A new sample-processing unit for the fluorescent  microsphere method

Raab, Stephan; Thein, E.; Harris, A. G.; Meßmer, K.

doi:10.1152/ajpheart.1999.276.5.h1801

Cited by 39 publications

(48 citation statements)

References 5 publications

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“…The left jugular vein was used for injection of adenosine (300 g ⅐ kg Ϫ1 ⅐ min Ϫ1 over 10 s) to induce maximum coronary blood flow, which was confirmed by a significant drop in LV systolic blood pressure and heart rate (Ͼ20%) immediately after injection of adenosine. Fluorescence was extracted from digested tissue and reference blood sample by the method of Raab et al (25). Fluorescence intensity was measured with a luminescence spectrometer (model LS55B, PerkinElmer) at the optimal excitation-emission wavelength pair for each dye (blue, 365 and 415 nm; orange, 520 and 560 nm) with excitation and emission slit widths of 4 nm in scanning mode.…”

Section: Methodsmentioning

confidence: 99%

Treatment of subclinical hypothyroidism reverses ischemia and prevents myocyte loss and progressive LV dysfunction in hamsters with dilated cardiomyopathy

Khalife

Tang

Kuzman

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

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. Treatment of subclinical hypothyroidism reverses ischemia and prevents myocyte loss and progressive LV dysfunction in hamsters with dilated cardiomyopathy. Am J Physiol Heart Circ Physiol 289: H2409 -H2415, 2005. First published July 15, 2005; doi:10.1152/ajpheart.00483.2005.-Growing evidence suggests that thyroid dysfunction may contribute to progression of cardiac disease to heart failure. We investigated the effects of a therapeutic dose of thyroid hormones (TH) on cardiomyopathic (CM) hamsters from 4 to 6 mo of age. CM hamsters had subclinical hypothyroidism (normal thyroxine, elevated TSH). Left ventricular (LV) function was determined by echocardiography and hemodynamics. Whole tissue pathology and isolated myocyte size and number were assessed. TH treatment prevented the decline in heart rate and rate of LV pressure increase and improved LV ejection fraction. The percentage of fibrosis/necrosis in untreated 4-mo-old CM (4CM; 15.5 Ϯ 2.2%) and 6-mo-old CM (6CM; 21.5 Ϯ 2.4%) hamsters was pronounced and was reversed in treated CM (TCM; 11.9 Ϯ 0.9%) hamsters. Total ventricular myocyte number was the same between 4-and 6-mo-old controls but was reduced by 30% in 4CM and 43% in 6CM hamsters. TH treatment completely prevented further loss of myocytes in TCM hamsters. Compared with agematched controls, resting and maximum coronary blood flow was impaired in 4CM and 6CM hamsters. Blood flow was completely normalized by TH treatment. We conclude that TH treatment of CM hamsters with subclinical hypothyroidism normalized impaired coronary blood flow, which prevented the decline in LV function and loss of myocytes. thyroid hormones; remodeling; fibrosis; blood flow THE EFFECTS OF THYROID HORMONES (TH) on the cardiovascular system have been well studied. It is clear that both hypothyroidism and hyperthyroidism can lead to deleterious changes in cardiovascular function. Decreased TH levels have been reported in a variety of nonthyroidal illnesses (18), including congestive heart failure (12) and myocardial infarction (6). The decrease in TH levels also appears to be related to the severity of heart failure (12). This is not a minor point, because low 3,5,3'-triiodothyronine (T 3 ) concentrations are a strong, independent predictive marker of poor prognosis in cardiac patients and might represent a determining factor directly implicated in the evolution and prognosis of these conditions (14). Growing evidence also suggests that subclinical thyroid dysfunction might play an important role in heart failure (10, 21). This is highly relevant from a clinical standpoint because this patient group does not typically receive TH treatment.Development of heart failure is accompanied by a variety of neuroendocrine changes. Cardiac failure was shown to be associated with both a decline in circulating TH levels (11,17) and altered cardiac TH signaling, as evidenced by changes in myocardial expression of TH nuclear receptor isoforms (15,16). The observation that short-term TH administration improves cardiac performance, both in anim...

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Section: Methodsmentioning

confidence: 99%

Treatment of subclinical hypothyroidism reverses ischemia and prevents myocyte loss and progressive LV dysfunction in hamsters with dilated cardiomyopathy

Khalife

Tang

Kuzman

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

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“…Fluorescence was extracted from digested tissue and a reference blood sample with Raab's method. 21 Fluorescence intensity was measured with a luminescence spectrometer (model LS55B, Perkin-Elmer) at the optimal excitation/emission wavelength pair of each dye (blue, 365 and 415 nm; orange, 520 and 560 nm) with excitation and emission slit widths of 4 nm in scanning mode. Myocardial blood flow was subsequently calculated as outlined in the Molecular Probes product manual.…”

Section: Myocardial Blood Flow and Hemodynamicsmentioning

confidence: 99%

Low Thyroid Function Leads to Cardiac Atrophy With Chamber Dilatation, Impaired Myocardial Blood Flow, Loss of Arterioles, and Severe Systolic Dysfunction

et al. 2005

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Background-Although thyroid dysfunction has been linked to heart failure, it is not clear whether hypothyroidism alone can cause heart failure. Methods and Results-Hypothyroidism was induced in adult rats by treatment with 0.025% propylthiouracil (PTU) for 6 weeks (PTU-S) and 1 year (PTU-L). Echocardiographic measurements, left ventricular (LV) hemodynamics, isolated myocyte length (KOH method), myocardial blood flow (fluorescent microspheres), arteriolar morphometry, and gene expression (Western blot) were determined. Heart weight, heart rate, LV systolic blood pressure, LV ejection fraction, LV fractional shortening, and systolic wall thickness were reduced in PTU-S and PTU-L rats. LV internal diameter in systole increased by 40% in PTU-S and 86% in PTU-L. LV internal dimension in diastole was increased in PTU-S and PTU-L rats, but only PTU-L rats showed a significant increase in myocyte length due to series sarcomere addition.Resting and maximum (adenosine) myocardial blood flow were reduced in both PTU-S and PTU-L rats. Impaired blood flow was due to a large reduction in arteriolar length density and small arterioles in PTU-S and PTU-L (PϽ0.05 or greater for all of the above comparisons). Expression of sarcoplasmic/endoplasmic reticulum Ca 2ϩ -ATPase (SERCA)-2a and ␣-myosin heavy chain were reduced in hypothyroidism, whereas phospholamban and ␤-myosin heavy chain were increased. Conclusions-Hypothyroidism led to severe, progressive systolic dysfunction and increased chamber diameter/wall thickness ratio despite a reduction in cardiac mass. Chamber dilatation in PTU-L rats was due to series sarcomere addition, typical of heart failure. Hypothyroidism resulted in impaired myocardial blood flow due to a dramatic loss of arterioles. Thus, we have identified 2 important new mechanisms by which low thyroid function may lead to heart failure. (Circulation. 2005;112:3122-3130.)

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“…The robotic system was used to recover the FM of the tissue samples so that the fluorescence intensities could be measured with a luminescence spectrophotometer and an automated sampling unit (Perkin Elmer, Überlingen, Germany) to calculate organ blood flow. 15,16 …”

Section: Downloaded Frommentioning

confidence: 99%

Fluorescent Cardiac Imaging

et al. 2007

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Background-The purpose of the present study was to examine whether the effect of coronary stenoses of variable severity on myocardial perfusion can be quantitatively assessed in vivo by analysis of fluorescent cardiac imaging (FCI) compared with the gold standard, the fluorescent microsphere method. FCI is a novel technology to visualize coronary vessels and myocardial perfusion intraoperatively using the indocyanine green dye with an infrared-sensitive imaging device. Methods and Results-Graded stenoses and total vessel occlusion of the left anterior descending coronary artery were created in 11 open-chest pigs. Stenoses were graded to reduce resting left anterior descending coronary artery flow by 25%, 50%, 75%, and 100% of baseline flow measured by transit-time flowmeter. FCI images were analyzed with a digital image processing system. The impairment of myocardial perfusion was quantified by background-subtracted peak fluorescence intensity and slope of fluorescence intensity obtained with FCI and compared with myocardial blood flow assessed by fluorescent microsphere. All stenoses resulted in an impairment of myocardial perfusion visualized by FCI. Occlusion of the left anterior descending coronary artery resulted in a total perfusion defect (no fluorescence intensity) of the corresponding anterior myocardial wall. During graded stenosis and total vessel occlusion, normalized background-subtracted peak fluorescence intensity and slope of fluorescence intensity decreased significantly (PϽ0.0001). Both background-subtracted peak fluorescence intensity (rϭ0. Clinical Perspective p 1014At present, there are several technologies to assess intraoperative bypass function, including intraoperative coronary angiography, thermal coronary angiography, ultrasound transit-time flow measurement (TTFM), and high-frequency epicardial echocardiography. However, all these techniques have limitations such as invasivity, misinterpretation, or poor resolution, and the clinical impact of most of these methods remains an unsolved issue. 2,3 Recently, we described the value of a novel, indocyanine green (ICG) -based imaging system (LLS GmbH, Ulm, Germany) for intraoperative visualization of blood flow in 4 -6 Thus, indirect parameters to detect anastomotic stenoses were evaluated in the present study. Our group has previously shown that this technique also allows the visualization of myocardial perfusion, providing further information with respect to the blood supply to the corresponding myocardium. 8 Visualized by fluorescent cardiac imaging (FCI), coronary stenoses resulted in an impairment of myocardial perfusion, and vessel occlusion resulted in a total perfusion defect of the corresponding myocardial region. 4 Although high-quality images of myocardial perfusion were obtained by FCI, quantitative assessment of myocardial perfusion deficits was not yet possible. 4 The aims of the present study were to quantitatively assess the effect of different coronary stenoses on myocardial perfusion by analysis of FCI and to compare the...

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A new sample-processing unit for the fluorescent microsphere method

Cited by 39 publications

References 5 publications

Treatment of subclinical hypothyroidism reverses ischemia and prevents myocyte loss and progressive LV dysfunction in hamsters with dilated cardiomyopathy

Treatment of subclinical hypothyroidism reverses ischemia and prevents myocyte loss and progressive LV dysfunction in hamsters with dilated cardiomyopathy

Low Thyroid Function Leads to Cardiac Atrophy With Chamber Dilatation, Impaired Myocardial Blood Flow, Loss of Arterioles, and Severe Systolic Dysfunction

Fluorescent Cardiac Imaging

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