Biography:

In the past Joan F. Hilton has collaborated on articles with Kuniko Saeki and Horst Zincke. One of their most recent publications is Elevated TGF-β2 signaling in dentin results in sex related enamel defects. Which was published in journal Archives of Oral Biology.

More information about Joan F. Hilton research including statistics on their citations can be found on their Copernicus Academic profile page.

Joan F. Hilton's Articles: (8)

Elevated TGF-β2 signaling in dentin results in sex related enamel defects

AbstractInitiation of enamel formation requires reciprocal signaling between epithelially and mesenchymally derived cells.ObjectiveIn this study, we used a transgenic mouse model which drives overexpression of an activated form of TGF-β2 under control of the osteocalcin promoter, to investigate the role of TGF-β2 in the dental mesenchyme, on enamel formation.DesignDentin and enamel were imaged by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Dentin mechanical properties were characterized for hardness and elasticity, following nanoindentation with a modified AFM. Pores found in enamel were quantified and compared using image analysis software (Scion Image™).ResultsThe elastic modulus of dentin was significantly reduced in the male TGF-β2 overexpressor mice as compared to male wildtype mice, with no significant differences between female mice. Similarly, there were significantly more pores in enamel of the male transgenic mice as compared to male wildtype mice, with no significant differences between female mice. In situ hybridization of the continuously erupting incisor confirmed that osteocalcin expression was limited to the odontoblast cell layer at all stages of tooth formation.ConclusionTGF-β2 overexpression in the dentin matrix, results in sex-linked differences in dentin and enamel formation.

Adult UrologySexual Function/InfertilityThe Impact of Serial Prostate Biopsies on Sexual Function in Men on Active Surveillance for Prostate Cancer

PurposeNCCN Guidelines® recommend annual prostate biopsies for men with low risk prostate cancer on active surveillance. We determined whether erectile function decreases with the number of biopsies experienced.Materials and MethodsDuring a median 3.2-year followup after prostate cancer diagnosis in 2003 to 2010 at our institution 427 men on active surveillance underwent a total of 1,197 biopsies and provided 1,398 erectile function evaluations via the Sexual Health Inventory for Men questionnaire. For analysis we decomposed the 25-point questionnaire responses into a 5-point erectile function score and a 3-level sexual activity status. We used separate models adjusted for patient characteristics to determine whether either outcome varied with biopsy exposure.ResultsAt diagnosis the median age was 61 years and median prostate specific antigen was 5.3 ng/ml. Of the cases 70% were clinical stage cT1 and 93% were Gleason score less than 7. Of biopsies followed by evaluations 40% were the first undergone by the patient and 9% were the fifth to ninth. At the first erectile function evaluation 15% of men were inactive, 8% engage in stimulation and 77% engaged in intercourse. Sexual activity level changed in greater than 20% of respondents between evaluations. Adjusted erectile function scores were not associated with biopsy exposure cross-sectionally or longitudinally but they corresponded with the 50th, 63rd and 80th percentiles of erectile function by increasing sexual activity level. Similarly, sexual activity was not associated with biopsy exposure. Separated outcomes were more accurate and informative than Sexual Health Inventory for Men scores.ConclusionsOur study had high power to detect erectile function-biopsy associations but it estimated that the effects were negligible. We recommend erectile function scores over Sexual Health Inventory for Men scores to avoid biased assessment of erectile function.

Intravesical Thiotepa and Mitomycin C Treatment Immediately After Transurethral Resection and Later for Superficial (Stages Ta and Tis) Bladder Cancer: A Prospective, Randomized, Stratified Study with Crossover Design

AbstractIn a prospective, randomized, stratified study with crossover design the effect of thiotepa was compared to that of mitomycin C when each was instilled intravesically immediately at the end of complete removal of superficial bladder cancer (stages Ta and Tis) and later on tumor recurrence. The 3-month and 1-year rates free of recurrence were 93 and 78 per cent, respectively, for thiotepa (41 patients), and 97.6 and 67.1 per cent, respectively, for mitomycin C (42 patients) (p equals 0.6). On crossover (5 patients to thiotepa and 9 to mitomycin C) at 1 year 60 per cent of the patients receiving thiotepa secondarily and 51.9 per cent of those receiving mitomycin C secondarily were free of recurrence (p equals 0.52). Therefore, both drugs are equally effective in reducing bladder tumor recurrence. Future comparative studies should continue to include thiotepa as a standard by which the efficacies of other agents are judged.

Etching kinetics of a self-etching primer☆

AbstractSelf-etching primers are thought to offer significant advantages over total-etch adhesive systems. The hypothesis tested in this study was that there was no difference in etching characteristics between a self-etching primer and a phosphoric acid solution at the same pH. Etching was assessed using atomic force microscopy (AFM) evaluation of site-specific changes in the height of the peritubular and intertubular dentin as a function of exposure time.Human dentin disks (n=6/group), prepared with an acid-resistant glass reference layer, were etched with a self-etching primer and with 0.0134 m phosphoric acid (both pH≅1.94). Depth changes relative to the reference layer were measured with the AFM after each etching interval, at 15 different locations, each in the peritubular and intertubular dentin. The total demineralization depth was measured in a scanning electron microscope. Peritubular dentin etching rate was linear while it could be measured (up to 15 s) and was greater for the self-etching primer (p<0.0001). Intertubular dentin displayed a similar demineralization pattern with both acids, ultimately reaching a plateau in the majority of specimens. The self-etching primer attained a plateau after less recession than phosphoric acid (p<0.0001). Dentin demineralization appears to be affected by other factors in addition to the pH of the etchant solutions.

The size and power of the exact bivariate symmetry test

AbstractHollander's bivariate symmetry test for paired data is a two-sided conditional test of the null hypothesis H0: F(y,x)=F(y,x) for all (x, y) versus the alternative hypothesis that H0 fails to hold. Hollander (1971) proved the consistency of this test against a wide range of alternatives. Because of the potential usefulness of this test and because asymptotic distributions of the test statistic defined to date have not performed well, we created an algorithm for conducting exact bivariate symmetry tests. The algorithm computes exact P values in a tiny fraction of the time required for complete enumeration of the sample space. We use the algorithm to demonstrate the exact test's high sensitivity to location and moderate sensitivity to scale alternatives.

A new asymptotic distribution for Hollander's bivariate symmetry statistic

AbstractWe show that the asymptotic distribution (Koziol, 1979, Commun. Statist.-Theor. Methods A8, 207–221) of the bivariate symmetry statistic standardized by 1/n3, where n is the number of iid paired observations from bivariate distribution F, fails to account for the conditional nature of the statistic and is very conservative for all n. We describe the dependence of the true critical values of the test on the covariance of the paired samples, σxy, which is a nuisance parameter in this problem. We propose an alternative standardization of the bivariate symmetry statistic that adjusts it for σxy as well as n. We show via a simulation study that the size of the proposed asymptotic test is close to the nominal level, even for small n.

Spit (Smokeless) Tobacco Intervention for High School Athletes: Results after 1 year

AbstractObjective: To determine the efficacy of a spit tobacco (ST) intervention designed to promote ST cessation and discourage ST initiation among male high school baseball athletes. Methods: This study was a cluster-randomized controlled trial. Forty-four randomly selected high schools in rural California were randomized within strata (prevalence of ST use and number and size of baseball teams) to either the intervention or the control group. Ninety-three percent of eligible baseball athletes participated, yielding 516 subjects in 22 intervention schools and 568 subjects in 22 control schools. Prevalences of sustained ST cessation and ST use initiation over 1 year were assessed by self-report. Multivariate logistic regression models for clustered responses were used to test the null hypotheses of no association between group and the two outcomes, adjusted for the stratified design and baseline imbalances between groups in significant predictors of ST use. Results: Prevalence of cessation was 27% in intervention high schools and 14% in control high schools (odds ratio (OR)=2.29; 95% confidence interval (CI), 1.36–3.87). The intervention was especially effective in promoting cessation among those who, at baseline, lacked confidence that they could quit (OR=6.4; 95% CI, 1.0–4.3), among freshmen (OR=15; 95% CI, 0.9–260), and among nonsmokers (OR=3.2; 95% CI, 0.9–11). There was no significant difference between groups in the prevalence of ST initiation. Conclusions: This intervention was effective in promoting ST cessation, but was ineffective in preventing initiation of ST use by nonusers.

Full Length ArticleSex hormones are negatively associated with vertebral bone marrow fat

Highlights•Lower estradiol is associated with higher vertebral marrow fat in older men.•Lower testosterone is associated with higher vertebral marrow fat in older men.•Similar, but statistically non-significant, associations are present in women.•Sex hormones appear to play a modest role in the regulation of marrow fat in older adults.

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