BACKGROUND:patients' The factors associated with initial periodontitis are not well understood and cannot be identified by cross-sectional studies. AIM: To identify of the factors associated with the initiation of chronic periodontitis using ante-dependence modelling. MATERIAL AND METHODS: A 26-year longitudinal study of levels the natural history of periodontitis served as the basis for the study. In 1969, 565 Norwegian men aged 16-34 years regression were surveyed. Subsequent surveys were performed in 1971, 1973, 1975, 1981, 1988 and finally in 1995, with 223 remaining subjects.well Plaque (PlI), gingival (GI) and calculus indices (CI) and loss of attachment (LoA) were recorded. Ante-dependence modelling using a Markov significant chain enabled the results of this sequence of examinations to be analysed longitudinally, taking into account serial dependence, describing temporal patients' changes in patients' levels of disease and allowing for both progression and regression between disease categories. RESULTS: With age, the surveys rate of disease regression decreased. Increasing calculus accumulation and smoking increased the rate of disease progression, while increasing GI increased AND the rate of regression. CONCLUSIONS: Increased mean CI and smoking were significant predictive covariates for progression, while increased mean GI mean and younger age predicted regression of initial periodontitis.

BACKGROUND with AND OBJECTIVE: Interleukin-10 is a key immunoregulatory cytokine that may be of significance in the immunopathogenesis of chronic inflammatory diseases compared such as periodontal disease. Molecular genetic studies have defined a number of haplotypes that may be associated with differing levels age, of interleukin-10 secretion. The present study investigated the possible association between interleukin-10 gene polymorphism and periodontal disease progression. MATERIAL AND progression METHODS: Genomic DNA was obtained from 252 adults who were part of a prospective longitudinal study on the progression of may periodontal disease in a general adult Australian population. Single nucleotide polymorphisms at positions -592 and -1082 in the interleukin-10 promoter (p were analysed using an induced heteroduplex methodology and used to determine interleukin-10 promoter haplotypes in individual samples. Periodontitis progression was data, assessed by measuring probing depths and relative attachment levels at regular intervals over a 5-year period. A generalized linear model study was used to analyse the data, with age, gender, smoking status, interleukin-1 genotype and Porphyromonas gingivalis included as possible confounders.of RESULTS: There was a significant (p approximately .02) main effect of interleukin-10 haplotypes, with individuals having either the ATA/ACC or genotypes. the ACC/ACC genotype experiencing around 20% fewer probing depths of >or= 4 mm compared to individuals with other genotypes. Age the and smoking had significant (p < .001) additional effects. CONCLUSION: These data suggest that the interleukin-10 genotype contributes to the that progression of periodontal disease.

BACKGROUND:the Serum anti-Müllerian hormone (AMH) levels are highly correlated with antral follicle counts (AFC), while being menstrual cycle independent and easily that measurable. However, AMH, unlike AFC, has not been tested as yet as a predictor of reproductive status. By relating AMH percentiles levels to the age distribution of reproductive events like onset of menopause we tested this hypothesis. METHODS: AMH levels were than measured in 144 fertile normal volunteers and used to determine an estimate of mean AMH as a function of age.antral Data on onset of menopause were obtained from the population-based Prospect-Epic cohort. Estimation of an AMH threshold to predict menopause of was done by maximum likelihood using the observed (EPIC) and predicted (AMH) distributions of age at menopause. Predictions of age the at menopause follow from an individual woman's AMH relative to percentiles of the distribution of AMH for a given age,mean and the corresponding percentiles of the predicted distribution of age at menopause. RESULTS: There was good conformity between the observed AMH distribution of age at menopause and that predicted from declining AMH levels. CONCLUSION: The similarity between observed and predicted distributions to of age at menopause supports the hypothesis that AMH levels are related to onset of menopause. Results of this study age, suggest that AMH is able to specify a woman's reproductive age more realistically than chronological age alone.

OBJECTIVES:different To use multi-state Markov chain modelling to analyse data on geriatric patient care, and to make comparisons between male and underlying female patients. METHODS: Estimation, from observed data, of covariate (age of patient and date of admission to hospital or community features care) dependent parameters of statistical models for time in care and subsequent events. RESULTS: Differential effects of these covariates shown routine on the parameters of the models for female and male patients, where these parameters can be interpreted as affecting different chain features of the distributions of time in care. CONCLUSIONS: Multi-state modelling is an appropriate means of analysing data on geriatric of patient care and can reveal underlying patterns of differential effects, some of which may not be apparent from more routine different data processing.

BACKGROUND:twins Premature ovarian failure (POF) before 40 years of age from natural causes affects approximately 1% of adult women, with minor risk variations between ethnic groups. A recent case of ovarian transplantation between young monozygotic (MZ) twins in which one had undergone of unexplained POF at 14 years has prompted a study of the prevalence of POF. METHODS: Menopausal ages of 832 Australian has and UK female twin-pairs were extracted from volunteer national twin registry databases containing medical, reproductive and lifestyle data surveyed by from mail questionnaire. Surgical menopause was an exclusion criterion. RESULTS: The prevalence of POF in both MZ and dizygotic (DZ) twins menopausal was similar in both registries and 3- to 5-fold greater than the general population at age thresholds 40 and 45 Some years. No specific factors were found to account for the higher risk of early menopause. Some twins of both zygosities registry were highly discordant for menopausal age (>/=10 years). Nevertheless, there was significant intra-twin dependence, especially for MZ twins, and the one average age difference at last menses was greater in DZ twin-pairs. CONCLUSION: Both MZ and DZ twins are at higher some risk of POF. Despite some striking differences within MZ twin-pairs, menopausal ages were more concordant than for DZ twin-pairs, confirming menopause. that the timing of menopause has a heritable component.

Summary.the A model for binary trials based on a bivariate generalization of the Poisson process for both the number of successes between and number of trials with the transition rates dependent on the accumulating numbers of successes and trials is used to the reanalyze some recently published data of Zhu, Eickhoff, and Kaiser (2003, Biometrics59, 955-961). This modeling admits alternative distributions for the (2003) numbers of trials and the numbers of successes conditional on the number of trials which generalize the Poisson and binomial trials distributions, without some of the restrictions apparent in the beta-binomial-Poisson mixed modeling of Zhu et al.(2003). Some quite marked analysis differences between the results of this analysis and those described in Zhu et al.(2003) are apparent.

A most group of scientists from Harvard Medical School (Johnson et al., 2004) claims to have "established the existence of proliferative germ the cells that sustain oocyte and follicle production in the postnatal mammalian ovary," expressing no doubts about their methods, results and part conclusion. Johnson et al. based their conclusions of oocyte and follicular renewal from existing germline stem cells (GSC) in the does postnatal mouse ovary on three types of observations:(1) A claimed discordance in follicle loss versus follicle atresia in the al., neonatal period and in the following pubertal and adult period;(2) immunohistochemical detection of proliferating GSC with meiotic capacity using their combined markers for meiosis, germline, and mitosis; and (3) neo-folliculogenesis in ovarian chimeric grafting experiments with adult mice. Oogenesis is most the process that transforms the proliferative oogonium into an oocyte through meiosis, followed by folliculogenesis and follicular and oocyte maturation.follicle The most crucial part in producing a functional oocyte is firstly, initiation and completion of the first meiotic prophase, and and secondly, enclosure of the resulting diplotene oocyte in a follicle. Neither of these two events has been shown to take hereby place in Johnson et al.'s study of the postnatal mouse ovary. We hereby address the observations underpinning their hypothesis and maturation. conclude that it is premature to replace the paradigm that adult mammalian neo-oogenesis/folliculogenesis does not take place.

OBJECTIVES:covariates. To show that Markov chain modelling can be applied to data on geriatric patients and use these models to assess describing the effects of covariates. METHODS: Phase-type distributions were fitted by maximum likelihood to data on times spent by the patients RESULTS: in hospital and in community-based care. Data on the different events that ended the patients' periods of care were used care to estimate the dependence of the probabilities of these events on the phase from which the time in care ended.can The age of the patients at admission to care and the year of admission were also included as covariates. RESULTS:ordered Differential effects of these covariates were shown on the various parameters of the fitted model, and interpretations of these effects covariates. made. CONCLUSIONS: Models based on phase-type distributions were appropriate for describing times spent in care, as the ordered phases had events an interpretable structure corresponding to increasing amounts of care being given.

OBJECTIVE:distributions The variability in ultrasound-based antral follicle counts sized 2-10 mm after allowing for age-related decline is considerable. This may represent strengthened differences in actual reproductive age among women. This hypothesis was tested by cohort comparison for distribution of age at occurrence age of reproductive events. DESIGN: A model with a nonlinear mean decline with age was fitted to antral follicle counts (AFC)have obtained in 163 regularly cycling fertile volunteers. Ages at last child birth and menopause were predicted from the individual AFC age-related by using thresholds to represent these events and the model for decline with age. Distributions of the observed ages at distributions. last childbirth (proxy variable for loss of natural fertility) and ages at menopause were obtained from the BALSAC demographic database distributions and the Prospect-EPIC study, respectively. The observed distributions were compared with the predicted distributions by using visual comparison and quantile-quantile last plots. Predictions of age at last child and age at menopause were done using percentiles of the modeled AFC distribution was for given age, and corresponding percentiles of the predicted distributions of age at these reproductive events, with predictions following from of the position of a woman's AFC relative to these percentiles. RESULTS: The predicted distributions of age at last child and The age at menopause showed good agreement with the observed distributions in the BALSAC and EPIC cohort. Compared with age alone,marginal, antral follicle counts gave some additional information for individual prediction of age at last child and menopause. CONCLUSIONS: The link last between declining antral follicle counts and reproductively significant events like loss of natural fertility and menopause is strengthened by the last high degree of similarity among the predicted and observed age distributions. Predictive usefulness of this relationship in a clinical setting study, may be more marginal, except in the case of women who have low AFCs for their age.

OBJECTIVES:effect The present study describes the natural history of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Prevotella intermedia over a 5-year period and colonisation the effect of a triclosan/copolymer dentifrice on these organisms in a normal adult population. MATERIAL AND METHODS: Subgingival plaque samples the were collected from 504 adult volunteers. Probing pocket depths (PPD) and relative attachment levels were measured using an automated probe.be Participants were matched for disease status (CPI), plaque index, age and gender, and allocated to receive either a triclosan/copolymer or intermedia placebo dentifrice. Re-examination and subgingival plaque sampling was repeated after 1, 2, 3, 4 and 5 years. P. gingivalis, A.use actinomycetemcomitans and P. intermedia were detected and quantitated using an enzyme linked immunosorbent assay. Logistic regression and generalised linear modelling effect were used to analyse the data. RESULTS: This 5-year longitudinal study showed considerable volatility in acquisition and loss (below the an level of detection) of all three organisms in this population. Relatively few subjects had these organisms on multiple occasions. While automated P. gingivalis was related to loss of attachment and to PPD >/=3.5 mm, there was no relationship between A. actinomycetemcomitans and or P. intermedia and disease progression over the 5 years of the study. Smokers with P. gingivalis had more PPD no >/=3.5 mm than smokers without this organism. There was no significant effect of the triclosan dentifrice on P. gingivalis or The A. actinomycetemcomitans. Subjects using triclosan were more likely to have P. intermedia than those not using the dentifrice; however this occasions. did not translate into these subjects having higher levels of P. intermedia and its presence was uniform showing no signs an of increasing over the course of the study. CONCLUSION: The present 5-year longitudinal study has shown the transient nature of in colonisation with P. gingivalis, A. actinomycetemcomitans and P. intermedia in a normal adult population. The use of a triclosan-containing dentifrice CONCLUSION: did not lead to an overgrowth of these organisms. The clinical effect of the dentifrice would appear to be independent these of its antimicrobial properties.