Biomedical subjects

E Pesonen

Publications and source records attributed to E Pesonen.

At least 19 recordsLinked to original sources

PubMed2005

Computer-based detection and analysis of heart sound and murmur.

To develop a digital algorithm that detects first and second heart sounds, defines the systole and diastole, and characterises the systolic murmur. Heart sounds were recorded in 300 children with a cardiac murmur, using an electronic stethoscope. A Digital algorithm was developed for detection of first and second heart sounds. R-waves and T-waves in the electrocardiography were used as references for detection. The sound signal analysis was carried out using the short-time Fourier transform. The first heart sound detection rate, with reference to the R-wave, was 100% within 0.05-0.2R-R interval. The second heart sound detection rate between the end of the T-wave and the 0.6R-R interval was 97%. The systolic and diastolic phases of the cardiac cycle could be identified. Because of the overlap between heart sounds and murmur a systolic segment between the first and second heart sounds (20-70%) was selected for murmur analysis. The maximum intensity of the systolic murmur, its average frequency, and the mean spectral power were quantified. The frequency at the point with the highest sound intensity in the spectrum and its time from the first heart sound, the highest frequency, and frequency range were also determined. This method will serve as the foundation for computer-based detection of heart sounds and the characterisation of cardiac murmurs.

Adolescent↗

PubMed2004

Signal-averaged electrocardiography in normal newborn infants.

Signal-averaged electrocardiograms (SAECGs) were recorded with bipolar orthogonal and standard 12-lead settings in 29 term healthy newborn infants. SAECGs performed with the two lead configurations were similar in quality and quantity. For the duration of the QRS complex (QRSD), the upper limit of normality for newborn infants can be set to 100 ms. It is similar in individual bipolar orthogonal and individual standard 12-lead recordings as well as in filtered QRSD in the vectorcardiograms (the vector magnitude, VM, and the sum of extremity leads). In individual leads of bipolar orthogonal and standard 12-lead recordings, root-mean-square voltage of the terminal 40 ms of the QRS complex (RMS40) is widely scattered and unsuitable as discriminant variable. For VM and the sum of the extremity leads, the same reference values for RMS40 and duration of low-amplitude signal can be used as applied in adults. Individual lead recordings provide complementary information in addition to vectorcardiograms. There are practical advantages using standard 12-lead compared to conventional bipolar orthogonal configurations. The widespread use of standard 12-lead ECG in routine medical practice makes its utility advantageous also in performing signal-averaged electrocardiography.

Electrocardiography↗

PubMed2004

Extrinsic and intrinsic factors relating to intimal thickening in children.

Children already have intimal thickenings occupying over half of the vascular lumen. Intimal thickening is one of the first steps in atherogenesis. Classical risk factors such as hypercholesterolaemia, genetic background and acute noxious factors play a role in its development. Genetic origin of the children from high-risk groups for coronary heart disease seems to be a determinant of the magnitude of thickenings. Extrinsic factors such as infections also seem to play a role. The magnitude of the thickening is related to viral and bacterial infections. Infections may lead to endothelial injury and secondary intimal thickening. The process may advance stepwise with acute exacerbations of endothelial dysfunction and intimal thickening followed by incomplete healing. In particular, repeated acute infections might lead to permanent damage. Morphological evidence for early atherogenesis in children is presented.

Arteriosclerosis↗

PubMed2003

Coronary blood flow in healthy neonates: effects of left ventricular function and mass.

This study used transthoracic echocardiography, including pulsed-wave Doppler, to register coronary flow parameters in 55 healthy neonates. Intraobserver variability was tested in 20 neonates. A Doppler tracing of sufficient quality for analysis was obtained in the left anterior descending coronary artery (LAD) in 53 of 55 studies (96.4% feasibility) and in the right coronary artery (RCA) in 11 of 55 studies (20.0% feasibility). Estimation of intraobserver variability showed coefficients of variation of 7.5-8.0% for diastolic LAD Doppler flow parameters and volume flow but 17.5% for systolic peak flow velocity. Doppler flow parameters were significantly higher in the LAD than in the RCA. Correlation was found between LAD Doppler flow parameters and age, left ventricular (LV) mass, mitral peak early wave velocity as a measure of diastolic LV function, and the aortic velocity time integral/minute as a measure of systolic LV function. This study shows that diastolic LAD Doppler flow parameters and flow volume can be obtained in neonates by transthoracic echocardiography with acceptable reproducibility. In healthy neonates, left coronary flow parameters are linearly related to age, LV mass, and LV systolic and diastolic function. RCA flow parameters in neonates are lower than in the LAD.

Blood Flow Velocity↗

PubMed2002

Analysis of atrioventricular plane movements by Doppler tissue imaging and M-mode in children with atrial septal defects before and after surgical and device closure.

Our objective was to compare the effects of surgical and device closure of atrial septal defects (ASDs) on atrioventricular plane function. In healthy individuals, both short- and long-axis motion contribute to ventricular pump function. Short-axis function (i.e., the amplitude and velocity of atrioventricular plane movements) may be evaluated by M-mode and Doppler tissue imaging. The study group consisted of 19 children with ASD of the secundum type before and after surgical (n = 12) or device (n = 7) closure and 10 healthy controls. Surgical and device closures were uncomplicated and all defects were completely closed. Registrations of atrioventricular plane systolic and diastolic amplitude and velocity were made from the tricuspid and the mitral annulus and from the septum in the apical four-chamber view. Comparisons were made between examinations before and after closure, between the two subgroups of patients treated by surgical and device closure, respectively, and between the patient group and the control groups. Before ASD closure, all measurements were normal or near normal. After surgery, systolic amplitudes and velocities of the tricuspid annulus and in the septum decreased significantly, whereas no changes were seen in the device group. Less marked changes were seen in diastolic measurements. However, in the surgical group significant decrease to subnormal values were found in the tricuspid annulus and in the septum, which may indicate a decreased diastolic function postoperatively. Mitral valve annulus amplitude and velocity were not affected by the treatment. Atrioventricular function is normal in children with right ventricular volume overload. The decrease to subnormal values after open-heart surgery is not seen after device closure of the ASD, indicating that surgery affects right ventricular function.

Adolescent↗

PubMed2002

Coil embolization of a neonatal pulmonary arteriovenous malformation.

Pulmonary arteriovenous malformation (PAVM), as a part of Osler-Weber-Rendu Syndrome, in the neonate, is a rare hereditary vascular malformation. Large intrapulmonary right-to-left shunting, causing hypoxaemia and cyanosis, can be a life-threatening condition. Repeated transcatheter coil embolization procedures proved to be a favorable strategy to improve systemic arterial oxygen saturation, with a good outcome in a newborn child. While the radiation dose was high, the use of this amount of radiation was felt to be justified and its effects considered tolerable in the treatment of this patient's serious malformation.

Arteriovenous Malformations↗

PubMed2001

Reduced postnatal cerebral glucose metabolism measured by PET after asphyxia in near term fetal lambs.

The effects of fetal asphyxia on cerebral function and development, involve the transition from fetal to neonatal life. Changes in cerebral glucose metabolism may be an early postnatal indicator of fetal asphyxia. The objective is to develop an experimental lamb model involving the transition from fetal to neonatal life and to examine the effect of fetal asphyxia with cerebral hypoxic ischemia on early postnatal cerebral glucose metabolism. Fetal asphyxia was induced by total umbilical cord occlusion in eight near-term fetal lambs (134-138 days) with the ewe under isoflurane-opiate anesthesia. The mean occlusion time until cardiac arrest was 14.5 (4.2) min (SD). Lambs were immediately delivered and standardized resuscitation was instituted after 2 min asystole. At 4 hr postnatal age, [18-F]Fluoro-2-deoxy-glucose (18-FDG) was injected intravenously in eight asphyxiated lambs and in eight controls. Cerebral glucose metabolism was examined by positron emission tomography (PET). As a result the mean arterial blood pressure, acid-base values, blood glucose and serum lactate at 4 hr postnatal age did not differ significantly between lambs subjected to umbilical cord occlusion and controls. EEG was abnormal in all lambs subjected to cord occlusion and normal in the controls at 4 hr postnatal age. Global cerebral metabolic rate (CMRgl) as determined by PET was significantly lower in lambs subjected to cord occlusion mean/median (SD) 22.2/19.6 (8.4) micromol/min/100 g) than in controls mean/median (SD) 37.8/35.9 (6.1); P < 0.01). Global CMRgl is significantly reduced in newborn lambs 4 hr after fetal asphyxia induced by umbilical cord occlusion. A reduction in CMRgl is an early indicator of global hypoxic cerebral ischemia.

Acidosis↗

PubMed2001

Activated protein C and inflammation in human myocardium after heart surgery.

To assess possible interactions between inflammation and activation of the anticoagulant protein C system during post-ischemic reperfusion protein C, APC, neutrophil L-selectin expression and myocardial myeloperoxidase activity (MPO) were measured in 19 patients undergoing cardiopulmonary bypass. After reperfusion for 10 min, APC to protein C ratio (APC/PC) increased from pre-reperfusion value 1.43 +/- 0.12 (mean +/- SEM) to 2.25 +/- 0.29, p = 0.015. Negative correlations were observed between APC/PC and MPO activity (Spearman r -0.64, p = 0.007) and APC/PC and neutrophil L-selectin expression (r = -0.7, p = 0.007, demonstrating that post-ishemic protein C activation was associated with decreased neutrophil tissue sequestration. Thus, physiological protein C activation may be involved in regulation of the inflammatory injury during reperfusion of human ischemic coronary circulation.

Adult↗

PubMed2001

Structural variation of tracheids in Norway spruce (Picea abies [L.] Karst.).

The orientation of cellulose microfibrils in the cell wall and the shape and the dimensions of the cells of earlywood of four Norway spruce (Picea abies [L.] Karst.) stems grown in Finland were studied by X-ray diffraction and optical microscopy. The average microfibril angle (MFA) decreased and the diameter of the cell increased rapidly up to rings 5-10 from the pith and remained at the same level after that. The average MFA close to the pith was over 20 degrees and decreased to about 8 degrees after ring 10 from the pith. The average diameter of the cells was 35 microm in the outer rings. The shape of the cross section of the lumen changed from circular to rectangular from the pith to the bark. The tracheid length increased also as a function of the distance from the pith. The thickness of the cell wall varied between 2.8 and 3.5 microm. Automatic cell lumen and cell wall recognition procedures were developed for the analysis of the images of the cross sections of the cells.

Cell Wall↗

PubMed2001

High-frequency components in ECG analysed in guinea-pig Langendorf preparations.

High-frequency components in ECG during global ischaemia were studied in isolated guinea-pig hearts perfused ad modum Langendorf. Electrocardiograph recordings were carried out from the epicardial surface both in normo- and low-flow perfusion. After bandpass filtering (5-500 Hz), signal-averaging, was undertaken. The high-frequency components either increased or decreased after low-flow perfusion was instituted. Root-mean-square voltage (RMS) of the depolarization signal correlated poorly with the signal amplitude, but highly with the first and second derivative, i.e. the velocity and the acceleration of the signal. It is concluded that high-frequency components are not pathological phenomena per se, but reflect the shape of the original electrocardiographic signal.

Animals↗

PubMed2001

Plasma cyclic guanosine monophosphate reflecting the severity of persistent pulmonary hypertension of the newborn.

The aim of the study was to examine the relationship between the plasma concentration of cyclic guanosine monophosphate (cGMP) and pulmonary pressure and hypoxia defined by oxygenation index (OI) in newborn infants with severe persistent pulmonary hypertension (PPHN) on inhaled nitric oxide (NO). In this prospective study, 18 newborn infants having Doppler ultrasound-diagnosed PPHN and treated with NO were investigated. The ratio of pulmonary artery to systemic artery pressure (PAP/SAP) and OI was assessed before treatment and at 0.5, 1, 12, and 24 h from the beginning of NO. At these time points, plasma concentrations of cGMP could be determined in 11 patients. The association of birth asphyxia as assessed by Apgar 1 min and 5 min and plasma cGMP before the NO treatment was examined. The initial median plasma concentration of cGMP was 37.3 pmol/ml (IQR 13.3-79.6). After the start of NO, cGMP increased significantly within 60 min (p = 0.003) and peaked at 12 h. Initial plasma cGMP was associated with Apgar score (1 and 5 min). OI decreased within 30 min of NO and PAP/SAP within 60 min. Persistent high PAP/SAP after 1 h of NO was associated with low cGMP concentration (r = 0.70, p = 0.02). We conclude that a significant increase in plasma cGMP is already evident after 60 min of NO therapy. This effect is accompanied by changes in oxygenation index and in pulmonary artery pressure. Initial plasma concentrations of cGMP were associated with hypoxia assessed as Apgar score.

Apgar Score↗

PubMed2001

Role of natriuretic hormones in the diagnosis of patent ductus arteriosus in newborn infants.

UNLABELLED: Haemodynamically significant patent ductus arteriosus worsens respiratory distress by initiating pulmonary congestion and inactivating of surfactant. Excepting size of the ductus, several factors influence ductal flow. CONCLUSION: Atrial natriuretic hormones provide clinically useful data, especially in serial follow-up of the patient.

Atrial Natriuretic Factor↗

PubMed2000

Endothelial dysfunction after repeated Chlamydia pneumoniae infection in apolipoprotein E-knockout mice.

BACKGROUND: Arterial relaxation is largely regulated by endothelial nitric oxide (NO). Its diminished activity has been associated with incipient atherosclerosis. We investigated the endothelium-dependent relaxation of aorta in apolipoprotein E-knockout (apoE-KO) mice exposed to single or repeated Chlamydia pneumoniae inoculation. METHODS AND RESULTS: Forty-eight apoE-KO mice, 8 weeks old, were inoculated intranasally with C pneumoniae (n=24) or saline (n=24) every 2 weeks over a 6-week period. Twenty mice (10 infected and 10 controls) were killed at 2 weeks and 6 weeks, respectively, after the first inoculation. The smooth muscle tone of aortic rings was measured in vitro at both time points. The norepinephrine-precontracted thoracic aortic rings were successively exposed to methacholine in the absence and presence of N:(G)-nitro-L-arginine methyl ester (L-NAME) and diclofenac. The methacholine-induced relaxation was attenuated in the infected mice at 6 weeks in both the absence and presence of L-NAME (P:<0.05 and P:<0.01, respectively). When administered together with L-NAME, diclofenac enhanced the relaxation of the L-NAME-pretreated aortas in infected mice at 2 weeks (P:<0.05) but not in noninfected mice. The relaxation response from infected mice tended to differ in the same manner at 6 weeks (P:<0.1). No intimal thickening was detected at either time point. CONCLUSIONS: C pneumoniae impairs arterial endothelial function, and the NO pathway is principally involved. Cyclooxygenase-dependent vasoconstricting products may also account for the infection-induced impaired relaxation. These findings further support the role of C pneumoniae infection in atherosclerosis development.

Alkaline Phosphatase↗

PubMed2000

Coronary flow abnormalities in neonates with aortic stenosis.

Left coronary artery flow velocities in neonates were determined noninvasively with transthoracic pulsed wave Doppler ultrasonography. In normal subjects (n = 30) there was diastolic flow predominance with median (range) peak flow velocity in diastole, 23.8 cm/s (12.7 to 51.3 cm/s), and median peak flow velocity in systole, 12.7 cm/s (7.8 to 35.0 cm/s). In 3 neonates with severe aortic stenosis, retrograde left coronary flow throughout systole was observed before surgery. In these patients there was forward systolic flow 4 to 8 days after successful surgical valvulotomy was performed.

Aortic Valve Stenosis↗

PubMed2000

Nitric oxide and hyperoxia in oxidative lung injury.

UNLABELLED: Therapy with inhaled nitric oxide is usually given with high concentrations of oxygen. As nitric oxide (NO) is a free radical and hyperoxia increases oxygen radical production, we examined the effect of short exposure to NO or oxygen (O2) or both, on free radical-mediated changes in macromolecules, i.e. lipids and proteins, in vivo. Wistar rats were exposed to > 95% O2 or 40 ppm NO, or both, for 6 h. Rats in 21% O2 served as controls. Lipid peroxidation was quantified as expired pentane, oxidative protein modification as carbonyl concentration, and pulmonary neutrophil accumulation as myeloperoxidase activity in the lungs. Hyperoxia for 6 h caused higher expired pentane (4.83 +/- 1.39 pmol/min/100 g) and protein carbonylation (15.91 +/- 2.49 nmol/mg) compared to controls (2.26 +/- 1.00 pmol/min/100 g, and 7.40 +/- 1.12 nmol/mg, respectively; both p < 0.05). After exposure to NO in air, protein carbonylation (14.50 +/- 5.44 nmol/mg) and myeloperoxidase activity (4.85 +/- 1.52 mU/mg) were higher than in controls (myeloperoxidase 2.49 +/- 0.56 mU/mg; both p < 0.05). NO with hyperoxia decreased pentane (2.56 +/- 1.51 pmol/min/ 100 g) and protein carbonylation (11.38 +/- 3.58 nmol/mg) compared to hyperoxia (both p < 0.05). CONCLUSION: In vivo, 6 h exposure to hyperoxia or to 40 ppm NO induces free radical-mediated lung injury. The combination of hyperoxia and 40 ppm NO significantly attenuates free radical-mediated effects in the lungs compared to hyperoxia or 40 ppm NO in air.

Animals↗

PubMed2000

Transcatheter closure of post-infarction ventricular septal defect with the Amplatzer Septal Occluder device.

There is an 80-90% mortality rate within the first 2 months of the occurrence of a post-infarction ventricular septal defect (VSD) with medical treatment alone. The muscular VSD presents a technical problem for the surgeon. Surgical treatment was unsuccessful in two patients. They were treated successfully using the Amplatzer Septal Occluder, with improvement in their condition.

Aged↗

PubMed1999

Infection-associated intimal thickening in the coronary arteries of children.

OBJECTIVES: based on autopsy material from children this study investigated the possible relationship of clinically evident infection prior to death with intimal thickening of the coronary arteries. BACKGROUND: viral infections are suggested to be associated with intimal thickening in the coronary arteries both in animals and man. METHODS: the coronary arteries were examined in 175 autopsied children 0-15 years of age (median 7 days). Semi-serial cross sections of the coronary arteries were screened for maximal intimal thickening at 0.2 mm intervals. The length of the internal elastic lamina, the areas of arterial media and intima were measured from cross-sections. Irregular linings of the arteries were mathematically transformed to circles. The percentage of intimal and musculoelastic layer area to luminal area encircled by arterial media was calculated. RESULTS: intimal thickening increased with age but was also associated with the presence of infectious disease at death. Already in the newborn children, who died shortly after the birth, the percentage of intimal and musculoelastic layer area to luminal area encircled by arterial media was big, maximally 55%. In the left coronary artery the mean percentages were 32 and 21% in the groups with viral and bacterial infections, respectively as compared to 16% in the group with no evidence of infection. CONCLUSION: infections in general and viral infections in particular, seem to be associated with intimal thickening, which may predispose coronary arteries to atherosclerosis. Atherogenesis might have a rapid dynamic component.

Adolescent↗

PubMed1999

Cardiopulmonary bypass and activation of antithrombotic plasma protein C.

OBJECTIVE: We hypothesized that antithrombotic plasma-activated protein C plays a defensive antithrombotic role during coronary ischemia and postischemic reperfusion. METHODS AND RESULTS: We evaluated protein C activation during cardiopulmonary bypass and coronary reperfusion in 20 patients undergoing coronary bypass surgery. During cardiopulmonary bypass and during the 10 minutes after aortic unclamping, the plasma levels of protein C (mean +/- standard error of the mean) decreased from 123% +/- 7% to 74% +/- 5% of normal mean. In contrast, the levels of activated protein C in plasma increased from 122% +/- 8% to 159% +/- 21%, and the activated protein C/protein C ratio increased from 1.04 +/- 0.08 to 2.29 +/- 0. 31 (P =.006, 2-tailed Wilcoxon signed rank test). Patients were stratified on the basis of the increase in activated protein C in the coronary sinus plasma at 10 minutes after reperfusion by means of the arbitrary value of 1.5 for the activated protein C/protein C ratio. Within 24 hours, the patients with low increases in activated protein C (ratio < 1.5, n = 8) had a significantly (P <.05) lower cardiac output and mean pulmonary artery pressure, as well as a higher systemic vascular resistance, than patients (n = 11) with high increases in activated protein C (ratio > 1.5). The rapid increase in activated protein C during the first 10 minutes after aortic unclamping indicated protein C activation in the reperfused vascular beds. CONCLUSIONS: The antithrombotic protein C pathway was significantly activated during cardiopulmonary bypass mainly during the minutes after aortic unclamping in the ischemic vascular beds. Suboptimal protein C activation during ischemia may impair the postischemic recovery of human heart and circulation.

Adult↗