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Biomedical subjects

A Stapleton

Publications and source records attributed to A Stapleton.

At least 19 recordsLinked to original sources

Outcome of post-prostatectomy radiotherapy in one institution.

We present a retrospective study to evaluate the outcome of postoperative radiotherapy for biochemical or clinical recurrent prostate cancer. Twenty-six patients (median age 60 years) underwent radiotherapy after radical prostatectomy between January 1997 and January 2004. Seven patients received adjuvant radiotherapy and 19 received salvage radiotherapy. The median prostate-specific antigen at diagnosis was 8.6 (0.9-89) and most (23 patients) presented with T(3)N(0) disease. The median follow up was 19.5 months (5-84 months). All patients received a dose of 61.2 Gy at 1.8 Gy per fraction, 20 initially receiving 45 Gy to the lesser pelvis. The median dose to the bladder, rectum and left femoral head were 55.6, 57.5 and 33.8 Gy, respectively. All patients were managed radiotherapeutically by the first author. Twenty-four patients are alive. Two patients have died, one from oesophageal cancer and the second from metastatic prostate cancer. Two other patients also developed metastatic disease. Four asymptomatic patients with a rising prostate-specific antigen are under observation. None of the 26 patients has developed a local recurrence. Seven patients have developed grade 1 late bowel effects and three a grade 2 late effect. Eight patients suffer from grade 1 late genitourinary effects and two from grade 2 effects. One patient developed impotence, whereas 23 patients were rendered impotent postoperatively. There were no grade 3/4 late effects. Postoperative radiotherapy is well tolerated and provides effective local control.

Aged↗

Variation in frequency of the virulence-factor gene in Escherichia coli clones colonizing the stools and urinary tracts of healthy prepubertal girls.

To provide information on virulence expression of Escherichia coli in healthy hosts, stool, periurethral, and urine samples were collected weekly from healthy 3-6-year-old girls who lived in a small rural community. Dominant and nondominant clones were defined in stool specimens, and the expression of virulence factors was determined. We found that healthy girls commonly shared dominant clones. P adhesin, hemolysin, and type I adhesin were commonly found in clones in the stool and in clones in the urinary tract. In addition, expression of virulence factors, among both dominant and nondominant clones in the stool, changed from week to week. The presence of P adhesin was a marker for the persistence of a dominant clone in the stool and was associated with an increased likelihood that a nondominant clone would be detected in the urinary tract. Type I adhesin was ubiquitous among stool strains, with orientation of the fimbrial switch being both in the "off" position and in both the "on" and "off" positions. In summary, the intestinal flora of healthy girls is complex, with frequent changes in virulence expression.

Adhesins, Escherichia coli↗

Clonal relationships and extended virulence genotypes among Escherichia coli isolates from women with a first or recurrent episode of cystitis.

To identify bacterial predictors of recurrence and/or persistence in acute cystitis, extended virulence genotypes were compared with clonal background and epidemiologic status among 74 Escherichia coli urine isolates from women with first or recurrent episodes of urinary tract infection (UTI). Sequential isolates from patients with recurrent UTI were classified, using macrorestriction analysis, as having caused an isolated recurrence versus a single or multiple same-strain recurrences. papA, papG allele II, iha, and iutA predicted multiple same-strain recurrences, whereas nfaE and the absence of sfaS or fyuA predicted isolated recurrences. Phylogenetic group B2 accounted for 70% of isolates and for most of the putative virulence factors (VFs) studied. The meningitis-associated O18:K1:H7 clonal group comprised 18% of isolates, exhibited multiple VFs, and caused "once-only" recurrences less commonly than did other strains. These findings identify specific VFs and clonal groups against which preventive interventions might be beneficial and illustrate the importance of delineating pathogenetically relevant subgroups within the "recurrent cystitis" population.

Acute Disease↗

Effects of vaginal intercourse with and without a condom on vaginal flora and vaginal epithelium.

Effects of a single episode of intercourse on vaginal flora and epithelium were examined in subjects randomly assigned to groups that used no condom or lubricated nonspermicide condoms. Subjects were evaluated at visits before (1 month and 1-2 days) and after (8-12 h, 2-3 days, and 6-8 days) an index episode of sexual intercourse. The 22 subjects who used no condoms had significantly more Escherichia coli and a high concentration (> or =10(5) cfu/mL) of E. coli in the vagina (both, P<.001) and urine (all <10(5) cfu/mL; P=.004) at visit 3 than at visits 1 and 2. The 20 subjects who used condoms had a trend toward more vaginal E. coli (P=.06) and a significant increase in other enteric gram-negative rods (P=.001) after intercourse. Intercourse was not associated with gross, colposcopic, or histologic vaginal epithelial abnormalities.

Adult↗

Effects of oral contraceptive pill use on vaginal flora and vaginal epithelium.

The objective of this study was to examine the effect of oral contraceptive (OC) use on vaginal discharge, epithelium, and flora. Thirty women who planned to use OC for contraception were evaluated before and 2 months after the start of OC use. At both visits, genital symptoms and exposures were assessed by questionnaire; vaginal signs were assessed by speculum examination and colposcopy; vaginal microflora was evaluated by quantitative culture; and a vaginal biopsy was obtained for histopathologic evaluation. Variables were compared between the initial visit and after 2 months of OC use. It was found that OC use did not change the gross, colposcopic, or histologic appearance of the vaginal epithelium or characteristics of vaginal or cervical discharge. Vaginal flora essentially remained unchanged after 2 months of OC use, except that a small decrease occurred in the number of subjects with > or =10(5) colony forming units/mL of H(2)O(2) producing Lactobacillus from 16 at baseline to 9 (p = 0.04) and in the total number of subjects with Ureaplasma urealyticum from 17 at baseline to 10 of 29 (p = 0.04). The results indicate minimal effect of OC use on the vaginal epithelium and vaginal and cervical discharge, and a small effect on vaginal flora.

Adolescent↗

Expression of virulence factors among Escherichia coli isolated from the periurethra and urine of children with neurogenic bladder on intermittent catheterization.

BACKGROUND: Patients with neurogenic bladder caused by spinal cord injury or myelomeningocele empty their bladder several times a day by intermittent catheterization. Bacteriuria without symptoms of infection is frequently present in these patients. Occasionally a clone of Escherichia coli that has been carried for weeks without symptoms causes a symptomatic urinary tract infection. Virulence factors are commonly expressed among E. coli causing infection in patients with normal urinary tracts. However, it is unknown whether expression of virulence factors by an E. coli clone colonizing the neurogenic bladder increases the risk of subsequent infection. In this study we examined the prevalence of virulence factor expression among E. coli isolated from the periurethra and urine of patients with neurogenic bladder. METHODS: The prevalence of virulence factors was examined among E. coli isolated from the periurethra and urine in patients with neurogenic bladder who received intermittent catheterization and were followed for 6 months. Representative isolates from the 37 clonal types of E. coli detected in the periurethra and urine of children with neurogenic bladder were assessed for O antigen, hemolysin, aerobactin, serum resistance and type I and P-adhesin. RESULTS: All clones were serum-resistant and expressed type I adhesin, none expressed aerobactin and two expressed hemolysin. The presence of P-adhesin was not unique to clones associated with symptomatic infection. The presence of P-adhesin carried for weeks in a clone did not predict subsequent infection in the neurogenic bladder. CONCLUSION: Bacterial virulence factors did not predict infection of the neurogenic bladder.

Adolescent↗

Host factors in susceptibility to urinary tract infections.

In summary, a variety of intrinsic and acquired factors influence the risk of RUTI in otherwise normal women, including history of prior UTIs, the woman's genetic background, and exposures to spermicides, sexual activity and antibiotics. Further studies are directed towards understanding the interplay between these factors and their relative importance among various subpopulations of women with RUTI, such as otherwise healthy pre- and post-menopausal women.

Animals↗

Biochemical separations by continuous-bed chromatography.

Innovations in column-packing media for biomolecule purification have progressed from large spherical, porous polysaccharide beads to advanced polymeric supports. Continuous-bed technology is a radical new technology for chromatography based on the polymerization of advanced monomers and ionomers directly in the chromatographic column. The polymer chains form aggregates which coalesce into a dense, homogeneous network of interconnected nodules consisting of microparticles with an average diameter of 3000 A. The voids or channels between the nodules are large enough to permit a high hydrodynamic flow. Due to the high cross-linking of the polymer matrix, the surface of each nodule is nonporous yet the polymeric microparticles provide a very large surface area for high binding capacity. This paper will demonstrate the properties and advantages of using a continuous bed support for high resolution biomolecule separations at high flow-rates without sacrificing capacity.

Animals↗

papG alleles of Escherichia coli strains causing first-episode or recurrent acute cystitis in adult women.

The distribution of the three alleles of the P adhesin gene papG (classes I-III) was assessed among 74 Escherichia coli urine isolates from women with first-episode or recurrent cystitis, and papG genotype was compared with clinical origin, O serogroup, agglutination of Gal(alpha1-4)Gal-coated latex beads and human or sheep erythrocytes, and hemolysin production. The class-III-only papG genotype (27% of strains) predominated over the I + III (3%) and II-only (7%) genotypes, irrespective of clinical category. In contrast to the class II papG allele, the class III allele was significantly concentrated in serogroups O6 and O18. Agglutination phenotypes corresponded significantly but incompletely with papG genotype, whereas hemolysin production and papG positivity were tightly correlated. These findings suggest that in acute cystitis in adult women, the class III papG allele predominates, confers distinctive agglutination phenotypes, and is restricted to specific E. coli lineages.

Adhesins, Escherichia coli↗

Comparison of Escherichia coli strains recovered from human cystitis and pyelonephritis infections in transurethrally challenged mice.

Urinary tract infection, most frequently caused by Escherichia coli, is one of the most common bacterial infections in humans. A vast amount of literature regarding the mechanisms through which E. coli induces pyelonephritis has accumulated. Although cystitis accounts for 95% of visits to physicians for symptoms of urinary tract infections, few in vivo studies have investigated possible differences between E. coli recovered from patients with clinical symptoms of cystitis and that from patients with symptoms of pyelonephritis. Epidemiological studies indicate that cystitis-associated strains appear to differ from pyelonephritis-associated strains in elaboration of some putative virulence factors. With transurethrally challenged mice we studied possible differences using three each of the most virulent pyelonephritis and cystitis E. coli strains in our collection. The results indicate that cystitis strains colonize the bladder more rapidly than do pyelonephritis strains, while the rates of kidney colonization are similar. Cystitis strains colonize the bladder in higher numbers, induce more pronounced histologic changes in the bladder, and are more rapidly eliminated from the mouse urinary tract than pyelonephritis strains. These results provide evidence that cystitis strains differ from pyelonephritis strains in this model, that this model is useful for the study of the uropathogenicity of cystitis strains, and that it would be unwise to use pyelonephritis strains to study putative virulence factors important in the development of cystitis.

Animals↗

Prevention of urinary tract infection.

Recurrent UTI remains an exceedingly common clinical problem among women of all ages. Among otherwise healthy premenopausal and postmenopausal women, increased susceptibility to recurrences seems to be conferred by intrinsic host factors, such as nonsecretor genotype or estrogen status, and by exogenous exposures or behaviors, such as use of a diaphragm with spermicide, antimicrobial use, and sexual behavior. The natural history of recurrent UTIs is notable for a temporal clustering phenomenon, the tendency of women to revert to a baseline infection pattern after the cessation of preventive interventions, and repeated serial reinfections of the urinary tract from the fecal reservoir, often by genetically identical organisms. Low-dose antimicrobial regimens given daily, three times weekly, or postcoitally are effective in preventing recurrences in most women with a predisposition to frequent infection. Intermittent patient-initiated self-treatment is an appropriate and effective option in some patients with lower recurrence rates. In postmenopausal women, estrogen replacement therapy, particularly vaginally applied estriol creams, may also significantly reduce the rate of recurrent UTI. Ongoing investigations in the areas of microbial ecology of the vaginal flora, the molecular basis for host-parasite interactions within the urinary tract, and vaccine development may eventually lead to improved means to prevent recurrent urinary tract infections more effectively.

Adult↗

Antecedent antimicrobial use increases the risk of uncomplicated cystitis in young women.

To examine whether antecedent antimicrobial use influenced subsequent relative risk of urinary tract infection (UTI) in premenopausal women, data were analyzed from two cohorts of women observed prospectively for 6 months to determine risk factors for UTI. Using a Cox proportional hazards model to adjust for covariates, we found that 326 women in a University cohort and 425 women in a health-maintenance organization cohort were at increased risks for UTI (2.57 [95% confidence interval (CI), 1.24-5.32] and 5.83 [95% CI, 3.17-10.70], respectively) if antimicrobials had been taken during the previous 15-28 days but not during the previous 3, 7, or 14 days. The increased risks were noted both for women whose antimicrobial use was for treatment of a previous UTI and for women who received antimicrobials for other illnesses. These results suggest that recent antimicrobial use increases a woman's risk of UTI, perhaps by altering the indigenous urogenital flora and predisposing to vaginal colonization with uropathogens.

Adolescent↗

Noninvasive evaluation of coronary artery disease and myocardial viability through stress echocardiography and myocardial perfusion imaging.

Today, primary care providers are managing clinical problems that were frequently addressed by a "specialist". Consequently, they must keep current with myriad state-of-the-art diagnostic modalities. In the case of coronary artery disease, knowledge about the reversibility of left ventricular dysfunction conceptualized as "hibernating" and "stunned" myocardium has resulted in an increased utilization of noninvasive cardiac imaging techniques to facilitate clinical decision making. These procedures provide diagnostic and prognostic information about coronary artery disease and left ventricular function beyond that provided by the conventional exercise stress test. The most commonly employed of these are the stress echocardiogram and stress myocardial nuclear perfusion procedures. Both modalities can be performed in conjunction with physical or pharmacologically induced stress, and may be performed on an outpatient basis. Knowledge of how these procedures are performed and the clinical data they provide will facilitate primary care providers as they care for this growing population.

Cardiotonic Agents↗

Effect of secretor status on vaginal and rectal colonization with fimbriated Escherichia coli in women with and without recurrent urinary tract infection.

The prevalence and duration of rectal and vaginal colonization with P- and F-fimbriated Escherichia coli and the relationship of colonization with these strains to blood group secretor status was investigated. Rectal and vaginal E. coli isolates were prospectively collected twice monthly for 6 months from 20 young women with and 20 without a history of recurrent urinary tract infection (UTI). Rectal and vaginal colonization with P- and/or F-fimbriated E. coli was highly prevalent. Nonsecretors who developed UTI during the study period were significantly more likely to be colonized rectally with F-fimbriated E. coli than were the infected secretors (56% vs. 27%; P = .042) or uninfected nonsecretors (56% vs. 31%; P = .046). Persistent vaginal and rectal E. coli colonization with fimbriated organisms occurred commonly in the study patients but was not often temporally associated with the development of UTI. Results suggest that nonsecretors are more susceptible than secretors to colonization with F adhesin-bearing E. coli isolates.

Adhesins, Escherichia coli↗

Chromosomal restriction fragment length polymorphism analysis of Escherichia coli strains causing recurrent urinary tract infections in young women.

To determine whether recurrent, symptomatic urinary tract infections (UTIs) in a given individual are due to the same or different strains, 71 Escherichia coli strains that caused recurrent UTIs were prospectively collected from 23 infection-prone young women and studied by chromosomal restriction fragment length polymorphism (RFLP) analysis using pulsed-field gel electrophoresis. Thirty-five strains from women with first-episode UTIs were also studied. Overall, 30 (68%) of 44 recurrent UTIs were caused by a strain previously identified in that person. In contrast, 32 of 35 strains from first-episode UTIs had unique RFLP profiles. Analysis of a subset of subjects established that the majority of recurrent UTIs were due to reinfection, not persistence of the pathogen within the urinary tract, and suggested that the colonic flora was the reservoir for these reinfecting strains.

Adolescent↗

Comparison of expression of virulence factors by Escherichia coli causing cystitis and E. coli colonizing the periurethra of healthy girls.

The prevalence of virulence factors possessed by Escherichia coli colonizing the periurethra was examined and compared with that of E. coli causing urinary tract infection. One hundred two E. coli isolates obtained from the periurethra and urine of 7 non-sexually active girls at risk for cystitis were characterized for genetic relatedness and examined for expression of six virulence factors. Expression of virulence factors in colonizing clones of E. coli were compared with expression in clones from symptomatic infection. All virulence factors except P adhesin were commonly expressed by colonizing clones of E. coli that did not go on to infect the urinary tract. Although P adhesin-expressing E. coli were commonly isolated from episodes of cystitis, the presence of P adhesin on periurethral E. coli did not usually predict subsequent infection. By itself, expression of virulence factors on periurethral E. coli is not enough to predict subsequent infection.

Agglutination Tests↗

Cloning and expression of soluble epoxide hydrolase from potato.

Five cDNAs encoding a putative soluble epoxide hydrolase (sEH) from potato were isolated and characterized. The cDNAs contained open reading frames encoding 36 kDa polypeptides which were highly homologous to the carboxy terminal region of mammalian sEH. When one of the cDNAs was expressed in a baculovirus system a soluble 38 kDa protein with epoxide hydrolase activity was produced. The recombinant enzyme hydrolyzed a commonly used diagnostic substrate for the soluble form of mammalian EH. Inhibitor profiles of the recombinant potato and mammalian sEH were also similar. The expression of sEH in potato was found to be regulated by both developmental and environmental signals. Levels of mRNA for sEH were higher in meristematic tissue than in mature leaves. This mRNA was also observed to accumulate on wounding and application of exogenous methyl jasmonate.

Amino Acid Sequence↗