Prediction of adverse events by in vivo gene expression profiling exemplified for phytopharmaceuticals containing salicylates and the antidepressant imipramine

BACKGROUND AND OBJECTIVE

Gene expression profiles of Sprague-Dawley (SD) rats treated with a standardized willow bark extract (WB), its salicin rich ethanol fraction (EtOH-FR) or the tricyclic antidepressant imipramine were evaluated for their potential to induce adverse events. Treatments had shown antidepressant-like effects.

METHODS

Gene expression profiles (Agilent Whole Genome Array, n=4/group) obtained from the peripheral blood of male SD rats treated with WB (STW 33-I), EtOH-FR (30 mg/kg bw) or imipramine (20 mg/kg bw) were analysed comparatively by the Ingenuity Systems Programme, which allows to conduct model calculations of thresholds for theoretical potential adverse events (AE).

RESULTS

The number of genes regulated by the three treatments were 1673 (WB), 117 (EtOH-FR) and 1733 (imipramine). The three treatments related to 47 disease clusters. The WB extract reached the threshold for a potential AE in one disease cluster (cardiac hypertrophy), whereas the EtOH-FR exceeded the threshold in 5 disease clusters (cardiac arteriopathy and stenosis, glomerular injury, pulmonary hypertension, alkaline phosphatase levels ⇑). Imipramine treatment hit 13 disease clusters: tachycardia, palpitation, myocardial infarction, arrhythmias, heart block, precipitation of congestive heart failure; urinary retention, altered liver functions. Those correspond to known potential adverse events. Glomerular injury and altered liver functions are part of the side effect profile of salicylic acid derivatives in agreement with the findings for the salicin rich EtOH-FR.

CONCLUSION

There is no linear relationship between the number of constituents of a drug (preparation) and the number of different targets hit in a biological system on the gene expression level. Therefore, the number of genetic targets in a biological system does not necessarily increase with the complexity of the treatment corresponding to the non-linear behaviour of biological systems. Regarding gene expression levels AE of single treatments are not necessarily additive in combination treatments. The applied method appears to be an interesting screening tool for the prediction of potential AE. The phenomena that imipramine crossed the potential threshold for AEs several times whereas the WB extract did reach the threshold level only once, however not backed by clinical data for this AE, deserves to be further investigated. It questions the commonly assumed principle that substances with low number or without AE will have a poor efficacy.

[Altered hip muscle activation in patients with chronic non-specific low back pain]

BACKGROUND

The aim of this study was to examine postural control in patients with chronic non-specific low back pain (CNRS). Furthermore the influence of visual information (eyes open versus eyes closed) was analyzed.

MATERIAL AND METHODS

A total of 8 patients with CNRS and 12 healthy control subjects were examined. Surface electromyography (SEMG) recordings were made from 5 trunk and 5 lower limb muscles as well as one hip muscle during application of distal lateral perturbation.

RESULTS

Healthy controls (mean ± standard deviation: 96.42±64.77 µV) showed a significantly higher maximum amplitude of the gluteus medius muscle in comparison to patients with CNRS (56.29±39.63 µV). Furthermore activation of several lower limb muscles was found to be dependent on visual information.

CONCLUSION

Patients showed an altered reflex response of the gluteus medius muscle which could be associated with reduced hip stability.

The effect of various iodine supplementations and two different iodine sources on performance and iodine concentrations in different tissues of broilers

1. The objective of this study was to determine the influence of iodine (I) supplementation of feed, within the range of the European guidelines, on the performance of broiler chickens and I transfer into different organs and tissues, especially meat. The main emphasis was to assess whether broiler meat could be enriched and used as an I source in human nutrition. 2. Two experiments were performed, one with KI and the other with Ca(IO(3))(2). For each experiment, 288 d-old broiler chicks were divided into 4 groups (72 birds/group) and fed on diets with supplementations between 0 and 5 mg I/kg feed. The birds were reared to 35 d of age under standard conditions. Six birds per group were slaughtered at 35 d and samples of blood, thyroid gland, liver, pectoral and thigh meat taken. 3. Iodine treatment did not significantly affect the growth and slaughter performance of the broiler chickens. In all investigated parameters, I concentrations increased significantly with increasing I intake of the animals. The lowest I concentrations were measured in the meat, but they were considerably higher in blood serum, liver and thyroid gland. Since the I content of meat was still low in the highest supplemented group (highest median concentration: 67·8 µg I/kg thigh meat), there is no evidence that this could substantially improve I supply in human nutrition.

Preparation Temperature Effects in Microcrystalline Silicon Thin Film Solar Cells

Microcrystalline silicon solar cells were prepared at various substrate temperatures using a plasma enhanced chemical vapor deposition technique at 95 MHz. Devices in superstrate configuration, i.e. prepared on transparent glass/ZnO substrates with deposition sequence p-i-n, suffer from a reduction of short wavelength response upon increasing substrate temperature. As underlying mechanism adverse effects on the p-i interface region are discussed. For devices in substrate configuration (deposition sequence n-i-p on Ag/ZnO back-reflectors) a pronounced efficiency maximum with a highest value of 8.7 % is observed at substrate temperatures of about 250 °C. Comparing the dark J-V characteristics obtained for different device thicknesses at substrate temperatures of 200 °and 250 °C, respectively, improved i-layer material and transport properties are suggested in the latter case. The results illustrate the sensitivity ofmicrocrystalline silicon devices with respect to the employed substrate temperature by effects on the absorber layer material properties on the one hand and by effects related to the device design, e.g. the specific deposition sequence of the individual layers, on the other hand.

Investigation of Textured Back Reflectors for Microcrystalline Silicon Based Solar Cells

Microcrystalline silicon (μc-Si:H) solar cells require an effective light trapping in the near infrared (NIR) to enhance the long wavelength spectral response. For this purpose we investigated back reflectors based on texture-etched ZnO/Ag stacks prepared on glass substrates by magnetron sputtering. With decreasing sputter pressure the resulting surface texture of the glass/Ag/ZnO substrates after etching exhibits a larger feature size and root mean square roughness. The increase in feature size corresponds to an increase of diffuse reflectivity. Applied in microcrystalline solar cells prepared by VHF plasma enhanced chemical vapour deposition (PECVD), the reflectors showing the largest feature size (prepared at the lowest possible sputter pressure) yielded the highest long wavelength spectral response. The μc-Si n-i-p cells prepared on the latter back reflector exhibited efficiencies of 6.9 % (short circuit current density jsc= 18.8 mA/cm2) and 7.5 % (jsc=25 mA/cm2) for an i-layer thickness of 1 μm and 3.5 μm, respectively.

More Insights Into the ZnO/a-SiC:H(B) Interface - An Improved TCO/p Contact

Solar cells based on amorphous silicon (a-Si:H) exhibit a decreased fill factor if ZnO is used as front electrode instead of SnO2. This is due to a poor electric contact between the ZnO and the p-type a-SiC:H(B) layer. To gain a deeper understanding of the chemical and electronic properties of the ZnO/p interface, in-situ XPS measurements were applied to thin a-SiC:H(B) films deposited on ZnO. The effects of CO2 and H2 plasma pretreatments on clean ZnO surfaces and the influence of deposition conditions on the ZnO/a-SiC:H interface were investigated. Upon H2 plasma treatment the formation of SiOx by chemical transport of Si from the reactor walls is observed. Furthermore, a shift of all core levels towards higher binding energies indicates the formation of an accumulation layer. CO2 plasma treatments show no effects on ZnO. Depth profiling across the ZnO/a-SiC:H interface indicates SiO2 formation on ZnO. The depth profile of ZnO related core levels exhibits two features: a reduction of the ZnO at the interface, and, after longer sputter times, a core level shift towards higher binding energy due to an hydrogen induced accumulation layer in the n-type ZnO. The latter causes a depletion of the p-layer resulting in an enhanced series resistance and diminished fill factor. To reduce the depletion layer thin highly conductive microcrystalline layers were introduced, increasing the fill factor up to 74%.

Optoelectronic Properties of Thin Amorphous and Micro-Crystalline p-Type Films Developed for Amorphous Silicon-Based Solar Cells

VIIF-PECVD at 110 MI-z was used to deposit micro-crystalline p-layers on glass substrates for detailed analysis and onto ZnO coated substrates for incorporation into p-i-n solar cell structures. Solar cell and film analysis confirmed that the films incorporated into the solar cells contained significant crystalline silicon volume fractions despite being only 30 nm thick. The p-i-n solar cells employing a micro-crystalline silicon p-layer deposited on ZnO coated substrates had series resistances, fill factors and Voc similar to those of the reference solar cells deposited onto SnO2 coated substrates and having optimized amorphous silicon-carbon p-layers. The short circuit current of the micro-crystalline p-layer case was 10 percent lower than that of the reference cell indicating that further optimization is required.

Changes in creatine transporter function during cardiac maturation in the rat

BACKGROUND

It is well established that the immature myocardium preferentially utilises non-oxidative energy-generating pathways. It exhibits low energy-transfer capacity via the creatine kinase (CK) shuttle, reflected in phosphocreatine (PCr), total creatine and CK levels that are much lower than those of adult myocardium. The mechanisms leading to gradually increasing energy transfer capacity during maturation are poorly understood. Creatine is not synthesised in the heart, but taken up exclusively by the action of the creatine transporter protein (CrT). To determine whether this transporter is ontogenically regulated, the present study serially examined CrT gene expression pattern, together with creatine uptake kinetics and resulting myocardial creatine levels, in rats over the first 80 days of age.

RESULTS

Rats were studied during the late prenatal period (-2 days before birth) and 7, 13, 21, 33, 50 and 80 days after birth. Activity of cardiac citrate synthase, creatine kinase and its isoenzymes as well as lactate dehydrogenase (LDH) and its isoenzymes demonstrated the well-described shift from anaerobic towards aerobic metabolism. mRNA levels of CrT in the foetal rat hearts, as determined by real-time PCR, were about 30% of the mRNA levels in the adult rat heart and gradually increased during development. Creatine uptake in isolated perfused rat hearts increased significantly from 3.0 nmol/min/gww at 13 days old to 4.9 nmol/min/gww in 80 day old rats. Accordingly, total creatine content in hearts, measured by HPLC, increased steadily during maturation (30 nmol/mg protein (-2 days) vs 87 nmol/mg protein (80 days)), and correlated closely with CrT gene expression.

CONCLUSIONS

The maturation-dependant alterations of CK and LDH isoenzyme activities and of mitochondrial oxidative capacity were paralleled by a progressive increase of CrT expression, creatine uptake kinetics and creatine content in the heart.