Tissue reaction following endobronchial application of iopamidol and ioxithalamate in rats

Lung tissue reaction to endobronchial application of iopamidol and ioxithalamate were compared by chest radiograph and histological examination in the rat. Radiographs cleared within hours in both groups. Tissue reaction after ioxithalamate application was significantly more pronounced than with iopamidol and included macrophage response, partial atelectasis, and intra-alveolar and interstitial oedema. Different from iopamidol, ioxithalamate induced a significantly stronger reaction than tracheotomy alone. Because no important significant side effects were observed on chest radiographs or in lung histology, iopamidol is recommended for the radiological examination of the gastrointestinal tract in patients with an increased risk of aspiration.     

Diagnosis of prosthetic aortic graft infection by magnetic resonance imaging

The accuracy of magnetic resonance imaging (MRI) in the diagnosis of prosthetic aortic graft infection was evaluated in 18 patients with history and findings suggestive of this complication. The prospective interpretation of MRI was compared with surgical findings. Sixteen patients had a graft infection verified at operation. Fourteen patients had infection of the retroperitoneal portion of the graft; two patients had an infection limited to one of the groins; no graft infection was found at surgical exploration in the remaining two patients. Perigraft infection was correctly diagnosed on the basis of MRI findings in 14 of 16 cases; findings were false negative in one case, questionable in another case, and correctly excluded graft infection in two of two cases. MRI also defined the extent of infection in 14 of 16 cases. MRI findings that supported the clinical suspicion of graft infection were perigraft fluid collections remaining more than 3 months after surgery. Furthermore, local inflammation was suggested by an increased signal intensity of adjacent muscle on T2-weighted images in some cases. CT scans were performed in 12 patients; these enabled a correct diagnosis in five and provided indeterminate or false information in seven. These results indicate that MRI is helpful in the diagnosis of aortic graft infection. Furthermore, MRI provides information about the extent of infection crucial for planning therapy.     

Cluster significance testing using the bootstrap

Many of the statistical methods currently employed to analyze fMRI data depend on a response template. However, the true form of the hemodynamic response, and thereby the response template, is often unknown. Consequently, cluster analysis provides a complementary, template-free method for exploratory analysis of multidimensional fMRI data sets. Clustering algorithms currently being applied to fMRI data separate the data into a predefined number of clusters (k). A poor choice of k will result in erroneously partitioning well-defined clusters. Although several clustering algorithms have been successfully applied to fMRI data, techniques for statistically testing cluster separation are still lacking. To address this problem we suggest a method based on Fisher's linear discriminant and the bootstrap. Also introduced in this paper is a measure based on the projection of multidimensional data from two clusters onto the vector, maximizing the ratio of the between- to the within-cluster sums of squares. The resulting one-dimensional distribution may be readily visualized and used as a heuristic for estimating cluster homogeneity. These methods are demonstrated for the self-organizing maps clustering algorithm when applied to event-related fMRI data.     

Three-dimensional analysis of the regional contractility of the normal and the cardiomyopathic left ventricle using cine-magnetic resonance imaging

The left ventricular regional contractile pattern, global function and mass of normal subjects and patients with idiopathic dilated cardiomyopathy was compared using cine magnetic resonance imaging (MRI) in a short-axis imaging plane. Left ventricular ejection fraction and mass were 64.3 +/- 2.5% and 115 +/- 10 g in normal hearts and 23.5 +/- 3.1% and 194 +/- 20 g in dilated cardiomyopathic hearts (p less than 0.001 and p less than 0.002). Left ventricular end-diastolic wall thickness was homogeneous in normal hearts except for the posterior wall at the basal level, which was significantly thinner compared to the anterolateral wall and the septum (p less than 0.02). End-diastolic wall thickness in the cardiomyopathic group was significantly more heterogeneous and was thinner at the apical compared to the basal level (p less than 0.02) as well as in the segment of the posterior compared to the anterolateral and septal wall (p less than 0.005 and p less than 0.03). In normal hearts, left ventricular end-systolic wall thickness was progressively greater from base to apex for the anterolateral (p less than 0.01) and posterior wall (p less than 0.02) and the septum (p less than 0.02). Such a uniform gradient of end-systolic wall thickness was not present in hearts with dilated cardiomyopathy. It was even reversed for the anterolateral wall with decreasing thickness from base to apex (p less than 0.03). Left ventricular mean systolic wall thickening increased progressively from base to apex (p less than 0.005) in normal hearts, whereas there was no significant gradient from base to apex in hearts with dilated cardiomyopathy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Normal and diffusely abnormal myocardium in humans: functional and metabolic characterization with P-31 MR spectroscopy and cine MR imaging

The current study tested the concept that cine magnetic resonance (MR) imaging and phosphorus-31 MR spectroscopy might be used to provide a comprehensive evaluation of the functional and metabolic status of the myocardium in humans. Thirteen patients with congestive cardiomyopathy and eight healthy volunteers were imaged at 1.5 T with the one-dimensional chemical shift imaging technique for localization of P-31 MR spectroscopy and an electrocardiographically referenced gradient refocused sequence for imaging of the heart. Prominent peaks in the PDE and PME regions were observed in cardiomyopathic patients, but only the former peak was measured. The PCr/beta-ATP peak ratio was not significantly lower in cardiomyopathic patients compared with healthy subjects (1.51 +/- 0.08 vs 1.54 +/- 0.04). The ratios of PDE/PCr (0.80 +/- 0.07 vs 0.54 +/- 0.10) (P less than or equal to .01) and PDE/beta-ATP (1.19 +/- 0.10 vs 0.84 +/- 0.08) (P less than or equal to .05) were significantly higher in patients with dilated cardiomyopathy compared with healthy volunteers. Left ventricular systolic wall thickening was significantly lower and left ventricular peak and end-systolic wall stress and mass were significantly higher in cardiomyopathic patients compared with healthy volunteers. Thus, localized, gated P-31 MR spectroscopy combined with cine MR imaging allowed identification of both abnormal myocardial phosphate metabolism and abnormal ventricular function. While this study suggests that increased myocardial PDEs may be a marker for abnormal myocardium, the sensitivity and specificity of this marker need to be further evaluated.     

Calcium inhibition of glycolysis contributes to ischaemic injury

STUDY OBJECTIVE--The purpose of the study was to confirm that [Ca2+]i and .[H+]i increase during ischaemia in hypertensive hearts but not in thyrotoxic hearts, and that the rise in [Ca2+]i and [H+]i inhibits glycolysis, causing a rise in phosphomonoester sugars and thereby influencing postischaemic recovery. DESIGN--Rats were made hypertensive by aortic banding and thyrotoxic by injection of L-thyroxine. [Ca2+]i was studied in isolated hearts by surface fluorometry assessing calcium dependent changes in the fluorescent dye INDO-1, while [pH]i and phosphomonoester sugars were studied by 31P nuclear magnetic resonance (NMR). Global ischaemia was carried out by turning off all flow to the heart for 30 min. Hearts were then reperfused for 30 min. SUBJECTS--72 Sprague-Dawley rats, weight 500-600 g, were used. Left ventricular hypertrophy was generated by aortic banding in 36, half of which were treated with verapamil. Eighteen were injected with L-thyroxine and there were 18 controls. MEASUREMENTS AND RESULTS--With all groups, developed pressure immediately declined after the onset of global ischaemia. During ischaemia the phosphomonoester sugars rose less in the hearts of thyrotoxic rats and the verapamil treated aortic constricted rats than in those of untreated aortic constricted and normal rats. During ischaemia there was no significant difference in [pH]i among the four groups. During ischaemia intracellular calcium rose least in thyrotoxic and verapamil treated aortic constricted rats, and most in untreated aortic constricted and normal rats. Intracellular calcium rose 10-15 min after the onset of ischaemia in verapamil treated pressure overload and control hearts; calcium rose immediately after the onset of ischaemia in the untreated aortic constricted hearts, but negligibly in hearts from thyroxine treated animals. Verapamil treatment of the aortic constricted hearts prevented the rise in intracellular calcium, and attenuated phosphomonoester sugar accumulation. Postischaemic recovery was complete in hearts in thyroxine treated and verapamil treated aortic constricted rats, but not in hearts from untreated aortic constricted and normal rats. Postischaemic recovery was inversely related to ischaemic diastolic [Ca2+]i and phosphomonoester sugar levels, but was not related to ischaemic values for [pH]i. CONCLUSIONS--Postischaemic recovery may depend on the ability of the cell to maintain mitochondrial activity as evidenced by oxygen consumption, thereby controlling the voltage of the cell, and influencing the ability of the myocardium to maintain its calcium homeostasis.     

Diagnosis and grading of malignancy in squamous epithelial lesions of the larynx with DNA cytophotometry

For diagnostic purposes 14 histologically benign, 15 dysplastic, and 16 malignant squamous epithelial lesions were subjected to DNA cytophotometry. Results were computed according to an algorithm for DNA diagnosis and grading of malignancy. In cases of unequivocally malignant or benign lesions all DNA diagnoses agreed with the histologic diagnoses. In one case the allegedly faulty DNA diagnosis of cancer was proven to be correct on clinical follow-up. Within the group of histologically mild to moderate dysplasias the algorithm identified four cases as malignant that were proved to be malignant either in the follow-up or at another site of the same lesion. With the aid of the DNA malignancy grade two groups of patients with squamous epithelial carcinomas of the larynx could be discerned with a highly significant difference according to their survival times.