Familiality and partitioning the variability of femoral bone mineral density in women of child-bearing age

The contributions of polygenic loci and environmental factors to femoral bone mineral density (BMD in g/cm 2 ) variability were estimated in modified family sets consisting of women of child-bearing age. Femoral BMDs were measured in 535 women who were members of 137 family sets consisting minimally of an index, her sister, and unrelated female control. The family set could also include multiple sisters and first cousins. Women included in these family sets were all between 20 and 40 year of age to minimize the cohort effects of maturation and menopause on measures of BMD. BMDs were measured at three femoral sites using dual photon densitometry. Values were regressed on age and Quetelet Index which explained 13–15% of the variability in BMD (dependent on site). Subsequent variance components analysis on the residuals indicated that unmeasured polygenic loci accounted for substantial additional variability: 67% for femoral neck, 58% for Wards triangle, and 45% for trochanter. These results suggest that polygenic loci account for approximately half of the variability in maxmal femoral BMD.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48002/1/223_2004_Article_BF00298785.pd

Original Contribution Performance-based Physical Functioning in African-American and Caucasian Women at Midlife: Considering Body Composition, Quadriceps Strength, and Knee Osteoarthritis

In 2000, body composition, x-ray–defined knee osteoarthritis, and self-reported knee pain information from a cross-sectional, community-based study of 211 African-American and 669 Caucasian women in southeast Michigan (mean age, 47 years) was related to performance-based physical functioning measures to characterize development of functional limitations. Body composition was assessed with bioelectrical impedance. Functioning measures were gait assessment, timed walk, timed stair climb with and without videography, and isometric quadriceps strength. Knee osteoarthritis was determined by Kellgren-Lawrence score from radiography, whereas knee pain was self-reported. Almost 31 % of mid-aged women walked at functionally inadequate speeds, and over 12 % walked at speeds considered typical of frailty in older women. Ten percent of women had skeletal muscle mass levels less than a proposed cutpoint for increased physical disability risk in older adults. Gait measures correlates included increasing age, increasing fat mass (in kilograms), knee joint pain, and reduced quadriceps strength. Stair climbing correlates included skeletal muscle mass (in kilograms) and its change, painful knee osteoarthritis, and reduced quadriceps strength. Race differences in walking measures and stair climbing time diminished when the authors accounted for other factors. Compromised physical functioning began earlier than expected, with indications that approximately 12–31 % of women might benefit from interventions to forestall future decline

Aspartate 458 of human glutathione synthetase is important for cooperativity and active site structure

International audienceHuman glutathione synthetase (hGS) catalyzes the second ATP-dependent step in the biosynthesis of glutathione (GSH) and is negatively cooperative to the γ-glutamyl substrate. The hGS active site is composed of three highly conserved catalytic loops, notably the alanine rich A-loop. Experimental and computational investigations of the impact of mutation of Asp458 are reported, and thus the role of this A-loop residue on hGS structure, activity, negativity cooperativity and stability is defined. Several Asp458 hGS mutants (D458A, D458N and D458R) were constructed using site-directed mutagenesis and their activities determined (10%, 15% and 7% of wild-type hGS, respectively). The Michaelis-Menten constant (K(m)) was determined for all three substrates (glycine, GAB and ATP): glycine K(m) increased by 30-115-fold, GAB K(m) decreased by 8-17-fold, and the ATP K(m) was unchanged. All Asp458 mutants display a change in cooperativity from negative cooperativity to non-cooperative. All mutants show similar stability as compared to wild-type hGS, as determined by differential scanning calorimetry. The findings indicate that Asp458 is essential for hGS catalysis and that it impacts the allostery of hGS

The experience of pain and emergent osteoarthritis of the knee

Discrepancies exist between radiographic osteoarthritis of the knee (OAK) and report of knee joint pain. Little is known about how these two definitions of osteoarthritis (OA) and their correlates differ between African American (AA) and Caucasian (CA) women. Objective: We compared the prevalence of radiographic OAK and knee joint pain in AA and CA women, and the congruency of these outcomes according to age, body size, and knee injury. Design: A cross-sectional study of African American and Caucasian women aged 40–53 years (N=829) in Southeast Michigan used the Kellgren and Lawrence Atlas of Standard Radiographs of Arthritis to characterize radiographs of both knee joints (weight bearing) and self-report of knee pain. Results: Current pain was a significantly more sensitive predictor of radiographic OAK among AA women (Se=0.51) compared to CA women (Se=0.35). Specificity was similar between AA women (Sp=0.77) and CA women (Sp=0.82). Positive predictive value was significantly greater for AA compared with CA women (PV+ =0.40 and PV+ =0.15, respectively). The odds of having radiographic OAK increased with BMI >32 kg/m2 in both groups. Knee pain was related to BMI in CA women, but not AA women. Previous knee injury was associated with knee pain in both AA and CA women (OR=3.0 and OR=2.4). Conclusions: Joint pain in AA women was more likely to be associated with radiographic OAK as compared with CA women. This suggests differences in these two groups in both how pain is experienced in the OAK process and in the prevalence of non-OAK related pain in knee jointsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83247/1/lachance et al 2001.pd

ASPARTATE 458 of Human Glutathione Synthetase is Important for Cooperativity and Active Site Structure

Article discussing ASPARTATE 458 of human glutathione synthetase

Systems

"In the late 1950s, experiments such as the cybernetic sculptures of Nicolas Schöffer or the programmatic music compositions of John Cage and Iannis Xenakis transposed systems theory from the sciences to the arts. By the 1960s, artists as diverse as Roy Ascott, Hans Haacke, Robert Morris, Sonia Sheridan, and Stephen Willats were breaking with accepted aesthetics to embrace open systems that emphasized organism over mechanism, dynamic processes of interaction among elements, and the observer’s role as an inextricable part of the system. Jack Burnham’s 1968 Artforum essay “Systems Aesthetics” and his 1970 “Software” exhibition marked the high point of systems-based art until its resurgence in the changed conditions of the twenty-first century." -- Publisher's website

Clinical supervision in school counselling and career counselling: Is it time to develop a new story?

Supervision provides benefits for school counsellors and career counsellors such as support, an opportunity to gain new ideas and strategies, and personal and professional development. Despite this, studies have also shown that school counsellors perceive that the amount of time they participate in supervision is inadequate. In career counselling, there is little evidence that supervision has even been established as a mainstream professional practice. The reasons for this curious situation, whereby little time is spent on a potentially beneficial activity, are uncertain. The present study investigated the supervisory experiences of a group of school counsellors and career counsellors for a six month period following their completion of an intensive supervision training program. Participants recorded their supervisory experiences in a structured diary. Even though the participants were well informed about supervision, the findings of the present study are consistent with those of previous studies. This history of repeatedly similar findings suggests that it may be timely to ask some fundamental questions about supervision in these two professions. Such questions in turn suggest possible new research directions

Aspartate 458 of human glutathione synthetase is important for cooperativity and active site structure

Human glutathione synthetase (hGS) catalyzes the second ATP-dependent step in the biosynthesis of glutathione (GSH) and is negatively cooperative to the γ-glutamyl substrate. The hGS active site is composed of three highly conserved catalytic loops, notably the alanine rich A-loop. Experimental and computational investigations of the impact of mutation of Asp458 are reported, and thus the role of this A-loop residue on hGS structure, activity, negativity cooperativity and stability is defined. Several Asp458 hGS mutants (D458A, D458N, D458R) were constructed using site-directed mutagenesis and their activities determined (10, 15 and 7% of wild-type hGS, respectively). The Michaelis-Menten constant (K(m)) was determined for all three substrates (glycine, GAB, ATP): glycine K(m) increased by 30 - 115 fold, GAB K(m) decreased by 8 - 17 fold, and the ATP K(m) was unchanged. All Asp458 mutants display a change in cooperativity from negative cooperativity to non-cooperative. All mutants show similar stability as compared to wild-type hGS, as determined by differential scanning calorimetry. The findings indicate that Asp458 is essential for hGS catalysis and that it impacts the allostery of hGS