Effect of daily short-duration weight-bearing on disuse-induced deterioration of musculoskeletal system

Objectives:

To investigate deterioration of musculoskeletal system due to prolonged disuse and the potential of daily short-duration weight-bearing as countermeasures.

Methods:

Twenty-four adult male Sprague-Dawley rats were divided into Control Group (CG, no intervention), Tail-suspension Group (TG, tail-suspension without treatment), and Weight-Bearing Group (WBG, tail-suspension with 20 min/day, 5 days/week body weight loading). After four weeks of treatment, femur and tibia, soleus and extensor digitorum longus were evaluated for bone and muscle quality respectively. Tensile properties of bone-tendon insertion (BTI) were evaluated using patella-patellar tendon complex.

Results:

Disuse induced deterioration on bone, muscle, and BTI after four weeks. Compared with CG, TG and WBG showed significant decrease in bone mineral density (BMD) of trabecular bone in distal femur (4.3-15.2%), muscle mass (31.3-52.3%), muscle cross-sectional area (29.1-35%), and failure strength of BTI (23.9-29.4%). Tensile test showed that the failure mode was avulsion of bone at the BTI. No significant difference was detected between TG and WBG for all assessments on bone, muscle, and BTI.

Conclusions:

Disuse caused deterioration of bone, muscle, and BTI while daily short-duration of weight-bearing did not prevent this deterioration. Mechanical stimulation with higher intensity and longer duration may be necessary to prevent musculoskeletal deterioration resulted from prolonged disuse.     

Deep oxidation of glucose in enzymatic fuel cells through a synthetic enzymatic pathway containing a cascade of two thermostable dehydrogenases

A sensitive glutamate biosensor is prepared based on glutamate dehydrogenase/vertically aligned carbon nanotubes (GLDH, VACNTs). Vertically aligned carbon nanotubes were grown on a silicon substrate by direct current plasma enhanced chemical vapor deposition (DC-PECVD) method. The electrochemical behavior of the synthesized VACNTs was investigated by cyclic voltammetry and electrochemical impedance spectroscopic methods. Glutamate dehydrogenase covalently attached on tip of VACNTs. The electrochemical performance of the electrode for detection of glutamate was investigated by cyclic and differential pulse voltammetry. Differential pulse voltammetric determinations of glutamate are performed in mediator-less condition and also, in the presence of 1 and 5 μM thionine as electron mediator. The linear calibration curve of the concentration of glutamate versus peak current is investigated in a wide range of 0.1-500 μM. The mediator-less biosensor has a low detection limit of 57 nM and two linear ranges of 0.1-20 μM with a sensitivity of 0.976 mA mM(-1) cm(-2) and 20-300 μM with a sensitivity of 0.182 mA mM(-1) cm(-2). In the presence of 1 μM thionine as an electron mediator, the prepared biosensor shows a low detection limit of 68 nM and two linear ranges of 0.1-20 with a calibration sensitivity of 1.17 mA mM(-1) cm(-2) and 20-500 μM with a sensitivity of 0.153 mA mM(-1) cm(-2). The effects of the other biological compounds on the voltammetric behavior of the prepared biosensor and its response stability are investigated. The results are demonstrated that the GLDH/VACNTs electrode even without electron mediator is a suitable basic electrode for detection of glutamate.     

Constructing the electricity-carbohydrate-hydrogen cycle for a sustainability revolution

In this opinion, we suggest the electricity-carbohydrate-hydrogen (ECHo) cycle which bridges primary energies and secondary energies. Carbohydrates are sources of food, feed, liquid biofuels, and renewable materials and are a high-density hydrogen carrier and electricity storage compounds (e.g. >3000 Wh/kg). One element of this ECHo cycle can be converted to another reversibly and efficiently depending on resource availability, needs and costs. This cycle not only supplements current and future primary energy utilization systems for facilitating electricity and hydrogen storage and enhancing secondary energy conversion efficiencies, but also addresses such sustainability challenges as transportation fuel production, CO(2) utilization, fresh water conservation, and maintenance of a small closed ecosystem in emergency situations.     

ErbB2 overexpression in p53-inactivated mammary epithelial cells

Functional loss of p53 and ErbB2 overexpression are the frequent genetic alterations in human breast carcinomas. Here, we found that ErbB2 expression was upregulated in primary cultured mammary epithelial cells (MECs) isolated from mice with a defect in exons 5 and 6 of the p53 gene (p53(Delta5,6)). The reporter gene activity in the p53(Delta5,6) MECs transfected with the -756bp flanking region of the hErbB2 gene was higher than the wild type MECs. p53 inactivation selectively increased the level of AP-2alpha, but not AP-2beta and AP-2gamma and a mutation of the two AP-2 binding sites completely inhibited the reporter activity.     

Effects of feeding dry propylene glycol to early postpartum Holstein dairy cows on production and blood parameters

In all, 18 multiparous and 19 primiparous Holstein dairy cows were used in a completely randomized design with restrictions to evaluate the effects of feeding propylene glycol (PG) as a dry product, via two delivery methods, on production and blood parameters. PG treatments were administered from parturition through 21 days postpartum. Treatments were: (i) control, no PG; (ii) top dress, 162.5 g PG/day by top dressing onto the total mixed ration (TMR) and; (iii) mixing, 162.5 g PG/day as a part of the TMR by incorporating it into the TMR. PG used was a dry product which contained 65% pure PG and 35% silicon dioxide as the dry carrier. Coccygeal blood was sampled on 4, 7, 14 and 21 days in milk (±1.50 pooled s.d.). Supplementation of dry PG by top dressing onto, or incorporating into, the TMR had no effects on average dry matter intake, milk yield and composition, serum insulin, serum and plasma metabolites and milk ketones. Concentrations of urine ketones tended (P = 0.10) to be reduced by PG supplementation from 41.5 to 15.2 mg/dl. Supplementation of PG tended (P = 0.07) to decrease the incidence for subclinical ketosis from 39% to 24% and 13% for cows fed a TMR supplemented with no dry PG, with dry PG as a top dress and dry PG as a part of the TMR, respectively. It is concluded that supplementing PG as a dry product via incorporating into the TMR is as effective as when used as a top dress, based on the efficacies of both delivery methods to numerically reduce urine ketones concentrations and, therefore, the incidence for subclinical ketosis during the first 21 days of lactation. However, it should be noted that the number of cows used in the current study was minimal, and more cows are needed to confirm the efficacy of supplementing PG as a dry product on reducing the prevalence of subclinical ketosis in dairy cows during the first month of lactation.