Efectos del tratamiento con ácido zoledrónico en pacientes adultos con osteogénesis imperfecta

Background and objectiveOsteogenesis imperfecta (OI) is a genetic disorder that results in bone fragility. Several studies have demonstrated the effectiveness of bisphosphonate therapy. The aim of this study was to evaluate the effects of intravenous zoledronic acid on bone mineral density (BMD) and biochemical markers of bone turnover in adults with OI.Material and methodsWe carried out a prospective non-randomized study in patients with osteoporosis or severe osteopenia (T score <?2) related to OI and intolerance or contraindication to oral bisphosphonates. The patients were treated with a zoledronic acid infusion every 6 months. Densitometry was carried out annually. Calcium (Ca), phosphate (P), intact parathormone (PTH), 25 hydroxyvitamin D and biochemical markers of bone turnover [bone alkaline phosphatase (BAP), beta-cross-laps (CTX) and urinary deoxypyridoxine (DOP)] were measured every year. Adverse events and new fractures were registered.ResultsTen patients (2 men and 8 women) were treated. Treatment increased BMD measured in the lumbar spine after 24 (0.738±0.141 vs 0.788±0.144 g/cm²; p=0.048) and 36 months (0.720±0.139 vs 0.820±0.128; p=0.01). Significant increases in BMD were also observed after 24 months in the femoral neck (0.677±0.121 vs 0.703±0.122 g/cm²; p<0.016). Serum Ca, P, BAP and CTX concentrations remained unchanged. PTH concentrations increased and vitamin D concentrations decreased after 36 months of treatment. DOP excretion decreased significantly after 24 months. Seven patients had mild influenza-like symptoms occurring within the first 24 h after the first infusion. No severe adverse events were observed. None of the patients had new fractures.ConclusionZoledronic acid seems to be a safe and effective treatment option in adults with osteoporosis related to OI.     

A comparison of a moderately hypofractionated IMRT planning technique used in a randomised UK external beam radiotherapy trial with an in-house technique for localised prostate cancer

AimTo compare the radiotherapy technique used in a randomised trial with VMAT and an in-house technique for prostate cancer.BackgroundTechniques are evolving with volumetric modulated arc therapy (VMAT) commonly used. The CHHiP trial used a 3 PTV forward planned IMRT technique (FP_CH). Our centre has adopted a simpler two PTV technique with locally calculated margins.Materials and methods25 patients treated with FP_CH to 60 Gy in 20 fractions were re-planned with VMAT (VMAT_CH) and a two PTV protocol (VMAT_60/52 and VMAT_60/48). Target coverage, conformity index (CI), homogeneity index (HI), monitor units (MU) and dose to the rectum, bladder, hips and penile bulb were compared.ResultsPTV coverage was high for all techniques. VMAT_CH plans had better CI than FP_CH (p ≤  0.05). VMAT_60/52/48 plans had better CI than VMAT_CH. FP_CH had better HI and fewer MU than VMAT (p ≤  0.05). More favourable rectum doses were found for VMAT _CH than FP_CH (V_48.6, V_52.8, V₅₇, p ≤  0.05) with less difference for bladder (p ≥  0.05). Comparing VMAT_CH to VMAT_60/52/48 showed little differences for the bladder and rectum but VMAT_CH had larger penile bulb doses (V_40.8, V_48.6, mean, D_2, p ≤  0.05). Femoral head doses (V_40.8) were similarly low for all techniques (p = ≥ 0.05).ConclusionVMAT produced more conformal plans with smaller rectum doses compared to FP_CH albeit worse HI and more MU. VMAT_60/52 and VMAT_60/48 plans had similar rectal and bladder doses to VMAT_CH but better CI and penile bulb doses which may reduce toxicity.     

Effects of Long-Term Alendronate Treatment on a Large Sample of Pediatric Patients with Osteogenesis Imperfecta

Objective: Osteogenesis imperfecta (OI) is a group of inherited diseases characterized by reduced bone mass, recurrent bone fractures, and progressive bone deformities. Here, we evaluate the efficacy and safety of long-term treatment with alendronate in a large sample of Chinese children and adolescents with OI.Methods: In this prospective study, a total of 91 children and adolescents with OI were included. The patients received 3 years' treatment with 70 mg alendronate weekly and 500 mg calcium daily. During the treatment, fracture incidence, bone mineral density (BMD), and serum levels of the bone turnover biomarkers (alkaline phosphatase [ALP] and cross-linked C-telopeptide of type I collagen [β-CTX]) were evaluated. Linear growth speed and parameters of safety were also measured.Results: After 3 years of treatment, the mean annual fracture incidence decreased from 1.2 ± 0.8 to 0.2 ± 0.3 (P<.01). BMD at the lumbar spine and femoral neck significantly increased by 74.6% and 39.5%, with their BMD Z-score increasing from -3.0 to 0.1 and from -4.2 to -1.3, respectively (both P<.01 vs. baseline). In addition, serum ALP and β-CTX levels decreased by 35.6% and 44.3%, respectively (both P<.05 vs. baseline). Height significantly increased, but without an obvious increase in its Z-score. Patient tolerance of alendronate was good.Conclusion: Three years' treatment with alendronate was demonstrated for the first time to significantly reduce fracture incidence, increase lumbar spine and femoral neck BMD, and decrease bone turnover biomarkers in Chinese children and adolescents with OI.Abbreviations:ALP = alkaline phosphataseβ-CTX = cross-linked C-telopeptide of type I collagenBMD = bone mineral densityBP = bisphosphonateDXA = dual-energy X-ray absorptiometry25OHD = 25-hydroxyvitamin DOI = osteogenesis imperfectaPTH = parathyroid hormone     

Distal skeletal tibia assessed by HR-pQCT is highly correlated with femoral and lumbar vertebra failure loads

Dual energy X-ray absorptiometry (DXA) is the standard for assessing fragility fracture risk using areal bone mineral density (aBMD), but only explains 60–70% of the variation in bone strength. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides 3D-measures of bone microarchitecture and volumetric bone mineral density (vBMD), but only at the wrist and ankle. Finite element (FE) models can estimate bone strength with 86–95% precision. The purpose of this study is to determine how well vBMD and FE bone strength at the wrist and ankle relate to fracture strength at the hip and spine, and to compare these relationships with DXA measured directly at those axial sites. Cadaveric samples (radius, tibia, femur and L4 vertebra) were compared within the same body. The radius and tibia specimens were assessed using HR-pQCT to determine vBMD and FE failure load. aBMD from DXA was measured at the femur and L4 vertebra. The femur and L4 vertebra specimens were biomechanically tested to determine failure load. aBMD measures of the axial skeletal sites strongly correlated with the biomechanical strength for the L4 vertebra (r = 0.77) and proximal femur (r = 0.89). The radius correlated significantly with biomechanical strength of the L4 vertebra for vBMD (r = 0.85) and FE-derived strength (r = 0.72), but not with femur strength. vBMD at the tibia correlated significantly with femoral biomechanical strength (r = 0.74) and FE-estimated strength (r = 0.83), and vertebral biomechanical strength for vBMD (r = 0.97) and FE-estimated strength (r = 0.91). The higher correlations at the tibia compared to radius are likely due to the tibia’s weight-bearing function.     

BMI,hypertension and low bone mineral density in adult men and women

The aim of this work was to estimate the body mass index (BMI) at which risk of hypertension is lowest in men and women, while concurrently considering the protective role of adipose tissue in osteoporosis. Healthy, occupationally active inhabitants of the city of Wroc?aw, Poland, 1218 women and 434 men were studied. BMI, systolic and diastolic blood pressures, bone mineral density (BMD) of the trabecular compartment and distal radius of the non-dominant hand were recorded. Overweight in young women (≤45 years) was associated with increased risk of hypertension, whereas the risk of low bone mineral was decreased for the same BMI. In older women (>45 years), a BMI > 27 was the threshold for increased risk of hypertension. In this age group, extremely slim women (BMI < 21) had the highest risk of low bone mineral density. In younger males (≤45 years), risk of hypertension was lowest among the thinnest subjects (BMI < 21). Increase in BMI over 21 kg/m² increased the risk of hypertension. The probability of low bone mineral density was the same in all BMI categories of men. In older men (>45 years), the thinnest (BMI < 21) had higher risk of hypertension. To begin from BMI = 25 kg/m², there was a monotonous increase in risk of hypertension in men. Higher risk for low bone mineral density was observed in older men with the BMI < 23.Among younger adults, risk of hypertension and low bone mineral density increase at BMI ≥ 21 kg/m² in men and BMI ≥ 23 kg/m² in women. Among older men and women, the BMI threshold was 27 kg/m².     

In situ deformation of growth plate chondrocytes in stress-controlled static vs dynamic compression

Longitudinal bone growth in children/adolescents occurs through endochondral ossification at growth plates and is influenced by mechanical loading, where increased compression decreases growth (i.e., Hueter-Volkmann Law). Past in vivo studies on static vs dynamic compression of growth plates indicate that factors modulating growth rate might lie at the cellular level. Here, in situ viscoelastic deformation of hypertrophic chondrocytes in growth plate explants undergoing stress-controlled static vs dynamic loading conditions was investigated. Growth plate explants from the proximal tibia of pre-pubertal rats were subjected to static vs dynamic stress-controlled mechanical tests. Stained hypertrophic chondrocytes were tracked before and after mechanical testing with a confocal microscope to derive volumetric, axial and lateral cellular strains. Axial strain in hypertrophic chondrocytes was similar for all groups, supporting the mean applied compressive stress’s correlation with bone growth rate and hypertrophic chondrocyte height in past studies. However, static conditions resulted in significantly higher lateral (p < 0.001) and volumetric cellular strains (p ≤ 0.015) than dynamic conditions, presumably due to the growth plate’s viscoelastic nature. Sustained compression in stress-controlled static loading results in continued time-dependent cellular deformation; conversely, dynamic groups have less volumetric strain because the cyclically varying stress limits time-dependent deformation. Furthermore, high frequency dynamic tests showed significantly lower volumetric strain (p = 0.002) than low frequency conditions. Mechanical loading protocols could be translated into treatments to correct or halt progression of bone deformities in children/adolescents. Mimicking physiological stress-controlled dynamic conditions may have beneficial effects at the cellular level as dynamic tests are associated with limited lateral and volumetric cellular deformation.     

Blood lead level and its relationship to essential elements in preschool children from Nanning,China

ObjectiveOur study aimed to assess the distribution of blood lead level and its relationship to essential elements in preschool children in an urban area of China.Design and methodsA total of 6741 children aged 0- to 6-year-old were recruited. Levels of lead, zinc, copper, iron, calcium, and magnesium in whole blood samples were determined using atomic absorption spectrometry.ResultsThe mean blood lead level (BLL) and the prevalence of BLL ≥ 10 μg/dl (5.26 ± 4.08 μg/dl and 6.84%, respectively) increased with age gradually, and there was a gender-difference for blood lead, copper, zinc and iron levels. Compared with the group of children who had BLLs < 5 μg/dl, the groups of 5 ≤ BLLs < 10 μg/dl and 10 ≤ BLLs < 15 μg/dl showed higher blood zinc, iron and magnesium levels, and a lower blood calcium level. A positive correlation of lead with zinc, iron and magnesium, and a negative correlation of lead with calcium were found in the group of children with BLL < 5 μg/dl.ConclusionAge- and gender-differences were found when assessing the BLL and intoxication prevalence in preschool children. Metabolic disorder of essential elements was found even with a low level of lead exposure.     

Dietary boron does not affect tooth strength,micro-hardness,and density,but affects tooth mineral composition and alveolar bone mineral density in rabbits fed a high-energy diet

The objective of this study was to determine whether dietary boron (B) affects the strength, density and mineral composition of teeth and mineral density of alveolar bone in rabbits with apparent obesity induced by a high-energy diet. Sixty female, 8-month-old, New Zealand rabbits were randomly assigned for 7 months into five groups as follows: (1) control 1, fed alfalfa hay only (5.91 MJ/kg and 57.5 mg B/kg); (2) control 2, high energy diet (11.76 MJ and 3.88 mg B/kg); (3) B10, high energy diet + 10 mg B gavage/kg body weight/96 h; (4) B30, high energy diet + 30 mg B gavage/kg body weight/96 h; (5) B50, high energy diet + 50 mg B gavage/kg body weight/96 h. Maxillary incisor teeth of the rabbits were evaluated for compression strength, mineral composition, and micro-hardness. Enamel, dentin, cementum and pulp tissue were examined histologically. Mineral densities of the incisor teeth and surrounding alveolar bone were determined by using micro-CT. When compared to controls, the different boron treatments did not significantly affect compression strength, and micro-hardness of the teeth, although the B content of teeth increased in a dose-dependent manner. Compared to control 1, B50 teeth had decreased phosphorus (P) concentrations. Histological examination revealed that teeth structure (shape and thickness of the enamel, dentin, cementum and pulp) was similar in the B-treated and control rabbits. Micro CT evaluation revealed greater alveolar bone mineral density in B10 and B30 groups than in controls. Alveolar bone density of the B50 group was not different than the controls. Although the B treatments did not affect teeth structure, strength, mineral density and micro-hardness, increasing B intake altered the mineral composition of teeth, and, in moderate amounts, had beneficial effects on surrounding alveolar bone.     

Zoledronic Acid Versus Alendronate In The Treatment of Children With Osteogenesis Imperfecta: A 2-Year Clinical Study

Objective: Bisphosphonates have been demonstrated to increase the bone mineral density (BMD) of osteogenesis imperfecta (OI) patients. We aimed to compare the efficacy and safety of intravenous zoledronic acid and oral alendronate in patients with OI.Methods: A total of 161 patients with OI ranging from 2 to 16 years old were included and randomized at a 2:1 ratio to receive either weekly oral alendronate (ALN) 70 mg or a once-yearly infusion of zoledronic acid (ZOL) for 2 years. The primary endpoints were percentage change from baseline in lumbar spine (LS) BMD and change in Z-scores of LS BMD.Results: A total of 136 patients with OI completed the 2-year clinical study, 90 of whom were assigned to receive ALN, while 46 received ZOL treatment. The percentage change in LS BMD was 60.01 ± 7.08% in the ALN group and 62.04 ± 5.9% in the ZOL group (P = .721). The corresponding BMD Z-score increased by 0.50 ± 0.05 in the ALN group and 0.71 ± 0.06 in the ZOL group (P = .013). ZOL was superior to ALN in reducing the clinical fracture rate (hazard ratio, 0.23; 95% confidence interval, 0.118 to 0.431). There was no difference in the incidence of severe side effects between the two groups.Conclusion: A once-yearly 5 mg infusion of ZOL and weekly oral ALN had similar effects in increasing BMD and reducing bone resorption in children and adolescents with OI. ZOL was superior to ALN in reducing the clinical fracture rate.Abbreviations: 25OHD = 25-hydroxyvitamin D; ALN = alendronate; ALP = alkaline phosphatase; β-CTX = cross-linked C-telopeptide of type I collagen; BMD = bone mineral density; BP = bisphosphonate; FN = femoral neck; LS = lumbar spine; OI = osteogenesis imperfecta; SAE = severe adverse event; ZOL = zoledronic acid     

Efecto de los movimientos explosivos y de impacto aplicados en piscina sobre la composición corporal,la fuerza y la densidad mineral ósea de mujeres mayores de 60 años

BackgroundOsteoporosis is characterised by loss of bone mass and deterioration of bone tissue microarchitecture that leads to fragility related to the risk of fractures. The aim of the study is to analyse the effects of a training program based on explosive movements and impact, assessed in a swimming pool, on body composition, explosive strength and bone mineral density in women over 60 years old.Material and methodsA total of 35 healthy physically active women (60 ± 4.19 years) were divided into a training pool group using multi jumps (JG) and a control group (CG). JG trained for 24 weeks, 3 times a week, an hour and a half per session. Body composition testing, explosive strength, and bone mineral density were assessed before and after the program.ResultsThere were differences in the explosive force (JG vs CG = P < .05 to .001) and the estimated power (JG vs CG = P < .05 to .002) between JG vs CG, with significant increases in JG. There were no significant differences in the percentage of fat and lean mass, bone mineral density lumbar and femoral between groups, although slightly significant increases in bone mineral density lumbar and femoral could be seen in JG after program implementation (JG pre-test vs JG post- test = P < .05).ConclusionsThe training program with impact and explosive movements assessed in a pool induces gains in muscle strength and power with slight adaptations in body mass index in women over 60 years.     

The effect of adding zinc to vitamin A on IGF-1, bone age and linear growth in stunted children

A randomized, double-blind, placebo controlled trial of a single dose of 200,000 I.U. of vitamin A with daily zinc supplementation was conducted with children in Mojo village, Surabaya City. Children aged 48 to 60 months were randomized to receive a single dose of 200,000 I.U. of vitamin A plus zinc sulfate (n = 12) or a single dose of 200,000 I.U. of vitamin A (n = 12) plus placebo six days a week for six months. Children were evaluated weekly for nutrient intake and for IGF-1, C-reactive protein levels, gamma globulin levels, serum zinc, serum retinol, bone age and the index height for age at six months.At the end of the study, there was a significant increase in the serum retinol level (p < 0.03), serum zinc level (p < 0.03), IGF-1 hormone (p < 0.04) and Z-score height for age (p < 0.001), bone age (p < 0.01), and gamma globulin level (p < 0.04) and a significant decrease in the amount of infection/inflammation measured by CRP level (p < 0.001). There was also a significant correlation between CRP level and height for age (p < 0.01), and between gamma level and height for age (p < 0.01).These results suggest that combined vitamin A and zinc supplementation reduces the risk of infection and increases linear growth among children, and thus may play a key role in controlling infection and stunted growth for children under five years old.     

Is bone density associated with intervertebral disc pressure in healthy and degenerated discs?

The coupling of the intervertebral disc (IVD) and vertebra as a biomechanical unit suggests that changes in the distribution of pressure within the IVD (intradiscal pressure, IDP) as a result of disc degeneration can influence the distribution of bone density within the vertebra, and vice versa. The goal of this study was to assess the correspondence between IDP and bone density in the adjacent vertebrae, with emphasis on how this correspondence differs between healthy and degenerated IVDs. Bone density of the endplates and subchondral bone in regions adjacent to the anterior and posterior annulus fibrosus (aAF and pAF, respectively) and nucleus pulposus (NP) was measured via quantitative computed tomography (QCT) in 61 spine segments (T7-9, T9-11, T10-12; 71 ± 14 years). IDP was measured in the aAF, NP, and pAF regions in 26 of the spine segments (68 ± 16 years) while they were tested in flexed (5°) or erect postures. Disc degeneration was assessed by multiple grading schemes. No correlation was found between bone density and IDP in either posture (p > 0.104). Regional variations in IDP and, to a greater extent bone density, were found to change with advancing degeneration: both IDP (p = 0.045) and bone density (p = 0.024) decreased in the NP region relative to the aAF region. The finding of only a modest correspondence between degeneration-associated changes in IDP and bone density may arise from complexity in how IDP relates to mechanical force transmission through the endplate and from limitations of the available IVD grading schemes in estimating the mechanical behavior of the IVD.     

Prevalence and resting behaviour of dengue vectors,Aedes aegypti and Aedes albopictus in dengue high risk urban settings in Colombo,Sri Lanka

Understanding local geographical variation in vector density and bionomics related to virus transmission are critical for planning effective vector control programs to control dengue virus transmission. This study investigated the prevalence and resting behaviour of Aedes aegypti and Ae. albopictus in three dengue high-risk areas in the Colombo District, Sri Lanka. Monthly sampling of resting adult mosquitoes was conducted from August 2019 to February 2020. Thirty-seven percent of the households (289/776) harboured Aedes mosquitoes, and 603 Aedes mosquitoes were collected. The proportion of Ae. aegypti was higher in the overall collection during the collection period (94% [569/603]), and 62% (352/569) were females. Significant monthly variations in Ae. aegypti were observed with respect to the indices: number of females per surveyed house (F/SH; p = 0.001), number of females per Aedes positive house (F/PH; p = 0.029), adult house index (AHI; p = 0.001), adult density (AD; p = 0.005) and resting ratio (RR; p = 0.001). AHI, AD, and RR had statistically significant positive correlations with monthly rainfall (p = 0.001, p = 0.011, and p = 0.002 respectively) and one-month lagged dengue cases (p = 0.002, p = 0.005, and p < 0.001 respectively). A statistically significantly higher proportion of Ae. aegypti females were caught resting indoors (N = 309, 88%) than outdoors (N = 43, 12%; p < 0.001). The most common resting areas were bedrooms (51%) & living/dining rooms (37%), and places were under or on furniture (47%) & hangings (34%) for Ae. aegypti. Conversely, 74% of female Ae. albopictus were collected outdoors. Results of this study could have strong implications to improve vector surveillance and control by early detection of dengue to detect outbreaks and minimization of disease transmission.     

Improving stress shielding following total hip arthroplasty by using a femoral stem made of β type Ti-33.6Nb-4Sn with a Young’s modulus gradation

Stress shielding-related bone loss occurs after total hip arthroplasty because the stiffness of metallic implants differs from that of the host femur. Although reducing stem stiffness can ameliorate the bone resorption, it increases stress at the bone–implant interface and can inhibit fixation. To overcome this complication, a novel cementless stem with a gradient in Young’s modulus was developed using Ti-33.6Nb-4Sn (TNS) alloy. Local heat treatment applied at the neck region for increasing its strength resulted in a gradual decrease in Young’s modulus from the proximal to the distal end, from 82.1 to 51.0 GPa as calculated by a heat transfer simulation. The Young’s modulus gradient did not induce the excessive interface stress which may cause the surface debonding. The main purpose of this study was to evaluate bone remodeling with the TNS stem using a strain-adaptive bone remodeling simulation based on finite element analysis. Our predictions showed that, for the TNS stem, bone reduction in the calcar region (Gruen zone 7) would be 13.6% at 2 years, 29.0% at 5 years, and 45.8% at 10 years postoperatively. At 10 years, the bone mineral density for the TNS stem would be 42.6% higher than that for the similar Ti-6Al-4V alloy stem. The stress–strength ratio would be lower for the TNS stem than for the Ti-6Al-4V stem. These results suggest that although proximal bone loss cannot be eliminated completely, the TNS stem with a Young’s modulus gradient may have bone-preserving effects and sufficient stem strength, without the excessive interface stress.     

A new measure of trip risk integrating minimum foot clearance and dynamic stability across the swing phase of gait

Minimum toe clearance (MTC) is thought to quantify the risk of the toe contacting the ground during the swing phase of gait and initiating a trip, but there are methodological issues with this measure and the risk of trip-related falls has been shown to also be associated with gait speed and dynamic stability. This paper proposes and evaluates a new measure, trip risk integral (TRI), that circumvents many issues with MTC as typically calculated at a single point by considering minimum foot clearance across the entire swing phase and taking into account dynamic stability to estimate risk of falling due to a trip rather than risk of the foot contacting the floor. Shoes and floor surfaces were digitized and MTC and TRI calculated for unimpaired younger (N = 14, age = 26 ± 5), unimpaired older (N = 14, age = 73 ± 7), and older adults who had recently fallen (N = 11, age = 72 ± 5) walking on surfaces with no obstacles, visible obstacles, and hidden obstacles at slow, preferred, and fast gait speeds. MTC and TRI had significant (F ≥ 5, p ≤ 0.005) but differing effects of gait speed and floor surface. As gait speed increased (which increases risk of trip-related falls) MTC indicated less and TRI greater risk, indicating that TRI better quantifies risk of falling due to a trip. While MTC and TRI did not differ by subject group, strong speed-related effects of TRI (F ≥ 8, p ≤ 0.0007) resulted in improved TRI for fallers due to their slower self-selected preferred gait. This demonstrates that slower gait is both an important covariate and potential intervention for trip-related falls.     

Changes in masticatory muscle activity in children with cerebral palsy

The objective of the study was to determine whether children with cerebral palsy (CP) have abnormal bilateral masseter and temporal muscle activation during mastication. The muscular activity of 32 children aged between 7 and 13 years was assessed during the task of non-habitual mastication by means of surface electromyograms. During non-habitual mastication, the amplitude of all assessed muscles in the inactive period and the amplitude of the Right Masseter and Left Temporal muscles in the active period of children with CP was greater (p < 0.05) in relation to the group of children with Typical Development (TD). Considering each muscle individually, only the duration of the active period of Right Masseter and Right Temporal muscles in children with CP was lower (p < 0.05) than in the TD children. Considering the four analyzed muscles, the duration of time of general active period, when at least one muscle should be activated, was higher in children with CP (p < 0.05) than in children with TD showing greater time variation in inactivation (p < 0.05). The higher muscle activity during the phases of the masticatory cycle, with longer duration of the active period and with greater variability between the muscles to inhibit this activity show greater difficulty in coordinating the muscles of mastication in children with CP compared to children with TD.     

The upper and lower segments of subscapularis muscle have different roles in glenohumeral joint functioning

Subscapularis muscle is divided into two independent segments, upper and lower (USUB and LSUB), but the role of each segment in glenohumeral functioning is unclear. We compared the electromyographic (EMG) activity of USUB and LSUB during a variety of shoulder movements, with and without an external translation force. Intramuscular electrodes were inserted in USUB and LSUB segments of 20 adults without pathology and EMG activity was measured in stabilization trials (with and without an anterior or posterior directed force at the humerus and isometric rotations) and two shoulder positions (shoulder neutral, abduction). Maximal voluntary isometric contraction (MVIC) trials were performed in abduction, internal and external rotation of the shoulder. In MVIC trials, USUB showed higher activity during internal rotation (p = 0.03), whereas LSUB showed higher activity during external rotation (p < 0.01). In stabilization trials, the interaction effects were significant for muscle segment × condition (p < 0.01), and approached significance for muscle segment × position (p = 0.06). In the neutral position, the pattern of activity for LSUB was similar to USUB. In the abducted position the LSUB, unlike USUB, was more active during external rotation (p = 0.06) and also showed increased activity in response to the posterior directed force at the humerus (p = 0.04). Our results suggest that USUB primarily acts as an agonist for internal rotation. In contrast LSUB was particularly active in external rotation in the abducted position and demonstrated increased EMG activity in response to the posteriorly directed force at the humerus in that position, suggesting more of a role in glenohumeral stabilization.     

Cotyledonary responses to maternal selenium and dietary restriction may influence alterations in fetal weight and fetal liver glycogen in sheep

To examine the effects of maternal supranutritional selenium (Se) and nutrient restriction during mid and late gestation on placental characteristics and fetal liver glycogen, ewes received either adequate Se (ASe) or high Se (HSe) prior to breeding. On d 64 of gestation, ASe and HSe ewes remained at 100% of requirements (controls; CON) or were restricted (RES; 60% of requirements). On d 135 of gestation, fetal weight (P ≤ 0.08) was greatest in both HSe and CON ewes. Placentome number, mass, and caruncular and cotyledonary weight were not different (P ≥ 0.17) among treatments. Fetal mass:placental mass ratio was less (P = 0.06) in RES compared to CON ewes. Compared to ASe, HSe exhibited increased (P ≤ 0.08) cellular proliferation and DNA concentration and decreased (P = 0.07) cellular size in cotyledonary tissue. Nutritional restriction decreased (P ≤ 0.08) cotyledonary protein concentration and cellular size. VEGF receptor 1 (Flt) mRNA in cotyledonary tissue was greater in HSe compared with ASe ewes (P = 0.06) and in RES compared with CON ewes (P = 0.08). There was no effect of diet on caruncular growth variables (P ≥ 0.13) or on placental vascularity (P ≥ 0.11). Progesterone was greater (P ≤ 0.08) in ASe–RES ewes compared to all groups at d 90 and ASe–CON and HSe–CON at d 104. Although fetal glucose and cortisol concentrations were not affected by diet, fetal liver glycogen was greater (P = 0.04) in ASe–RES compared to ASe–CON and HSe–RES ewes with HSe–CON being intermediate. Both Se and nutritional plane may impact placental function and fetal growth, as fetal weight and liver glycogen are altered despite similar placental vascularity measurements.     

Patients at risk for trace element deficiencies: Bariatric surgery

Obesity is a worldwide epidemic associated with diseases such as diabetes mellitus and cardiovascular disease. Current methods for weight loss are not very effective, particularly for those with morbid obesity. Surgical therapy may be recommended for those with a BMI ≥ 40 kg/m², or BMI ≥ 35 kg/m² with co-morbidities. This therapy can produce significant weight loss and improve/resolve co-morbidities including hypertension and hyperlipidemia. Yet successes may be tempered by adverse effects on trace element absorption and status. A PubMed literature search identified studies from January 1980 to February 2013 for inclusion in a meta-analysis. Publications that contained keywords ‘bariatric surgery or gastric bypass,’ ‘trace element or mineral or zinc or iron or copper or iodine or manganese’, and ‘absorption or status or rate or level’ were identified. Inclusion criteria were human markers that reflect changes in trace element status before and after bariatric surgery. The meta-analysis found a decrease in blood copper, zinc, hemoglobin, as well as an increase in iron, regardless of the type of surgery. The pooled effect sizes and 95% confidence intervals were 0.17 and −0.09 to 0.43 for plasma/serum iron (p = 0.20); −0.49 and −0.67 to −0.31 for blood hemoglobin (p = 0.00); −0.47 and −0.90 to −0.05 for plasma/serum copper (p = 0.03); −0.77 and −1.20 to −0.35 for plasma/serum zinc (p = 0.00). Differences in levels of these minerals pre- and post-surgery may have been influenced by the time period after surgery, a pre-existing deficiency, type and dose of vitamin–mineral supplements, and malabsorption due to elimination of parts of the gastrointestinal tract.     

Trace elements,oxidative stress and glycemic control in young people with type 1 diabetes mellitus

Trace elements and oxidative stress are associated with glycemic control and diabetic complications in type 1 diabetes mellitus. In this study, we analyzed the levels of serum copper, zinc, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) and urinary MDA and 8-hydroxy-2′-deoxyguanosine (8-OHdG) in 33 type 1 diabetic patients with optimal and suboptimal glycemic control (HbA_1C < 9.0%) and 40 patients with poor glycemic control (HbA_1C ≥ 9%) and 27 age- and sex-matched non-diabetic controls to evaluate the differences between these markers in different glycemic control states. Diabetic patients, especially poor-glycemic-control subjects (HbA_1C ≥ 9%), exhibited significantly lower levels of serum zinc and increased levels of serum copper (and, therefore, increased serum copper-to-zinc ratios), serum SOD, blood MDA, and urinary MDA and 8-OHdG, relative to non-diabetic subjects. Furthermore, significant correlations existed in these patients between the serum copper, serum copper-to-zinc ratio, and urinary MDA (all p < 0.001) and the levels of urinary 8-OHdG (p = 0.007) and HbA_1C. Our results suggest that high serum copper levels and oxidative stress correlate with glycemic control. Therefore, strict glycemic control, decreased oxidative stress, and a lower copper concentration might prevent diabetic complications in patients with type 1 diabetes mellitus.