Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In clinical and experimental studies we assessed images of digital subtraction coronary angiography (DSA) for evaluating regional myocardial perfusion. Myocardial perfusion was assessed by injecting contrast medium into the coronary artery, and by imaging the regional myocardium using DSA. On the time-density curve obtained from the myocardial region of interest, we calculated the time to peak concentration (TPC) and the exponential washout rate (T). TPC and T were measured in five patients with stable effort angina pectoris (AP) and left anterior descending (LAD) lesions before and after percutaneous transluminal coronary angioplasty (PTCA). The values of 1/T increased significantly from 0.09 +/- 0.02 l/sec to 0.21 +/- 0.04 l/sec (p less than 0.01) after PTCA, but l/TPC did not change. No significant difference in ejection fractions was observed between the patients with AP and the normal subjects (n = 7), while the regional percent area shrinkage in the anterolateral and apical regions supplied by the LAD was significantly decreased in the patients with AP compared with those of normal subjects (anterolateral: 39.8 +/- 8.8% vs 51.3 +/- 6.8%, apical: 36.6 +/- 8.4% vs 52.4 +/- 13.4%, both p less than 0.01). In 10 anesthetized dogs with varying degrees of reduction in the left circumflex coronary artery (LCX) blood flow (CBF: categories of stenosis (S1-S5), we compared 1/TPC and 1/T with regional myocardial function (systolic wall thickening: %WTh). With varying LCX stenosis, there were no significant changes in heart rate and mean aortic pressure and significant linear correlations were observed between %WTh and 1/TPC (r = 0.51), between %WTh and 1/T (r = 0.55). At S1 (CBF: 100-90% of the control), neither %WTh nor 1/TPC differed from that of the controls, but 1/T was significantly decreased (80% of the controls, p less than 0.01). From S3 (CBF: 79-60%) to S5 (CBF: 39-0%), %WTh, 1/TPC and 1/T were significantly decreased from those of the control levels (all p less than 0.01). However, at S5 (CBF: 39-0%) the values of 1/TPC (71% of controls) and 1/T (33%) did not differ from those at S4; whereas, %WTh was markedly reduced and the systolic thinning of the ventricular wall occurred at S5. Therefore, in critical coronary stenosis, 1/T was more sensitive than 1/TPC or wall dynamics for assessing myocardial ischemia. Both 1/TPC and 1/T, as well as %WTh, were useful for assessing moderate myocardial ischemia; however, these DSA indices had considerable limitations for evaluating the severity of myocardial ischemia when CBF was markedly reduced.
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PMID:[Comparison of myocardial perfusion assessments by digital subtraction angiography with those of left ventricular wall dynamics]. 213 31

Cerebral perfusion was examined in various types of occlusive disease by computed tomographic CBF method. The method utilized has several advantages over conventional studies using isotope, providing high resolution images in a direct relation to CT anatomy. Ten representative cases were presented from 25 consecutive cases of occlusive disease studied by this method. The method included inhalation of 40 to 60% xenon with serial CT scanning for 25 min. K (build-up rate), lambda (partition coefficient) and CBF values were calculated from HU for each pixel and Xe in expired air, based on Fick's principle, and displayed on CRT as K-, lambda- and CBF-map separately. CBF for gray matter of normal control was 82 +/- 11 ml/100 gm/min and that for white matter was 24 +/- 5 ml/100 gm/min. The ischemic threshold for gray matter appeared to be approximately 20 ml/100 gm/min, as blood flow in focus of complete infarction was below this level. Blood flow between 20-30 ml/100 gm/min caused some change on CT, such as localized atrophy, cortical thinning, loss of distinction between gray and white matter and decreased or increased density, which were considered to be compatible with pathological changes of laminar necrosis or gliosis with neuronal loss. In a case with occlusion of middle cerebral artery with subsequent recanalization, causing hemorrhagic infarct, hyperemia was observed in the infarcted cortex that was enhanced by iodine. Periventricular lucency observed in two cases, where blood flow was decreased below threshold, could be classified as "watershed infarction" mainly involving white matter. In moyamoya disease, blood flow in the anterior circulation was decreased near ischemic level, whereas that in basal ganglia and territory of posterior cerebral artery was fairly preserved, which was compatible with general angiographic finding of this disease.
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PMID:[Tomographic analysis of CBF in cerebral infarction]. 662 81

The complexation, surface adsorption, and foam film stabiliztation of the oppositely charged surfactants, sodium dodecyl sulfate (SDS) and dodecyl trimethylammonium bromide (C12TAB), is analyzed. The SDS:C12TAB mixing ratio is systematically varied to investigate whether the adsorption of equimolar or irregular catanionic surfactant complexes, and thus a variation in surface charge (i.e., surface excess of either SDS or C12TAB), governs foam film properties. Surface tension measurements indicate that SDS and C12TAB interact electrostatically in order to form stoichometric catanionic surfactant complexes and enhance surface adsorption. On the other hand it can be demonstrated that the SDS:C12TAB mixing ratio and, thus, a change in surface charge and composition plays a decisive role in foam film stabilization. The present study demonstrates that varying the mixing ratio between SDS and C12TAB offers a tool for tailoring surface composition and foam film properties, which are therefore not exclusively mediated by the presence of equimolar catanionic surfactant complexes. The SDS:C12TAB net amount and mixing ratio determine the type, stability, and thinning behavior of the corresponding foam film. These observations indicate the formation of a mixed surface layer, composed of the catanionic surfactant species surrounded by either free SDS or C12TAB molecules in excess. Furthermore, a systematic variation in CBF-NBF transition kinetics is rationalized on the basis of a microscopic phase transition within the foam films. Fundamental knowlegde gained from this research gives insight into the surface adsorption and foam film formation of catanionic surfactant mixtures. The study helps researchers to understand basic mechanisms of foam film stabilization and to use resources more efficiently.
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PMID:Surface Adsorption of Oppositely Charged SDS:C(12)TAB Mixtures and the Relation to Foam Film Formation and Stability. 2636 33