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C Stauffer

Publications and source records attributed to C Stauffer.

10 recordsLinked to original sources
PubMed2000

Expression of a catalytically inactive H118Y mutant of nm23-H2 suppresses the metastatic potential of line IV Cl 1 human melanoma cells.

Nm23-H1 and nm23-H2 are putative metastasis suppressor genes that encode nucleoside diphosphate kinase (NDPK) A and B. NDPKs form oligomers distributed between soluble and particulate fractions of cells and therefore may exert their effects as either soluble or bound proteins. To determine whether metastasis-related functions of NDPKs are mediated by their catalytic activity in membrane bound or soluble complexes, we have stably transfected highly metastatic human melanoma Line IV Cl 1 cells with wild-type and catalytically inactive (H118Y) nm23-H1 and nm23-H2 genes and assayed their metastatic potential in nude mice. Transfection with wild-type nm23-H1 and nm23-H2 genes and catalytically inactive nm23-H1 did not significantly (all p > 0.10) alter the metastatic potential of Line IV Cl 1 cells while transfection with catalytically inactive nm23-H2 significantly (p < 0.01) reduced their metastatic potential. The lack of effect of transfection with wild-type and catalytically inactive nm23-H1 suggests that neither soluble nor membrane bound NDPK A affect the metastatic potential of Line IV Cl 1 cells. The metastasis suppressive effect of catalytically inactive NDPK B overexpression suggests that competition with bound complexes containing catalytically active NDPK B inhibits metastasis of Line IV Cl 1 cells. These results imply that bound NDPK B promotes metastasis and suggest that inhibition of its function or of its binding to critical sites may be a useful approach to limit the development of metastases in human melanoma.

Amino Acid Substitution↗
PubMed2000

Practical applications of genotypic surveys for forensic STR testing.

Legitimate genotype frequency estimation for multiallelic loci relies on component allele frequencies, as population surveys represent only a fraction of possible DNA profiles. Multilocus genotypes from two ethnic human populations, African American (n=195) and U.S. Caucasian (n=200), were compiled at 13 STR loci that are used worldwide in forensic investigation (D3S1358, vWA, FGA, D16S539, TH01, TPOX, CSF1PO, D8S1179, D21S11, D18S51, D5S818, D13S317, and D7S820). Sex-specific AmpFlSTR multiplexes provided stringent PCR-based STR typing specifically optimized for multicolor fluorescence detection. Heterozygosity at each STR locus ranged from 0.57 to 0.89 and encompassed from seven (TH01) to twenty-one (D21S11) alleles. Homozygosity tests, tests based on the distinct numbers of observed homozygous and heterozygous classes, log likelihood ratio tests, and exact tests assessed that the degree of divergence from theoretical Hardy-Weinberg proportions for all 13 STRs does not have practical consequence in genotype frequency estimation. Departures from linkage equilibrium, between loci, that imposed significance to forensic calculations were not indicated by observed variance of the number of heterozygous loci or Karlin interclass correlation tests. For forensic casework, reliable multilocus profile estimates may be obtained from the product of component genotype frequencies, each calculated through application of the Hardy-Weinberg equation to population database allele frequency estimates reported here. The average probability that two randomly selected, unrelated individuals possess an identical thirteen-locus DNA profile was one in 1.8x10(15) African Americans and one in 3.8x10(14) U.S. Caucasians.

Black or African American↗
PubMed1999

Mitochondrial DNA regions HVI and HVII population data.

Data from 1393 unrelated individuals have been compiled from eight population groups: African Americans, Africans (Sierra Leone), U.S. Caucasians, Austrians, French, Hispanics, Japanese, and Asian Americans. The majority of the mtDNA sequences were observed only once within each population group (i.e., ranging from a low of 60.3% (35/58) of the Asian American sequences to a high of 85.3% (93/109) of the French sequences). Genetic diversity ranged from 0.990 in the African sample to 0.998 in African Americans. Random match probability ranged from 2.50% in the Asian American sample to 0.52% in U.S. Caucasians. The average number of nucleotide differences between individuals in a database is greatest for the African American and African samples (14.1 and 13.1, respectively), and the least variable are the Caucasians (ranging from 7.2 to 8.4). Substitutions are the predominate polymorphism, and at least 92% of the substitutions are transitions. The most prevalent transversions are As substituted for Cs and Cs substituted for As. For most population groups these transversions occurred predominately in the HVI region; however, the African, African American, and Hispanic samples also demonstrated a large portion of their C to A and A to C transversions in the HVII region (at sites 186 and/or 189). Most insertions occur in the HVII region at sites 309.1 and 315.1, within a stretch of C's. Insertions of an additional C are common in all population groups. The sequence data were converted to SSO mtDNA types and compared with population data on Caucasians, Africans, Asians, Japanese, and Mexicans described by Stoneking et al. [M. Stoneking, D. Hedgecock, R.G. Higuchi, L. Vigilant, H.A. Erlich, Population variation of human mtDNA control region sequences detected by enzymatic amplification and sequence-specific oligonucleotide probes, Am. J. Hum. Genet. 48 (1991) 370-382] using an R x C contingency table test. Differences between major population groups (i.e., between African, Caucasian, and Asian) are quite evident, and similar ethnic population groups carried similar SSO polymorphism frequencies. There were only a few SSO types that showed significant differences between subpopulation groups. The SSO data alone can not be used to describe the population genetics with complete sequence data. However, the results of the SSO comparisons are similar to other analyses, and differences in sequence data in regions HVI and HVII are greater between major population groups than between subgroups.

DNA, Mitochondrial↗
PubMed1999

Building pyramids.

Explore the source record for details and available documents.

Age Distribution↗
PubMed1997

The phylogenetic relationships of seven European Ips (Scolytidae, Ipinae) species.

In Central Europe seven lps species are characterized by differences in morphology, structure of galleries, host specificity and aggressiveness. These species were analysed by allozyme markers and by sequencing 567 bp of the mitochondrial cytochrome oxidase I gene, in order to define their phylogenetic relationships. Orthotomicus erosus and Tomicus minor were taken as outgroup species. The data revealed high inter-specific and low intra-specific sequence divergence. Plotting the observed sequence divergence caused by transversions (Tv) and transitions (Ts) and the level of saturation for Ts and Tv of each codon position showed that the third positions were highly saturated by multiple substitutions. Maximum parsimony analysis produced two groups: (1) I. typographus, I. cembrae, I. amitinus, I. duplicatus and I. acuminatus; (2) I. mannsfeldi, I. sexdentatus and the two outgroups. In all analyses the species of the first cluster were put together and I. typographus and I. cembrae, and I. mannsfeldi and O. erosus emerged as sister pairs. The data do not support a common ancestor for the seven European lps species. The eight-spined bark beetles (except I. mannsfeldi) and I. acuminatus formed a monophyletic group. The close relationship of I. mannsfeldi and O. erosus supports the latter belonging to the genus lps as proposed by Wood (1982) and Escherich (1923). However, more genetic markers and more species of the genera Orthotomicus and Pityokteines have to be analysed to resolve the phylogenetic positions of I. sexdentatus I. mannsfeldi within the tribe lpinl.

Amylases↗
PubMed1984

Effect of ammonium on bacterial adherence to bladder transitional epithelium.

The virulence of urease-producing bacteria depends on the ability of urease to degrade urea into ammonia and thereby to alkalinize the urine. Infections caused by urease-producing organisms such as Proteus mirabilis are particularly difficult to manage clinically. We have shown that the layer of glycosaminoglycans at the bladder surface protects against infection by blocking the adherence of bacteria to the epithelium. To determine whether urease-producing urinary pathogens owe their virulence in part to an ability to inactivate the protective effect of the glycosaminoglycan layer, we tested the ability of ammonium chloride to alter bacterial adherence to the normal vesical mucosa. We used an in vivo adherence assay that we have described previously in rabbits. Control animals received sodium chloride adjusted to the same pH as the ammonium chloride. We found that 0.25 M ammonium chloride significantly increases bacterial adherence to normal vesical mucosa as compared to adherence in controls receiving 0.25 M sodium chloride (p less than 0.05). These data suggest that urease plays a hitherto undescribed role in bacterial virulence by altering the antiadherence activity of the glycosaminoglycan layer present at the transitional cell surface.

Adhesiveness↗
PubMed1980

Bladder-surface glycosaminoglycans: an efficient mechanism of environmental adaptation.

The transitional epithelium of the urinary bladder secretes and binds to its surface a glycosaminoglycan than inhibits the adherence of bacteria. Synthetic sulfonated glycosaminoglycans instilled intraluminally into bladders whose natural mucin layer has been removed are as effective as the natural mucin in preventing bacterial adherence. It also appears that adherence of calcium and protein is reduced in the presence of both the natural mucin layer and the synthetic sulfonated glycosaminoglycan sodium pentosanpolysulfate, suggesting that the antiadherence activity of both natural and synthetic surface glycosaminoglycans in the bladder extends to the molecular and ionic levels.

Adsorption↗
PubMed1980

Antibacterial activity of bladder surface mucin duplicated in the rabbit bladder by exogenous glycosaminoglycan (sodium pentosanpolysulfate).

Previous data from our laboratory suggest that the transitional epithelium of the urinary bladder secretes and binds to its surface a glycosaminoglycan. The presence of this substance at the bladder surface markedly reduces the ability of microorganisms to adhere to the mucosa. Furthermore, this glycosaminoglycan can be removed (with acid) and replaced by intravesical instillation of a synthetic sulfonated glycosaminoglycan (heparin), whose presence is as effective as that of the natural glycosaminoglycan in reducing adherence. We conducted the current study with a different sulfonated glycosaminoglycan to determine whether the antiadherence activity is generalized to heparin congeners and whether the antiadherence effect of heparin is independent of its known anticoagulant activity. In this study we examined the sulfonated glycosaminoglycan, sodium pentosanpolysulfate, which lacks significant anticoagulant activity, and found it to have a mechanism of antiadherence analogous to that of heparin and almost equally as active on a weight basis.

Animals↗
PubMed1979

In vitro adherence of radioactively labeled Escherichia coli in normal and cystitis-prone females.

Numerous investigators report data obtained using an in vitro quantitative assay for measuring bacterial adherence to epithelial cells. We found this assay to contain significant sources of error in the large variation in number of bacteria bound per cell and in the dependence on the investigator's visual counting of bacteria bound per cell. In the modified assay described here, we eliminated the need for visual counting of bacteria by incorporating the use of radioactively labeled Escherichia coli. This allowed quantitation of bacterial adherence to as many as 50,000 vaginal cells, whereas the visual counting system limits the determination to perhaps 50 cells. We feel that the use of radioactively labeled bacteria in place of the visual counting system increases the validity and sensitivity of this assay. Using the modified method, we found no statistically significant differences among values for adherence of E. coli type 04 to the vaginal cells of control and cystitis-prone women at either pH 6.4 or 4.0.

Adhesiveness↗