Characterisation of Lesions after Stereotactic Radiosurgery for Brain Metastases: Impact of Delayed Contrast Magnetic Resonance Imaging.

AIMS: To investigate if brain metastases and radiation injuries after stereotactic radiosurgery (SRS) have different signal intensity (SI) time courses up to 55 min after contrast agent application and if delayed contrast magnetic resonance imaging (MRI) contributes to improve diagnostic accuracy. MATERIALS AND METHODS: Thirty-four consecutive patients treated with SRS for cerebral metastases were prospectively enrolled in the study. T1-weighted images were acquired on a 3-Tesla MR unit at three time points, at 2 (TP1), 15 (TP2) and 55 (TP3) min after administering contrast agent. A simultaneous, matched-pairs approach was used for region of interest analysis of the entire contrast-enhancing lesion (SI-e), the centre (SI-c), the border of the lesion (SI-b) and the adjacent non-contrast-enhancing tissue (SI-p). SIs of brain metastases and radiation injuries after SRS were compared using a two-level, linear, mixed-effects regression model. RESULTS: In total, 41 lesions were analysed: 16 metastases and 25 radiation injuries. The SI time course of SI-e, SI-c and SI-b proved to be significantly different for both entities (P < 0.001) from TP2 to TP3. The SI of 39/41 lesions increased from TP1 to TP2 for the three parameters. Radiation injuries showed a further signal increase at least for SI-c from TP2 to TP3, whereas for all the three parameters SI decreased in all metastases. CONCLUSION: Brain metastases and radiation injuries after SRS have a characteristic and statistically significantly different SI time course on sequential gadolinium enhancement MRI when late MR studies are included.

[Computed tomography in cats with craniofacial trauma with regard to maxillary and orbital fractures]. / Computertomographische Untersuchung des Schädels von Katzen mit kraniofazialem Trauma im Hinblick auf Maxilla- und Orbitafrakturen.

OBJECTIVE: Computed tomographic examination of the skull of cats with craniofacial trauma. Analysis of diagnostic findings with regard to the occurrence of isolated and combined maxillary and orbital fractures. MATERIAL AND METHODS: Prospective study (August 2006 - June 2010): Computed tomography (CT) of the skull of cats with craniofacial trauma. RESULTS: Thirty-eight cats met the inclusion criteria. Breeds were 36 Domestic Shorthair cats, one Maine Coon and one Somali cat. Age at admission ranged from 11 to 187 months. The ratio of the numbers of males to females was 22:16 (1.4). Computed tomographic examination revealed a maxillary fracture in 27 (71%) animals. Sixteen (42%) cats had multiple maxillary fractures (≥2). Twenty-eight animals (74%) displayed orbital fractures. Combined maxillary and orbital fractures occurred in 26 (68%) patients. The odds ratio of this combined occurrence was 87 (p<0.001). Sixteen (57%) of 28 cats with orbital fractures showed multiple orbital fractures (≥2). The incidence of bilateral orbital fractures was 67% (25 patients). The medial orbital wall was the most commonly fractured orbital wall (66%), and the orbital floor the second most common (61%). CONCLUSION: Computed tomographic examination of the skull of cats with craniofacial trauma showed that maxillary and orbital fractures are more common than previously described. Combined maxillary and orbital fractures occurred in more than half of the patients. In cats, orbital fractures mainly affect the medial orbital wall and the orbital floor. CLINICAL RELEVANCE: Cats with craniofacial trauma often have maxillary and orbital fractures. The additional information taken from the computed tomographic examination could lead to an optimised therapeutical concept.

Heart rate variability in patients suffering from structural heart disease and decreased AV-nodal conduction capacity. Insights into the formation of heart rate variability.

METHODS: Time and frequency domain analysis were conducted during a period of 600 s each. We performed a special protocol consisting of five different "pacing" periods: 1) recording of normal sinus rhythm (SR1); 2) atrial pacing with a rate 15% higher than the intrinsic heart rate; 3) ventricular pacing triggered by atrial activation (VAT, with a short AV-delay of 80 ms); 4) AV-sequential pacing with an atrial rate 15% higher than the intrinsic heart rate and a very short AV delay of 80 ms (DDD); 5) normal sinus rhythm (SR2). Only patients with normal AV-nodal conduction or with AV-block I degrees were included. The influence of a structural heart disease as well as a non-sustained VT on Holter ECG and a depressed EF on HRV parameters were analyzed using a multivariate analysis. All patients were lying in a supine position. Blood pressure was measured continuously and the frequency of breathing was controlled. RESULTS: No differences in HRV between the two sinus rhythm periods SR1 versus SR2 could be detected. Neither SR1 vs VAT showed a significant difference for SDNN and r-MSSD. In contrast, HRV during SR1 compared to AAI, and HRV during VAT compared to AAI were significantly different (p < 0.001). When comparing HRV during DDD, which should be zero, and AAI, we found a significantly lower SDNN and r-MSSD (1.2 ms vs 4 ms, p < 0.04). The presence of structural heart disease, a non-sustained ventricular tachycardia, a depressed ejection fraction of less than 0.50 did not reveal a significant influence on the HRV parameters (multivariate analysis). The mean Wenckebach in patients with structural heart disease tended to be greater (437 ms vs 350 ms, p = 0.05); an increase in the Wenckebach was not correlated to a change in HRV parameters (p = ns). CONCLUSION: Heart rate variability derived from consecutive RR-intervals is predominantly caused by periodicity in sinus-node impulse formation. A conduction variability of the AV-node exists, but is very low. The presence of a structural heart disease, a non-sustained ventricular tachycardia on Holter ECG, as well as a depressed ejection fraction of less than 0.50 showed no significant influence on the HRV parameters. Therefore, one can apply the calculation of heart rate variability for risk stratification in patients suffering from structural heart disease and moderate AV-nodal conduction disturbances. Attenuation of the oscillation of the heart rate, i. e. heart rate variability (HRV), is associated with an increased risk for mortality in patients with structural heart disease. Many of these patients also suffer from conduction disturbances, e. g. AV-nodal conduction delays. Whether the calculation of HRV in those patients is recommendable has not been investigated yet. Therefore, we conducted a study consisting of 20 consecutive patients in order to determine the formation of HRV, the influence of structural heart disease, the presence of a nonsustained ventricular tachycardia (VT), and a reduced ejection fraction (EF) on the HRV parameters during an elective electrophysiologic study.

Angiotensin-converting enzyme in non-neoplastic kidney diseases.

BACKGROUND: The angiotensin I-converting enzyme (ACE, CD143, kininase II) plays a critical role in controlling the level of vasoactive peptides such as angiotensins and kinins in the local circulations and tissue interstitium. Because recent work has documented a vessel-, organ-, and species-specific pattern of endothelial ACE expression in the vascular system, we have analyzed whether or not changes of this pattern occur in vessels, tubules, and interstitium of the human kidney that is affected by different non-neoplastic diseases. METHODS: Using a set of well-characterized monoclonal antibodies (mAbs), ACE was assessed on renal tissue of 135 patients by immunohistochemistry, including an additional analysis at the ultrastructural level. A semiquantitative evaluation allowed the estimation and comparison of ACE content in different renal compartments. These data were compared with several clinical findings, diagnosis, therapeutic modalities, and histological features. RESULTS: In contrast to the normal human kidney, where ACE is abundant in the brush border of the proximal tubule but is usually absent in endothelial cells of any vessel type, an endothelial neoexpression of ACE was observed in different diseases. In general, this neoexpression was associated with histological sites of interstitial fibrosis and showed some selectivity for glomerular endothelial cells in diabetes mellitus and chronic arterial hypertension. There was also a loss of epithelial ACE in the proximal tubule in certain pathological conditions, for example, in chronic fibroplastic processes, acute pyelonephritis, and different stages of acute renal failure. CONCLUSIONS: Neoexpression of ACE by renal endothelial cells, as well as changes of the tubular ACE content, is a common finding in diseased human kidneys. As associated with certain tissue sites, clinical and/or morphological features, these changes may be involved in parenchymal remodeling and renal pathophysiology.

Perfusion of rat testes and accessory sex organs: a new method.

Rat testes and accessory sex organs were perfused in situ by recirculating an artificial medium through the hemicorpus preparation previously developed for studies of skeletal muscle. The advantages and limitations of this system for studying the male productive tract were examined. The electrolyte and gas composition of the perfusate remained constant and glucose levels did not fall below normal during 3 h of perfusion. Testicular water content, temperature, and ATP and GTP levels were normal at 90 min. The mean arterial pressure was 40 mm Hg and the flow rates, measured with microspheres, were normal to high to the caput epididymides, ventral prostate and seminal vesicles and approximately half normal to the testes in preparations from 90 day old rats perfused at 35 ml/min. Administration of vasodilators indicated the absence of significant vasoconstriction in the hemicorpus. There was appreciable testosterone metabolism by the preparation and in addition, there was absorption of testosterone by the plastic tubing of the perfusion apparatus. Testosterone levels in the perfusate rose for 90 min in response to hCG. There was a dose-response relationship between hCG (20-1000 mIU/ml of medium) and testosterone levels at 90 min. FSH, prolactin, insulin and vitamins had no significant effect on hCG-stimulated testosterone levels. This perfusion system should prove useful for studies of hormone action.