Esophageal varices: correlation of left gastric venography and endoscopy in patients with portal hypertension

Selective left gastric venography was performed via percutaneous transheptic catheterization in 100 patients with portal hypertension to study hemodynamics and left gastric collaterals. Flow was hepatofugal in 81 patients, while 63 had varices supplied by the left gastric vein; azygos/hemiazygos collaterals were seen in 27 patients, gastrorenal shunts in 18, and other collaterals in 58. In 79 cases, enlarged, tortuous veins arising from thin parallel vessels at the esophagogastric junction on venography corresponded with varices on endoscopy in both size and course. Venography failed to show small varices which were seen endoscopically, whereas endoscopy often interpreted non-tortuous veins as varices. Using endoscopy as a reference, the sensitivity of venography for varices was 76%, specificity 100%, and accuracy 78%. There was a significant correlation between venographic demonstration of varices and previous hematemesis. Left gastric venography is necessary prior to embolization of varices and is also useful in their diagnosis as well as study of hemodynamics and assessment of bleeding risk.     

EEG filtering based on blind source separation (BSS) for early detection of Alzheimer's disease.

OBJECTIVE: Development of an EEG preprocessing technique for improvement of detection of Alzheimer's disease (AD). The technique is based on filtering of EEG data using blind source separation (BSS) and projection of components which are possibly sensitive to cortical neuronal impairment found in early stages of AD. METHODS: Artifact-free 20s intervals of raw resting EEG recordings from 22 patients with Mild Cognitive Impairment (MCI) who later proceeded to AD and 38 age-matched normal controls were decomposed into spatio-temporally decorrelated components using BSS algorithm 'AMUSE'. Filtered EEG was obtained by back projection of components with the highest linear predictability. Relative power of filtered data in delta, theta, alpha 1, alpha 2, beta 1, and beta 2 bands were processed with Linear Discriminant Analysis (LDA). RESULTS: Preprocessing improved the percentage of correctly classified patients and controls computed with jack-knifing cross-validation from 59 to 73% and from 76 to 84%, correspondingly. CONCLUSIONS: The proposed approach can significantly improve the sensitivity and specificity of EEG based diagnosis. SIGNIFICANCE: Filtering based on BSS can improve the performance of the existing EEG approaches to early diagnosis of Alzheimer's disease. It may also have potential for improvement of EEG classification in other clinical areas or fundamental research. The developed method is quite general and flexible, allowing for various extensions and improvements.     

A comparative study of synchrony measures for the early diagnosis of Alzheimer's disease based on EEG

It is well known that EEG signals of Alzheimer's disease (AD) patients are generally less synchronous than in age-matched control subjects. However, this effect is not always easily detectable. This is especially the case for patients in the pre-symptomatic phase, commonly referred to as mild cognitive impairment (MCI), during which neuronal degeneration is occurring prior to the clinical symptoms appearance. In this paper, various synchrony measures are studied in the context of AD diagnosis, including the correlation coefficient, mean-square and phase coherence, Granger causality, phase synchrony indices, information-theoretic divergence measures, state space based measures, and the recently proposed stochastic event synchrony measures. Experiments with EEG data show that many of those measures are strongly correlated (or anti-correlated) with the correlation coefficient, and hence, provide little complementary information about EEG synchrony. Measures that are only weakly correlated with the correlation coefficient include the phase synchrony indices, Granger causality measures, and stochastic event synchrony measures. In addition, those three families of synchrony measures are mutually uncorrelated, and therefore, they each seem to capture a specific kind of interdependence. For the data set at hand, only two synchrony measures are able to convincingly distinguish MCI patients from age-matched control patients, i.e., Granger causality (in particular, full-frequency directed transfer function) and stochastic event synchrony. Those two measures are used as features to distinguish MCI patients from age-matched control subjects, yielding a leave-one-out classification rate of 83%. The classification performance may be further improved by adding complementary features from EEG; this approach may eventually lead to a reliable EEG-based diagnostic tool for MCI and AD.     

Hepatic vascular anomalies in nonparasitic cysts of the liver.

Vascular abnormalities demonstrated by angiography in 3 patients with nonparasitic liver cyst are described. In two cases of polycystic liver, dilated and mutually anastomosing hepatic vein branches were seen around a cyst as opacified by hepatic venography, and in one case of solitary liver cyst, anastomoses between large portal branches and a right hepatic vein was demonstrated by celiac angiography. These vascular abnormalities most likely represent developmental malformation along with aberrant bile duct formation expressed in the form of cystic liver. To exclude the possibility of these changes being secondary to expansion of the cyst, an angiographic study of excised polycystic liver was carried out, and it was found that cyst enlargement produced displacement and thinning but no anastomosis of the intrahepatic blood vessels.     

Hypoxia correlates with angiogenesis in cervical cancers

Background Tissue hypoxia stimulates the induction of the angiogenic substances vascular endothelial growth factor and erythropoietin in the locus of the tissue. We have previously demonstrated that erythropoietin promotes angiogenesis by binding to its receptor in the endothelial cells of uterine and ovarian malignancies. In the present study, we examined whether malignant uterine cervix tissue showed hypoxia and whether hypoxia correlated with high vascular density through vascular endothelial growth factor.Methods To detect tissue hypoxia, we estimated the content of ATP in squamous cell carcinoma of the uterine cervix and in the normal cervix, using liquid chromatography columns. Surgically resected samples were fixed in Zamboni solution and processed for immunohistochemical microscopy to identify the endothelial cells and the location of vascular endothelial growth factor, with the use of anti-factor VIII and anti-vascular endothelial growth factor₁₆₅ antibody, respectively. The microvessels in a definite area were counted in sections of each specimen.Results Significantly lower ATP levels and significantly higher vascular density were seen in squamous cell carcinoma than in the controls (P < 0.05). The microvessel number in relation to ATP content was significantly higher in squamous cell carcinoma than in the controls (P < 0.001). Moreover vascular endothelial growth factor, the hyperplastic epithelium of the squamous cell carcinoma contained the immunoreactivity, with characteristic histopathological features suggesting retention of tissue fluid.Conclusion Squamous cell carcinoma of the uterine cervix showed hypoxia which correlated with abundant vascularity. Vascular endothelial growth factor expressed in the hyperplastic epithelium appears to promote angiogenesis in squamous cell carcinoma of the uterine cervix.     

Reversible ventricular dysfunction takotsubo cardiomyopathy

BACKGROUND: Recently, many cardiologists have recognized the existence of a rapidly reversible form of heart failure of unknown origin characterized by a takotsubo-shaped, dyskinetic left ventricle on left ventriculography. AIM: To determine the detailed clinical features of takotsubo cardiomyopathy. METHODS: Thirteen elderly patients (11 women and 2 men with a mean age of 75.3 years) who had normal coronary arteries and takotsubo-like left ventricular dysfunction were prospectively enrolled in this study. RESULTS: Cardiac enzymes did not increase significantly, but the mean plasma norepinephrine level was very high on admission (0.98 microg/l). Coronary angiography revealed normal coronary arteries in all patients, but left ventriculography showed apical akinesis combined with basal hyperkinesis, i.e., a takotsubo (Japanese octopus fishing pot)-shaped ventricle. Left ventricular wall motion normalized within a mean of 16.9 hospital days in 12 patients, but 1 patient died of acute renal failure on hospital day 7. Cardiac events did not recur during a follow-up period of 0.5 to 5 years. CONCLUSION: Takotsubo cardiomyopathy seems to be a new type of acute heart failure, which generally has a good prognosis and does not recur. Myocardial damage by catecholamine overload, adrenoceptor hypersensitivity, and changes of catecholamine dynamics due to stress may cause this condition.