Circular test structure for the determination of piezoelectric constants of Sc x Al1-x N thin films applying Laser Doppler Vibrometry and FEM simulations

Piezoelectric scandium aluminium nitride (Sc _x Al_1-x N) thin films offer a large potential for the application in micro electromechanical systems, as advantageous properties of pure AlN thin films are maintained, but combined with an increased piezoelectric actuation and sensing potential. Sc _x Al_1-x N thin films with x = 27% have been prepared by DC reactive magnetron sputtering to find optimized deposition parameters to maximize the piezoelectric constants d₃₃ and d₃₁. For the accurate and simultaneous measurement of these constants Laser Doppler Vibrometry has been applied and compared to finite element (FEM) simulations. The electrode design has been optimized to rotational symmetric structures enabling a 180° phase shifted excitation, so that a straight-forward comparison of experimental displacement curves with those obtained from FEM is feasible.

Structure elucidation and in vitro cytotoxicity of ochratoxin α amide, a new degradation product of ochratoxin A

The mycotoxin ochratoxin A is a secondary metabolite occurring in a wide range of commodities. During the exposure of ochratoxin A to white and blue light, a cleavage between the carbon atom C-14 and the nitrogen atom was described. As a reaction product, the new compound ochratoxin α amide has been proposed based on mass spectrometry (MS) experiments. In the following study, we observed that this compound is also formed at high temperatures such as used for example during coffee roasting and therefore represents a further thermal ochratoxin A degradation product. To confirm the structure of ochratoxin α amide, the compound was prepared in large scale and complete structure elucidation via nuclear magnetic resonance (NMR) and MS was performed. Additionally, first studies on the toxicity of ochratoxin α amide were performed using immortalized human kidney epithelial (IHKE) cells, a cell line known to be sensitive against ochratoxin A with an IC50 value of 0.5 μM. Using this system, ochratoxin α amide revealed no cytotoxicity up to concentrations of 50 μM. Thus, these results propose that the thermal degradation of ochratoxin A to ochratoxin α amide might be a detoxification process. Finally, we present a sample preparation and a HPLC-tandem mass spectrometry (HPLC-MS/MS) method for the analysis of ochratoxin α amide in extrudates and checked its formation during the extrusion of artificially contaminated wheat grits at 150 and 180 °C, whereas no ochratoxin α amide was detectable under these conditions.

Matrix binding of ochratoxin A during roasting

The mycotoxin ochratoxin A is degraded during coffee roasting by up to 90%. During this process, the two known degradation products, 14R-ochratoxin A and 14-decarboxy-ochratoxin A are formed. However, there is still an unexplained loss of more than 50% ochratoxin A. Here, we describe the binding of ochratoxin A to coffee polysaccharides via esterification as a further thermal reaction. This ester formation was studied by heating ochratoxin A with methyl α-d-glucopyranoside, a model compound to mimic polysaccharides. From this experiment, (22 → 6') ochratoxin A-methyl-α-d-glucopyranoside ester was isolated and characterized as a reaction product, showing the general ability of ochratoxin A for esterification with carbohydrates at roasting temperatures. Subsequently, a sample preparation protocol for the detection of ochratoxin A saccharide esters based on an enzymatic cleavage and purification using immunoaffinity chromatography was developed and applied. The detection was carried out by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Using this method, it was possible to detect ochratoxin A polysaccharide esters formed during roasting of artificially contaminated coffee, confirming the results of the previous model experiments. Thus, the formation of ochratoxin A esters is a further explanation for the loss of ochratoxin A during coffee roasting.

Potential new treatments for diabetic kidney disease

Antifibrotic agents, antioxidant agents, ET-a receptor antagonists, and a few other agents with nonspecific or multifaceted mechanisms of action have been evaluated and progressed to small clinical studies in human subjects. Although there are limited data at the present time, these early evaluations have produced some favorable results that at least warrant further investigation. There is certainly not enough compelling evidence to justify the routine use of any of these products specifically for DKD at the moment; however, more well-controlled and adequately powered studies in several hundred patients will help determine which of these may have a place in the DKD treatment armamentarium of the future.

Alcohol consumption and other psycho-social conditions as important factors in the development of diabetic foot ulcers

AIMS

To characterize bio-psycho-social factors, particularly mental disorders and self-harm behaviour, associated with the development of diabetic foot ulcers.

METHODS

Two groups of diabetic patients with and without foot ulcers (n=47 in each group) with similar sex, age and diabetes duration were assessed for mental disorders using the Composite International Diagnostic Interview. Self-harm behaviour, quality of life, depressive symptoms and self-compassion were rated using different standard questionnaires.

RESULTS

Patients from the ulcer group visited their practitioners and/or psychotherapists less frequently in the last 12 months than patients in the control group 0 vs. 13%; P=0.026). The ulcer group patients had a history of increased alcohol consumption (43 vs. 19%; P=0.025), lower levels of education (8 vs. 10 grades; P=0.014) and income (1190 vs. 1535 €/month; P=0.039). Additionally, they were less likely to be diagnosed with anxiety disorders (11 vs. 32%; P=0.022). No significant differences in glycated haemoglobin, body mass index, smoking and direct self-harm behaviour were identified.

CONCLUSIONS

Patients with foot ulcers tend to exhibit lower health-conscious behaviour, particularly higher lifetime alcohol consumption, lower utilization of medical services and less general anxiety. Practitioners should be aware of these behaviours, since early detection of diabetes patients at psycho-social risk and consecutive psychological intervention may be an effective preventive strategy in avoiding the development of foot ulcers.

[Class I antiarrhythmic drugs: mechanisms, contraindications, and current indications]

Class I antiarrhythmic drugs are sodium channel inhibitors that act by slowing myocardial conduction and, thus, interrupting or preventing reentrant arrhythmia. Due to proarrhythmic effects and the risk of ventricular tachyarrhythmia, class I antiarrhythmics should not be administered in patients with structural heart disease. Nevertheless, there remains a broad spectrum of arrhythmias--among the most common being atrial fibrillation--that can successfully be treated with class I antiarrhythmic drugs. This review gives an overview on the classification, antiarrhythmic mechanisms, indications, side effects, and application modes of class I antiarrhythmic drugs.

Which gynecological and obstetric patients want to attend psychosomatic services?

OBJECTIVE

The aim of this study is to explore the wish of gynecological and obstetric inpatients to attend psychosomatic services. Predictors influencing this wish are evaluated.

METHOD

Three groups of patients participated in the study. The groups consisted of patients diagnosed with malignant gynecological diseases (n = 175), benign gynecological diseases (n = 302), and obstetric diseases (n = 238). The following domains were assessed in a cross-sectional design: symptoms of anxiety and depression (HADS), physical complaints (GBB-24), health-related quality of life (SF-12), and the wish to attend psychosomatic services.

RESULTS

34% of the participants indicated that they wanted to attend psychosomatic services during their stay in the hospital. The group of patients diagnosed with malignant gynecological diseases had the highest proportion of women who stated that wish (43%). Multiple logistic regression models showed that former psychotherapeutic experiences as well as low psychological quality of life predicted the wish to attend psychosomatic services in patients diagnosed with malignant gynecological or obstetric diseases.

CONCLUSION

It was shown that a considerable proportion of patients wanted to attend psychosomatic care during their hospitalization. Contrary to physical and sociodemographic variables, psychological factors were significant predictors of the inpatient's wish to attend psychosomatic services. This suggests that the subjective estimation of impairments is a major predictor of the wish to attend psychosomatic care.

Global modulation of cellular transcription by human cytomegalovirus is initiated by viral glycoprotein B

Human cytomegalovirus (HCMV) infection alters the expression of many cellular genes, including IFN-stimulated genes (ISGs) [Zhu, H., Cong, J.-P., Mamtora, G., Gingeras, T. & Shenk, T. (1998) Proc. Natl. Acad. Sci. USA 95, 14470-14475]. By using high-density cDNA microarrays, we show that the HCMV-regulated gene expression profile in fibroblasts does not differ substantially from the response generated by IFN. Furthermore, we identified the specific viral component triggering this response as the envelope glycoprotein B (gB). Cells treated with gB, but not other herpesviral glycoproteins, exhibited the same transcriptional profile as HCMV-infected cells. Thus, the interaction of gB with its as yet unidentified cellular receptor is the principal mechanism by which HCMV alters cellular gene expression early during infection. These findings highlight a pioneering paradigm for the consequences of virus-receptor interactions.

Near-infrared reflectance spectroscopy for noninvasive monitoring of metabolites

An important class of substances in clinical chemistry are metabolites in body fluids, which are accessible by near-infrared spectroscopy without sample treatment using reagentless, fast and readily automated in vitro assays. Furthermore, noninvasive sensing systems are under development for the determination of blood glucose, especially for diabetic patients or for monitoring in intensive care and surgery. Near-infrared diffuse reflectance spectrometry of skin was employed allowing a certain tissue volume to be integrally probed. For calibration, the partial least-squares (PLS) algorithm was used either based on wide spectral intervals or using special spectral variable selection. Capillary blood glucose reference concentrations were obtained by finger pricking and an automated laboratory method (hexokinase/G6P-DH). Clear evidence is provided for the physical effect, as manifested by the spectral glucose absorptivities, underlying the individual single-person calibration models, which still require improvements in the methodology in the normo- and hypoglycemic concentration range. In extending the potential of noninvasive blood assays by infrared spectroscopy, a novel technique is presented for probing the intravascular fluid space by using fast spectral near-infrared measurements of skin tissue. The pulsatile blood spectrum can be derived from reflectance spectra of oral mucosa by Fourier analysis (near-infrared plethysmography). Future applications and prospects for noninvasive blood assays are discussed.

DNA microarrays of the complex human cytomegalovirus genome: profiling kinetic class with drug sensitivity of viral gene expression

We describe, for the first time, the generation of a viral DNA chip for simultaneous expression measurements of nearly all known open reading frames (ORFs) in the largest member of the herpesvirus family, human cytomegalovirus (HCMV). In this study, an HCMV chip was fabricated and used to characterize the temporal class of viral gene expression. The viral chip is composed of microarrays of viral DNA prepared by robotic deposition of oligonucleotides on glass for ORFs in the HCMV genome. Viral gene expression was monitored by hybridization to the oligonucleotide microarrays with fluorescently labelled cDNAs prepared from mock-infected or infected human foreskin fibroblast cells. By using cycloheximide and ganciclovir to block de novo viral protein synthesis and viral DNA replication, respectively, the kinetic classes of array elements were classified. The expression profiles of known ORFs and many previously uncharacterized ORFs provided a temporal map of immediate-early (alpha), early (beta), early-late (gamma1), and late (gamma2) genes in the entire genome of HCMV. Sequence compositional analysis of the 5' noncoding DNA sequences of the temporal classes, performed by using algorithms that automatically search for defined and recurring motifs in unaligned sequences, indicated the presence of potential regulatory motifs for beta, gamma1, and gamma2 genes. In summary, these fabricated microarrays of viral DNA allow rapid and parallel analysis of gene expression at the whole viral genome level. The viral chip approach coupled with global biochemical and genetic strategies should greatly speed the functional analysis of established as well as newly discovered large viral genomes.

Cocultures of fetal and adult cardiomyocytes yield rhythmically beating rod shaped heart cells from adult rats

Different models of isolated cardiomyocytes are generally used for biochemical, biophysical, and pharmacological studies. Fetal cardiomyocytes can be easily cultured for several weeks regaining their ability for rhythmical and synchronous contractions. For investigations, differentiated myocytes derived from adult hearts are closer to the in situ situation. Unfortunately, these cells at best exhibit irregular and asynchronous contractions at very low frequencies. Already 1 d after seeding calcium-tolerant rod-shaped adult cardiomyocytes on a suitable substrate, the differentiated cells begin to dedifferentiate forming a confluent monolayer. After 7-10 d their beating activities are like those of fetal cells. Therefore, we tried to combine the advantages of both cell types to achieve fully differentiated cardiomyocytes, rod-shaped and rhythmically beating, isolated from adult hearts. Using contractile fetal cells as a substrate for the adult cardiomyocytes, freshly seeded differentiated adult myocytes are paced by the contraction frequency of the fetal monolayer. As a consequence, the rod-shaped adult cardiomyocytes reach frequencies of more than 140 cycles/min without external electrical stimulation. This model enables us to study cardiomyocytes in a state very similar to the in situ situation with respect to morphology, integrity, and contractile behavior.

Inter-alpha-trypsin inhibitor of human serum: an inhibitor of polymorphonuclear granulocyte elastase

Inter-alpha-trypsin inhibitor (ITI) was separated from human serum in a single step using ion-exchange chromatography via the fast protein liquid chromatographic system. The inhibitor preparation, identified as ITI by specific immunological assays, inhibited human polymorphonuclear granulocytic elastase besides bovine trypsin. Hence, ITI is the third candidate of the plasma proteinase inhibitors (in addition to alpha 1-proteinase inhibitor and alpha 2-macroglobulin) capable of inhibiting lysosomal granulocytic elastase.

Inhibitory action of vagal nerve and spinal cord afferents on discharge pattern of bulbar respiratory modulated neurons

Single vagal nerve stimuli delivered during burst discharge of respiratory modulated neurons entailed lengthening of an interspike interval in 37% of all units tested. Occasionally stimuli delivered to the spinal cord caused lengthening of interspike intervals in respiratory modulated neurons and in other bulbar units the discharge of which was not modulated with respiration. Vagal stimuli often entailed lengthening of the following interspike interval, while the interval during which stimuli were applied remained unaltered; latencies suggested that inhibitory pathways were polysynaptic. In expiratory-inspiratory (EI) and inspiratory (I) neurons, lengthenings of intervals roughly doubled those noted in inspiratory-expiratory (IE) and expiratory (E) units. Lengthening of intervals depended on stimulus incidence within the intervals and was greatest when stimuli were delivered during the late part of the intervals. In EI and I units, lengthening of intervals occurred mainly during the middle part of burst discharge, in IE and E neurons, however, towards the end of the burst. Conditioning of discharge of respiratory modulated neurons could be demonstrated.

Microelectrophoretic application of putative neurotransmitters onto various types of bulbar respiratory neurons

Six putative neurotransmitters and the beta-receptor excitant isoproterenol were applied to bulbar respiratory neurons classified according to their burst discharge in the respiratory cycle and, for comparison, also to "unspecific" cells. With glycine inhibition occurred in I and prevailed in unspecific neurons. With GABA inhibition preponderated in I and E neurons. Glutamate excited E neurons. With dopamine inhibition prevailed in I and unspecific neurons. The majority of E neurons remained unaffected. With NE excitation occurred in EI and preponderated in I, IE, E and unspecific neurons, while some IE and E neurons were inhibited. The effects of isoproterenol did not allow any clear statement about receptor properties. In I units, however, activation was more frequent than inhibition. With 5-HT excitation prevailed in IE neurons. About half of the I cells remained unaffected and in the remainder inhibition preponderated over activation. This suggests the existence of two 5-HT-specific receptors in I and IE neurons. Comparison of the single effects revealed differences in the receptor properties of the various cell types. Results suggest that some cell types possess dopaminergic receptors and that these differ from NE-receptors, which have been found in all cell types. NE-receptor stimulation apparently can result in neuronal activation or inhibition.