Lung tumour growth kinetics in SPC-c-Raf-1-BB transgenic mice assessed by longitudinal in-vivo micro-CT quantification

<p>Abstract</p> <p>Background</p> <p>SPC-c-Raf-1-BxB transgenic mice develop genetically induced disseminated lung adenocarcinoma allowing examination of carcinogenesis and evaluation of novel treatment strategies. We report on assessment of lung tumour growth kinetics using a semiautomated region growing segmentation algorithm.</p> <p>Methods</p> <p>156 non contrast-enhanced respiratory gated micro-CT of the lungs were obtained in 12 SPC-raf transgenic (n = 9) and normal (n = 3) mice at different time points. Region-growing segmentation of the aerated lung areas was obtained as an inverse surrogate for tumour burden. Time course of segmentation volumes was assessed to demonstrate the potential of the method for follow-up studies.</p> <p>Results</p> <p>Micro-CT allowed assessment of tumour growth kinetics and semiautomated region growing enabled quantitative analysis. Significant changes of the segmented lung volumes over time could be shown (<it>p </it>= 0.009). Significant group differences could be detected between transgenic and normal animals for time points 8 to 13 months (<it>p </it>= 0.043), when marked tumour progression occurred.</p> <p>Conclusion</p> <p>The presented region-growing segmentation algorithm allows in-vivo quantification of multifocal lung adenocarcinoma in SPC-raf transgenic mice. This enables the assessment of tumour load and progress for the study of carcinogenesis and the evaluation of novel treatment strategies.</p

Ultrasonography and Infrared Thermography as a Comparative Diagnostic Tool to Clinical Examination to Determine Udder Health in Sows

The aim of the study was to examine whether the use of infrared thermography and ultrasonography can complement or replace the clinical examination of the sows’ mammary glands for pathological alterations. Sows of different parities with inconspicuous udders on palpation before and after birth (n = 35) and sows at the time of weaning (n = 107) were examined. Thermal images were taken from both sides of the udder, while ultrasound pictures were taken from four sides of the respective mammary glands. Within three weeks before birth, a statistically significant increase in the average surface temperature of the glands of about 1.54 °C and of the thickness of the parenchyma of about 1.39 cm could be observed. After weaning, in 10.3% of the examined sows, roundish hyperechogenic nodules were detected sonographically in the glands´ parenchyma. The average skin temperature above the nodules was 1.24 °C lower compared to the total skin area of the altered complex. However, scratches on the udder skin showed similar temperature changes. In two sows, the nodules remained undetected during the clinical examination. Therefore, sonography seems to be superior compared to clinical and thermographic investigations, although it proved to be very time-consuming

Electrocution as an alternative euthanasia method to blunt force trauma to the head followed by exsanguination for non-viable piglets

BACKGROUND: On farms, the currently approved and most widely practised method of euthanising non-viable piglets is blunt force trauma to the head followed by exsanguination. However, the use of this method is criticised due to public perceptions and aversion to the methodology by caretakers. Therefore, electrocution after electrical stunning was examined as an alternative approach in 80 hybrid piglets. Initially, electrocution was simulated with finite element analysis using a computer piglet-model, where current density in the heart was visualised and size and position of the electrodes were defined. The following step investigated electrical parameters for electrocution in anaesthetised piglets; first, with a constant voltage power source and then with a constant current power source. The electrical stunning was examined using the constant current supply. Finally, the results of electrical stunning and electrocution were verified in 25 healthy piglets with a body weight between 1 and 2 kg. Unconsciousness was proven by testing palpebral, corneal and nociceptive reflexes. Time of death was confirmed by electroencephalography (EEG) and electrocardiography (ECG) records. RESULTS: Stunning succeeded with the preset of 1.3 A and 50 Hz, placing the electrodes on both sides of the head between the eyes and ears using different timespans between 8 and 20 s. Prolonged electrical flow resulted in reduced paddling movements after the epileptic seizure, and allowed undisturbed reflex tests and installation of electrodes for EEG and ECG recording during electrocution. Using 0.75 A and 400 Hz, pin-shaped electrodes were first positioned on both sides of the chest for 5 s, followed by a break of 20–30 s and a second current flow, whereby the electrodes were placed above the withers and the sternum for 5 s. Cardiac arrest and an isoelectric EEG were induced within 3 min after the onset of the electrical flow through the chest. The most obvious indicator of effective stunning and electrocution was termination of rhythmic breathing. Piglets with cardiac arrest showed only single gasps lasting up to 3 min after electrocution. CONCLUSIONS: The evaluated stunning and electrocution protocol might ease concerns about timely piglet euthanasia. However, this should be verified in non-viable piglets to exclude influencing factors like dehydration and diseases

Combined micro-PET/micro-CT imaging of lung tumours in SPC-raf and SPC-myc transgenic mice.

INTRODUCTION: SPC-raf and SPC-myc transgenic mice develop disseminated and circumscribed lung adenocarcinoma respectively, allowing for assessment of carcinogenesis and treatment strategies. The purpose of this study was to investigate the technical feasibility, the correlation of initial findings to histology and the administered radiation dose of combined micro-PET/micro-CT in these animal models. MATERIAL AND METHODS: 14 C57BL/6 mice (4 nontransgenic, 4 SPC-raf transgenic, 6 SPC-myc transgenic) were examined using micro-CT and (18)F-Fluoro-deoxyglucose micro-PET in-vivo. Micro-PET data was corrected for random events and scatter prior to reconstruction with a 3D-FORE/2D-OSEM iterative algorithm. Rigid micro-PET/micro-CT registration was performed. Tumour-to-non-tumour ratios were calculated for different lung regions and focal lesions. Diffuse tumour growth was quantified using a semiautomated micro-CT segmentation routine reported earlier. Regional histologic tumour load was assessed using a 4-point rating scale. Gamma radiation dose was determined using thermoluminescence dosimeters. RESULTS: Micro-CT allowed visualisation of diffuse and circumscribed tumours in SPC-raf and SPC-myc transgenic animals along with morphology, while micro-PET provided information on metabolism, but lacked morphologic detail. Mean tumour-to-non-tumour ratio was 2.47 for circumscribed lesions. No significant correlation could be shown between histological tumour load and tumour-to-nontumour ratio for diffuse tumours in SPC-raf transgenic animals. Calculation of the expected dose based on gamma dosimetry yielded approximately 140 mGy/micro-PET examination additional to approximately 200 mGy due to micro-CT. CONCLUSIONS: Combined micro-PET/micro-CT imaging allows for in-vivo assessment of lung tumours in SPC-raf and SPC-myc transgenic mice. The technique has potential for the evaluation of carcinogenesis and treatment strategies in circumscribed lung tumours

Placement of TLD on anaesthetized mouse.

<p>A: Cranial view showing TLD positions 1–7 (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044427#pone-0044427-t002" target="_blank">table 2</a>). B: Lateral view showing TLD positions 8 and 9 (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044427#pone-0044427-t002" target="_blank">Table 2</a>).</p

TLD positions 1–9 and corresponding dose mean values and standard deviation 75 minutes after intraperitoneal administration of 10 MBq ¹⁸F-FDG.

<p>TLD positions 1–9 and corresponding dose mean values and standard deviation 75 minutes after intraperitoneal administration of 10 MBq ¹⁸F-FDG.</p

Correlation of histology to micro-CT and micro-PET.

<p>Advanced tumor in SPC-myc transgenic animal (A–D). Histology (A) and micro-CT (B) show focal tumor growth. Micro-CT/micro-PET registration (C) and micro-PET show the focal increase of glucose metabolism (D). Asterisk and arrow indicate corresponding lung areas in histology, micro-CT and micro-PET.</p

Results of TLD-measurements at different positions (mean doses with standard deviation).

<p>Designations of positions according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044427#pone-0044427-t002" target="_blank">table 2</a>. White columns: measured dose of the TLD, black columns: calculated dose for the mice according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0044427#pone.0044427.e005" target="_blank">equation 5</a>.</p

Segmentation of aerated lung volume as a surrogate to assess the multifocal tumor spread in SPC-raf transgenic animals.

<p>Micro-CT showing the diffuse bilateral tumour growth (A). Seed points are placed manually in the aerated lung (B). Segmentation of the aerated lung is performed applying a region growing algorithm (C).</p