Plasma Copper and Bone Mineral Density in Osteopenia: An Indicator of Bone Mineral Density in Osteopenic Females

Copper concentrations in blood plasma have been determined in 25 osteopenic females using inductively coupled plasma–mass spectrometry. A high degree of correlations has been demonstrated between the copper concentrations in plasma and the bone mineral density of the lumbar spine as measured using dual energy X-ray absorptiometry and quantitative computerized tomography. Results clearly indicate the involvement of copper in bone health and osteopenia. It is further suggested that plasma copper might be useful as a cheap and simple method indicative of bone mineral density in osteopenic postmenopausal females.     

Anaerobic degradation of protocatechuate (3,4-dihydroxybenzoate) by Thauera aromatica strain AR-1

The denitrifying bacterium Thauera aromatica strain AR-1 grows anaerobically with protocatechuate (3,4-dihydroxybenzoate (DHB)) as sole energy and carbon source. This bacterium harbors two distinct pathways for degradation of aromatic compounds, the benzoyl-coenzyme A (CoA) pathway for benzoate degradation and the hydroxyhydroquinone (HHQ) pathway for degradation of 3,5-DHB. In order to elucidate whether protocatechuate is degraded via the benzoyl-CoA or the HHQ pathway, induction experiments were carried out. Dense suspensions of cells grown on protocatechuate or benzoate readily degraded benzoate and protocatechuate but not 3,5-DHB. Dense suspensions of 3,5-DHB-grown cells degraded 3,4- and 3,5-DHB at similar rates, but benzoate was not degraded. 3,5-DHB hydroxylating activity was found only in cells grown with this substrate. HHQ dehydrogenase activity was found in extracts of cells grown with 3,5-DHB and at a low rate also in protocatechuate-grown cells, but not in extracts of cells grown with benzoate. Activities of protocatechuyl-CoA synthetase and protocatechuyl-CoA reductase leading to 3-hydroxybenzoyl-CoA were found in extracts of cells grown with protocatechuate. There was no repression of the HHQ pathway by the presence of protocatechuate, unlike by degradation of benzoate. We conclude that protocatechuate is not degraded via the HHQ pathway because there was no evidence of a hydroxylation reaction involved in this process. Instead, our results strongly suggest that protocatechuate is degraded via a pathway which connects to the benzoyl-CoA route of degradation.     

Long-term four-year exercise has a positive effect on menopausal risk factors: the Erlangen Fitness Osteoporosis Prevention Study

The purpose of the study was to determine the effect of long-term exercise on coronary heart disease, osteoporotic risk factors, and physical fitness parameters in postmenopausal women. Forty early postmenopausal women (age 55.1 +/- 3.3 years) with no medication or illness affecting bone metabolism exercised (high impact aerobic, multilateral jumps, multi-set resistance exercise) for 50 months (EG), while 28 women (age 55.5 +/- 3.0 years) served as a nontraining control (CG). Both groups were supplemented with calcium and cholecalciferol. Bone mineral density (BMD) was measured at the lumbar spine, hip, and forearm by dual energy x-ray absorptiometry. Blood lipids were determined using serum samples, and body composition was determined using the bioimpedance technique. Further, maximum isometric strength was determined (Schnell M3, Schnell Trainer). The BMD at the lumbar spine (+1.0%, p = 0.037) and the total hip (-0.3%, p = 0.194) were maintained in the EG, while significant (p < 0.001) decreases were observed in the CG (lumbar spine -3.2; total hip -2.3%). Differences between both groups were significant (p < 0.001). Significant differences between EG and CG were also observed, respectively, for total cholesterol (-6.1 vs. +3.5%, p = 0.008), HDL-cholesterol (+14.1 vs. -7.1%, p = 0.007), triglycerides (-10.2 vs. +27.5%, p = 0.002), body fat (-3.3 vs. +1.3%, p = 0.041), and waist-hip-ratio (-3.5 vs. +0.2%, p > 0.001). Maximum isometric strength significantly (p < 0.001) increased in the EG, while strength parameters decreased in the CG (-0.5 to -6.4%). Thus, the study demonstrated that multipurpose high-intensity exercise programs significantly affect relevant menopausal risk factors and, therefore, may be individually considered as an alternative to hormone replacement therapy.     

Effect of whole-body electromyostimulation on energy expenditure during exercise

The application of whole-body electromyostimulation (WB-EMS) in the area of fat reduction and body shaping has become more popular recently. Indeed, some studies prove positive outcomes concerning parameters related to body composition. However, there are conflicting data as to whether EMS relevantly impacts energy expenditure (EE) during or after application. Thus, the main purpose of the study was to determine the acute effect of WB-EMS on EE. Nineteen moderately trained men (26.4 ± 4.3 years) were randomly assigned to a typically used low-intensity resistance exercise protocol (16 minutes) with (85 Hz) and without WB-EMS. Using a crossover design, the same subjects performed both tests after completely recovering within 7 days. Energy expenditure as the primary endpoint of this study was determined by indirect calorimetry. The EE during low-intensity resistance exercise with adjuvant WB-EMS was significantly higher (p = 0.008) than that during the control condition (412 ± 60 vs. 352 ± 70 kcal; effect size; d = 0.92). This study clearly demonstrates the additive effect of WB-EMS on EE in moderately trained subjects during low-intensity resistance exercise training. Although this effect was statistically significant, the fast and significant reductions of body fat observed in recent studies suggest that the effect of WB-EMS on EE may still be underestimated by indirect calorimetry because of the inability of indirect calorimetry to accurately assess EE during "above-steady state conditions." Although from a statistically point of view WB-EMS clearly impacts EE, the relatively small effect did not suggest a broad application of this device in this area. However, taking other positive outcomes of this technology into account, WB-EMS may be a time-saving option at least for subjects unwilling or unable to exercise conventionally.     

Power training is more effective than strength training for maintaining bone mineral density in postmenopausal women.

Physical exercise has a favorable impact on bones, but optimum training strategies are still under discussion. In this study, we compared the effect of slow and fast resistance exercises on various osteodensitometric parameters. Fifty-three postmenopausal women were randomly assigned to a strength training (ST) or a power training group (PT). Both groups carried out a progressive resistance training, a gymnastics session, and a home training over a period of 12 mo. During the resistance training, the ST group used slow and the PT group fast movements; otherwise there were no training differences. All subjects were supplemented with Ca and vitamin D. At baseline and after 12 mo, bone mineral density (BMD) was measured at the lumbar spine, proximal femur, and distal forearm by dual-energy X-ray absorptiometry. We also measured anthropometric data and maximum static strength. Frequency and grade of pain were assessed by questionnaire. After 12 mo, significant between-group differences were observed for BMD at the lumbar spine (P < 0.05) and the total hip (P < 0.05). Whereas the PT group maintained BMD at the spine (+0.7 +/- 2.1%, not significant) and the total hip (0.0 +/- 1.7%, not significant), the ST group lost significantly at both sites (spine: -0.9 +/- 1.9%; P < 0.05; total hip: -1.2 +/- 1.5%; P < 0.01). No significant between-group differences were observed for anthropometric data, maximum strength, BMD of the forearm, or frequency and grade of pain. These findings suggest that power training is more effective than strength training in reducing bone loss in postmenopausal women.     

Isolation and growth of a bacterium able to degrade nitrilotriacetic acid under denitrifying conditions

A Gram-negative bacterium was isolated from river sediment which was able to grow with nitrilotriacetic acid as a combined carbon, nitrogen and energy source in the absence of molecular oxygen using nitrate as the terminal electron acceptor. Batch growth parameters and mass balances are reported for growth under both aerobic and denitrifying conditions.The strain was characterized with respect to its substrate spectrum and other physiological properties. This denitrifying isolate is serologically unrelated to the comprehensively described Gram-negative obligately aerobic NTA-degrading bacteria all of which belong to the -subclass of Proteobacteria. Chemotaxonomic characterization, which revealed the presence of spermidine as the main polyamine and ubiquinone Q-8, excludes the new isolate from the phylogenetically redefined genus Pseudomonas and indicates a possible location within the -subclass of Proteobacteria close to, but separate from the genus Xanthomonas.     

Cyclic AMP modulates insulin binding and induces post-receptor insulin resistance of glucose transport in isolated rat adipocytes

The effect of cAMP on insulin binding and insulin stimulation of glucose transport was investigated in isolated rat adipocytes. Preincubation for 30 min in medium containing 16 mmol/l glucose and either db-cAMP or bromo-cAMP in concentrations of 10(-4)-10(-3) M inhibited high affinity binding of insulin by 15 to 30% and glucose transport by 30 to 50%. Preincubation with IBMX (10(-4)-10(-3) M) reduced insulin binding by 25% and glucose transport by 70%. Closer analysis of these data indicated that preincubation with these compounds caused not only a decrease in insulin binding but also a post-receptor resistance. High intracellular cyclic AMP-levels seem therefore to induce insulin resistance at both receptor and post-receptor levels.     

Impact of testing strategy on expression of upper-body work capacity and one-repetition maximum prediction after resistance training in college-aged men and women

The purpose of this study was to assess the effect of resistance training on upper-body muscular strength and the expression of work capacity and muscular endurance. In addition, a training-induced change in the relationship between muscular strength and endurance was assessed by testing changes in the accuracy of using endurance repetitions to predict 1 repetition maximum (1RM) bench press before and after training. College-aged men (n = 85) and women (n = 62) completed a 12-week linear periodization resistance training program. Before and after training, the subjects were assessed for 1RM and repetitions to fatigue (RTFs) with a submaximal load. After pretraining 1RM determination, the subjects were randomly assigned to perform RTFs at 65% 1RM (n = 74) or 90% 1RM (n = 73). Pretraining and posttraining RTFs were conducted at the same respective % 1RM. Work capacity was determined from repetition weight × RTF. After training, there was a significant increase in 1RM in both men (～14%) and women (～23%). Posttraining RTF was not different from pretraining RTF at 65 %1RM (18.2 ± 5.1 and 19.0 ± 6.0, respectively) but was significantly reduced in the 90% 1RM group (6.1 ± 3.6 vs. 4.5 ± 2.7, respectively). Likewise, there was a differential effect of training on the expression of work capacity, which increased in the 65 % 1RM group (123 ± 155 kg-reps) but decreased in the 90% 1RM group (-62 ± 208 kg-reps); the effect was independent of gender within each testing group. In conclusion, the changes in muscular strength associated with resistance training produced an increase in work capacity when tested with a 65 % 1RM load without a change in endurance. In contrast, both work capacity and endurance decreased when tested with 90% 1RM. Thus, the impact of strength training on work capacity and muscle endurance is specific to the load at which endurance testing is performed.