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The particles in the examined cyclone fly ash were all smaller than 0.25 mm. in diameter, and particles smaller than 0.075 mm. in diameter accounted for 88.4 % of the ash weight. This result indicates that cyclone fly ash consists of particles with a small diameter. The metals in the cyclone fly ash were enriched in small particles. The highest concentrations for zinc, copper, lead, cadmium and molybdenum in the cyclone fly ash were found in the smallest particle size fraction (< 0.075 mm.) and for Barium, chromium, nickel, Vanadium and Cobalt in the second to smallest particle size fraction (0.075-0.125 mm.). From an environmental and toxicological standpoint, the smallest particles are of the greatest concern when ash is handed at landfill disposal sites (transport and disposal especially in stormy weather conditions), and some studies have reported risks to workers from prolonged exposure to ash. The results of the comparison of various dissolution methods for metals showed that the digestion procedures with nitric acid alone (USEPA 3051) or with a mixture of nitric acid + hydrogen peroxide (USEPA 3050B) slightly underestimated the metal concentrations in the cyclone fly ash. Although the use of hydrofluoric acid is often necessary for the determination of a number of elements associated with siliceous minerals, its use can result in loss of trace elements during dissolution.

A four-stage sequential leaching procedure was applied to assess the bioavailability and environmental mobility of heavy metals (Cr, Fe, Cu, Ni and Cd) in total suspended particulate (TSP) material emitted from an opencast chrome mine complex (Kemi, Northern Finland). TSP material was collected on glass fibre filters by a high-volume sampler, and a sequential leaching procedure was used to determine the distribution of heavy metals between the water-soluble fraction (H2O), environmentally mobile fraction (CH3COONH4), the fraction bound to carbonate and oxides (HONH3Cl + CH3COOH), and the fraction bound to silicates and organic matter, that is the environmentally immobile fraction (HNO3+ HF + HCl). The sequential leaching procedure was also applied to the certified reference materials VKI (QC Loam Soil A) and PACS-2 (Marine Sediment) to evaluate the accuracy and reproducibility of the leaching procedure. The heavy metals were determined by graphite furnace atomic absorption spectrometry (GFAAS) and flame atomic absorption spectrometry (FAAS). The concentrations of metals in the water-soluble fraction (H2O) decreased in the order Fe >Cu >Cr >Ni >Cd, and in the environmentally mobile fraction (CH3COONH4) in the order Cu >Fe >Ni >Cr >Cd.

The intraesophageal pressure difference (ΔPes) was measured in 46 preterm infants, 36 with respiratory distress (RDS). It was 12.7±2.9 mm Hg (mean±SEM) in severe RDS, 9.6±3.2 mm Hg in moderate RDS, and 5.2±1.6 mm Hg in infants with mild disease, measured at the age of 8 h. These intergroup differences were highly significant (P<0.001). During the first 96 h of life the ΔPesdecreased to 6.1±1.1 mm Hg in severe RDS and to 4.8±1.2 mm Hg in moderate RDS. These changes were also highly significant (P<0.001) when compared with respective initial values. In infants with mild disease and in healthy preterm infants, the ΔPesdid not alter significantly during the first 96 h of life.

Variability of heart rate (HRV) and transthoracic electric impedance respirogram (TEZ) were examined by spectral analysis in three groups of neonates: healthy term babies (22), healthy preterm babies (21), and preterm babies with respiratory distress syndrome (RDS) (11). Heart rate, TEZ, Ptco2, and Ptcco2were monitored during quiet sleep on the 1st, 3rd, and 5th day of postnatal life. Autospectra for trend-corrected segments of heart rate and TEZ as well as their cross-spectra and coherence spectra were computed. The peak of HRV spectral density was in < 0.2 Hz [low frequency (LF)] area (< 12 cycles/ min) in all the neonates. Intergroup comparisons of average band-integrated spectra revealed that the LF spectral density of HRV was greater in the term babies than in the preterm babies on day 3. In the babies with RDS, both LF and high-frequency (HF, > 0.2 Hz) were abnormally low throughout the study. In the term infants, the TEZ amplitude spectrum was flat on day 1. On later days, a peak corresponding to the average respiratory rate emerged. In the healthy preterm babies, there was a LF peak in TEZ autospectrum on all days. In the babies with RDS, the peak of ventilator frequency was initially present; finally, the respiratory activity accumulated in the LF area. In the cross-spectra of term babies, there was a LF peak on all days. On day 5, an additional HF peak appeared, representing respiratory sinus arrhythmia. In the healthy preterm babies, only a LF peak was present. In babies with RDS, there were three peaks in the cross-spectra: one in the LF area, another corresponding to the ventilator frequency, and a third one representing the first harmonic of the ventilator frequency. With increasing age, the ventilator-induced peaks disappeared and only LF activity remained. No correlation was found between the spectral patterns of HRV and cross-spectra and the values of PtcO2and Ptcco2. The spectral patterns of HRV and TEZ indicate that in newborn infants most of the activity is generated by LF mechanisms. Respiratory sinus arrhythmia is detected in term infants when regular breathing becomes organized. In RDS, respiratory sinus arrhythmia HRV is induced by ventilator. In both groups of preterm babies, the LF regulation of HRV seems to be more firmly connected with regulation and mechanics of respiration.

Abstract: A quantitative method for studying the frequency-specific relationships between heart rate (HR) and fetal breathing movements (FBM) was developed. The reactivity of periodic HR variation in relation to FBM was investigated by means of power spectral analysis. Seven fetal lambs were studied during the third trimester of gestation using a chronic animal model. HR variability increased at the rate of FBM, as shown by an increase of spectral density at >035 Hz in the HR autospectrum and in the cross-spectrum of HR and respirogram, as well as by an increase in the shorterm variability index CVS. FBM were associated with the increased HR variation in all but the lowest frequency bands (007-10 Hz). Although respiratory sinus arrhythmia was found, only 10 per cent of the total HR variability and 25 per cent of the joint-density of HR and respirogram appeared at <035 Hz during FBM. The greatest variation in both the HR and respirogram spectra appeared at <007 Hz. Although the low-frequency variability of HR and respirogram was simultaneous, it was on the whole not synchronised. The existence of multiple control systems that simultaneosly link the cardiac and respiratory control mechanisms to each other in the fetal lamb is postulated.

We studied the pulsatile component of cerebral circulation with transcephalic electrical impedance (ΔZ) in six preterm newborns, three of whom had severe cerebral bleeding, peri-intraventricular haemorrhage (PIVH). The transcephalic electrical impedance ΔZ signal, ECG, arterial blood pressure, (aBP) and respirogram were recorded on analogue magnetic tape for 30 min. Artefact-free stationary segments (lasting for 2 min) of the four signals were digitised. A digital multivariate autoregressive (MAR) model was used to study frequency-specific variability in the signals and to quantify interrelations between the variabilities of ΔZ, HR, aBP and respiratory signals. MAR modelling describes a system where all the signals simultaneously explain each other. The inherent variability of ΔZ was lower and the influences of respiration and aBP on ΔZ significantly greater in infants with severe PIVH than in controls. These changes were observed at high frequencies corresponding to respiration and heart rate. This may be interpreted as a marker of pressure passivism in the cerebral circulation following PIVH. We conclude that in preterm babies the application of MAR modelling, together with transcephalic impedance, may be a new, helpful and quantitative method for the study of simultaneous interrelations between variables of cerebral and systemic circulations and respiration.

The objective of the study was to investigate the features of cardiovascular and respiratory autonomic nervous regulation in asthmatic and control children. Cardiorespiratory reactivity was studied by continuous and non-invasive recording of the electrocardiogram, finger systolic arterial pressure (SAP) and flow-volume spirometry in supine and upright positions and during a deep breathing test in 19 children with bronchial asthma and 10 healthy control children (age 8-11 years). The periodic variability components of R-R intervals (the time between successive heart beats) and SAP in relation to respiration were assessed using spectral analysis techniques. Nine asthmatic children without beta,-agonist medication had a lower respiratory rate and larger high frequency (HF) variability of SAP than the controls, and 10 asthmatic children with beta2-agonist medication had greater low-frequency (LF) variability of SAP and LF/HF ratio of R-R intervals, but their respiratory rate did not differ from the controls. No intergroup differences were found in the postural change of variables. Stable bronchial asthma appears to increase respiratory-induced alterations in systolic blood pressure in children. Beta2-agonist medication, on the other hand, increases sympathetic cardiovascular activity in children with asthma.

ABSTRACT: ß-Blockers are used in pregnancy-associated hypertension and in postnatal cardiac arrhythmias, and the neonate may get them in breast milk. We therefore studied the effects of ß-adrenergic medication on interrelations between heart rate (HR), respiration, and arterial blood pressure (aBP) in newborn lambs. The influence of sleep state on these cardiorespiratory interrelations was also examined. HR, aBP, and respiration (based on transthorack electrical impedance) were recorded and the sleep state was visually documented in five healthy chronically instrumented newborn lambs before the age of 30 d. Propranolol was given (1 mg/kg). Two-min stationary segments of the three signals were analyzed using a multivariate autoregressive model, which yields oscillations of the signals and intersignal relationships as source contributions. The variabilities of aBP and HR were greatest at the low frequencies (<0.25 Hz) and so were their intersignal relationships (including baroreflex). The respiratory variability was greatest at the frequencies corresponding to the respiratory rate. Daring quiet sleep, the variabilities in HR, aBP, and respiration were lowest. The impact of respiratory oscillations on other signals increased but the impact of aBP variability decreased during quiet sleep. ß-Blockade and sleep state affected separately the cardiovascular and respiratory variables and their interrelations. ß-Blockade reduced HR and increased pulse pressure. The overall heart rate variability and the respiratory low-frequency contribution to heart rate variability decreased due to the ß-blockade. We postulate that the ß-adrenergic system is an important regulator of HR and HR variability IB neonatal lambs and also of the low-frequency components of the respiratory sinus arrhythmia. However, inasmuch as the interrelations between HR and aBP were not altered by the ß-blockade, even high doses of propranolol do not seem hazardous for the cardiovascular system in neonatal lambs.

Lapinleimu H, Viikari J, Jokinen E, Routi T, Salo P, Hollo O, Niinikoski H, Rönnemaa T, Leino A, Välimäki I, Simell O. Cholesterol measurement by reflotron dry chemistry in infants, children and adults. Scand J Clin Lab Invest 1994; 54: 61-65.Cholesterol values measured with the Reflotron® dry chemistry (Boehringer Mannheim, Mannheim, Germany) and enzymatic (CHOD-PAP) routine method in 4150 venous blood samples from 580 infants aged 7 months, 1778 children aged 13 months to 19 years, and 1792 adults aged 18-63 years showed good correlation between the two assay systems (r > 0.92). However, the mean cholesterol concentrations were 4.5%, 3.7% and 2.3% lower in infants, children and adults, respectively, if measured with the Reflotron analyser as compared with values obtained with the CHOD-PAP method. These differences in the values were greater when cholesterol values were low (significance for the slope of regression line, p < 0.001). Values were below the detection limit of the Reflotron assay (2.59 mmoll-1) in 104 (4.4%) and 4 (0.2%) of all paediatric and adult samples, respectively. When measured with the CHOD-PAP method, 75 (72%) and 3 (75%) of these same samples showed values which exceeded the 2.59mmoir' detection limit. We conclude that Reflotron dry chemistry analyser is precise in fast measurement of serum cholesterol both in all paediatric subjects and adults. A particular problem in paediatric age groups is that about 4% of children have values below the detection limit of the Reflotron analyser.

Autonomic cardiac control of children with diabetes mellitus (DM, n=12), juvenile rheumatoid arthritis (JRA, n = 12) and healthy controls (n=12) was studied by a procedure consisting of a deep breathing test and an intermittent tilting test. Frequency selective entrainment of HR could be produced by tilting and deep breathing. No statistically significant intergroup differences were detected in the patterns of average heart rate (HR), overall or beat-to-beat heart rate variability (HRV) or HRV spectra. The DM group had an 8% higher HR and a limited short-term HRV response in relation to HR throughout the whole test procedure compared to controls. This increased HR causes an extra load to the cardiovascular system. We conclude that in spite of elevated HR and changed short-term chronotropic HR control in DM no features of autonomic failure could be detected in children with JRA.

Abstract: Transcephalic electrical impedance offers a technique for non-invasive, cotside monitoring of neonatal cerebral circulation but the exact nature of the signal is somewhat ambiguous. The impedance signal is examined in an animal project where the ventilator settings are adjusted (20 min−1–10 min−1–40 min−1 for 10 min periods each) to produce circulatory changes. Six juvenile pigs are intubated, and ECG, arterial blood pressure, carotid flow (CF) by electromagnetic flowmeter and impedance are continuously monitored and stored on analogue tape. Cardiac output by thermodilution, blood oxygen (pO2) and carbon dioxide (pCO2) tensions are measured. ECG is converted to heart rate, mean blood pressure is integrated, and the high-frequency (1.50–4.00 Hz) component of the impedance signal ΔZ is computed using autoregressive spectral estimation. Stroke volume, peripheral vascular resistance (PVR) and cerebral vascular resistance (CVR) are calculated. pCO2 and CF increase and pO2 decreases during hypoventilation. CF correlates positively with cardiac output, stroke volume, ΔZ and pCO2, and negatively with pO2 and CVR. ΔZ correlates positively with heart rate and cardiac output, and negatively with PVR and CVR. It is concluded that the impedance signal is related to the amount of blood transmitted to the brain by every beat of the heart, depending on the changes in both the systemic circulation and the cerebral vascular compliance.

β-Blockers are used in pregnancy-associated hypertension and in postnatal cardiac arrhythmias, and the neonate may get them in breast milk. We therefore studied the effects of β-adrenergic medication on interrelations between heart rate (HR), respiration, and arterial blood pressure (aBP) in newborn lambs. The influence of sleep state on these cardiorespiratory interrelations was also examined. HR, aBP, and respiration (based on transthorack electrical impedance) were recorded and the sleep state was visually documented in five healthy chronically instrumented newborn lambs before the age of 30 d. Propranolol was given (1 mg/kg). Two-min stationary segments of the three signals were analyzed using a multivariate autoregressive model, which yields oscillations of the signals and intersignal relationships as source contributions. The variabilities of aBP and HR were greatest at the low frequencies (0.25 Hz) and so were their intersignal relationships (including baroreflex). The respiratory variability was greatest at the frequencies corresponding to the respiratory rate. Daring quiet sleep, the variabilities in HR, aBP, and respiration were lowest. The impact of respiratory oscillations on other signals increased but the impact of aBP variability decreased during quiet sleep. β-Blockade and sleep state affected separately the cardiovascular and respiratory variables and their interrelations. β-Blockade reduced HR and increased pulse pressure. The overall heart rate variability and the respiratory low-frequency contribution to heart rate variability decreased due to the β-blockade. We postulate that the β-adrenergic system is an important regulator of HR and HR variability IB neonatal lambs and also of the low-frequency components of the respiratory sinus arrhythmia. However, inasmuch as the interrelations between HR and aBP were not altered by the β-blockade, even high doses of propranolol do not seem hazardous for the cardiovascular system in neonatal lambs. (Pediatr Res 29: 272–277, 1991)

Abstract: Our aim was to develop a signal analysis method for revealing interrelationships between heart rate and blood pressure and for displaying the influence of autonomic nervous control on these signals in a chronic lamb model. A chronically instrumented neonatal lamb model was made to record ECG and direct arterial blood pressure (N=15). Continuous two-minute recordings of blood pressure (BP) and ECG were digitised. The instantaneous heart rate signal (IHR) was derived from the ECG. The IHR and BP signals were bandpass filtered. Autospectra, cross-spectra, coherence spectra and phase spectra for the signals were computed to study the relative magnitudes and inter-relationships of the cardiovascular signals under normal conditions and during beta-adrenergic blockade. It was noted that both in the BP and IHR there were oscillations at the frequency of <0·1 Hz and also at the respiratory rate around 0·6 Hz. Beta-blockade reduced the oscillations of the IHR in <30-day-old lambs. It did not affect the coherence spectra or the phase lag between the signals. During quiet sleep the variability of blood pressure was decreased. In over-30-day-old-lambs the beta-blockade did not affect the variabilities of the cardiovascular parameters. These findings indicate that in neonatal lambs the sympathetic control system is a major regulator of cardiovascular interactions.

Heart rate, short-term heart rate variability, long-term heart rate variability (LTV), mean arterial blood pressure and R-to-pulse time were recorded in 28 infants during the acute phase of respiratory distress syndrome (RDS). The patients were classified by a clinical scoring system into three classes related to the severity of the disease. The LTV was initially significantly (p < 0.01) lower in infants with severe RDS (class III) than in those with moderate or mild disease (classes II and I). Only in class III the LTV increased significantly (p < 0.001) during recovery. Also the mean arterial blood pressure was decreased in class III during the first 24 h of life. The R-to-pulse time proved not to be related to the severity of RDS. Reasonable assistance was achieved by multiparametric circulatory monitoring: a considerably disturbed circulatory control (tendency to hypotension and attenuated chronotropic cardiac control) was observed in the most severe form of RDS. No specific circulatory therapy was applied on the basis of the findings.

ABSTRACT: Variability of heart rate (HRV) and transthoracic electric impedance respirogram (TEZ) were examined by spectral analysis in three groups of neonates: healthy term babies (22), healthy preterm babies (21), and preterm babies with respiratory distress syndrome (RDS) (11). Heart rate, TEZ, Ptco2, and Ptcco2were monitored during quiet sleep on the 1st, 3rd, and 5th day of postnatal life. Autospectra for trend-corrected segments of heart rate and TEZ as well as their cross-spectra and coherence spectra were computed. The peak of HRV spectral density was in < 0.2 Hz [low frequency (LF)] area (< 12 cycles/min) in all the neonates. Intergroup comparisons of average band-integrated spectra revealed that the LF spectral density of HRV was greater in the term babies than in the preterm babies on day 3. In the babies with RDS, both LF and high-frequency (HF, > 0.2 Hz) were abnormally low throughout the study. In the term infants, the TEZ amplitude spectrum was flat on day 1. On later days, a peak corresponding to the average respiratory rate emerged. In the healthy preterm babies, there was a LF peak in TEZ autospectrum on all days. In the babies with RDS, the peak of ventilator frequency was initially present; finally, the respiratory activity accumulated in the LF area. In the cross-spectra of term babies, there was a LF peak on all days. On day 5, an additional HF peak appeared, representing respiratory sinus arrhythmia. In the healthy preterm babies, only a LF peak was present. In babies with RDS, there were three peaks in the cross-spectra: one in the LF area, another corresponding to the ventilator frequency, and a third one representing the first harmonic of the ventilator frequency. With increasing age, the ventilator-induced peaks disappeared and only LF activity remained. No correlation was found between the spectral patterns of HRV and cross-spectra and the values of PtcO2and Ptcco2. The spectral patterns of HRV and TEZ indicate that in newborn infants most of the activity is generated by LF mechanisms. Respiratory sinus arrhythmia is detected in term infants when regular breathing becomes organized. In RDS, respiratory sinus arrhythmia HRV is induced by ventilator. In both groups of preterm babies, the LF regulation of HRV seems to be more firmly connected with regulation and mechanics of respiration.

Heart rate variations in long-term electrocardiographic recordings were studied in 68 normal term and 30 premature neonates, and apneic periods were documented from two simultaneously recorded respirograms in 18 of the term babies. Phasic variation in heart rate occurred in all term and 26 premature babies, and periods of fixed heart rate occurred in 8 premature infants. Frequent episodes of sinus tachycardia, short periods of bradycardia, and sudden cardiac arrhythmias were detected in both groups. Respirograms showed 167 periods of apnea in the 18 infants studied; at least one period ≥ 2 sec. occurred in all, terminating by 10 sec. in the majority. Apnea elicited a bradycardic response on 27 occasions, with nodal escape rhythm in 5.

Oscillations of skin blood flow and heart rate can be synchronised using external rhythmic thermal stimulation in healthy adults and infants. We examined the effect of thermal stimulation on the cutaneous circulation and heart rate of an anencephalic neonate using cutaneous laser Doppler flowmetry and ECG monitoring. The results suggest that synchronisation of SBF and HR to thermal stimulation can also be induced in an anencephalic newborn.

A considerable reduction of heart-rate variation(HRV) has been described in adult diabetic patients with peripheral neuropathy1,indicating severe autonomic denervation of the heart.We studied 13 diabetic subjects(9 boys,4 girls,age 11.5 range 7-15 yrs) and 20 normal children(10 boys,10 girls, age 12,range 7-15 yrs)by our computerized heart-rate monitoring system2to test whether the HRV would be affected early in juvenile diabetes.The duration of the disease was 3.5 yrs(range 1/2 - 14 yrs).In the younger subjects (7-11yrs) the diabetic children had a lower relative HRV(9.1%)than the normals(12.8%).In the older group(12-15yrs) no difference was found.No cor relation existed between the HRV and duration of the disease.Thus the nervous control of the heart may be affected earlier than expected but the mechnism is obscure.1.Wheeler,T.& Watkins,P.J.:Brit.Med.J.4:584,1973.2.Kero,P.:Acta Paed.Scand.suppl 250,1974.

While the EEG is routinely used in the estimation of cortical damage, there is no clinical method to assess the function of lower CNS centres. We have previously shown that variation of heart rate is markedly decreased in neonates with RDS, respiratory distress syndrome /1,2/. In the present study, long-term records of the ECG were taken from 6 patients with signs of decerebration /age 7 days to 14 years/. 500 R-R intervals derived from the ECG were measured with a PDP 8/L computer and the mean heart rate, its beat-to-beat and overall variation were estimated. The mean heart rate and beat-to-beat variation were of the same magnitude as in a severe RDS, but the overall variation was only half of that in RDS. Periodic components of variation of heart rate could also be identified in all patients. These few cases indicate the feasibility of this non-invasive method and warrant further studies. Literature: 1. P.Kero: Acta Paediatr. Scand. Suppl. 250, 1974. 2. P.A. Tarlo, I. Välimäki and P.M. Rautaharju: J. Appl. Physiol 31:70, 1971.

Nineteen patients were involved in an outbreak of infection caused by Yersinia pseudotuberculosis serotype 3. No epidemics attributable to this microorganism have been previously reported; the most extensive known cluster of cases involved four children in one family and their pet dog. The key finding in the outbreak described in the present study was the bacteriologic identification of serotype 3 in stool specimens from patients with clinically typical yersiniosis. Twelve cases were identified by isolation of Y pseudotuberculosis from stool specimens. An ELISA permitted serological diagnosis of the remaining seven cases. The antibody response was unusually slow in some patients. A noteworthy feature of the outbreak was the high incidence of postinfection complications, which developed in 10 of 19 patients. In spite of active screening of the respective families and environments of the patients, no transmitting factor was found, and the precise source of the infection remains unknown.

Our research group has previously demonstrated the advantages of pulse conducted exercise test (PCXT) in paediatric ergometry (1). Because our fully-automated version of PCXT is based on the feed-back derived from the subject's heart rate (2), it cannot be used in testing the effect of factors (e. g. drugs) affecting heart rate.For our present experiments on the effect ß-blocking agents we have designed so called work-conducted version of the test (WCXT).Before ß-blockade the PCXT is carried out by increasing the work load to accelerate the heart rate by 8 beats/min/min. With this system the loading will be individually optimal for every patient. The work profile is recorded on magnetic tape.When the subject is on a ß-blocking drug the WCXT is carried out playing back the record of work profile to control electronically the ergometer load. During the WCXT the work profile and the both heart rate profiles (correspondig to the PCXT and WCXT) are simultaneously copied for further analysis.The system appears accurate and relatively simple to use.1. Petäjoki, M-L., Arstila, M., and Välimäki, I. : Acta Paediat. Belg. 1974, 28, Suppl. p. 40-47.2. Arstila, M., Viherä, P., Wendelin, H., Petäjoki, M-L., and Välimäki, I. : Abstract 59 in Proc. of III Nordic Meeting on Med. and Biol. Engineering. Finn. Soc. for Med. and Biol. Engineering. Tampere 1975.