We report new associations between several TNF-alpha SNPs and susceptibility to cervical cancer that support the involvement of the TNF- alpha promoter region in development of cervical cancer.

A total of 41 Clostridium botulinum serotype E strains from different geographic regions, including Canada, Denmark, Finland, France, Greenland, Japan, and the United States, were compared by multilocus sequence typing (MLST), amplified fragment length polymorphism (AFLP) analysis, variable-number tandem-repeat (VNTR) analysis, and botulinum neurotoxin (bont) E gene sequencing. The strains, representing environmental, food-borne, and infant botulism samples collected from 1932 to 2007, were analyzed to compare serotype E strains from different geographic regions and types of botulism and to determine whether each of the strains contained the transposon-associated recombinase rarA, involved with bont/E insertion. MLST examination using 15 genes clustered the strains into several clades, with most members within a cluster sharing the same BoNT/E subtype (BoNT/E1, E2, E3, or E6). Sequencing of the bont/E gene identified two new variants (E7, E8) that showed regions of recombination with other E subtypes. The AFLP dendrogram clustered the 41 strains similarly to the MLST dendrogram. Strains that could not be differentiated by AFLP, MLST, or bont gene sequencing were further examined using three VNTR regions. Both intact and split rarA genes were amplified by PCR in each of the strains, and their identities were confirmed in 11 strains by amplicon sequencing. The findings suggest that (i) the C. botulinum serotype E strains result from the targeted insertion of the bont/E gene into genetically conserved bacteria and (ii) recombination events (not random mutations) within bont/E result in toxin variants or subtypes within strains.

No abstract

Retention kinetics for insoluble particles that deposit in the lung oftentimes resemble a multicomponent process during alveolar clearance, with each component appearing to follow simple first-order kinetics. Inasmuch as alveolar macrophages (AM) are thought to play an important role in particle removal from the lung, a study was undertaken to examine particle-AM relationships during the clearance of particles to obtain information on potential AM mechanisms that could provide the underlying bases for the lung retention kinetics of the particles. Adult, Fischer 344 rats were intratracheally instilled with 1.6 x 10(7) (approximately 86 micrograms) polystyrene microspheres (approximately 2 microns diam). On Days 7, 14, 57, 85, and 176 thereafter, subgroups were killed, their lungs were lavaged, recovered cells (greater than 95% AM) were counted, the frequency distribution of the particles among the AM was determined (e.g., zero, 1 to 2, 3 to 4 particles/AM), and the total numbers of particles lavaged were estimated. The lavaged lungs were solubilized, and unlavaged particles were also counted. The sums of the lavaged and unlavaged particles were used to estimate retained lung burdens at each postinstillation time. The lung retention data followed a pattern consistent with the sum of two negative exponential components, i.e., an earlier, more rapid component and a slower, longer term component. The rates at which the AM disappeared from a given particle category also were biphasic for AM that contained up to 14 microspheres. The rates of both the earlier and longer term components of such disappearance were found to increase with increasing AM burdens. Over an AM burden range of 1 to 10 microspheres, the proportion of AM that disappeared via rapid components also increased as the particle burden defining an AM category increased. At higher particle burdens, the proportion of AM that disappeared by an early component appeared to markedly diminish; an early component for AM disappearance was no longer resolvable for AM that contained greater than 15 microspheres. The net effect of these phenomena was that retained lung burdens over time became progressively contained in AM with lesser burdens of particles. The results from this study suggest that the rate(s) of translocation of particle-containing AM from the lung during lung clearance may be related to their individual particulate burdens. These findings, however, are also consistent with a gradual redistribution of particles among the lung's AM population over time concurrent with AM removal from the lung. Regardless, the biphasic nature of the lung retention data qualitatively was generally evident for particle-containing AM as well.

The sizes of the alveolar macrophage (AM) and interstitial macrophage (IM) populations in the lungs of adult Fischer-344 rats were determined during steady state. AM labeled with opsonized erythrocytes during an in situ phagocytic assay were lavaged from excised lungs. The lungs were then dispersed into single-cell suspensions with collagenase and mechanical agitation, and the remaining mononuclear phagocytes were identified following a second labeling step. The size of the AM population was 1.3 X 10(7) cells, or approximately equal to 3% of the total lung cell population. The AM were negative for cytoplasmic myeloperoxidase granules. The size of the IM population was 8 X 10(6) cells, or approximately equal to 2% of the total lung cell population. IM were also negative for myeloperoxidase and, like AM, demonstrated marked Fc gamma R-mediated phagocytic activity. The high cell yields (approximately equal to 4 X 10(8) cells/lung; viability, greater than 85%) and the percentages of type II cells (11%) and ciliated epithelial cells (less than 0.5%) indicated the enzymatic dispersion method resulted in a highly efficient and representative sampling of the lung parenchyma. The collagenase method used in this study to disperse the lung cells into single-cell suspensions, in conjunction with additional cell separation techniques, may be of potential use for isolating enriched populations of IM, as well as other lung cell types, for in vitro study.