Detection of monoester signals in human myocardium by 31P-MRS.
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2,3-Diphosphoglycerate↗
Biomedical subjects
L Sieverding
Publications and source records attributed to L Sieverding.
Effects of cardiopulmonary bypass and inhaled nitric oxide on platelets in children with congenital heart defects.
UNLABELLED: Nitric oxide (NO) reduces platelet aggregation in vitro. However, repeated measurements of platelet aggregation in infants and small children are impossible due to the large blood samples required. Instead, the expression of different platelet receptors mediating platelet adhesion (CD 36 and CD 42b), activation (CD 42b and CD 61) and aggregation (CD 41a) was measured repeatedly by flow cytometry. First, the expression of platelet receptors was quantified in platelet suspensions of 20 healthy volunteers after incubation with different concentrations of NO (0, 25, 100 and 640 ppm) and compared to changes in platelet aggregation and intrathrombocytic cGMP levels. It was then studied in 21 infants and children before, during and up to 3 days after cardiopulmonary bypass surgery. Seven of these patients required NO inhalation postoperatively. The in vitro experiments showed a reduced expression of the CD 41a, CD 42b and CD 61 receptors with increasing doses of NO, predominantly affecting the CD 41a receptor (-11% at 100 ppm and -20% at 640 ppm). This significant effect is in keeping with the observed NO-induced inhibition of platelet aggregation (-44% at 100 ppm) and the rise in platelet cGMP levels (+69% at 100 ppm). In patients without inhaled NO, the expression of CD 41a was slightly attenuated during cardiopulmonary bypass surgery (-15%) but increased significantly afterwards (2 h: +31%, 1st day: +129%, 2nd day: +120%, 3rd day: +111%). Comparable results were obtained regarding the other adhesion molecules CD 36, CD 42b and CD 61. In patients with inhaled NO the same pattern was observed and analysis of variance did not reveal any significant difference between both groups of patients. CONCLUSIONS: NO (> or = 100 ppm) decreases the expression of different platelet adhesion molecules and platelet aggregation, presumably via an increase in intracellular cGMP. However, due to the low dose range used in the clinical setting (1-40 ppm) this is clinically not relevant. Immediately after cardiopulmonary bypass surgery the expression of these adhesion molecules is reduced, but recovers on the 1st postoperative day.
Administration, Inhalation↗
High-resolution cardiac imaging using an interleaved 3D double slab technique.
A three-dimensional (3D) gradient-echo sequence with interleaved double-slab excitation was developed and optimized for the requirements in pediatric cardiac imaging. For this purpose high contrast between blood and myocardium signal should be obtained without the use of contrast agents. An acceptable measuring time for a large region examined with high spatial resolution should be achieved as well, especially with regard to the small structures of the heart and vessels of infants. The presented approach works with gradient moment nulling and a short echo time of 5.5 ms resulting in generally high signal intensity and only minor signal losses due to turbulent flow. The sequence allows simultaneous ECG-gated recording of two separately excited slabs with small thickness (10 mm) and with a distance of several centimeters between them. Thus, common effects of presaturation in 3D imaging can be avoided, although a relatively short measuring time is achievable. In order to get a 3D data set with good signal homogeneity of blood and of the other structures across a large volume of interest several double-slab measurements with suitable positions must be performed. The latter aspect is especially important for postprocessing techniques as multiple planar reconstruction and maximum intensity projection. Examples of applications of the new technique and appropriately postprocessed images are presented allowing demonstration even of subtle cardiac malformations.
Artifacts↗
Molecular and cytogenetic [correction of cytogenate] analysis of an X/autosomal translocation: 45,X,dic(X;17)(p22.2;p13)
We present an unusual case of monosomy 17p13-pter and monosomy Xp22.2-pter due to a dicentric translocation chromosome X/17 in a female newborn with severe anomalies. The karyotype was identified as 45,X,dic(X;17)(p22.2;p13) by high resolution GTG banding in lymphocytes. R banding showed the translocational X-chromosome to be late replicating, and there was no spreading of X-inactivation onto the autosomal segment. Furthermore, it could be demonstrated by C banding that the X-centromere in the translocation chromosome was inactive. The results of short tandem repeat (STR) typing confirmed the partial monosomy X and 17 as well as the paternal origin of the two chromosomes X and 17 which were involved in the translocation chromosome formation. The cell stage of the structural rearrangement was consistent with paternal meiosis as well as with postzygotic mitosis. The monosomy was confirmed in lymphocytes and fibroblasts, and mosaicism was not detected.
Chromosome Banding↗
Proton-decoupled myocardial 31P NMR spectroscopy reveals decreased PCr/Pi in patients with severe hypertrophic cardiomyopathy.
Disturbed myocardial energy metabolism may occur in patients with primary hypertrophic cardiomyopathy (HCM). A noninvasive way to gain insight into cardiac energy metabolism is provided by in vivo 31P nuclear magnetic resonance (NMR) spectroscopy. 31P NMR spectroscopy with proton decoupling was performed in 13 patients aged 13-36 years with HCM on a 1.5 T Magnetom with a double resonant surface coil. A 2D chemical shift imaging (CSI) sequence in combination with slice selective excitation was used to acquire spectra of the anteroseptal region of the left ventricle (volume element: 38 mL). The chemical shifts of the phosphorus metabolites, intracellular pHi, and coupling constants J(alphabeta) and J(gammabeta) were calculated. Peak areas of 2,3-diphosphoglycerate (DPG), Pi, and adenosine triphosphate (ATP) were determined and corrected for blood contamination, saturation, and differences in nuclear Overhauser enhancements (NOE). The maximum thickness of the interventricular septum (IVSmax) was determined from tomographic long-axis images and expressed as number of standard deviations above the mean of the normal population (Z score). The patients were then divided into 2 groups: 6 patients with moderate HCM (HCMm, Z score < or = 5) and 7 patients with severe HCM (HCMs, Z score > 5). No differences between both groups and a control group of healthy volunteers (n = 16) were found with respect to phosphocreatine (PCr)/gamma-ATP ratio, pHi, or the coupling constants. Only the PCr/Pi ratio differed significantly from the control group (HCM(all), alpha < 0.05, HCMs, alpha < 0.02, 2-sided U test). The decrease of the PCr/Pi ratio in patients with HCM is probably caused by ischemically decreased oxygen supply in the severely hypertrophied myocardium.
Adenosine Triphosphate↗
Technical considerations for inhaled nitric oxide therapy: time response to nitric oxide dosing changes and formation of nitrogen dioxide.
UNLABELLED: The aim of the present study was to analyse the time response to nitric oxide (NO) dosing changes as well as the formation of nitrogen dioxide (NO2) with different ventilation systems, respirator settings and application sites during NO inhalation. The inspired NO and NO2 concentrations were continuously measured using chemiluminiscence within a dummy ventilatory system equipped with two different respirator systems (Siemens Servo 900c and Bear BP 2001). NO was either introduced into the afferent limb of the ventilatory circuit close to the endotracheal tube (site A) or into the so-called low pressure port of the Servo 900c respirator, far away from the endotracheal tube (site B). In addition, the decay of the inspired NO concentration after cessation of the NO gas flow was studied. This decay was considerably prolonged when NO was introduced at site B (time constants: tau = 7.19 min versus tau = 0.29 min). Within the concentration range studied (0-25 ppm NO) a linear correlation between the NO and NO2 concentration was found. At site A and an inspired oxygen concentration of > 0.95 NO2 formation amounts to 1.14% +/- 0.11% of the NO concentration. Using this value one can calculate the NO2 formation for a given NO dose. For example, when 40 ppm NO are applied, a concentration of 0.45 ppm NO2 can be expected, which is well below the relevant toxic concentrations. However, when NO was introduced at site B, NO2 formation was significantly increased to 1.61% +/- 0.16%. Passage of the ventilated gas through soda lime led only to a slight and insignificant reduction in NO2 concentration. The continuous flow respirator BP 2001 showed a significantly lower NO2 concentration when compared to the non-continuous flow respirator Servo 900c (0.64 +/- 0.11% vs.1.14 +/- 0.11%). CONCLUSION: The application of NO close to the endotracheal tube is associated with a much faster response of the actual inspired NO concentration to dosing changes and shows the lowest NO2 formation. In order to avoid toxic NO2 concentrations, an upper limit of 40 ppm NO is recommended for continuous NO inhalation.
Analysis of Variance↗
Phosphorus J coupling constants of ATP in human myocardium and calf muscle.
Proton-decoupled 31P NMR spectroscopy of the heart and calf muscle of healthy volunteers was performed with a 1.5 T whole-body imager. By use of two-dimensional chemical-shift imaging in combination with slice-selective excitation, well-resolved localized spectra (elements of 38 ml) were obtained within 20 to 35 min from which the homonuclear J coupling constants of ATP could be determined. In myocardium, J gamma beta = 16.03 +/- 0.17 Hz and J alpha beta = 15.82 +/- 0.23 Hz were obtained, while the values in calf muscle were J gamma beta = 17.16 +/- 0.12 Hz and J alpha beta = 16.04 +/- 0.09 Hz. The difference in J gamma beta was significant. According to the literature, a possible reason for greater ATP J coupling constants is a smaller fraction of ATP complexed to magnesium. However, the chemical-shift difference between alpha- and beta-ATP, which is also a measure for the fraction of ATP complexed to magnesium, showed only a small difference in ATP complexation: 88% in myocardium and 90% in calf muscle. This small difference cannot account for the observed difference in J gamma beta.
Adenosine Triphosphate↗
[Improvement of perioperative hemodynamics and gas exchange by inhalation of nitric oxide in children with congenital cardiopulmonary defects].
OBJECTIVES: In critically ill infants and children before or after surgery for congenital cardiopulmonary disease it was evaluated whether continuous NO inhalation can reduce pulmonary artery pressure (PAP) and improve arterial oxygen saturation (SaO2). METHODS: All patients (n = 24; age 1 day-6.5 years) were intubated and artificially ventilated. They had either secondary pulmonary hypertension (n = 16), acute respiratory distress syndrome (n = 3), or reduced SaO2 (n = 5) due to pulmonary hypoperfusion. NO was introduced into the afferent limb of the ventilator circuit close to the endotracheal tube, while continuously measuring the inspired NO and O2 concentrations. The initially applied concentration of NO was 20 +/- 2.0 ppm. RESULTS: The hemodynamic condition and/or oxygen saturation was significantly improved by NO in 23 patients (95%). Mean PAP declined significantly from 45 +/- 7 to 28 +/- 3.7 mm Hg, while mean systemic arterial pressure remained constant (56 +/- 2.1 vs. 58 +/- 2.5 mm Hg). This was related to a selective reduction in pulmonary vascular resistance by 48 +/- 8.5%. SaO2 increased significantly (p < 0.05) from 83 +/- 2.5% to 93 +/- 1.5% due to a decreased intrapulmonary right-to-left shunt. NO therapy was applied with a median of 6 days (range 1.5-36 days). During NO inhalation methemoglobin concentration was significantly increased (0.77 +/- 0.05% vs. 1.46 +/- 0.15%), but neither was oxygen transport capacity affected, nor was any evidence for accumulation observed. Using a model ventilatory circuit, a nitric dioxide (NO2) formation of 1.14 +/- 0.11% of the applied NO concentration was measured, i.e. approximately 0.5 ppm NO2 at 40 ppm NO. This amount of NO2 in the inspired gas is well below toxicologically relevant concentrations. CONCLUSIONS: Low-dose NO inhalation selectively reduces PAP and improves SaO2 in children with congenital cardiopulmonary disease during perioperative intensive care. It is expected that the overall hemodynamic improvement is related to a reduced afterload of the subpulmonary ventricle without changes in coronary perfusion pressure, as is often observed with other vasodilators applied intravenously. We recommend an upper dose limit of 40 ppm NO for continuous NO inhalation to avoid possible toxicologically relevant NO2 concentrations.
Administration, Inhalation↗
Imaging of the human cardiovascular system using the rapid echo flow-rephased spin-echo technique.
Using a flow-rephased spin-echo technique with a short echo time of TE = 9.7 msec, "white blood" multislice and single slice first echo images of the human heart were acquired using standard 1.5 T whole-body imagers. The technique almost completely eliminates phase shifts for flow with constant velocity and constant acceleration, so the investigations with healthy volunteers show images which are almost free of the artifacts often found in ECG-gated standard spin-echo imaging of the heart. T1-weighted images with good contrast between tissue and blood are achieved at any time during the whole heart cycle. The results obtained indicate that the technique might be helpful for imaging small vessels, vessels which contain slowly flowing blood, and vessels located in regions with static field inhomogeneities, for example, lung vessels.
Adult↗
[Toxic epidermal necrolysis (Lyell's syndrome) after rubella].
Rubella was confirmed clinically and serologically in a 14-year-old boy who had been admitted with mild general symptoms and an exanthematous rash presenting with medium size maculae. Within only three days the exanthema had faded. Five days later the boy again became ill with high fever (40 degrees C) and renewed erythema with at first irregular then rosette-like and widely confluent spots. On admission several nonspecific inflammatory signs were markedly elevated (erythrocyte sedimentation rate, C-reactive protein, alpha-globulin). There were mild abnormalities of left-ventricular repolarization at the electrocardiography. The skin changes were progressive and at first interpreted as erythema exudativum multiforme. Fever persisted, despite antibiotic treatment, and signs of epidermolysis appeared. After the diagnosis of non-staphylogenic Lyell's disease was made high-dosage prednisolone administration was begun (initially 3 mg/kg in 6 hours, then 2.5 mg/kg daily for 8 days). The patient's condition and the electrocardiographic findings returned to normal within 2 days. The epidermolysis was arrested within a few hours and the blisters dried out within 24 hours. There were no complications. Since no drugs were given before the second day of epidermolysis being noted, it is highly likely that rubella precipitated Lyell's disease.
Adolescent↗
Noninvasive blood flow measurement and quantification of shunt volume by cine magnetic resonance in congenital heart disease. Preliminary results.
Based on the phase difference method as described by Nayler et al. we developed a gradient-echo sequence, which refocuses flow related phase shifts even for infants with their higher peak velocity, higher acceleration and faster heart rates. A repetition time (TR) of 15 ms provides a high temporal resolution for dynamic studies. Modification of the flow-rephasing gradient-echo sequence in slice select direction leads to a defined phase shift and the resultant phase difference images allow blood flow measurements in the great arteries and the calculation of blood volume per heart cycle (flow volume) to assess left and right ventricular stroke volume. This can also be achieved by calculation of the ventricular volume from contiguous slices of the whole heart, but, this in excessive measuring times. Both methods were applied in 6 examinations of children with congenital heart diseases (1 pulmonary sling, 1 coarctation of the aorta, 1 ventricular septal defect, 3 atrial septal defects). The age of the patients ranged from 3 months to 13.4 years (mean age 4.9 years). The regression analyses of both methods show a high correlation for systemic flow (y = -0.98 + 1.08 x, r = 0.99, SEE = 2.59 ml) and for pulmonary flow (y = -1.40 + 0.96 x, r = 0.99, SEE = 4.70 ml). The comparison of flow calculated Qp:Qs ratio and chamber size calculated Qp:Qs ratio with data obtained by heart catheterization show also a regression line close to the line of identity (y = -0.01 + 1.04 x, r = 0.98, SEE = 0.15 and y = 0.28 + 0.96 x, r = 0.81, SEE = 0.47, respectively).
Adolescent↗
[Anomalous origin of the left coronary artery from the pulmonary artery. Variability of clinical aspects, echocardiography and angiography findings].
OBJECTIVES: Analysis of symptoms, diagnostical difficulties and follow-up in infants and children with anomalous origin of the left coronary artery from the pulmonary artery. METHODS: Retrospective study; 12 children between 3 weeks and 2 years old; time period: 1980-1991. RESULTS: Three infants were detected on routine examination because of a new cardiac murmur, the others presented with signs of cardiac failure. Cross sectional echocardiography and color Doppler flow mapping allowed to verify the suspected diagnosis. However, in one infant a false-negative cross sectional echocardiographic result was obtained. In this case nuclear magnetic resonance imaging was able to delineate the exact anatomy. Mean preoperative left ventricular ejection fraction: 33 +/- 4%; percentage of infants below the age of 6 months: 92%; surgery related mortality: 66%; mean follow-up of the remaining 4 patients being in good clinical condition: 2.9 +/- 1 years. CONCLUSIONS: 1. An anomalous origin of the left coronary artery should be included into the differential diagnosis when a new cardiac murmur is detected. 2. Possibility of false-negative echocardiographic results is emphasized. 3. With early symptoms and highly reduced left ventricular function, the mortality is still high.
Angiocardiography↗
[Intensive care of children after heart surgery. Risk groups and possible complications].
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Cardiac Surgical Procedures↗
[Congenital coronary artery anomalies].
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Coronary Vessel Anomalies↗
[Mucocutaneous lymph node syndrome (Kawasaki syndrome) from the cardiological viewpoint].
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Angiography↗
Morphological diagnosis of congenital and acquired heart disease by magnetic resonance imaging.
Since 1987, the authors have examined 60 patients (21 girls, 39 boys) with a variety of congenital and acquired heart diseases by means of ECG-gated magnetic resonance imaging (MRI) using a multislice spin-echo technique. The patients' ages ranged from 10 days to 20 years (mean age 3.7 years), distributed as follows: 9 patients (15%) less than or equal to 4 weeks; 26 (43.4%) greater than 4 weeks less than or equal to 1 year; 9 (15%) greater than 1 year less than or equal to 6 years; 14 (23.3%) greater than 6 years less than or equal to 15 years; and 2 (3.3%) greater than 15 years less than or equal to 20 years. In 4 cases the quality of the images on the first study were of no diagnostic value and so a second investigation took place. Thus, 60 studies could be analysed, and the findings were compared with the previous diagnoses made on the basis of echocardiography (n = 60) and angiocardiography (n = 47). The 66 anomalies of the vessels included 6 that had been misdiagnosed (2, small patent ductus arteriosus (PDA); 1, pulmonary sling; 2, palliative shunt; 1, aortopulmonary collaterals). Amendment of the previous diagnosis was achieved in 8 cases. In 1 case an aorticopulmonary window was first detected by MRI and in another, a recoarctation of the aorta. The extent of an aortic aneurysm could be defined and a dissection of the aortic wall excluded. In 5 cases MRI gave more information on the pulmonary vascular status.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
[Dynamic magnetic resonance tomography in pediatric cardiology: broadening of diagnostic possibilities by flow-rephasing gradient-echo sequences].
Based on the phase difference method as described by Nayler et al., we developed a gradient-echo sequence, which refocuses flow-related phase shifts. With regard to the higher peak velocity and higher acceleration in infants, we reduced the echo time (TE) to 5 ms. This is effective in rephasing the flow signals even for faster heart rates. Phase shifts are further minimized by reducing the voxel size. The slice thickness down to 2 mm also improves anatomic resolution. A repetition time (TR) of 15 ms provides high temporal resolution for dynamic studies. Modification of the flow-rephasing gradient-echo sequence allows blood flow measurements in the great arteries and the calculation of blood flow volume to assess left and right ventricular stroke volume. This can also be achieved by calculating the ventricular volume from contiguous slices of the whole heart; however, it results in excessive measuring times. Compared with conventional spin-echo techniques, anatomical analysis is improved. The size of atrial septal defects (ASD) can be measured more exactly. Small atrial or ventricular septal defects (VSD), which are not detectable on spin-echo images, are demonstrated on the gradient-echo images and semi-quantitative estimation of the pressure in the right and left ventricle can be made. Pulmonary arteries and veins are clearly differentiated from bronchial structures and are traced to subsegmental levels. Without ECG-gating, contiguous slices of interesting parts of the cardiovascular system can be obtained and successfully used for secondary angiographic reconstructions.
Child↗
[Sudden death caused by a heart tumor].
Primary cardiac tumors in infancy and childhood are extremely rare. In the young age group the clinical symptoms often are variable and can make diagnosis difficult. Depending on the histological character and especially the localisation of the mass the clinical appearance may lead to the first diagnosis or at least to further investigation. While myocardial tumors (rhabdomyomas and fibromas) mainly cause rhythmic disturbances, the intracavitary tumors (like myxomas) frequently disturb hemodynamics. Echo-cardiography is the main diagnostic technique, followed by angiocardiography, computertomography and nuclearmagneticresonance imaging.
Child↗