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Selected AbstractsEchocardiographic Assessment of Left Ventricular Mass in Neonatal and Adult Mice: Accuracy of Different Echocardiographic MethodsECHOCARDIOGRAPHY, Issue 10 2006Alexander Ghanem M.D. Echocardiography is an established method to estimate left-ventricular mass (LVM) in mice. Accuracy is determined by cardiac size and morphology and influenced by mathematical models. We investigated accuracy of three common algorithms in three early developmental stages. High-resolution echocardiography was performed in 35 C57/BL6-mice. Therefore, two-dimensional-guided M-mode echocardiography and parasternal short- and long-axis views in B-mode were obtained. LVM was assessed in vivo applying Penn (P), Area Length (AL), and Truncated Ellipsoid (TE) algorithms and validated with histomorphometry. Regression analysis of all mice showed fair estimation of LVM assessed with M-mode-based Penn algorithm (y = 0.6*x , 0.12, r: 0.71). In contrast two-dimensional assessment of LVM revealed close linear relationship with histomorphometry (yAL= 1.21*x , 12.1, r: 0.88, yTE= 1.38*x , 2.88, r: 0.86). Bias was lowest for LVM-AL at diastole underestimating 3.2%. In concordance with the summarized data, LVM-P revealed lower regression coefficients and significant underestimation in all three subgroups. Small hearts (<50 mg, n = 12) correlated best with LVM-AL at systole. Hearts of adolescent (50,75 mg, n = 13) and adult (75,100 mg, n = 10) mice revealed close linear relationship with LVM-AL and LVM-TE at diastole. Echocardiographic assessment of LVM is feasible in hearts weighting less than 50 mg and can be estimated best in systole. Hearts weighting more than 50 mg are estimated most accurately by means of LVM-AL at diastole. [source] Variability of southeastern Queensland rainfall and climate indicesINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 6 2004Bradley F. Murphy Abstract The variability of climate indices and rainfall in southeastern (SE) Queensland (Qld) is studied. Using high-resolution gridded rainfall data for all of Australia and global sea-surface temperatures (SSTs), the relationship between Australia-wide rainfall (and in SE Qld in particular) and SST indices and the southern oscillation index (SOI) have been investigated. It is found that SE Qld is more subject to the breakdown of correlations between the SOI and rainfall than any other part of Australia. Model predictions suggest that this is probable in the future. Considering only time scales longer than interannual, it was found that SSTs in the central tropical Pacific Ocean (TPO; represented by the Niño-4 index) correlated best with SE Qld rainfall. Eastern TPO (Niño-3) SSTs and the SOI produced successively weaker correlations. The time series of the second modes of variability of SSTs over the Pacific and Indian Oceans were shown to have limited impact on SE Qld rainfall variability. The data were split into periods before and after 1946, when Australian mean rainfall changed. Whereas the SOI correlations with rainfall in SE Australia were similar in both periods, in SE Qld the correlations were very weak in the earlier period (0.06) but very strong in the later period (0.72). The Niño-4 index correlated better than the Niño-3 index in both periods, but both indexes showed smaller changes from the earlier to the later periods than the SOI. Copyright © 2004 Royal Meteorological Society. [source] Manganese ions as intracellular contrast agents: proton relaxation and calcium interactions in rat myocardiumNMR IN BIOMEDICINE, Issue 2 2003Wibeke Nordhøy Abstract Paramagnetic manganese (Mn) ions (Mn2+) are taken up into cardiomyocytes where they are retained for hours. Mn content and relaxation parameters, T1 and T2, were measured in right plus left ventricular myocardium excised from isolated perfused rat hearts. In the experiments 5,min wash-in of MnCl2 were followed by 15,min wash-out to remove extracellular (ec) Mn2+ MnCl2, 25 and 100,µM, elevated tissue Mn content to six and 12 times the level of control (0,µM MnCl2). Variations in perfusate calcium (Ca2+) during wash-in of MnCl2 and experiments including nifedipine showed that myocardial slow Ca2+ channels are the main pathway for Mn2+ uptake and that Mn2+ acts as a pure Ca2+ competitor and a preferred substrate for slow Ca2+ channel entry. Inversion recovery analysis at 20,MHz revealed two components for longitudinal relaxation: a short T1,,,1 and a longer T1,,,2. Approximate values for control and Mn-treated hearts were in the range 600,125,ms for T1,,,1 and 2200,750,ms for T1,,,2. The population fractions were about 59 and 41% for the short and the long component, respectively. The intracellular (ic) R1,,,1 and R2,,,1 correlated best with tissue Mn content. Applying two-site exchange analyses on the obtained T1 data yielded results in parallel to, but also differing from, results reported with an ec contrast agent. The calculated lifetime of ic water (,ic) of about 10,s is compatible with a slow water exchange in the present excised cardiac tissue. The longitudinal relaxivity of Mn ions in ic water [60 (s mM),1] was about one order of magnitude higher than that of MnCl2 in water in vitro [6.9 (s mM),1], indicating that ic Mn-protein binding is an important potentiating factor in relaxation enhancement. Copyright © 2003 John Wiley & Sons, Ltd. [source] Comparison of visual acuity measurements and Purkinje's vessel shadow perception for prediction of postoperative visual acuity in different ophthalmological diseasesACTA OPHTHALMOLOGICA, Issue 2 2007Stephan Schulze Abstract. Purpose:, Prediction of postoperative visual acuity (VA) is extremely important to the patient and highly relevant to the surgeon. However, objective evaluation of the macula is frequently impossible in cases such as mature cataract, cataract in high myopia or vitreous haemorrhage. This study compares different preoperative examination techniques used to predict postoperative VA. Methods:, We retrospectively evaluated the charts of all patients who underwent any of the following procedures at our hospital in 2004: phacoemulsification for mature cataract or cataract in high myopia; vitrectomy for diabetic vitreous haemorrhage; macular pucker, and macular hole. The following methods were evaluated: preoperative distance and reading VA; laser interferential VA; Purkinje's vessel shadow perception, and postoperative distance VA. Results:, Complete documentation was available for 136 patients (29 mature cataracts, 25 immature cataracts in high myopia, 42 vitreous haemorrhages, 19 macular puckers, 21 macular holes). In cases of preoperative mature cataract, a positive Purkinje's vessel shadow perception predicted a postoperative VA , 20/50 (odds ratio 11.2). In cases of high myopia, interferential VA correlated best with visual outcome (p < 0.05). In macular surgery laser interferential VA predicted postoperative VA to be better and preoperative reading VA predicted it to be worse than it actually turned out after surgery. Laser interferential VA and last known VA prior to vitreous haemorrhage (mean of 20 months previously) correlated best with postoperative VA (p < 0.05) in cases of vitreous haemorrhage. Purkinje's vessel shadow perception , if positive , predicted a postoperative VA , 20/300 in these cases (odds ratio 15.0). Conclusions:, Postoperative VA after vitrectomy for macular pucker or macular hole and in cases of cataract in high myopia is best predicted by laser interferential VA. Postoperative VA after vitrectomy for diabetic vitreous haemorrhage is best predicted by prehaemorrhage VA or laser interferential VA, especially when prehaemorrhage VA is unknown. Positive Purkinje's vessel shadow perception is an excellent method of predicting postoperative VA , 20/300 in cases of vitreous haemorrhage and VA = 20/50 in mature cataract. [source] | ||||||||||