ABSTRACT
PURPOSE: To characterize an experimental setup for ultra-high dose rate (UHDR) proton irradiations, and to address the challenges of dosimetry in millimetre-small pencil proton beams. METHODS: At the PSI Gantry 1, high-energy transmission pencil beams can be delivered to biological samples and detectors up to a maximum local dose rate of â¼9000 Gy/s. In the presented setup, a Faraday cup is used to measure the delivered number of protons up to ultra-high dose rates. The response of transmission ion-chambers, as well as of different field detectors, was characterized over a wide range of dose rates using the Faraday cup as reference. RESULTS: The reproducibility of the delivered proton charge was better than 1 % in the proposed experimental setup. EBT3 films, Al2O3:C optically stimulated luminescence detectors and a PTW microDiamond were used to validate the predicted dose. Transmission ionization chambers showed significant volume ion-recombination (>30 % in the tested conditions) which can be parametrized as a function of the maximum proton current density. Over the considered range, EBT3 films, inorganic scintillator-based screens and the PTW microDiamond were demonstrated to be dose rate independent within ±3 %, ±1.8 % and ±1 %, respectively. CONCLUSIONS: Faraday cups are versatile dosimetry instruments that can be used for dose estimation, field detector characterization and on-line dose verification for pre-clinical experiments in UHDR proton pencil beams. Among the tested detectors, the commercial PTW microDiamond was found to be a suitable option to measure real time the dosimetric properties of narrow pencil proton beams for dose rates up to 2.2 kGy/s.
Subject(s)
Protons , Reproducibility of ResultsABSTRACT
Mode-locked vertical external-cavity semiconductor lasers (VECSELs) are a wavelength-versatile laser that relies on a semiconductor saturable absorber mirror (SESAM) to initiate pulsed emission while simultaneously significantly influencing the pulse's properties. A SESAM can be characterized using a nonlinear reflectivity setup, realized here in the red spectral range around 660 nm and achieving a moderate peak-to-peak variation of 0.17%. We use our home-built mode-locked VECSEL to reach a high maximum fluence up to 430â µJ/cm2 with strongly chirped 7.5 ps pulses. This allows the first-of-its-kind characterization of GaInP quantum well SESAMs, thereby revealing saturation fluences of 38â µJ/cm2 and 34â µJ/cm2 with modulation depths of 5% and 10.3% for SESAMs comprising one or two active quantum wells, respectively. For all structures, a nonsaturable loss of 2.8% is found and attributed to scattering loss.
ABSTRACT
BACKGROUND: As the number of individuals with obesity increases, so too will the demand for a precise, cost-effective and safe method to better risk-stratify this heterogenous population. Visceral adipose tissue (VAT) area, a body composition measurement has been associated with the many facets of the metabolic syndrome. AIM: To determine the precision of dual energy X-ray absorptiometry (DXA) in providing body composition measurements, including VAT area, using the Hologic Horizon A scanner. METHOD: Thirty participants (mean age 64 years, 47% male), underwent two sequential body composition scans. The coefficient of variation (CV) and least significant change (LSC) were calculated for android/gynoid ratio, appendicular lean/height2, lean/height2, total body fat and lean mass, total body mass, and subcutaneous adipose tissue (SAT) and VAT area. Participants were stratified according to age (<70 or ≥70 years), body mass index (BMI) (≤30 kg/m2 or >30 kg/m2) and sex (male or female). The CV was calculated for each parameter and then analysed for differences between groups. RESULTS: The CV for all parameters was <3% with the exception of SAT (3.86%). The CV of VAT area was 2.63% with a LSC at 95% confidence of 7.28%. Apart from the CV differences between males and females for android/gynoid ratio (male: 3.56% vs. female: 1.74%, p = 0.01) and SAT area (5.04% vs. 2.46%, p = 0.01), there were no significant differences identified between the calculated CV for all other body composition parameters when participants were stratified by age, BMI and sex. CONCLUSION: DXA scanning, using the Hologic Horizon A system, is capable of providing precise body composition measurements.
Subject(s)
Body Composition , Absorptiometry, Photon , Aged , Body Mass Index , Female , Humans , Intra-Abdominal Fat , Male , Middle Aged , ObesityABSTRACT
Epidemiological studies consistently demonstrate that lowered serum testosterone is not only common in men with established Type 2 diabetes, but also predicts future diabetic risks and increased mortality. Preclinical studies report plausible mechanisms by which low testosterone could mediate dysglycaemia. Exogenous testosterone treatment consistently reduces fat mass, increases muscle mass and improves insulin resistance in some studies, but the majority of currently available randomized controlled trials (RCTs) do not report a consistent glycaemic benefit. In men with diabetes, testosterone treatment effects on androgen deficiency-like clinical features are inconsistent, and effects on sexual dysfunction may be attenuated compared with men without diabetes. The long-term risks of testosterone treatment in older men without medical disease of the hypothalamic-pituitary-testicular axis are not known. Current RCTs are not definitive, owing to their small size, short duration and enrolment of men with mostly relatively good baseline glycaemic control not specifically selected for the presence of androgen deficiency symptoms. Although large, well-designed clinical trials are needed, given the benefit-risk ratio of testosterone treatment is not well understood, routine serum testosterone testing or testosterone treatment of asymptomatic men with Type 2 diabetes is currently not recommended. Carefully selected, symptomatic men with low testosterone who are informed of the lack of high-level evidence regarding the long-term benefits and risks of this approach may be offered a trial of testosterone treatment in combination with lifestyle measures, weight loss and optimization of comorbidities.
Subject(s)
Diabetes Mellitus, Type 2/metabolism , Hypogonadism/metabolism , Insulin Resistance , Obesity/metabolism , Testosterone/deficiency , Adipose Tissue/metabolism , Androgens/therapeutic use , Blood Glucose/metabolism , Body Composition , Diabetes Mellitus, Type 2/complications , Diabetes Mellitus, Type 2/drug therapy , Erectile Dysfunction/complications , Erectile Dysfunction/drug therapy , Erectile Dysfunction/metabolism , Hormone Replacement Therapy , Humans , Hypoglycemic Agents/therapeutic use , Hypogonadism/complications , Hypogonadism/drug therapy , Libido , Male , Obesity/complications , Risk Assessment , Testosterone/therapeutic use , Treatment OutcomeABSTRACT
BACKGROUND: Obesity and dysglycemia (comprising insulin resistance, the metabolic syndrome and type 2 diabetes), that is diabesity, are associated with reduced circulating testosterone and, in some men, clinical features consistent with androgen deficiency. OBJECTIVE: To review the metabolic impact of late-onset hypogonadism. METHODS: Comprehensive literature search with emphasis on recent publications. RESULTS: Obesity is one of the strongest modifiable risk factors for late-onset hypogonadism, and coexisting diabetes leads to further hypothalamic-pituitary-testicular axis suppression. The hypothalamic-pituitary-testicular axis suppression is functional and hence potentially reversible, and occurs predominantly at the level of the hypothalamus. While definitive mechanistic data are lacking, the evidence suggests that hypothalamic-pituitary-testicular axis suppression is mediated by dysregulation of pro-inflammatory cytokines leading to hypothalamic inflammation. Dysregulation of central leptin and insulin signaling may also contribute. In contrast, recent data challenge the paradigm that estradiol excess is a major contributor to hypothalamic-pituitary-testicular axis suppression. Instead, relative estradiol signaling deficiency may contribute to metabolic dysregulation in men with diabesity. While weight loss and optimization of comorbidities can reverse functional hypothalamic-pituitary-testicular axis suppression, testosterone treatment leads to metabolically favorable changes in body composition and to improvements in insulin resistance. DISCUSSION: The relationship between diabesity and late-onset hypogonadism is bidirectional. Preliminary evidence suggests that, in carefully selected men, lifestyle measures and testosterone treatment may have additive effects. CONCLUSIONS: While recent research has provided new insights into mechanistic and clinical aspects of diabesity-associated late-onset hypogonadism, more evidence from well-designed large trials is needed to guide the optimal clinical approach to such men.
Subject(s)
Energy Metabolism , Hypogonadism/metabolism , Metabolic Syndrome/metabolism , Testosterone/deficiency , Age of Onset , Animals , Biomarkers/blood , Diabetes Mellitus, Type 2/epidemiology , Diabetes Mellitus, Type 2/metabolism , Hormone Replacement Therapy , Humans , Hypogonadism/diagnosis , Hypogonadism/drug therapy , Hypogonadism/epidemiology , Insulin Resistance , Male , Metabolic Syndrome/diagnosis , Metabolic Syndrome/drug therapy , Metabolic Syndrome/epidemiology , Obesity/epidemiology , Obesity/metabolism , Prognosis , Risk Assessment , Risk Factors , Testosterone/blood , Testosterone/therapeutic useABSTRACT
Women with early, estrogen receptor-positive breast cancer are treated with adjuvant endocrine therapy, using aromatase inhibitors or selective estradiol receptor modulators such as tamoxifen, to deprive breast tissue from the deleterious effects of estradiol action, hence improving long-term prognosis. Aromatase inhibitors and, in premenopausal women, tamoxifen accelerate bone loss and increase fracture risk. Therefore, all women commencing endocrine therapy need a targeted work-up to assess the baseline fracture risk, and monitoring of bone health during endocrine therapy should be individualized based on this baseline risk. While high-level evidence specific to early breast cancer is lacking, non-pharmacologic measures to maintain optimal bone health such as weight-bearing exercise and calcium and vitamin D sufficiency should be implemented in all women. Antiresorptive treatment should be initiated in all women with preexisting fragility fractures (including vertebral morphometric fractures) and should be considered in women with areal bone mineral density (BMD) T-scores < -2.0 (or Z-scores in women aged <50 years) or those experiencing rapid bone loss (≥5% per year), taking into consideration the baseline BMD and other risk factors for fracture. Further clinical trial evidence is required to provide definitive guidance regarding criteria to initiate antiresorptive treatment, choice of agents, and duration of treatment, taking into account potential oncologic benefits of antiresorptive therapy on breast cancer-related outcomes.
Subject(s)
Breast Neoplasms/drug therapy , Cancer Survivors , Fractures, Bone/prevention & control , Tamoxifen/adverse effects , Aromatase Inhibitors/adverse effects , Aromatase Inhibitors/pharmacology , Bone Density/drug effects , Bone Density Conservation Agents/therapeutic use , Female , Fractures, Bone/chemically induced , Humans , Risk Factors , Tamoxifen/pharmacologyABSTRACT
BACKGROUND: Globally there are several operational definitions for sarcopenia, complicating clinical and research applications. OBJECTIVE: The objective of the Australian and New Zealand Society for Sarcopenia and Frailty Research (ANZSSFR) Task Force on Diagnostic Criteria for Sarcopenia was to reach consensus on the operational definition of sarcopenia for regional use by clinicians and researchers. METHOD: A four-Phase modified Delphi process was undertaken in which 24 individuals with expertise or a recognised interest in sarcopenia from different fields across Australia and New Zealand were invited to be Task Force members. An initial face-to-face meeting was held in Adelaide, South Australia, in November 2017, followed by two subsequent online Phases conducted by electronic surveys. A final Phase was used to approve the final statements. Responses were analysed using a pre-specified strategy. The level of agreement required for consensus was 80%. RESULTS: In Phase 2, 94.1% of Task Force respondents voted in favour of adopting an existing operational definition of sarcopenia. In Phase 3, 94.4% of respondents voted in favour of adopting the European Working Group on Sarcopenia in Older People (EWGSOP) definition as the operational definition for sarcopenia in Australia and New Zealand. CONCLUSION: With consensus achieved, the ANZSSFR will adopt, promote and validate the EWGSOP operational definition of sarcopenia for use by clinicians and researchers in Australia and New Zealand.
Subject(s)
Sarcopenia/diagnosis , Aged , Aged, 80 and over , Australia , Consensus , Female , Humans , Male , New Zealand , Surveys and QuestionnairesABSTRACT
A 74-year-old man presented to the Andrology Clinic for management of potential complications of androgen deprivation therapy for prostate cancer. He had a rising prostate-specific antigen with a concurrent rise in alkaline phosphatase and bone remodeling markers. This was despite treatment with a radical prostatectomy, androgen deprivation, and anti-resorptive therapy. A follow-up dual-energy X-ray absorptiometry scan revealed a marked increase in his bone mineral density at both the lumbar spine and femoral neck. This increase, especially in the context of rising bone remodeling markers, was unlikely due to the effect of anti-resorptive therapy alone. Subsequent whole-body bone scintigraphy demonstrated a "superscan" phenomenon which is characterized by uniform and avid tracer retention throughout the skeleton, in this case due to widespread skeletal metastasis, so that the usual physiological uptake in the kidneys is no longer observed and can be misinterpreted as a "normal" scan if the absence of the kidneys is not recognized. This case highlights the importance of considering diffuse metastatic disease when there is a rapid increase in bone mineral density, even in individuals treated with anti-resorptive therapy.
Subject(s)
Bone Density Conservation Agents/therapeutic use , Bone Density/physiology , Osteoporosis/diagnostic imaging , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/physiopathology , Absorptiometry, Photon/methods , Aged , Androgen Antagonists/adverse effects , Bone Neoplasms/diagnostic imaging , Bone Neoplasms/physiopathology , Bone Neoplasms/secondary , Femur Neck/physiopathology , Humans , Lumbar Vertebrae/physiopathology , Male , Osteoporosis/chemically induced , Osteoporosis/physiopathology , Prostatectomy , Radionuclide ImagingABSTRACT
We present a detailed experimental and theoretical study of the acoustic phonon modes in rolled-up multilayers with thickness of the layers in the nanometre and diameters in the micrometre range. We compare our results to planar, unrolled multilayers grown by molecular beam epitaxy. For the planar multilayers the experimentally obtained acoustic modes exhibit properties of a superlattice and match well to calculations obtained by the Rytov model. The rolled-up superlattice tubes show intriguing differences compared to the planar structures which can be attributed to the imperfect adhesion between individual tube windings. A transfer matrix method including a massless spring accounting for the imperfect adhesion between the layers yields good agreement between experiment and calculations for up to five windings. Areas with sufficient mechanical coupling between all windings can be distinguished by their acoustic mode spectrum from areas where individual windings are only partially in contact. This allows the spatially resolved characterization of individual tubes with micrometre spatial resolution where areas with varying interface adhesion can be identified.
ABSTRACT
The effects of sepiolite addition (0, 1, 3 and 5wt%) were evaluated on dynamic-mechanical behaviour, water uptake, thermal and optical properties of thermoplastic starch (TPS)/poly (butylene adipate-co-terephthalate) (PBAT) nano-biocomposites, with different TPS/PBAT (w/w) ratios and nanofiller contents. The results highlighted the improvement of the dynamic-mechanical behaviour with the addition of sepiolite, producing high performance materials. An increase of 25°C in the Tg of TPS was recorded by DMTA analysis at sepiolite content of 5wt%. The sepiolite influenced the crystallisation of nano-biocomposites, without causing interference in the crystal organisation, evidenced by DSC analysis. The addition of sepiolite nanoclay decreased the water adsorption rate and water adsorption capacity of the corresponding nano-biocomposites. For such multiphase systems, the successful use of natural sepiolite brought a clear benefit, without the need of any modifications or additional processes to produce advanced nano-biocomposites.
Subject(s)
Aluminum Silicates/chemistry , Biocompatible Materials/chemistry , Magnesium Silicates/chemistry , Nanoparticles/chemistry , Polyesters/chemistry , Starch/chemistry , Adsorption , Calorimetry, Differential Scanning , Clay , Color , Elastic Modulus , Models, Theoretical , Temperature , Water/chemistryABSTRACT
BACKGROUND: Obese men commonly have reductions in circulating testosterone and report symptoms consistent with androgen deficiency. We hypothesized that testosterone treatment improves constitutional and sexual symptoms over and above the effects of weight loss alone. METHODS: We conducted a pre-specified analysis of a randomized double-blind, placebo-controlled trial at a tertiary referral center. About 100 obese men (body mass index (BMI)⩾30 kg m-2) with a repeated total testosterone level ⩽12 nmol l-1 and a median age of 53 years (interquartile range 47-60) receiving 10 weeks of a very-low-energy diet (VLED) followed by 46 weeks of weight maintenance were randomly assigned at baseline to 56 weeks of intramuscular testosterone undecanoate (n=49, cases) or matching placebo (n=51, controls). Pre-specified outcomes were the between-group differences in Aging Male Symptoms scale (AMS) and international index of erectile function (IIEF-5) questionnaires. RESULTS: Eighty-two men completed the study. At study end, cases showed significant symptomatic improvement in AMS score, compared with controls, and improvement was more marked in men with more severe baseline symptoms (mean adjusted difference (MAD) per unit of change in AMS score -0.34 (95% confidence interval (CI) -0.65, -0.02), P=0.04). This corresponds to improvements of 11% and 20% from baseline scores of 40 and 60, respectively, with higher scores denoting more severe symptoms. Men with erectile dysfunction (IIEF-5⩽20) had improved erectile function with testosterone treatment. Cases and controls lost the same weight after VLED (testosterone -12.0 kg; placebo -13.5 kg, P=0.40) and maintained this at study end (testosterone -11.4 kg; placebo -10.9 kg, P=0.80). The improvement in AMS following VLED was not different between the groups (-0.05 (95% CI -0.28, 0.17), P=0.65). CONCLUSIONS: In otherwise healthy obese men with mild to moderate symptoms and modest reductions in testosterone levels, testosterone treatment improved androgen deficiency symptoms over and above the improvement associated with weight loss alone, and more severely symptomatic men achieved a greater benefit.
Subject(s)
Androgens/therapeutic use , Diet, Reducing , Hormone Replacement Therapy , Hypogonadism/drug therapy , Hypogonadism/physiopathology , Obesity/physiopathology , Testosterone/therapeutic use , Aging , Androgens/blood , Androgens/deficiency , Australia/epidemiology , Depression , Diet, Reducing/adverse effects , Double-Blind Method , Humans , Hypogonadism/etiology , Hypogonadism/psychology , Libido/physiology , Male , Middle Aged , Obesity/blood , Obesity/complications , Obesity/psychology , Quality of Life , Testosterone/blood , Treatment OutcomeABSTRACT
Deciphering the underlying causes of idiopathic male infertility is one of the main challenges in reproductive medicine. This is especially relevant in infertile patients displaying normal seminal parameters and no urogenital or genetic abnormalities. In these cases, the search for additional sperm biomarkers is of high interest. This study was aimed to determine the implications of the sperm miRNA expression profiles in the reproductive capacity of normozoospermic infertile individuals. The expression level of 736 miRNAs was evaluated in spermatozoa from eight normozoospermic infertile males using TaqMan® qRT-PCR. Results were contrasted with data from 10 control normozoospermic fertile individuals analyzed under the same conditions. Clustering analysis of miRNA expression data separated the individuals according to their fertility condition (fertile and infertile). Fifty-seven miRNAs were differentially expressed (DE-miRNAs) between populations; 20 of them was regulated by a host gene promoter that in three cases comprised genes involved in fertility. The predicted targets of the DE-miRNAs (n = 8,606) unveiled a significant enrichment of biological processes related to embryonic morphogenesis and chromatin modification. Normozoospermic infertile individuals exhibit a specific sperm miRNA expression profile clearly differentiated from normozoospermic fertile individuals. This miRNA cargo has potential implications in the individuals' reproductive competence.
Subject(s)
Fertility/genetics , Infertility, Male/genetics , MicroRNAs/genetics , Spermatozoa/metabolism , Gene Expression Profiling , Humans , Infertility, Male/metabolism , Male , MicroRNAs/metabolism , Sperm Count , Sperm Motility/physiologyABSTRACT
Quantification of abdominal visceral adipose tissue (VAT) is important to understand obesity-related comorbidities. We hypothesized that dual X-ray absorptiometry (DXA) measurements of VAT would correlate with traditional gold standards of magnetic resonance imaging (MRI) and computed tomography (CT) in older men. Deming regression and Bland-Altman plots were used to assess the agreement between VAT measured simultaneously by DXA and MRI (n=95) in a cohort of older males participating in a randomized trial of testosterone replacement for diabetes. We also correlated DXA with single-slice CT (n=102) in a cohort of older males undergoing testosterone deprivation for prostate cancer. Lunar Prodigy DXA scanners using enCORE software was used to measure VAT. DXA VAT volume strongly correlated with MRI VAT volume (r=0.90, P<0.0001) and CT VAT area (r=0.83, P<0.0001). As DXA assesses VAT volume in a smaller compartment than MRI, Bland-Altman analysis demonstrated DXA systematically underestimated VAT by an approximately 30% proportional bias. DXA VAT volume measured by Lunar Prodigy DXA scanners correlate well with gold standard MRI and CT quantification methods, and provides a low radiation, efficient, cost-effective option. Future clinical studies examining the effects of interventions on body composition and regional fat distribution may find DXA an appropriate volumetric method to quantify VAT.
Subject(s)
Absorptiometry, Photon , Intra-Abdominal Fat/diagnostic imaging , Magnetic Resonance Imaging , Obesity/diagnostic imaging , Tomography, X-Ray Computed , Adiposity , Aged , Australia/epidemiology , Body Mass Index , Comorbidity , Cross-Sectional Studies , Humans , Intra-Abdominal Fat/physiopathology , Male , Obesity/complications , Obesity/physiopathology , Reproducibility of ResultsABSTRACT
BACKGROUND: Sarcopenia (loss of muscle mass) is common in cirrhosis and is associated with poor outcomes. Current teaching recommends the use of protein supplementation and exercise, however, this fails to address many other factors which contribute to muscle loss in this setting. AIMS: To summarise existing knowledge regarding the aetiology of sarcopenia in cirrhosis, diagnostic modalities and the clinical significance of this condition. In addition to discuss recent research findings that may allow the development of more effective treatments. METHODS: We conducted a Medline and PubMed search using the search terms 'sarcopenia', 'muscle', 'body composition', 'cirrhosis', 'liver' and 'malnutrition' from inception to October 2015. RESULTS: Cirrhotic patients with sarcopenia have reduced survival, experience increased rates of infection and have worse outcomes following liver transplantation. The aetiology of this condition is more complex than simple protein and calorie malnutrition. Cirrhosis also results in depleted glycogen stores and metabolic alterations that cause excessive protein catabolism, increased activation of the ubiquitin-proteasome pathway and inappropriate muscle autophagy. Satellite cell differentiation and proliferation is also reduced due to a combination of elevated myostatin levels, reduced IGF-1 and hypogonadism. Although there is some evidence supporting the use of late evening snacks, branched chain amino acid supplementation and high protein/high calorie diets, well designed clinical trials addressing the effects of treatment on body composition in cirrhosis are lacking. CONCLUSION: Sarcopenia in cirrhosis has a complex pathogenesis and simple dietary interventions are insufficient. Improved understanding of the multiple mechanisms involved should allow the development of more effective therapies, which target the specific underlying metabolic derangements.
Subject(s)
Liver Cirrhosis/complications , Liver Cirrhosis/diagnosis , Sarcopenia/diagnosis , Sarcopenia/etiology , Adult , Body Composition , Female , Humans , Liver Cirrhosis/therapy , Liver Transplantation/adverse effects , Liver Transplantation/trends , Malabsorption Syndromes/complications , Malabsorption Syndromes/diagnosis , Malabsorption Syndromes/therapy , Middle Aged , Proteolysis , Sarcopenia/therapy , Treatment OutcomeABSTRACT
The origin of the martensitic transition in the magnetic shape memory alloy Ni-Mn-Ga has been widely discussed. While several studies suggest it is electronically driven, the adaptive martensite model reproduced the peculiar nonharmonic lattice modulation. We used femtosecond spectroscopy to probe the temperature and doping dependence of collective modes, and scanning tunneling microscopy revealed the corresponding static modulations. We show that the martensitic phase can be described by a complex charge-density wave tuned by magnetic ordering and strong electron-lattice coupling.
ABSTRACT
The incorporation of nano-sized sepiolite clays into thermoplastic starch/poly(butylene adipate-co-terephthalate) (TPS/PBAT) blends has been investigated with the goal of improving the matrix properties. TPS/PBAT nano-biocomposites were elaborated with two different proportions of the polymeric phases. The influence of the sepiolite nanoclays on the mechanical, thermal and structural properties of the corresponding blends was evaluated. SEM images confirmed the good dispersion of the sepiolite clay, with a low occurrence of small aggregates in the polymeric matrix. Wide-angle X-ray diffraction showed no significant alteration of the crystalline structures of PBAT and starch induced by the sepiolite clay. The addition of sepiolite slightly affected the thermal degradation of the nano-biocomposites; however, the mechanical tests revealed an increase in some mechanical properties, demonstrating that sepiolite is a promising nanofiller for TPS-based materials.
Subject(s)
Biocompatible Materials/chemistry , Magnesium Silicates/chemistry , Polyesters/chemistry , Polymers/chemistry , Starch/chemistryABSTRACT
UNLABELLED: In this longitudinal case-control study, acute fracture was associated with low serum testosterone, which was transient in 43% of men. While assessment of gonadal status is part of the assessment of bone fragility, measurement of testosterone in the early period after fracture may overestimate the prevalence of androgen deficiency. INTRODUCTION: Measurement of circulating testosterone is recommended in the evaluation of bone fragility in men. Since acute illness can transiently decrease circulating testosterone, we quantified the association of acute fracture and serum testosterone levels. METHODS: A case-control study was conducted involving 240 men with a radiologically confirmed minimal trauma fracture presenting to a tertiary referral hospital and 89 age-matched men without a history of minimal trauma fracture serving as controls. Follow-up testosterone levels 6 months after baseline were available for 98 cases and 27 controls. Results were expressed as the median and interquartile (IQR) range. RESULTS: Compared to controls, cases had lower total testosterone [TT, 7.2 (3.5, 10.8) vs 13.6 (10.9, 17.1) nmol/L, p < 0.001]. The 143 cases treated as inpatients had lower testosterone levels than the 97 cases treated as outpatients [TT 4.7 (2.3, 8.1) vs 10.3 (7.5, 12.7) nmol/L, p < 0.001]. Group differences in calculated free testosterone (cFT) were comparable to the group differences in TT. At follow-up, in 98 cases, median TT increased from 6.5 nmol/L (3.2, 8.5) to 9.6 nmol/L (6.9, 12.0) p < 0.0001, and SHBG remained unchanged. Of cases with low testosterone, 43% with TT <10 nmol/L and/or cFT <230 pmol/L at presentation were reclassified as androgen sufficient at follow-up. TT was unchanged in the controls. CONCLUSIONS: Low testosterone levels in men presenting with an acute fracture may, at least in part, be due to an acute, fracture-associated, stress response. To avoid over diagnosis, evaluation for testosterone deficiency should be deferred until recovery from the acute event.
Subject(s)
Osteoporotic Fractures/blood , Testosterone/blood , Absorptiometry, Photon/methods , Acute Disease , Aged , Aged, 80 and over , Bone Density/physiology , Case-Control Studies , Comorbidity , Follow-Up Studies , Hip Joint/physiopathology , Humans , Lumbar Vertebrae/physiopathology , Male , Middle Aged , Osteoporotic Fractures/physiopathology , Testosterone/deficiencyABSTRACT
Starch/PBAT blends were produced by reactive extrusion with tartaric acid (TA) as an additive. The effects of TA, glycerol and starch+PBAT on the mechanical, optical and structural properties of the films were evaluated, with formulations based in a constrained mixture design. Tartaric acid acts as a compatibiliser and promotes the acid hydrolysis of starch chains. These two functions explain the observed film resistance and opacity. TA reduced the weight loss in water. Scanning electron microscopy (SEM) images showed that TA reduces the interfacial tension between the polymeric phases, resulting in more homogeneous films. Nuclear magnetic resonance ((13)C CPMAS) and Fourier transform infrared spectroscopy (FT-IR) suggest that tartaric acid is able to react with the hydroxyl groups of the starch by esterification/transesterification reactions, confirming its role as a compatibiliser. The addition of TA results in materials with better properties that are suitable for use in food packaging.
Subject(s)
Polyesters/chemistry , Starch/chemistry , Tartrates/chemistry , Esterification , Glycerol/chemistry , Magnetic Resonance Spectroscopy , Manihot/chemistry , Microscopy, Electron, Scanning , Spectroscopy, Fourier Transform Infrared , Water/chemistryABSTRACT
Although men with type 2 diabetes (T2D) frequently have lowered testosterone levels, it is not well established whether this is ascribable to the diabetic state per se, or because of other factors, such as obesity. Our objective was to determine the prevalence and correlates of low testosterone in middle-aged men with diabetes. We conducted a cross-sectional study in 240 men including 80 men with type 1 diabetes (T1D), 80 men with T2D and 80 men without diabetes. Prevalence of a total testosterone ≤8 nmol/L was low, occurring in none of the men with T1D, 6.2% of men with T2D and 2.5% of men without diabetes. Men with T1D had higher testosterone levels compared with men without diabetes (p < 0.001), even after adjustment for body mass index (BMI) and age (p < 0.02). While men with T2D had lower testosterone compared with controls (p = 0.03), this was no longer significant when BMI and age were taken into account (p = 0.16). In the entire cohort, TT remained inversely associated with BMI independent of age, sex hormone-binding globulin and diabetic status (p = 0.01), whereas calculated free testosterone (cFT) was independently and inversely associated with age (p < 0.001), but not with BMI (p = 0.47). These results suggest that marked reductions in circulating testosterone are uncommon in middle-aged men with diabetes. Increasing BMI and age are dominant drivers of lowered total and cFT, respectively, independent of the presence or absence of diabetes.
Subject(s)
Obesity/complications , Testosterone/blood , Adult , Aged , Body Mass Index , Cross-Sectional Studies , Diabetes Mellitus, Type 1/blood , Diabetes Mellitus, Type 1/complications , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/complications , Humans , Male , Middle Aged , Obesity/epidemiology , Prevalence , Sex Hormone-Binding Globulin/analysis , Victoria/epidemiologyABSTRACT
Our objective was to evaluate the effectiveness of implementing standardized guidelines to mitigate metabolic and bone side effects of androgen deprivation therapy (ADT) in men with non-metastatic prostate cancer. We conducted a 2-year prospective cohort study at a tertiary referral teaching hospital. Overall, 236 men (mean age 69.8 ± 7.1) commencing ADT for non-metastatic prostate cancer attended a baseline clinic visit between 2007 and 2011, and 153 men were eligible for follow-up after 2 years of continuous ADT. Of these, 113 men had data available for analysis at 2 years. At baseline, 87% of the men were overweight or obese, 61% had hypertension, 56% had hypercholesterolaemia, 27% prior cardiovascular disease, 11% osteoporosis and 40% osteopaenia. After 2 years of ADT, there was an increase in waist circumference (+2.8 ± 6.3 cm, p = 0.002), and, in men without diabetes, in HbA1c (+0.13 ± 0.34%, p = 0.019). Despite this, due to treatment, there were significant reductions in total cholesterol (-0.35 ± 1.00 mmol/L, p < 0.001), and blood pressure (systolic -7.6 ± 19.3 mmHg; diastolic -4.7 ± 11.6 mmHg, p < 0.001). After 2 years, men not receiving anti-resorptive therapy experienced a significant decline in lumbar spine (-0.042 ± 0.134 g/cm(2) , p = 0.012) and total hip bone mineral density (BMD) (-0.026 ± 0.036 g/cm(2) , p < 0.001), whereas bisphosphonate treatment maintained stable BMD. Prevalence of anaemia increased from 13.8 to 32.5%. Older age independently predicted a greater drop in haemoglobin (p = 0.005). We conclude that a structured approach to assess and treat men undergoing ADT effectively improves cardiovascular risk factors and prevents bone decay. Larger studies are needed to determine effects on cardiovascular outcomes, fracture prevention and survival.