The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
W. Hamish B. Wallace - One of the best experts on this subject based on the ideXlab platform.
-
A Validated Normative Model for Human Uterine Volume from Birth to Age 40 Years
PloS one, 2016Co-Authors: Tom Kelsey, Richard A. Anderson, Eleanor Ginbey, Moti M. Chowdhury, Louise Bath, W. Hamish B. WallaceAbstract:Transabdominal pelvic ultrasound and/or pelvic Magnetic Resonance Imaging are safe, accurate and non-invasive means of determining the size and configuration of the internal female genitalia. The assessment of uterine size and volume is helpful in the assessment of many conditions including disorders of sex development, precocious or delayed puberty, infertility and menstrual disorders. Using our own data from the assessment of MRI scans in healthy young females and data extracted from four studies that assessed uterine volume using transabdominal ultrasound in healthy females we have derived and validated a Normative Model of uterine volume from birth to age 40 years. This shows that uterine volume increases across childhood, with a faster increase in adolescence reflecting the influence of puberty, followed by a slow but progressive rise during adult life. The Model suggests that around 84% of the variation in uterine volumes in the healthy population up to age 40 is due to age alone. The derivation of a validated Normative Model for uterine volume from birth to age 40 years has important clinical applications by providing age-related reference values for uterine volume.
-
A Normative Model of Serum Inhibin B in Young Males
PloS one, 2016Co-Authors: Tom Kelsey, Richard A. Anderson, Amy E. Miles, Rod T. Mitchell, W. Hamish B. WallaceAbstract:Inhibin B has been identified as a potential marker of Sertoli cell function in males. The aim of this study is to produce a Normative Model of serum inhibin B in males from birth to seventeen years. We used a well-defined search strategy to identify studies containing data that can contribute to a larger approximation of the healthy population. We combined data from four published studies (n = 709) and derived an internally validated Model with high goodness-of-fit and normally distributed residuals. Our results show that inhibin B increases following birth to a post-natal peak of 270 pg/mL (IQR 210–335 pg/mL) and then decreases during childhood followed by a rise at around 8 years, peaking at a mean 305 pg/mL (IQR 240–445 pg/mL) at around age 17. Following this peak there is a slow decline to the standard mature adult normal range of 170 pg/mL (IQR 125–215 pg/mL). This Normative Model suggests that 35% of the variation in Inhibin B levels in young males is due to age alone, provides an age-specific reference range for inhibin B in the young healthy male population, and will be a powerful tool in evaluating the potential of inhibin B as a marker of Sertoli cell function in pre-pubertal boys.
-
A Validated Age-Related Normative Model for Male Total Testosterone Shows Increasing Variance but No Decline after Age 40 Years
PloS one, 2014Co-Authors: Tom Kelsey, Richard A. Anderson, Rod T. Mitchell, Ashley Whelan, W. Hamish B. WallaceAbstract:The diagnosis of hypogonadism in human males includes identification of low serum testosterone levels, and hence there is an underlying assumption that normal ranges of testosterone for the healthy population are known for all ages. However, to our knowledge, no such reference Model exists in the literature, and hence the availability of an applicable biochemical reference range would be helpful for the clinical assessment of hypogonadal men. In this study, using Model selection and validation analysis of data identified and extracted from thirteen studies, we derive and validate a Normative Model of total testosterone across the lifespan in healthy men. We show that total testosterone peaks [mean (2.5–97.5 percentile)] at 15.4 (7.2–31.1) nmol/L at an average age of 19 years, and falls in the average case [mean (2.5–97.5 percentile)] to 13.0 (6.6–25.3) nmol/L by age 40 years, but we find no evidence for a further fall in mean total testosterone with increasing age through to old age. However we do show that there is an increased variation in total testosterone levels with advancing age after age 40 years. This Model provides the age related reference ranges needed to support research and clinical decision making in males who have symptoms that may be due to hypogonadism.
-
Ovarian Volume throughout Life: A Validated Normative Model
PloS one, 2013Co-Authors: Tom Kelsey, Sarah K. Dodwell, A. Graham Wilkinson, Tine Greve, Claus Yding Andersen, Richard A. Anderson, W. Hamish B. WallaceAbstract:The measurement of ovarian volume has been shown to be a useful indirect indicator of the ovarian reserve in women of reproductive age, in the diagnosis and management of a number of disorders of puberty and adult reproductive function, and is under investigation as a screening tool for ovarian cancer. To date there is no Normative Model of ovarian volume throughout life. By searching the published literature for ovarian volume in healthy females, and using our own data from multiple sources (combined n=59,994) we have generated and robustly validated the first Model of ovarian volume from conception to 82 years of age. This Model shows that 69% of the variation in ovarian volume is due to age alone. We have shown that in the average case ovarian volume rises from 0.7 mL (95% CI 0.4–1.1 mL) at 2 years of age to a peak of 7.7 mL (95% CI 6.5–9.2 mL) at 20 years of age with a subsequent decline to about 2.8 mL (95% CI 2.7–2.9 mL) at the menopause and smaller volumes thereafter. Our Model allows us to generate normal values and ranges for ovarian volume throughout life. This is the first validated Normative Model of ovarian volume from conception to old age; it will be of use in the diagnosis and management of a number of diverse gynaecological and reproductive conditions in females from birth to menopause and beyond.
Tom Kelsey - One of the best experts on this subject based on the ideXlab platform.
-
A Validated Normative Model for Human Uterine Volume from Birth to Age 40 Years
PloS one, 2016Co-Authors: Tom Kelsey, Richard A. Anderson, Eleanor Ginbey, Moti M. Chowdhury, Louise Bath, W. Hamish B. WallaceAbstract:Transabdominal pelvic ultrasound and/or pelvic Magnetic Resonance Imaging are safe, accurate and non-invasive means of determining the size and configuration of the internal female genitalia. The assessment of uterine size and volume is helpful in the assessment of many conditions including disorders of sex development, precocious or delayed puberty, infertility and menstrual disorders. Using our own data from the assessment of MRI scans in healthy young females and data extracted from four studies that assessed uterine volume using transabdominal ultrasound in healthy females we have derived and validated a Normative Model of uterine volume from birth to age 40 years. This shows that uterine volume increases across childhood, with a faster increase in adolescence reflecting the influence of puberty, followed by a slow but progressive rise during adult life. The Model suggests that around 84% of the variation in uterine volumes in the healthy population up to age 40 is due to age alone. The derivation of a validated Normative Model for uterine volume from birth to age 40 years has important clinical applications by providing age-related reference values for uterine volume.
-
A Normative Model of Serum Inhibin B in Young Males
PloS one, 2016Co-Authors: Tom Kelsey, Richard A. Anderson, Amy E. Miles, Rod T. Mitchell, W. Hamish B. WallaceAbstract:Inhibin B has been identified as a potential marker of Sertoli cell function in males. The aim of this study is to produce a Normative Model of serum inhibin B in males from birth to seventeen years. We used a well-defined search strategy to identify studies containing data that can contribute to a larger approximation of the healthy population. We combined data from four published studies (n = 709) and derived an internally validated Model with high goodness-of-fit and normally distributed residuals. Our results show that inhibin B increases following birth to a post-natal peak of 270 pg/mL (IQR 210–335 pg/mL) and then decreases during childhood followed by a rise at around 8 years, peaking at a mean 305 pg/mL (IQR 240–445 pg/mL) at around age 17. Following this peak there is a slow decline to the standard mature adult normal range of 170 pg/mL (IQR 125–215 pg/mL). This Normative Model suggests that 35% of the variation in Inhibin B levels in young males is due to age alone, provides an age-specific reference range for inhibin B in the young healthy male population, and will be a powerful tool in evaluating the potential of inhibin B as a marker of Sertoli cell function in pre-pubertal boys.
-
A Validated Age-Related Normative Model for Male Total Testosterone Shows Increasing Variance but No Decline after Age 40 Years
PloS one, 2014Co-Authors: Tom Kelsey, Richard A. Anderson, Rod T. Mitchell, Ashley Whelan, W. Hamish B. WallaceAbstract:The diagnosis of hypogonadism in human males includes identification of low serum testosterone levels, and hence there is an underlying assumption that normal ranges of testosterone for the healthy population are known for all ages. However, to our knowledge, no such reference Model exists in the literature, and hence the availability of an applicable biochemical reference range would be helpful for the clinical assessment of hypogonadal men. In this study, using Model selection and validation analysis of data identified and extracted from thirteen studies, we derive and validate a Normative Model of total testosterone across the lifespan in healthy men. We show that total testosterone peaks [mean (2.5–97.5 percentile)] at 15.4 (7.2–31.1) nmol/L at an average age of 19 years, and falls in the average case [mean (2.5–97.5 percentile)] to 13.0 (6.6–25.3) nmol/L by age 40 years, but we find no evidence for a further fall in mean total testosterone with increasing age through to old age. However we do show that there is an increased variation in total testosterone levels with advancing age after age 40 years. This Model provides the age related reference ranges needed to support research and clinical decision making in males who have symptoms that may be due to hypogonadism.
-
Ovarian Volume throughout Life: A Validated Normative Model
PloS one, 2013Co-Authors: Tom Kelsey, Sarah K. Dodwell, A. Graham Wilkinson, Tine Greve, Claus Yding Andersen, Richard A. Anderson, W. Hamish B. WallaceAbstract:The measurement of ovarian volume has been shown to be a useful indirect indicator of the ovarian reserve in women of reproductive age, in the diagnosis and management of a number of disorders of puberty and adult reproductive function, and is under investigation as a screening tool for ovarian cancer. To date there is no Normative Model of ovarian volume throughout life. By searching the published literature for ovarian volume in healthy females, and using our own data from multiple sources (combined n=59,994) we have generated and robustly validated the first Model of ovarian volume from conception to 82 years of age. This Model shows that 69% of the variation in ovarian volume is due to age alone. We have shown that in the average case ovarian volume rises from 0.7 mL (95% CI 0.4–1.1 mL) at 2 years of age to a peak of 7.7 mL (95% CI 6.5–9.2 mL) at 20 years of age with a subsequent decline to about 2.8 mL (95% CI 2.7–2.9 mL) at the menopause and smaller volumes thereafter. Our Model allows us to generate normal values and ranges for ovarian volume throughout life. This is the first validated Normative Model of ovarian volume from conception to old age; it will be of use in the diagnosis and management of a number of diverse gynaecological and reproductive conditions in females from birth to menopause and beyond.
Richard A. Anderson - One of the best experts on this subject based on the ideXlab platform.
-
A Validated Normative Model for Human Uterine Volume from Birth to Age 40 Years
PloS one, 2016Co-Authors: Tom Kelsey, Richard A. Anderson, Eleanor Ginbey, Moti M. Chowdhury, Louise Bath, W. Hamish B. WallaceAbstract:Transabdominal pelvic ultrasound and/or pelvic Magnetic Resonance Imaging are safe, accurate and non-invasive means of determining the size and configuration of the internal female genitalia. The assessment of uterine size and volume is helpful in the assessment of many conditions including disorders of sex development, precocious or delayed puberty, infertility and menstrual disorders. Using our own data from the assessment of MRI scans in healthy young females and data extracted from four studies that assessed uterine volume using transabdominal ultrasound in healthy females we have derived and validated a Normative Model of uterine volume from birth to age 40 years. This shows that uterine volume increases across childhood, with a faster increase in adolescence reflecting the influence of puberty, followed by a slow but progressive rise during adult life. The Model suggests that around 84% of the variation in uterine volumes in the healthy population up to age 40 is due to age alone. The derivation of a validated Normative Model for uterine volume from birth to age 40 years has important clinical applications by providing age-related reference values for uterine volume.
-
A Normative Model of Serum Inhibin B in Young Males
PloS one, 2016Co-Authors: Tom Kelsey, Richard A. Anderson, Amy E. Miles, Rod T. Mitchell, W. Hamish B. WallaceAbstract:Inhibin B has been identified as a potential marker of Sertoli cell function in males. The aim of this study is to produce a Normative Model of serum inhibin B in males from birth to seventeen years. We used a well-defined search strategy to identify studies containing data that can contribute to a larger approximation of the healthy population. We combined data from four published studies (n = 709) and derived an internally validated Model with high goodness-of-fit and normally distributed residuals. Our results show that inhibin B increases following birth to a post-natal peak of 270 pg/mL (IQR 210–335 pg/mL) and then decreases during childhood followed by a rise at around 8 years, peaking at a mean 305 pg/mL (IQR 240–445 pg/mL) at around age 17. Following this peak there is a slow decline to the standard mature adult normal range of 170 pg/mL (IQR 125–215 pg/mL). This Normative Model suggests that 35% of the variation in Inhibin B levels in young males is due to age alone, provides an age-specific reference range for inhibin B in the young healthy male population, and will be a powerful tool in evaluating the potential of inhibin B as a marker of Sertoli cell function in pre-pubertal boys.
-
A Validated Age-Related Normative Model for Male Total Testosterone Shows Increasing Variance but No Decline after Age 40 Years
PloS one, 2014Co-Authors: Tom Kelsey, Richard A. Anderson, Rod T. Mitchell, Ashley Whelan, W. Hamish B. WallaceAbstract:The diagnosis of hypogonadism in human males includes identification of low serum testosterone levels, and hence there is an underlying assumption that normal ranges of testosterone for the healthy population are known for all ages. However, to our knowledge, no such reference Model exists in the literature, and hence the availability of an applicable biochemical reference range would be helpful for the clinical assessment of hypogonadal men. In this study, using Model selection and validation analysis of data identified and extracted from thirteen studies, we derive and validate a Normative Model of total testosterone across the lifespan in healthy men. We show that total testosterone peaks [mean (2.5–97.5 percentile)] at 15.4 (7.2–31.1) nmol/L at an average age of 19 years, and falls in the average case [mean (2.5–97.5 percentile)] to 13.0 (6.6–25.3) nmol/L by age 40 years, but we find no evidence for a further fall in mean total testosterone with increasing age through to old age. However we do show that there is an increased variation in total testosterone levels with advancing age after age 40 years. This Model provides the age related reference ranges needed to support research and clinical decision making in males who have symptoms that may be due to hypogonadism.
-
Ovarian Volume throughout Life: A Validated Normative Model
PloS one, 2013Co-Authors: Tom Kelsey, Sarah K. Dodwell, A. Graham Wilkinson, Tine Greve, Claus Yding Andersen, Richard A. Anderson, W. Hamish B. WallaceAbstract:The measurement of ovarian volume has been shown to be a useful indirect indicator of the ovarian reserve in women of reproductive age, in the diagnosis and management of a number of disorders of puberty and adult reproductive function, and is under investigation as a screening tool for ovarian cancer. To date there is no Normative Model of ovarian volume throughout life. By searching the published literature for ovarian volume in healthy females, and using our own data from multiple sources (combined n=59,994) we have generated and robustly validated the first Model of ovarian volume from conception to 82 years of age. This Model shows that 69% of the variation in ovarian volume is due to age alone. We have shown that in the average case ovarian volume rises from 0.7 mL (95% CI 0.4–1.1 mL) at 2 years of age to a peak of 7.7 mL (95% CI 6.5–9.2 mL) at 20 years of age with a subsequent decline to about 2.8 mL (95% CI 2.7–2.9 mL) at the menopause and smaller volumes thereafter. Our Model allows us to generate normal values and ranges for ovarian volume throughout life. This is the first validated Normative Model of ovarian volume from conception to old age; it will be of use in the diagnosis and management of a number of diverse gynaecological and reproductive conditions in females from birth to menopause and beyond.
Reid Kreutzwiser - One of the best experts on this subject based on the ideXlab platform.
-
closing the circle linking land use planning and water management at the local level
Land Use Policy, 2005Co-Authors: Nicole Carter, Reid KreutzwiserAbstract:Abstract The concepts of integrated and sustainable management have been discussed in detail in resource management literature, but there has been less attention to practical ways to implement and evaluate the success of these concepts at the local level. Use of a Normative Model, based on key principles, evaluative questions and benchmark criteria, provides a practical and adaptable tool for the implementation and evaluation of integrated and sustainable management. This paper illustrates a method by which land use planning and water management activities may be evaluated through the development of a Normative Model, and discusses lessons learned from an application of the Model to three study municipalities in the Province of Ontario, Canada.
F. P. Coetzee - One of the best experts on this subject based on the ideXlab platform.
-
Research Note: Sense-Seeking Systems as Normative Model for Innovative Sociocultural Systems
Systemic Practice and Action Research, 2000Co-Authors: F. P. CoetzeeAbstract:A concept of innovation as beneficial change that results from change in knowledge leads to a foundational Model of sociocultural systems, labeled the Sense-Seeking Systems Model, which proclaims that the essence of human striving is to seek and disclose and thereby to gain meaning or sense. Two of the most distinctive characteristics of the Model are that it entertains the concept of creation or discovery of sense as the raison d'être of human systems, and that systems characterized by this Model are intrinsically dynamic, with such dynamism emanating from interaction of multiple visions and reflected in the dialectical nature of such systems. A focus on sense-gaining highlights that where possible loss of sense threatens, the urge to regain sense induces aspiration for vision, and vision promises gain of sense. Emphasizing multiple visions, though, admits the necessity and sensibility of maintaining the likes of variety, inherent tension, debate, conflict, and dialectics for effecting innovation.
-
Research Note: Sense-Seeking Systems as Normative Model for Innovative Sociocultural Systems
Systemic Practice and Action Research, 2000Co-Authors: F. P. CoetzeeAbstract:A concept of innovation as beneficial change that results from change in knowledge leads to a foundational Model of sociocultural systems, labeled the Sense-Seeking Systems Model, which proclaims that the essence of human striving is to seek and disclose and thereby to gain meaning or sense. Two of the most distinctive characteristics of the Model are that it entertains the concept of creation or discovery of sense as the raison d'etre of human systems, and that systems characterized by this Model are intrinsically dynamic, with such dynamism emanating from interaction of multiple visions and reflected in the dialectical nature of such systems. A focus on sense-gaining highlights that where possible loss of sense threatens, the urge to regain sense induces aspiration for vision, and vision promises gain of sense. Emphasizing multiple visions, though, admits the necessity and sensibility of maintaining the likes of variety, inherent tension, debate, conflict, and dialectics for effecting innovation.