Lower bone turnover and relative bone deficits in men with metabolic syndrome: a matter of insulin sensitivity? The European Male Ageing Study

Summary

We examined cross-sectional associations of metabolic syndrome and its components with male bone turnover, density and structure. Greater bone mass in men with metabolic syndrome was related to their greater body mass, whereas hyperglycaemia, hypertriglyceridaemia or impaired insulin sensitivity were associated with lower bone turnover and relative bone mass deficits.

Introduction

Metabolic syndrome (MetS) has been associated with lower bone turnover and relative bone mass or strength deficits (i.e. not proportionate to body mass index, BMI), but the relative contributions of MetS components related to insulin sensitivity or obesity to male bone health remain unclear.

Methods

We determined cross-sectional associations of MetS, its components and insulin sensitivity (by homeostatic model assessment-insulin sensitivity (HOMA-S)) using linear regression models adjusted for age, centre, smoking, alcohol, and BMI. Bone turnover markers and heel broadband ultrasound attenuation (BUA) were measured in 3129 men aged 40–79. Two centres measured total hip, femoral neck, and lumbar spine areal bone mineral density (_aBMD, n?=?527) and performed radius peripheral quantitative computed tomography (pQCT, n?=?595).

Results

MetS was present in 975 men (31.2 %). Men with MetS had lower β C-terminal cross-linked telopeptide (β-CTX), N-terminal propeptide of type I procollagen (PINP) and osteocalcin (P?<?0.0001) and higher total hip, femoral neck, and lumbar spine _aBMD (P?≤?0.03). Among MetS components, only hypertriglyceridaemia and hyperglycaemia were independently associated with PINP and β-CTX. Hyperglycaemia was negatively associated with BUA, hypertriglyceridaemia with hip _aBMD and radius cross-sectional area (CSA) and stress–strain index. HOMA-S was similarly associated with PINP and β-CTX, BUA, and radius CSA in BMI-adjusted models.

Conclusions

Men with MetS have higher _aBMD in association with their greater body mass, while their lower bone turnover and relative deficits in heel BUA and radius CSA are mainly related to correlates of insulin sensitivity. Our findings support the hypothesis that underlying metabolic complications may be involved in the bone’s failure to adapt to increasing bodily loads in men with MetS.

     

New echocardiographic applications for assessing global left ventricular diastolic function

A number of promising and highly technological echocardiographic imaging tools have recently been introduced to assess left ventricular diastolic function (i.e., the capacity of the ventricle to relax and fill). They permit quantification of distinct features of intraventricular blood flow velocity and pressure fields and myocardial tissue velocities. However, accurate interpretation of the new images and clinical indices is still cumbersome, as basic knowledge about intraventricular hemodynamics and ventricular wall mechanics is often insufficient. This review article provides a comprehensive and original overview of the hemodynamical and mechanical events that occur during diastole and discusses how this new information can be used in the clinical and research setting to evaluate diastolic function in the healthy and the diseased heart. It furthermore aims to explain the underpinnings of the techniques in such a way that the underlying biomechanical concepts (fluid dynamics and wall mechanics) become less obscure to cardiologists and echocardiographers and such that the biomedical engineers are given some insights into the avalanche of diastolic performance indices that currently exist.     

Percutaneous single- and double-balloon aortic valvotomy in adolescents and young adults with congenital aortic stenosis

Percutaneous balloon aortic valvotomy was attempted in six consecutiveadolescents and young adults, (meanage 18 ± 5 years),with severe congenital aortic valvular stenosis. Peak systolicaortic valve gradient measurement and aortography was performedbefore and immediately after valvotomy, and a 1–6 monthsfollow-up. The single-balloon technique was used in two patientsand the double-balloon technique in four patients. After balloonvalvotomy the mean peak systolic aortic valve gradient (PSG)decreased from 122 ± 53 to 43 ± 20 mmHg (P >001). The haemodynamic improvement persisted at follow-up (PSG= 47 ±31 mmHg), except in one patient who had previouslyundergone aortic surgical valvotomy. One balloon valvotomy wasunsuccessful, presumably because of the selection of an inappropriatelysmall balloon. Two patients with critical aortic stenosis (PSG>165mmHg), who exhibited a thick aortic valve on echocardiographywith a relatively small aortic root and annulus, had a dramaticreduction in PSG. However, the degree of aortic regurgitationincreased significantly in both cases. The theoretical haemodynamicadvantage of the double versus the single balloon techniqueswas confirmed in one patient. We have demonstrated that percutaneousballoon aortic valvotomy using either the single- or double-balloontechnique is feasible in young adults with severe congenitalaortic stenosis. Further studies are required both to defineappropriate patients and the selection of balloon diameter andlength.     

A Sertoli cell-selective knockout of the androgen receptor causes spermatogenic arrest in meiosis

Androgens control spermatogenesis, but germ cells themselves do not express a functional androgen receptor (AR). Androgen regulation is thought to be mediated by Sertoli and peritubular myoid cells, but their relative roles and the mechanisms involved remain largely unknown. Using Cre/loxP technology, we have generated mice with a ubiquitous knockout of the AR as well as mice with a selective AR knockout in Sertoli cells (SC) only. Mice with a floxed exon 2 of the AR gene were crossed with mice expressing Cre recombinase ubiquitously or selectively in SC (under control of the anti-Müllerian hormone gene promoter). AR knockout males displayed a complete androgen insensitivity phenotype. Testes were located abdominally, and germ cell development was severely disrupted. In contrast, SC AR knockout males showed normal testis descent and development of the male urogenital tract. Expression of the homeobox gene Pem, which is androgen-regulated in SC, was severely decreased. Testis weight was reduced to 28% of that in WT littermates. Stereological analysis indicated that the number of SC was unchanged, whereas numbers of spermatocytes, round spermatids, and elongated spermatids were reduced to 64%, 3%, and 0% respectively of WT. These changes were associated with increased germ cell apoptosis and grossly reduced expression of genes specific for late spermatocyte or spermatid development. It is concluded that cell-autonomous action of the AR in SC is an absolute requirement for androgen maintenance of complete spermatogenesis, and that spermatocyte/spermatid development/survival critically depends on androgens.     

Factors Affecting Job Satisfaction and Their Correlation with Educational Standards among Dental Assistants

A disparity exists in the educational qualifications of dental assistants working in various public and private institutions in Riyadh, Saudi Arabia. The aim of this study was to assess the influence of professional and personal characteristics on job satisfaction among dental assistants. A cross-sectional survey was performed among dental assistants using a 24-item self-administered questionnaire. Multinomial logistic regression was used to assess the relationship between overall job satisfaction and other variables. The overall response rate was 72.1%. Factor analysis suggested that five underlying factors were related to job satisfaction. The mean score for overall job satisfaction was 3.86 (satisfied) out of 5. Among the work environment factors, the highest mean score, 4.26 (satisfied), was obtained for quality of service, and the lowest mean score, 2.78 (neutral), was obtained for the perception of income. The income and general prospects of the profession was significantly associated with overall job satisfaction. This study suggests that for dental assistants, professional and personal life, quality of service, perception of income and prestige and self-respect are important factors for job satisfaction. Despite differences in professional formation standards, in general, the study participants were considerably satisfied with their jobs.     

Father involvement with three-to-four-year olds at home: giving fathers a chance

This study examined fathers' perceptions regarding their home-based activities (HBA) and the influence of fathers' demographic characteristics on their perceptions and practices at home. A total of 396 fathers completed a survey questionnaire describing their demographic information, perceptions and their practices regarding their involvement in HBA. Results indicated that fathers have moderate level of practice concerning their HBA, yet they have low perception of their actual practice at HBA. In addition, there was a statistical significance in HBA due to fathers' age, educational level and specialisation which had an influence on their perceptions as well. Recommendations and implications of future research were discussed.     

CCL3L1 copy number, CCR5 genotype and susceptibility to tuberculosis

Background

22q11.2 deletion syndrome (22q11.2DS) is a common microdeletion syndrome, which occurs in approximately 1:4000 births. Familial autosomal dominant recurrence of the syndrome is detected in about 8-28% of the cases. Aim of this study is to evaluate the intergenerational and intrafamilial phenotypic variability in a cohort of familial cases carrying a 22q11.2 deletion.

Methods

Thirty-two 22q11.2DS subjects among 26 families were enrolled.

Results

Second generation subjects showed a significantly higher number of features than their transmitting parents (212 vs 129, P?=?0.0015). Congenital heart defect, calcium-phosphorus metabolism abnormalities, developmental and speech delay were more represented in the second generation (P?<?0.05). Ocular disorders were more frequent in the parent group. No significant difference was observed for the other clinical variables. Intrafamilial phenotypic heterogeneity was identified in the pedigrees. In 23/32 families, a higher number of features were found in individuals from the second generation and a more severe phenotype was observed in almost all of them, indicating the worsening of the phenotype over generations. Both genetic and epigenetic mechanisms may be involved in the phenotypic variability.

Conclusions

Second generation subjects showed a more complex phenotype in comparison to those from the first generation. Both ascertainment bias related to patient selection or to the low rate of reproductive fitness of adults with a more severe phenotype, and several not well defined molecular mechanism, could explain intergenerational and intrafamilial phenotypic variability in this syndrome.