Loss of Akt1 leads to severe atherosclerosis and occlusive coronary artery disease

The Akt signaling pathway controls several cellular functions in the cardiovascular system; however, its role in atherogenesis is unknown. Here, we show that the genetic ablation of Akt1 on an apolipoprotein E knockout background (ApoE^−/−Akt1^−/−) increases aortic lesion expansion and promotes coronary atherosclerosis. Mechanistically, lesion formation is due to the enhanced expression of proinflammatory genes and endothelial cell and macrophage apoptosis. Bone marrow transfer experiments showing that macrophages from ApoE^−/−Akt1^−/− donors were not sufficient to worsen atherogenesis when transferred to ApoE^−/− recipients suggest that lesion expansion in the ApoE^−/−Akt1^−/− strain might be of vascular origin. In the vessel wall, the loss of Akt1 increases inflammatory mediators and reduces eNOS phosphorylation, suggesting that Akt1 exerts vascular protection against atherogenesis. The presence of coronary lesions in ApoE^−/−Akt1^−/− mice provides a new model for studying the mechanisms of acute coronary syndrome in humans.     

Pulmonary venous occlusive disease

The present study deals with the radiation diagnosis of the rare disease--pulmonary venous occlusive disease. The follow-up covered three cases that ended with death. The clinical picture of the disease did not differ from the manifestations of primary pulmonary hypertension. All the patients underwent chest X-ray study in four standard projections. The morphological verification of its diagnosis was made on the basis of autopsy data. X-rat study promoted identification of such signs as peculiar changes in the lung pattern in form of its looping, reticulation, fine-focality along with reticular changes, the presence of Kerley lines, the diameter of root branches, enlargements of the pulmonary trunk without any symptoms of the enlarged left atrium.     

Diagnostic perspectives of mobile radiographic computerized tomography]

The authors assess mobile methods of x-ray computer-aided tomography (CAT) and suggest an organization and methodological scheme of its application. Their program of the first and up to now the only one in this country mobile CAT device is based on the new principles of mobile CAT application. It is realized in special hospitals of large regions, where the patients with the optimal indications for CAT are assembled. Over 15,000 examinations were carried out with the use of the suggested CAT program over 4 years, that resulted in detection of 1295 brain tumors, 804 cases with neoplastic involvement of the abdominal cavity and the retroperitoneal space. The authors claim that wide application of mobile CAT devices according to the program they suggest will help decide the problem of unavailability of such examinations, for it will rule out the principal cause of this unavailability--economic problems arising because of high price of this equipment. One mobile device may replace 3 permanent CAT devices, if used according to the program suggested by the authors.     

Validation study of skull three-dimensional computerized tomography measurements

Recent advances in imaging have led to high-resolution computerized tomography (CT) scanning with exquisitely detailed slice images of the skull and three-dimensional (3-D) surface reconstructions using computer software. It is possible to use CT scans to acquire morphologic information about the skull in a convenient digital form and to derive 3-D measurements from surface reconstruction images. Unfortunately, no effort has been made to date to test the validity of these measurements on laboratory specimens, and no compelling evidence is available from phantom studies to indicate the nature and magnitude of the errors inherent in the measurement technique. We have performed a pilot study to quantify the morphology of the skull based on surface features that can be found in CT scans and 3-D reconstructions. Comparative measurements were obtained from five skulls (two normal and three with dysmorphology) with calipers and a 3-D electromagnetic digitizer. These measurements were statistically compared with those based on original CT scan slices and reformatted 3-D images. It is concluded that 3D-CT measurement techniques are superior to those in which measurements are obtained directly from the original CT slices; 3-D CT methods, however, must be significantly improved before measurements based on these techniques can be used in studies that require a high degree of precision. The results are used to indicate the most fruitful areas of future study.     

Non-invasive measurement of coronary heart disease using electron beam computed tomography

PURPOSE OF REVIEW: Electron beam computed tomography is a non-invasive investigation that can quantify calcification within the walls of coronary arteries. Coronary arteries remodel to maintain luminal integrity, so that significant plaque may be present before the development of luminal stenoses. This has led to interest in techniques that assess the coronary artery wall, rather than the lumen. This review examines the power of coronary calcification detected by electron beam computed tomography to predict coronary heart disease events, and outlines recent studies in which it has been used as a surrogate marker for coronary heart disease. RECENT FINDINGS: The predictive power of coronary calcification has been shown to exceed that of traditional coronary heart disease risk factors and possibly also coronary angiography. This may justify the use of coronary calcification as a surrogate marker for coronary heart disease, and studies have thus examined cross-sectional associations between coronary calcification and potential risk factors in healthy individuals and patients with diabetes, end-stage renal failure and familial hypercholesterolaemia. Intervention studies can use the rate of change of coronary calcification detected by serial electron beam computed tomography imaging as an end-point, rather than relying on coronary heart disease events. As every participant reaches an end-point, sufficient power can be attained with smaller numbers at substantially less cost. SUMMARY: Coronary calcification detected by electron beam computed tomography may prove an invaluable tool in the selection of at-risk individuals suitable for primary prevention, and a useful surrogate marker for coronary heart disease in clinical trials.     

Computer graphics with computerized tomography for functional neurosurgery

A computer graphics technique for computer-assisted stereotactic surgery is presented. The program is designed to aid the surgeon by presenting an on-line graphics display of stereotactic probes and electrodes superimposed on cross sections of the human brain stem. This technique simulates an otherwise blind surgical procedure on a graphics screen for use during surgery. An earlier system based around the DEC MINC-11 BA computer system has been used by the authors for the performance of stereotactic surgery with conventional ventriculography. This system has been upgraded and is now configured about an even more compact microprocessor-based hardware system with expanded graphics capabilities, which also allows its use with computerized tomography.     

Disseminated pulmonary tuberculosis: significance of high-resolution computerized tomography]

Clinical and X-Ray studies were performed in 85 patients with disseminated pulmonary tuberculosis. All the patients underwent routine computerized tomography (CT) and high-resolution CT. According to the pathogenetic process, the authors identified hematogenic (n = 38), lymphogenic (n = 19), bronchogenic (n = 18) and mixed (n = 10) disseminations. High-resolution CT was found to have great advantages in detecting various types of tuberculous disseminations and in assessing the pattern of pulmonary abnormalities. Disseminated tuberculosis was revealed in 7 patients who had no pathological changes on routine lung X-ray films. The specific signs of hematogenic, lymphogenic disseminations and bronchgenic inoculations were identified in other forms of pulmonary tuberculosis. CT symptomatology is shown to be determined by the pathogenetic variant of its development and the stage of the process. Small focal changes in the lung were prevalent in patients with acute and subacute hematogenic forms of the disease. Infiltrates with decay cavities, thin-wall caverns, emphysema and bronchoectases were detected over the chronic course. Lymphogenic disseminations were characterized by the predominance of interstitial changes along with multiple minor foci. High-resolution CT had advantages in identifying decay cavities, signs of fibrosis and in evaluating mediastinal lymph nodes. CT data are of great significance for differential diagnosis of disseminated tuberculosis with lung metastases and diffuse interstitial diseases.     

Diagnostic accuracy of cerebral angiography and computerized transaxial tomography.

Computer tomography (CT) of the brain has become widely accepted as an accurate method of studying a variety of intracranial diseases. In a prospective controlled study one group of radiologists interpreted cerebral angiograms and another interpreted CT studies undertaken in the same patients. The overall rates of diagnostic accuracy were similar (81 and 84% for angiography and CT, respectively), albeit less than reported in the literature, and thus support the contention that CT scanning should be available as the initial neuroradiologic examination whenever possible.