Electric field and grain size dependence of Meyer-Neldel energy in C(60) films

Meyer-Neldel rule for charge carrier mobility measured in C(60)-based organic field-effect transistors (OFETs) at different applied source drain voltages and at different morphologies of semiconducting fullerene films was systematically studied. A decrease in the Meyer-Neldel energy E(MN) from 36 meV to 32 meV was observed with changing electric field in the channel. Concomitantly a decrease from 34 meV to 21 meV was observed too by increasing the grain size and the crystallinity of the active C(60) layer in the device. These empiric findings are in agreement with the hopping-transport model for the temperature dependent charge carrier mobility in organic semiconductors with a Gaussian density of states (DOS). Experimental results along with theoretical descriptions are presented.

Genome size evolution at the speciation level: the cryptic species complex Brachionus plicatilis (Rotifera)

BACKGROUND

Studies on genome size variation in animals are rarely done at lower taxonomic levels, e.g., slightly above/below the species level. Yet, such variation might provide important clues on the tempo and mode of genome size evolution. In this study we used the flow-cytometry method to study the evolution of genome size in the rotifer Brachionus plicatilis, a cryptic species complex consisting of at least 14 closely related species.

RESULTS

We found an unexpectedly high variation in this species complex, with genome sizes ranging approximately seven-fold (haploid '1C' genome sizes: 0.056-0.416 pg). Most of this variation (67%) could be ascribed to the major clades of the species complex, i.e. clades that are well separated according to most species definitions. However, we also found substantial variation (32%) at lower taxonomic levels--within and among genealogical species--and, interestingly, among species pairs that are not completely reproductively isolated. In one genealogical species, called B. 'Austria', we found greatly enlarged genome sizes that could roughly be approximated as multiples of the genomes of its closest relatives, which suggests that whole-genome duplications have occurred early during separation of this lineage. Overall, genome size was significantly correlated to egg size and body size, even though the latter became non-significant after controlling for phylogenetic non-independence.

CONCLUSIONS

Our study suggests that substantial genome size variation can build up early during speciation, potentially even among isolated populations. An alternative, but not mutually exclusive interpretation might be that reproductive isolation tends to build up unusually slow in this species complex.

[Regenerative therapy for tendon and ligament disorders in horses. Terminology, production, biologic potential and in vitro effects]

Conventional treatments of equine tendon injuries lead to an unsatisfactory healing process that usually results in a relatively high recurrence rate. Therefore, in recent years so-called regenerative therapeutics were studied scientifically in vitro and in laboratory animals. These include substances that ideally lead to the formation of replacement tissue, which in contrast to the low quality scar, has similar functional properties as the original intact tendon. Currently, a plethora of different substrates is either commercially available or can be produced in practice with the help of kits. The current knowledge on the production and the regenerative potential of nucleated cells like stem cells from bone marrow and fat tissue, of the blood products PRP (platelet rich plasma), ACP (autologous conditioned plasma), ACS (autologous conditioned serum) and of the scaffold substance UBM (urinary bladder matrix) are presented. Finally, the potential of some growth factors and of gene therapy is considered. Currently, it is assumed that the regeneration of tendon tissue is promoted by a complex interaction of scaffolds, growth factors and cells. At present, only very few studies are available which allow a comparison between these substances. Studies on the effect of regenerative substrates on tendons in live horses are presented elsewhere.

Contribution to FDG-PET/CT diagnostics and post-operative monitoring of patients with mycotic aneurysm of the thoracic aorta

Bacterial infection of the aorta is a life threatening condition calling for timely diagnostics and therapy. In the short communication presented here, the authors offer a case report on a patient of 70 years of age with aneurysm of the descending aorta caused by salmonella. The advantages of a new diagnostic hybrid modality are demonstrated and also the possibility of using it in the course of long-term monitoring of patients.

Diagnostics of "non-acute" vascular prosthesis infection using 18F-FDG PET/CT: our experience with 96 prostheses

INTRODUCTION

Vascular prosthesis infection (VPI) is a life-threatening complication that occurs in 0.5-5% of prostheses. Low-grade infections in non-acute patients are a diagnostic challenge requiring a new method with good diagnostic accuracy. The aim of this work was to define the accuracy of (18)F-FDG PET/CT in these settings and to identify essential parameters of the evaluation.

MATERIAL AND METHODS

PET/CT was performed prospectively in 76 consecutive patients with a total of 96 vascular prosthetic grafts in which infection was suspected. PET/CT scans were analysed in terms of the presence and intensity of focal and diffuse FDG uptake, the presence of an anastomotic pseudoaneurysm, the presence of an irregular boundary of infiltration, a combination of these, and the uptake ratio between the graft and blood background. The gold standard was based on operative/histopathological finding or a clinical follow up of >6 months.

RESULTS

Among the various assessed parameters only focal FDG uptake and an irregular graft boundary were significant predictors of VPI. Focal intense FDG uptake together with an irregular boundary of the lesion on CT scan predicted VPI with 97% probability, while smooth lesion boundaries and no focal FDG uptake predicted a probability of VPI of less than 5%. Even in lesions with nondiagnostic inhomogeneous focal FDG uptake (18/96) an irregular boundary effectively helped in decision-making with a probability of 28% (smooth) or 77% (irregular) for VPI.

CONCLUSION

PET/CT gave reliable results with an accuracy >95% in 75% of prostheses. PET/CT can identify those prostheses (25% of prosthesis) for which its diagnostic accuracy is diminished to 70-75%. In our series PET/CT was an excellent diagnostic modality for suspected VPI.

Pulmonary dysfunction and skeletal muscle changes in horses with RAO

BACKGROUND

Chronic pulmonary diseases (recurrent airway obstruction [RAO]) have been reported to alter skeletal muscle cells in humans. The purpose of this study was to evaluate a potential relationship between pulmonary and muscle variables in horses with a clinical diagnosis of RAO. Muscle biopsies from healthy horses and from horses with RAO were investigated and the relationship between the severity of lung disease and the degree of muscular changes was determined.

HYPOTHESIS

We hypothesized that chronic pulmonary disease can lead to changes of the skeletal muscle in horses.

ANIMALS

Fifteen healthy horses (control) and 50 horses with RAO were examined.

METHODS

In a prospective clinical trial, a complete lung examination was performed in all horses. In all horses, muscle enzyme activity at rest and after exercise and muscle biopsies from the M. gluteus medius were examined.

RESULTS

None of the horses had clinical or histologic signs of primary or neurogenic myopathies. According to the clinical, endoscopic, and radiographic findings and with a scoring system, the horses with RAO were grouped according to the severity of pulmonary findings (15 horses mild, 24 horses moderate, 11 horses severe RAO). Pathologic changes of the skeletal muscle (fiber atrophy or fiber hypertrophy, myofibrillar degeneration, hyperplasia of mitochondria, and ragged-red-like fibers) were identified in most horses with RAO but in only a few individual control horses. In addition, a marked depletion of muscle glycogen storage was evident in the RAO horses but not in the control group. Other pathologic changes of skeletal muscle such as centralized nuclei and regenerating fibers were rare, but were more frequent in horses with lung diseases than in the control group. The degree of muscle cell changes was also graded with a scoring system and correlated with the severity of pulmonary disease (r= 0.55).

CONCLUSION

Chronic pulmonary disease in horses is associated with structural changes in skeletal muscle.

CLINICAL IMPORTANCE

Because chronic pulmonary disease may affect muscles, early and effective therapy may prevent these changes. This finding could be of clinical importance but requires further studies.

[Influence of subclinical pulmonary findings on cardiac parameters in Icelandic horses]

In the present study we examined, if in Icelandic horses an increase in heart and/ or breathing rate is physiological and breed dependend or a sign of a pulmonary or cardiac disease. Therefore we examined 37 Icelandic horses with the prereport of being healthy. During clinical lung examination four horses showed symptoms of a pulmonary disease like increased breathing rate and enforced breathing at rest. These horses were excluded from the study. The other 33 horses were clinically normal. 17 of these horses were unridden (untrained) and 16 horses were regularly worked (trained). After clinical examination in all horses analysis of arterial blood gas, endoscopy with tracheo- bronchial secret analysis and radiographic examination of the lung were carried out. Additionally electro- and echocardiographic examinations and standardised exercise tests with determination of heart and breathing rate as well as plasma lactate values were performed in all horses. During electro- and echocardiographic examination no pathological findings were observed. In total 22 of the 33 horses showed abnormal lung findings. Seven horses had mild signs of RAO and 15 horses had mild signs of interstitial bronchitis. Three horses had additional pulmonary haemorrhage. Eleven out of the 33 horses showed no abnormal lung findings. The breathing rate at rest differed not significantly between horses with (21 +/- 1/min) or without (23 +/- 2/min) pulmonary findings. The heart rate also did not differ significantly between horses with (39 +/- 1/min) or without (42 +/- 1/min) pulmonary findings. In contrast to this the trained Icelandic horses with abnormal pulmonary findings had significantly higher heart rates (p = 0.01) and significantly lower breathing rates (p = 0.009) compared to those without abnormal pulmonary findings. During echocardiography Icelandic horses with abnormal pulmonary findings had significantly larger left atrial diameter (without abnormal pulmonary findings: 82 +/- 7 mm, with abnormal pulmonary findings: 90 +/- 8 mm, p = 0.02). Compared to the untrained Icelandic horses (5.4 +/- 2 mmol/l) the trained horses showed significantly lower plasma lactate values (3.1 +/- 2 mmol/l, p = 0.001) immediately after exercise. After exercise the icelandic horses with abnormal pulmonary findings had significantly higher breathing rates (p < 0.05) and longer recovery periods (30 minutes) than horses without abnormal respiratory findings (15 minutes). Recovery of heart rate after exercise showed no differences between groups.