Reduction of calprotectin and phosphate during testosterone therapy in aging men: a randomized controlled trial.

OBJECTIVES: To investigate the effect of testosterone treatment on biomarkers calprotectin, fibroblast growth factor 23 (FGF23), soluble Klotho, phosphate, calcium, parathyroid hormone, creatinine and estimated glomerular filtration rate. DESIGN: Randomized, double-blinded, placebo-controlled study. SETTING: Odense Androgen Study-the effect of Testim and training in hypogonadal men. PARTICIPANTS: Men aged 60-78 years old with a low normal concentration of free of bioavailable testosterone <7.3 nmol/L and waist circumference >94 cm recruited from 2008 to 2009 (N = 48) by advertisement. INTERVENTION: Participants were randomized to receive 5-10 g gel/50-100 mg testosterone (Testim®, Ipsen, France) or 5-10 g gel/placebo. RESULTS: The plasma levels of calprotectin and phosphate were significantly reduced in the group receiving testosterone therapy (gel) compared to the placebo group (p < 0.05). Testosterone treatment did not have any significant effect on plasma levels of FGF23 or soluble Klotho. The reduction in phosphate levels was inversely associated with bioavailable testosterone. CONCLUSION: Compared to the placebo group, 6 months of testosterone therapy (gel) reduced calprotectin and phosphate levels suggesting decreased inflammation and decreased cardiovascular risk.

Cost-Effectiveness Analysis of Surface Flow Constructed Wetlands (SFCW) for Nutrient Reduction in Drainage Discharge from Agricultural Fields in Denmark.

Constructed wetlands have been proposed as cost-effective and more targeted technologies in the reduction of nitrogen and phosphorous water pollution in drainage losses from agricultural fields in Denmark. Using two pig farms and one dairy farm situated in a pumped lowland catchment as case studies, this paper explores the feasibility of implementing surface flow constructed wetlands (SFCW) based on their cost effectiveness. Sensitivity analysis is conducted by varying the cost elements of the wetlands in order to establish the most cost-effective scenario and a comparison with the existing nutrients reduction measures carried out. The analyses show that the cost effectiveness of the SFCW is higher in the drainage catchments with higher nutrient loads. The range of the cost effectiveness ratio on nitrogen reduction differs distinctively with that of catch crop measure. The study concludes that SFCW could be a better optimal nutrients reduction measure in drainage catchments characterized with higher nutrient loads.

Cerebral energy metabolism during induced mitochondrial dysfunction.

BACKGROUND: In patients with traumatic brain injury as well as stroke, impaired cerebral oxidative energy metabolism may be an important factor contributing to the ultimate degree of tissue damage. We hypothesize that mitochondrial dysfunction can be diagnosed bedside by comparing the simultaneous changes in brain tissue oxygen tension (PbtO(2)) and cerebral cytoplasmatic redox state. The study describes cerebral energy metabolism during mitochondrial dysfunction induced by sevoflurane in piglets. METHODS: Ten piglets were included, seven in the experimental group (anesthetized with sevoflurane) and three in the control group (anesthetized with midazolam). PbtO(2) and cerebral levels of glucose, lactate, and pyruvate were monitored bilaterally. The biochemical variables were obtained by intracerebral microdialysis. RESULTS: All global variables were within normal range and did not differ significantly between the groups except for blood lactate that was slightly higher in the experimental group. Mitochondrial dysfunction was observed in the group of animals initially anesthetized with sevoflurane. Cerebral glucose was significantly lower in the experimental group than in the control group whereas lactate and lactate/pyruvate ratio were significantly higher. Pyruvate and tissue oxygen tension remained within normal range in both groups. Changes of intracerebral variables indicating mitochondrial dysfunction were present already from the very start of the monitoring period. CONCLUSION: Intracerebral microdialysis revealed mitochondrial dysfunction by marked increases in cerebral lactate and lactate/pyruvate ratio simultaneously with normal levels of pyruvate and a normal PbtO(2). This metabolic pattern is distinctively different from cerebral ischemia, which is characterized by simultaneous decreases in PbtO(2) and intracerebral pyruvate.

Influence of temperature on the binding of sodium aurothiosulphate to human serum albumin.

The influence of temperature on the binding of aurothiosulphate by human serum albumin was studied in unbuffered solutions at pH 7.4 and ionic strength 0.15 M by means of equilibrium dialysis. It was found that the high affinity association constant was temperature dependent. The thermodynamic characteristics of binding delta G1 degrees less than 0, delta H1 degrees greater than 0 and delta S1 degrees greater than 0 indicated that the binding process was endothermic and entropically driven. It was concluded that electrostatic interaction was predominantly involved in the binding of aurothiosulphate to the high affinity binding site on albumin. This is consistent with the molecular mechanism that the ligand binds as Au+ to a sulfhydryl group of albumin by replacing a hydrogen ion.

Influence of ionic strength on the binding of sodium aurothiosulphate to human serum albumin.

The effect of ionic strength on the binding of aurothiosulphate to human serum albumin has been studied at 37 degrees and neutral pH by equilibrium dialysis in unbuffered solutions. The effect of ionic strength is more pronounced on the lower association constants K2-K4 than on the high association constant K1. Furthermore a reduction in the number of lower affinity binding sites is observed at low ionic strength. The main ionic strength dependence on the association constants agrees with the Debye-Hückel theory. The extrapolated values of K1 and the sum of K2 to K4 at zero ionic strength are 7.6 X 10(5) M-1 and 1.1 X 10(5) M-1, respectively. It is shown that the observed changes in pH of the albumin solutions during dialysis contains valuable information of the aurothiosulphate-albumin interaction. A molecular binding mechanism is discussed.

The effect of pH on the binding of sodium aurothiosulphate to human serum albumin. A possible binding mechanism.

The effect of pH on the binding of aurothiosulphate to human serum albumin was studied in unbuffered solutions at 37 degrees and ionic strength 0.15-0.16 M. In the investigated pH range, 6.3-8.4, the effect of pH on the high affinity association constant K1 was very different from that on the lower affinity constants K2-K4. K1 was virtually constant except for a two-fold decrease in the narrow pH range 7.5-7.9, which was explained as a H+ induced local conformation change in the environment of site 1. Contrary to this, K2-K4 decreased monotonically with increasing pH, which could be entirely accounted for by a change in electrostatic interaction. A conceivable binding mechanism consistent with the results might be: that gold binds as Au+ to the high affinity binding site by exchanging a H+ and that this site might be the free sulphydryl group in cysteine or the terminal alpha-amino group; and that gold binds as Au(S2O3)3-(2) to the lower affinity binding sites which might be the protonated basic side chain group, i.e. epsilon-amino groups.

Effect of protein concentration on the binding of gold(I) to human serum albumin.

The binding of aurothiosulphate, gold(I), by human serum albumin has been studied by equilibrium dialysis at four different albumin concentrations, 37 degrees, pH 7.2-7.4 and ionic strength 0.15 M. The results show that the interaction of aurothiosulphate with albumin depends on albumin concentration. This observation is linked with the previous observation that the usual independent site description cannot be used to represent the clinically important low concentration data. All the observed dependences are satisfactorily accounted for by assuming that gold(I) competes with a highly bound contaminant for the high affinity (Cys(34)-SH) site. This description is supported by the experimental observation that a fraction of this site is originally blocked both in vivo and in in vitro. The present interpretation yields a high affinity binding constant 100 times larger than found previously and provides an explanation for the lack of correlation between dose and therapeutic and toxic effects in chrysotherapy.

Contamination by a competitive ligand as an explanation for the inverse dependence of HABA binding parameters upon the protein concentration.

There is evidence that the apparent association constant (K) and/or the number of binding sites (n) are inversely dependent upon protein concentration for a number and variety of ligands with no obvious structure-activity relationships. A model recently shown to explain this effect with an inorganic ligand has now been applied to 2-(4'-hydroxybenzeneazo) benzoic acid (HABA) and also explains the inverse protein dependence of the binding of this compound to human albumin. The model explains this inverse dependence on the basis of a highly bound contaminant which competes with the ligand for the high affinity site. HABA was found to interact with human albumin at three or more sites, the high affinity site which was about 95% contaminated had an association constant of 2 x 10(5)/M, an order of magnitude higher than that found previously when the effect of a contaminant was not considered. The association constant of the competitive contaminant was estimated to be about 5 x 10(6)/M. Since the model accounts for the phenomenon in terms of a property of the protein, rather than of the ligand, it could provide a general explanation for this effect with other ligand-acceptor combinations including a wide variety of drug and hormone receptor preparations.

A general method of deriving the best binding site model consistent with experimental binding data.

An analysis of binding data is presented which yields the best binding site model consistent with the experimental data. The analysis is applicable to homotropic binding and yields the number of independent sites, number of interacting sites (dimers and tetramers of sites), intrinsic association constants, and degree of interaction. The information is derived from the roots of a binding polynomial constructed by the fitted Adair constants.

Effect of a contaminating competitive ligand on ligand-binding curves. Inverse protein concentration dependence.

A theoretical binding model is considered which provides an explanation for the inverse protein concentration dependence observed for a variety of ligands. The model describes the inhibition of binding caused by a highly bound contaminant. The complete binding equation is derived and examined in terms of form, limits, and protein dependence. Furthermore, several approximate relations are derived which are useful for obtaining initial estimates of the model parameters and for a qualitative test of the applicability of the model. It is found that the binding curve may show a characteristic plateau at a saturation equal to the uncontaminated fraction of the protein and that the free ligand concentration at half saturation depends linearly on protein concentration. The practical implications of the present findings are discussed based on an analysis of simulated as well as experimental data.

Binding of sodium aurothiomalate to human serum albumin in vitro at physiological conditions.

The binding of aurothiomalate to human serum albumin was studied by equilibrium dialysis at 37 degrees C, pH 7.3-7.4, and ionic strength 0.15-0.16 mol/l. It was found that aurothiomalate was bound to albumin at one site with an apparent association constant K1 = 3.0 X 10(4) M-1 and at three or more sites with the sum of association constants of the order of 10(3) M-1. Valuable information of the aurothiomalate-albumin interaction was deduced from the observed changes of pH of the albumin solutions during dialysis. A conceivable binding mechanism consistent with the results might be that aurothiomalate binds as Au+ to the high affinity binding site by exchanging a H+ and that this site might be the sulphydryl group in cysteine34; and that aurothiomalate binds as monomeric anions to the lower affinity binding sites.

Gold in erythrocytes, whole blood, and plasma during long-term chrysotherapy.

The concentrations of gold in erythrocytes, whole blood, cell-rich plasma, and cell-free plasma were investigated in 17 patients with rheumatoid arthritis undergoing long-term chrysotherapy. Gold estimations were performed with a graphite tube atomic absorption spectrophotometer. Significant quantities of gold were found in isolated erythrocytes of 12 patients. There was no correlation between erythrocyte gold and therapeutic response, plasma gold, and gold in whole blood. Nor did gold in whole blood or plasma show any correlation with therapeutic responses and toxic reaction. However, all patients (3) with toxic reactions had a significantly higher gold concentration in the erythrocytes than the patients without toxic reactions. This result indicates that erythrocyte gold estimations could provide a useful warning of impeding toxic reactions.

A unified method for the determination of gold in biological fluids by flameless atomic absorption spectroscopy.

A new simple non-flame method of assaying serum, urine, and synovial fluid for gold by atomic absorption spectrometry (AAS) is presented. Variable absorption not due to gold is avoided by wet ashing and extraction of gold into methylisobutyl ketone. The amount of gold is determined directly in the organic phase by AAS. A linear relation between standard concentrations for serum, urine, and synovial fluid and absorption meter read-out values is obtained over the ranges 0 to 800 microgram gold/dl in serum and 0 to 80 microgram gold/dl in urine and synovial fluid. The estimated calibration curves for gold in serum, urine, and synovial fluid are found to be identical. The elimination of interferences, the high sensitivity (0.01 ppm), and the simplicity make this method superior to any other AAS methods and excellently applicable for routine determinations of gold concentrations in patients on chrysotherapy, and for research in that field as well.

Effect of two gold compounds on lysosomes.

The effect of two gold(I) compounds on stability of lysosomes in vitro was studied. Lysosomes from homogenates of rat kidney cortex were isolated by differential centrifugation. These lysosomes were incubated at 37 degrees C with widely varied concentrations of sodium aurothiomalate and sodium aurothiosulphate for 5, 35, and 65 minutes. Acid phosphatase activities were measured and used as an indication of lysosomal membrane stability in the presence and absence of drugs. The enhanced release of acid phosphatase from lysosomes by aurothiomalate and aurothiosulphate was related to dose, but the drugs differed substantially in their potencies. The disruptive effect on lysosomes was more marked for aurothiosulphate than for aurothiomalate. In addition, both drugs inhibited acid phosphatase activities at relatively high gold concentrations. Aurothiomalate had a moderate and aurothiosulphate a weaker inhibitory effect on the enzyme. Our results indicate that aurothiomalate and aurothiosulphate exert their beneficial effect in the treatment of rheumatoid arthritis through mechanism(s) other than lysosomal membrane stabilisation.

Microalbuminuria as a predictor of preeclampsia.

Urinary albumin concentration (UA) and albumin/creatinine ratio (UA/UC) in early morning specimens were assayed in 225 consecutive pregnant women at 20, 26, 28 and 30 weeks of gestation. 193 did not develop preeclampsia (control group), 14 developed preeclampsia later (preeclamptic group), 9 were excluded and 9 dropped out. Reference intervals of UA and UA/UC of healthy pregnant women (wk 20-30) was obtained. A statistically significant increase in urinary albumin excretion was observed with increasing gestational age as a normal phenomenon. There was no significant difference in the values of UA and UA/UC in the preeclamptic group when compared with the control group at the same stage of gestation. This indicates that microalbuminuria cannot be used as a predictor of preeclampsia.

Use of neural networks to diagnose acute myocardial infarction. I. Methodology.

We investigated several aspects of using neural networks as a diagnostic tool: the design of an optimal network, the amount of patients' data needed to train the network, the question of training the network optimally while avoiding overfitting, and the influence of redundant variables. The specific clinical problem chosen for illustration was the diagnosis of acute myocardial infarction, given only the electrocardiogram and the concentration of potassium in serum at the time of admission. We found that, in contrast to usual practice, the termination of the training process should be based on the generalization performance and not on the training performance. We also found that a principal component analysis can be used to eliminate redundant variables, thereby reducing the data space. The diagnostic performance of the neural network we used was 78%--superior to that of linear discriminant function analysis but similar to that of quadratic discriminant function analysis.

Use of neural networks to diagnose acute myocardial infarction. II. A clinical application.

We investigated the ability of neural networks to diagnose acute myocardial infarction (AMI) from laboratory data only. Several networks were trained with different combinations of data obtained at admission and within the first 12 h and 24 h after admission. The data used included the electrocardiogram (ECG) and the concentrations in serum of potassium, creatine kinase B-subunit (CKB), and lactate dehydrogenase isoenzyme 1 for 250 patients with suspected AMI. Based on admission data, the correct diagnosis was predicted for 76% of the patients in the test group from the ECG data only, and the best combination of ECG results with other variables yielded correct diagnoses for 85% of the test group. Using all of the data available within 24 h, the network predicted the correct diagnosis for 99% of the test data. Almost the same high predictability was obtained by using only two CKB values-recorded at admission and within 12 h after admission-or by using just the latter one. Neural networks and quadratic discriminant analysis performed similarly, but the neural networks were more robust for combinations with many laboratory data.