on a few strains of G. vaginalis. CONCLUSIONS: This work showed the inhibitory in vitro effect of bacteriocins of P. aeruginosa on strains of G. vaginalis. The results obtained suggest the probable topic application of bacteriocins as an alternative of conventional therapeutic on this infection biological control.     

Surface layer characterization after dual ion exchange of a leucite-reinforced dental porcelain

The dual ion-exchange technique has been shown to improve the strength of feldspathic dental porcelains by first replacing constituent alkali ions with smaller ions above the strain point, and then exchanging the smaller ions for larger ions at temperatures below the strain point. The strength increase is directly related to the thickness of the surface-exchanged layer. This study evaluated the thickness of the exchanged layer after dual ion exchange of a leucite-reinforced dental porcelain. Optec HSP porcelain disks were fabricated, submitted to a dual ion-exchange treatment, and indented at various loads before determining the biaxial flexure strength. The mean flexural strength for the ion-exchanged groups was significantly higher than for control groups, except when the depth of the median crack exceeded 138 microns. Wavelength Dispersive Spectrometry analyses on cross sections showed that the mean potassium amount in the glassy matrix was significantly lower (P < .001) for the treated specimens than for the controls. The mean thickness of the exchanged layer after dual ion exchange was estimated at 140 microns.     

Correlation between scanning laser ophthalmoscope microperimetry and anatomic abnormalities in patients with subfoveal neovascularization

PURPOSE: The purpose of the study is to identify the anatomic abnormalities associated with an absolute scotoma and the location and stability of fixation in patients with subfoveal neovascularization in age-related macular degeneration, presumed ocular histoplasmosis syndrome, and other disorders. METHODS: Scanning laser ophthalmoscope microperimetry was superimposed on color fundus photographs and fluorescein angiograms of 21 eyes with subfoveal neovascular membranes secondary to age-related macular degeneration (14 eyes) and presumed ocular histoplasmosis syndrome (7 eyes). The authors determined the location and the area occupied by the absolute scotoma and each of the following subretinal lesions: subretinal hemorrhage, neurosensory retinal detachment, retinal pigment epithelial (RPE) atrophy, RPE hyperplasia, atrophy of the choriocapillaris, hard exudates, and the subfoveal neovascular membrane. The area of absolute scotoma determined by scanning laser ophthalmoscope microperimetry was superimposed on the anatomic lesions. The authors calculated the relative risk ratio (RR) of an absolute scotoma occurring in regions corresponding to each anatomic abnormality, and determined the preferred location and stability of fixation in each eye. RESULTS: An absolute scotoma was present in areas of chorioretinal scar (RR = 107.61), RPE atrophy (RR = 9.97), subretinal hemorrhage (RR = 2.88), and the neovascular membrane (RR = 1.86). Fixation was stable in all patients with presumed ocular histoplasmosis syndrome but only 29% of patients with age-related macular degeneration. Fifty-five percent of patients with stable fixation fixated over an area of RPE hyperplasia. CONCLUSION: The relative risk of an absolute scotoma is highest over areas of chorioretinal scars, RPE atrophy, subretinal hemorrhage, and the neovascular membrane. Fixation is more stable in patients with subfoveal neovascularization from presumed ocular histoplasmosis syndrome than with age-related macular degeneration and frequently is present over an area of RPE hyperplasia.     

Proton magnetic resonance spectroscopy in primary blepharospasm

Single-volume proton magnetic resonance spectroscopy, localized to basal ganglia, was carried out in 10 patients with primary blepharospasm (PB) to assess the levels of N-acetyl aspartate (NAA), creatine-phosphocreatine, and choline-containing compounds. NAA was reduced significantly in patients compared with control subjects. This result suggests a striatal neuronal loss in PB.     

Correlation between the level of polyploidy and hypertrophy and degree of human atrial cardiomyocyte damage in certain congenital and acquired heart pathologies

Cardiomyocytes of right auricle of human heart were obtained during open heart surgery from 5 patients (aged from 3.6 to 6 years) with congenital heart diseases (atrial septal defect and tetralogy of Fallot, group I), from 6 patients (aged from 20 to 49 years) with mitral valve disease (group II) and from 5 patients (aged from 40 to 54 years) with ischemic heart disease (group III). Ploidy and area of cells were measured in isolated myocytes after the Feulgen staining. The degree of ultrastructural changes in myocytes was evaluated by means of scoring system (0 to 3). The hearts of group I patients contain 55 to 82% of cells with 2c DNA, 18 to 41% of cells with 4c DNA and 0 to 4% of cells with 8c DNA. In the hearts of group II patients the level of cell ploidy is high: the share of 2c-cells varies from 1 to 24%, that of 4c-cells--from 1 to 55%, that of 8c-cells--from 13 to 57%, that of 16c-cells--from 1 to 39%, the share of cells with 32c and more DNA--from 3 to 47%. The ploidy of myocytes of group III patients is not high: 2c-cells make 35 to 55%, 4c-cells--39 to 55%, 8c-cells--5 to 15%. The average cell areas in group II are 4 times larger than in group I, and twice as large as in group III. In most cases, cells of all ploidy levels are larger in patients with higher average cell sizes. In all patients with increased ploidy levels, cells grow in size, but the rate of this growth is lower than that of cell DNA content. In all patients the myocytes with different degrees of organelle damage are observed. In patients of groups I and III there is a direct correlation between the extent of myocyte ploidy and hypertrophy, on the one hand, and the degree of cell degeneration, on the other hand. In contrast, in group II patients an inverse relation between ploidy and extent of degenerative changes of cells is evident.     

Five inhibitory transmitters coexist in pelvic autonomic vasodilator neurons

Here we describe the localization of a potent vasodilator, calcitonin gene-related peptide (CGRP), in pelvic autonomic neurons containing four other inhibitory transmitters: vasoactive intestinal peptide (VIP), neuropeptide Y, nitric oxide and acetylcholine. These neurons mediate endothelium-independent vasodilation by releasing nitric oxide and one or more neuropeptides. Sixty percent of nerve cell bodies in guinea-pig paracervical ganglia with immunoreactivity (IR) for VIP, choline acetyltransferase (ChAT) and nitric oxide synthase (NOS), also contained IR for CGRP. Furthermore, many VIP-IR varicose nerve terminals at the adventitia-medial junction of the guinea-pig uterine artery contained IR for CGRP, ChAT and NOS. Both alpha-hCGRP and beta-hCGRP were potent dilators of the uterine artery (pD2 values 8.1, 8.3, respectively), but 1 microM hCGRP(8-37) did not antagonize dilations produced by either agonist. Dilations produced by alpha-hCGRP were unaffected by removal of the endothelium. Taken together with results of our previous studies, we propose that CGRP can contribute directly to autonomic vasodilation, possibly via CGRP2 receptors on smooth muscle cells, and that CGRP is the fifth inhibitory transmitter co-existing in pelvic vasodilator neurons.