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Biomedical subjects

N Baba

Publications and source records attributed to N Baba.

At least 163 records · Page 9Linked to original sources
PubMed1982

Digital processing methods for structural analysis of an electron micrograph.

Digital processing method using the scanning-densitometer with microcomputer provides a useful description system. It draws attention to the usefulness of local lattice averaging in clarifying images of periodic structures in crystals as well as crystalloids and para crystalline arrays in biological specimens. Digital processing of lattice images in crystal structures from the selected diffraction spots is successfully developed to the structural analysis of evaporated gold, graphitized carbon and human tooth enamel of hydroxyapatite. Furthermore, known microbody crystalloids in enzyme and icosahedral capsids in virus are confirmed and clarified by the procedure of selecting diffraction spectra transformed from the information taken with high resolution electron micrographs. The processed results can provide significant improvements in structural analysis of an electron micrograph.

Crystallography↗
PubMed1982

Digital processing methods using scanning densitometer and microcomputer for the structural analysis of a scanning electron micrograph.

The fundamental equation of image contrast with practical resolving power is shown taking account of the optical and specimen characteristics. Then, the structural factor which is used to indicate the scattering from the unit of structure to form the periodic object in a scanning electron microscopy can be derived straight-forwardly by digital processing. Based on the Fourier analysis, the reconstruction and subsequent interpretation of structural images such as biological specimens of rat microvilli have been successful. These microvilli must exhibit regularity of a hexagonal lattice consisting of rod-like crystalline arrays. Lattice defects are analysed by means of contrast enhancement, level slicing and histogram plotting techniques. The resolution of SEM can be tested from the granularity distance of coated films by the image sharpening by differentiation and subsequent superimposition of reconstructed images. Furthermore, the structural details in high brightness owing to reducing of the brightness level and filtering the high frequency component have been analysed.

Animals↗
PubMed1981

Biochemical and histologic correlates of ventricular end-diastolic pressure.

The associations of elevated left ventricular (LV) and right ventricular (RV) end-diastolic pressure (EDP) were evaluated in 28 patients with non-ischemic congestive cardiomyopathy. Right-sided endomyocardial biopsies from each patient were evaluated for ATP content, percent fibrosis and myocardial fiber diameter. The resting RVEDP and LVEDP and the post-angiographic LVEDP were correlated with the results from the biopsies. There was a correlation of the LVEDP with the RVEDP (r = 0.67, P less than 0.001) by a linear plot. There was no correlation of any EDP measurement with the percent fibrosis. There was, however, a rough correlation of the myocardial fiber diameter with RVEDP (r = 0.40, P less than 0.05). Myocardial ATP content correlated with the RVEDP (r = -0.53, P less than 0.005), the LVEDP (r = -0.65, P less than 0.001) and the post-angiographic LVEDP (r = -0.72, P less than 0.001). These data demonstrate that an elevated ventricular EDP correlates most closely with depressed levels of myocardial ATP. The myocardial cell diameter correlated less well and there was no correlation of EDP with fibrosis. Metabolic factors may be more important than histologic parameters in the elevated ventricular EDP of non-ischemic congestive cardiomyopathy.

Adenosine Triphosphate↗
PubMed1981

Alterations of circulatory responses to upright tilt in cardiac patients.

Circulatory responses to the upright tilt were studied in 20 normal subjects and 27 cardiac patients with ischemic heart disease or idiopathic cardiomyopathy. In normal subjects, the upright tilt caused obvious increases in heart rate and diastolic pressure, a slight decrease in systolic pressure and marked decreases in cardiac output and stroke volume. The circulatory changes during the tilt were less pronounced in the cardiac patients as compared with the normal subjects. The reductions of cardiac output and stroke volume and the increase in total peripheral resistance were all significantly diminished. A paradoxical increase in cardiac output during the tilt, an observation hitherto not well recognized, was observed in 5 cases with low cardiac index during the control period. Although several possibilities can be considered for the explanation of the diminished, sometimes paradoxical, circulatory responses to the tilt in cardiac patients, the improvement of the function of the diseased heart by preload reduction was proposed as an important factor. There was a significant negative correlation between the per cent changes of cardiac output and the per cent changes of PEP/LVET. It was suggested that the measurements of systolic time intervals during the tilt might be useful for evaluating the severity of the hemodynamic derangement in cardiac patients.

Adolescent↗
PubMed1981

Cardiovascular abnormalities in progeria. Case report and review of the literature.

The cardiovascular findings in cases of progeria are similar in many respects to the changes associated with aging. These changes include prominent atherosclerosis and calcification of the aortic and mitral valves, coronary arteries, and aorta. The coronary artery disease leads to ischemic changes in the myocardium, including well-defined infarcts. In addition, the present case demonstrates narrowing of the small intramural arteries, which may have contributed to myocardial fibrosis.

Adolescent↗
PubMed1980

Improvement of human myocardial mitochondria after dobutamine: a quantitative ultrastructural study.

Dobutamine is a new inotropic agent that may induce prolonged clinical improvement in patients with congestive cardiomyopathy. Sixteen patients with severe heart failure but without obstructive coronary disease were studied by serial functional class determinations and by noninvasive measurements of left ventricular function before and after bedrest control period and then after a 3-day infusion of dobutamine. An endomyocardial biopsy procedure was performed on 11 patients before and after the bedrest and on all 16 patients before and after dobutamine. Quantitative ultrastructural analysis of the biopsies was performed on electron micrographs (31,200 X) by a grid technique. The number of electron dense particles per 100 mitochondria did not change after bedrest but there was a significant decrease from 84 +/- 14 to 65 +/- 12 (P < .005) in the pre- to postdobutamine biopsies. The cristae to matrix ratio of the mitochondria did not change with bedrest but improved from 0.37 +/- 0.04 to 0.47 +/- 0.05 (P < .02) after dobutamine. The average mitochondrial size did not change significantly in the bedrest control nor in the dobutamine biopsy samples. However, when the 16 patients were divided into those who had a good clinical response (by functional class and noninvasive measurements of left ventricular function) and those who had no or little response, the 10 responders did decrease their average mitochondria size from 0.26 +/- 0.03 mu 2 to 0.23 +/- 0.02 mu 2 (P < .02). The mechanism by which a 3-day infusion of dobutamine induces a prolonged clinical improvement is not well understood. The use of quantitative ultrastructural technique in this study has demonstrated that there is a morphologic basis to the improvement.

Catecholamines↗
PubMed1979

Altered collagen composition in a prolapsing mitral valve with ruptured chordae tendineae.

A patient presented with mitral valve prolapse, ruptured chordae tendineae, severe mitral regurgitation and congestive heart failure. Pathologic studies demonstrated myxomatous changes of both mitral leaflets. Collagen analysis of the valve and of the chordae tendineae revealed the presence of type I collagen in normal quantities and a striking absence of type III and AB collagens. The altered collagen in this patient's mitral valve probably contributed to the development of his mitral valve disorder.

Chordae Tendineae↗
PubMed1978

Sebaceous carcinoma of the eyelid following radiation therapy.

This paper reports a case of a 12-year-old boy with fatal sebaceous carcinoma originating from the eyelid. The carcinoma developed 11 years after curative radiation therapy for bilateral retinoblastoma. Sebaceous carcinomas associated with previous irradiation are uncommon, and only five such cases have been published. Three of the patients were treated for benign disorders and the two other cases followed radiation therapy for bilateral retinoblastoma. Second malignant neoplasms in patients with bilateral retinoblastoma are thought to be related to a genetically inherited predisposition to the development of second malignant tumors. Radiation therapy is claimed to be an inducing factor in many cases but malignant neoplasms are also found in areas distant from the portals of irradiation as well as in patients not irradiated. Most of the secondary tumors were sarcomas, and usually osteogenic sarcomas.

Adolescent↗