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Biomedical subjects

I Välimäki

Publications and source records attributed to I Välimäki.

At least 19 recordsLinked to original sources
PubMed2005

Heavy metals (Cr, Zn, Ni, V, Pb, Cd) in lingonberries (Vaccinium vitis-idaea L.) and assessment of human exposure in two industrial areas in the Kemi-Tornio region, Northern Finland.

The concentration of Cr, Zn, Ni, V, Pb, and Cd were measured in lingonberries (Vaccinium vitis-idaea L.) sampled at 23 sampling sites around a ferrochrome and stainless steel works and opencast chromium mine in the Kemi-Tornio region, Northern Finland. Two different microwave-assisted digestion procedures were used for sample digestion, i.e., a mixture of HNO3 + H2O2 and a mixture of HNO3 + H2O2 + HCl + HF + H3BO3. According to the results, the digestion procedure with the mixture of HNO3 + H2O2 underestimated especially the Cr concentrations in plant material. The maximum concentrations of Cr (1.3 mg kg(-1), wet weight), Ni (358 microg kg(-1); ww), V (36 microg kg(-1); ww), and Cd (2.4 microg kg(-1); ww) in the immediate vicinity of the point sources were 33, 6, 4, and 8 times higher than the background levels, respectively. The dietary intakes of Cd and Pb were assessed and compared to the health criteria recommendations set by the joint Food and Agriculture Organization and World Health Organization Expert Committee on Food Additives (JECFA). The results showed that, depending on the consumption of lingonberries, human exposure based on the mean concentrations for Pb and Cd varied between 0.04% and 0.07% for Pb and between 0.04% and 0.09% for Cd compared to the tolerable total quantities of 25 microg kg(-1) for Pb and 7 microg kg(-1) for Cd per body weight per week set by JECFA.

Air Pollutants↗
PubMed2002

Estimation of environmental mobility of heavy metals using a sequential leaching of particulate material emitted from an opencast chrome mine complex.

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.

Journal Article↗
PubMed2001

Periodic spectral components of fetal heart rate variability reflect the changes in cord arterial base deficit values: a preliminary report.

Fetal distress changes the function of the autonomic nervous system. These changes are reflected in the fetal heart rate and can be quantified with power spectrum analysis of heart rate variability. The purpose of this study was to find out whether spectral components of fetal heart rate variability (FHRV) during labor are associated with fetal cord arterial base deficit values at birth. The association between FHRV and umbilical cord arterial base deficit was studied in 14 singleton fetuses with normal pregnancy at 35-40 weeks of gestation. Fetal ECG was recorded by scalp-electrode using a STAN Fetal ECG monitor (Cinventa Ab, Mölndal, Sweden). FHRV was quantified by computing Fast-Fourier-transformed heart rate (HR) spectra at three frequency bands: low-frequency (LF) 0.03-0.07 Hz, mid-frequency (MF) 0.07-0.13 Hz and high-frequency (HF) 0.13-1.0 Hz. We found that total FHRV and MF FHRV were lower in fetuses with cord arterial base deficit 8 to 12 mmol/L in comparison to the fetuses with normal cord arterial base deficit value (P=0.02 and P=0.01, respectively). A linear correlation was found between the spectral densities and the cord arterial base deficit values (r=0.4 and r=0.6, respectively). We conclude that the results suggest changes in the autonomic nervous cardiac control in fetuses with cord arterial base deficit between 8 to 12 mmol/L. The clinical applicability of our observations on FHRV in predicting fetal distress remains to be further studied.

Carbon Dioxide↗
PubMed2001

Development of left ventricular systolic and diastolic function in preterm infants during the first month of life: a prospective follow-up study.

OBJECTIVES: We studied the left ventricular systolic and diastolic function in preterm infants during the first month of life in comparison with the respective patterns in term neonates. STUDY DESIGN: Serial 2-dimensional/M-mode and Doppler transmitral flow velocity measurements were performed in 20 preterm (gestational age, 32 to 36 weeks) and 25 term infants between days 2 and 5 after birth and at age 1 month. RESULTS: After birth, the early velocity, early integral, early filling fraction, early and atrial velocity ratios, and early and atrial integral ratios were lower in the preterm than in the term infants (P <.01). During the first 4 weeks of life, these values, the atrial velocity, and the atrial integral increased gradually, whereas the atrial filling fraction, diastolic filling time, and deceleration time of early diastolic filling decreased slightly with postnatal age (P <.01) in the preterm infants. At age 1 month their diastolic function reached the level of term infants with the exception of early and atrial integral ratios and atrial filling fraction. The measures of systolic performance were within normal range, but midwall fractional shortening at 2 to 5 days (P <.05), and fractional shortening area (P <.05), as well as midwall fractional shortening (P <.01) at 1 month of age, were slightly inferior in the preterm than in the term infants. During the first month the left ventricular mass and left ventricular mass/body surface area ratio increased more markedly in the preterm than term infants, significantly in both groups (P <.05). CONCLUSIONS: The preterm diastolic patterns represent a transition between the patterns of the fetus and those of term neonates. These changes reflect an improvement in the left ventricular diastolic function, more markedly in relaxation than in compliance. The postnatal increase in the transmitral measures and left ventricular mass suggest marked myocardial adaptation to the extrauterine environment in the preterm infant already during the first month.

Blood Flow Velocity↗
PubMed2001

Maternal magnesium sulfate treatment is associated with reduced brain-blood flow perfusion in preterm infants.

OBJECTIVE: To examine the influence of antenatally administered magnesium sulfate (MgSO4) and ritodrine on cerebral blood flow and systemic hemodynamics in preterm infants. DESIGN: Prospective, observational study. SETTING: Neonatal intensive care unit of a university central hospital. PATIENTS: Fifty-five preterm infants age <33 wks of gestation. INTERVENTIONS: Serial Doppler examinations of the brain circulation, heart rate, systemic blood pressure, and echocardiographic assessment of ductus arteriosus shunting were performed during the first week of life in infants exposed antenatally to maternal MgSO4 (n = 19) or ritodrine treatment (n = 17), and in 19 nonexposed preterm controls. MEASUREMENTS AND MAIN RESULTS: Cerebral blood flow velocity measurements were obtained from the anterior cerebral artery and internal carotid artery. Perfusion pressure and indices of resistance and blood flow in both vessels were subsequently derived. Maternal MgSO4 had no effect on neonatal cerebral blood flow velocity or resistance, but was associated with decreased (p <.05) perfusion pressure and blood flow in the anterior cerebral artery and internal carotid artery during the first day of life. Systolic blood pressure and pulse pressure were also lower (p <.05) during the whole study period in the MgSO4-exposed infants when compared with the controls. Maternal ritodrine treatment, on the other hand, had no consistent effects on either neonatal cerebral or systemic hemodynamics. CONCLUSIONS: Our data indicate that maternal MgSO4 treatment, in contrast to antenatal ritodrine, is associated with lowered cerebral perfusion in preterm infants on the first day of life.

Analysis of Variance↗
PubMed2001

Apolipoprotein E phenotype regulates cholesterol absorption in healthy 13-month-old children--The STRIP Study.

High serum cholesterol concentration is one of the key risk factors in development of atherosclerosis, which may begin early in life and later progress to symptomatic coronary heart disease. In adults, apoE polymorphism strongly influences cholesterol metabolism, as subjects with apoE 3/4 or 4/4 (collectively called apoE4) phenotype absorb cholesterol effectively and thus also have higher cholesterol absorption-reflecting plant sterol concentrations in serum than subjects with other apoE phenotypes. Because of the inverse correlation of absorption and synthesis of cholesterol, concentrations of cholesterol synthesis-reflecting serum cholesterol precursor sterols are lower in subjects with apoE4 than in subjects with other phenotypes. To analyze whether apoE phenotype affects cholesterol absorption and synthesis in early childhood, we measured serum plant sterol (campesterol and sitosterol) and cholesterol precursor sterol (desmosterol and lathosterol) concentrations in healthy 13-month old children using gas-liquid chromatography. The 36 study children were participants in a randomized prospective trial (the Special Turku Coronary Risk Factor Intervention Project) aimed at decreasing exposure of the children to environmental atherosclerosis risk factors. The 16 apoE4 children had 30% to 50% higher cholesterol-adjusted campesterol and sitosterol concentrations in serum than the 20 apoE 3/3 children (p = 0.002 and p = 0.02, respectively). The concentrations of cholesterol precursor sterols in serum did not differ between the two groups of children. We conclude that the young apoE4 children may absorb cholesterol and plant sterols more effectively than the children with apoE 3/3 phenotype without compensatory reduction in endogenous synthesis of cholesterol.

Apolipoproteins E↗
PubMed2001

Antenatal magnesium sulphate exposure is associated with prolonged parathyroid hormone suppression in preterm neonates.

UNLABELLED: The effects of maternal magnesium sulphate treatment on neonatal mineral status and parathyroid hormone secretory response were studied in 8 exposed and 27 control preterm infants during the first 2 wk of life. Antenatal magnesium sulphate resulted in hypermagnesaemia during the first 3-7 d of life without affecting other serum mineral concentrations. CONCLUSION: Early hypermagnesaemia was associated with hypercalciuria during the first 3 d and parathyroid hormone suppression up to the age of 2 wk in the exposed infants.

Calcium↗
PubMed2000

Efficiency of left ventricular diastolic function increases in healthy full-term infants during the first months of life. A prospective follow-up study.

Postnatal changes in left ventricular diastolic filling and systolic cardiac performance were studied monthly by serial echocardiographic measurements from days 3-5 up to six months in 20 healthy full-term infants. The fractional shortening area (FSA = (left ventricular end-diastolic area - end-systolic area)/end-diastolic area) was assessed for systolic performance, and transmitral pulsed-wave Doppler flow velocity patterns were analysed for diastolic function. FSA remained stationary during the observation. After birth, left ventricular peak early (E) and atrial (A) velocities and the respective integrals were lower than at one month of age (47+/-5 vs. 63+/-6 cm/s and 44+/-6 vs. 57+/-5 cm/s and 3.33+/-0.40 vs. 4.05+/-0.53 cm and 2.74+/-0.40 vs. 3.18+/-0.53 cm; P < 0.05). During the next five months, the early parameters (E velocity and E integral) increased but the atrial indices (A velocity and A integral) did not change. During the whole observation the E/A velocity ratio, the E/A integral ratio and the early filling fraction (EFF) increased. The early filling deceleration time was longer during the first month than later (87+/-10 vs. 72+/-13 ms; P < 0.05). In conclusion, age-related changes were observed in the diastolic but not in the systolic performance in healthy full-term infants during the first six months. The most intensive changes took place in the early and atrial transmitral parameters during the first month of life, suggesting an improvement in both left ventricular relaxation and compliance. During the following five months, the early mitral parameters increased but the atrial diastolic values remained stable. These changes may mainly be determined by the improvement in left ventricular relaxation.

Aging↗
PubMed2000

Fatty acid composition of serum cholesterol esters as a reflector of low-saturated-fat, low-cholesterol diet in young children: the STRIP project. The Special Turku coronary Risk factor Intervention Project.

STRIP (the Special Turku coronary Risk factor Intervention Project) is an ongoing intervention trial which aims at a permanent reduction in the intake of saturated fat and cholesterol starting in childhood. A total of 75 intervention and 63 control children was studied consecutively at the ages of 7 and 13 mo, and 2, 3 and 5 y to evaluate the influence of such intervention on serum cholesterol ester (CE) fatty acid composition, a widely used biomarker of fatty acid intake. Analysis of 4-d food records showed that total intake of fat and of saturated fat increased with age in both groups of children but was constantly lower in intervention than in control children, e.g. at the age of 5 y the mean intakes of total fat and of saturated fatty acids were 31.1 E% and 33.9 E% and 12.1 E% and 14.6 E% in intervention and control children, respectively (p = 0.009 and 0.0001, respectively). Serum CE fatty acid compositions did not differ between the 2 groups at any age; the mean proportion of CE linoleic acid was 52.4% and 52.0% in 5-y-old intervention and control children, respectively. Correlation analysis showed, however, that the percentage of linoleic acid and of polyunsaturated fatty acids in CE reflected well the respective dietary intakes (r = 0.36; p = 0.0001 for both coefficients). In conclusion, CE fatty acid composition did not differ between the intervention and control groups, whereas CE linoleic and total polyunsaturated fatty acids reflected well the differences in their intakes at the individual level.

Child, Preschool↗
PubMed2000

Sodium intake of 1 to 5-year-old children: the STRIP project. The Special Turku Coronary Risk Factor Intervention Project.

The aim of this study is to examine sodium intake and dietary sodium sources of 1-5-y-old children in a prospective, randomized long-term coronary heart disease prevention trial, focused on dietary fat modification. Counselling included no advice about reducing salt in the children's diets. Food consumption of 100 intervention children and 100 control children was recorded for 3 consecutive days at the age of 13 mo and for 4 consecutive days at the ages of 3 and 5 y. Sodium intakes were calculated using the Micro Nutrica program. Children's mean daily sodium (NaCl) consumption (intervention and control children combined) was 1600+/-527 mg (4.0+/-1.3 g), 1900+/-504 mg (4.8+/-1.3 g) and 2200+/-531 mg (5.5+/-1.3 g) at the ages of 13 mo and 3 and 5 y, respectively. The intervention children consumed as much or slightly more sodium than the control children at all ages studied. Half the sodium consumption was derived from added salt in commercially prepared or homemade foods. Milk, meat products, bread and cereals were other important sodium sources. In conclusion, nutrition counselling in the Special Turku Coronary Risk Factor Intervention Project (STRIP) trial, with its main focus on the quality of fat in child nutrition, has had minimal influence on children's sodium intake. To avoid excessive sodium intake in children, dietary counselling should include information about salt use, and food manufacturers should be encouraged to provide more low-sodium products.

Child, Preschool↗
PubMed1999

Responsiveness of cutaneous vasculature to thermal stimulation during phototherapy in neonatal jaundice.

The present study was performed to measure the vasoregulatory reactions to dynamic changes in local skin temperature during open bed phototherapy. Periodic thermal stimulation using warm and cool air currents was applied to the skin of ten term infants with physiological jaundice, before and during open bed phototherapy. The reactivity of skin blood flow (SBF) and heart rate was measured using laser Doppler flowmetry and power spectral analysis. The baseline SBF increased significantly by 70% (P = 0.008) during phototherapy without any significant change in skin or rectal temperature. Before phototherapy, the rhythmic (0.08 Hz) thermal skin stimulation increased the oscillations of SBF (from 89 +/- 26 au to 213 +/- 37 au, P = 0.02) at the stimulation frequency band. This response was further increased (P = 0.03) during phototherapy (from 198 +/- 54 au to 658 +/- 115 au, P = 0.004). Phototherapy increased SBF in icteric otherwise healthy neonates. The cutaneous vasodilatation augments the cardiovascular responsiveness to thermal stimulation. These results suggest that open bed phototherapy does not inhibit the cardiovascular responsiveness to local thermal skin stimulation in healthy term infants.

Heart Rate↗
PubMed1999

Influence of maternal magnesium sulphate and ritodrine treatment on the neonate: a study with six-month follow-up.

Magnesium sulphate and ritodrine are commonly used drugs in the prevention of preterm delivery. However, the effects of these treatments on the newborn are controversial. It has previously been suggested that antenatal tocolytic magnesium sulphate decreases the incidence of cerebral palsy, but increases paediatric mortality. On the other hand, antenatal ritodrine treatment has been reported to increase the incidence of neonatal peri-intra-ventricular haemorrhage (PIVH). We investigated the cerebral ultrasonographic findings, neurological outcome and apparent life-threatening events (ALTE) among 63 infants, born before 33 wk of gestation, whose mothers were antenatally treated for premature birth with ritodrine or magnesium sulphate, and for pre-eclampsia with magnesium sulphate. Cerebral ultrasonography was performed during the first week of life and repeated before hospital discharge. The pathological findings were confirmed by a paediatric radiologist. A paediatrician and a physiotherapist performed the neurological follow-up examination of the survivors at 6 mo of age. We found Grade 3-4 PIVH in 15% of the infants exposed to maternal ritodrine treatment, in 9% of the infants whose mothers received tocolytic magnesium treatment, and in none of those exposed to maternal magnesium treatment for pre-eclampsia (p = 0.19). However, no differences were observed in 6-mo development or in the rate of paediatric mortality and ALTE among these three study groups. Because of the retrospective design and the limited number of subjects, the results of this study must be interpreted with caution.

Adult↗
PubMed1999

Serum cholesterol ester fatty acids in 7- and 13-month-old children in a prospective randomized trial of a low-saturated fat, low-cholesterol diet: the STRIP baby project. Special Turku coronary Risk factor Intervention Project for children.

To evaluate changes that occur in serum cholesterol ester fatty acid composition during the transition from typical infant feeding to a more adult type of nutrition, this study compared the effects on serum cholesterol ester fatty acids of breast milk or formula at the age of 7 mo with effects caused by 6-mo dietary intervention in 137 children. The intervention [Special Turku coronary Risk factor Intervention Project for children (STRIP baby project)] aimed at a reduction of saturated fat intake to 10% of energy after the age of 1 y without purposefully influencing total fat intake. Nutrient intakes were calculated from 3-d food records. At the age of 7 mo, i.e. before dietary education began, milk type markedly influenced dietary and serum cholesterol ester fatty acid composition (mean serum cholesterol ester 16:0 in breastfed vs formula-fed infants, 13.7% vs 12.0%, respectively, p < 0.001; serum cholesterol ester 18:2n-6 50.6% vs 57.6%, p < 0.001). At the age of 13 mo the calculated fat intake of the intervention and control children differed markedly but serum cholesterol ester fatty acid compositions in all children resembled closely those measured in 7-mo-old breastfed infants, e.g. at the age of 13 mo the relative proportions of 18:2n-6 were 49.9% and 51.1% in previously formula-fed intervention and control children, respectively, and 50.3% and 50.1% in previously breastfed intervention and control children, respectively. In conclusion, serum cholesterol ester fatty acid composition reflected differences in dietary fat quality (breast milk or formula) at the age of 7 mo, whereas dietary intervention as applied in the STRIP baby project had only a minimal effect.

Breast Feeding↗
PubMed1999

Spectral analysis of heart rate and blood pressure variability.

The cardiovascular system contains negative feedback and time-delay mechanisms resulting in oscillations in heart rate and blood pressure, which are apparent when these signals are measured over time. Specifically, spectral analysis and nonlinear analysis techniques allow quantification of heart rate and blood pressure variability. Alterations in heart rate and blood pressure variability as evidenced from the spectral characteristics of these physiological signals allow the clinicians to have indicators of aberrations of neural control in various conditions or when drugs such as beta blockers, adrenergic agents, methylxanthines, etc., are being administered.

Animals↗
PubMed1998

Increased amplitude modulation of continuous respiration precedes sudden infant death syndrome -detection by spectral estimation of respirogram.

The immaturity of the control of the autonomic nervous system has been suggested as one of the key factors in the pathophysiology of sudden infant death syndrome (SIDS). Therefore, the attenuated control of respiration may also cause more slow oscillatory breathing among infants at risk of SIDS. In this study, patterns of respiratory activity (RAV) and heart rate variability (HRV) were examined in Medilog-records prospectively obtained from 22 tape recordings made on 16 babies subsequently suffering from SIDS and from 22 matched control babies. A total of 248 signal segments, 120 s in duration, representing the state of regular breathing were visually selected for further analysis. The digitised signal sets were detrended, Fast-Fourier-transformed and autospectra as well as cross-spectra for the HRV and HRV were computed. The RAV and HRV were examined at two spectral bands: (1) a low frequency (LF) band 0.03-0.17 Hz (1.8-10 cycles/min) and (2) a high frequency (HF) band 0.3-1.3 Hz (18-90 cycles/min). Different parameters of each band were tested in the spectral analysis of cardiorespiratory control. The LF/HF-ratio of the spectral peak area of the respiratory activity and the LF/HF-ratio of the spectral band area of the respiratory activity were greater in the SIDS group when compared to the controls. No significant intergroup differences were found in the parameters of HRV, or the cross-spectral parameters. Interestingly, the technique appeared helpful in displaying that the victims of SIDS had a significantly greater amount of slow oscillation in the continuous respiratory signal (1.05+/-1.89 vs. 0.41+/-0.57, P=0.02). In the victims of SIDS the respiratory control system seems to be less stable and cause more slow oscillatory breathing and this can be detected using spectral analysis of respiratory activity even during breathing that visually seems to be regular.

Autonomic Nervous System↗
PubMed1998

[Salt intake in young children].

Among adult Finns salt intake is about twice as high as the recommended levels and almost five-fold greater than the physiological requirement. Information as to salt intake in children has hitherto been sparse. Daily sodium intake among 1-5-year-olds was investigated in this study, and the foodstuffs from which it was derived were identified. In all age groups, sodium intake was at least two-fold greater than the Nordic recommendations, and among five-year-olds it exceeded the recommended intake for adults. Approximately half of the sodium intake was found to have derived from salt used in cooking. Levels of sodium derived by children from dairy, meat and grain products were also relatively high. Sodium intake in children after infancy merits greater attention than previously accorded it, as permanent eating habits and taste preferences are already formed at this age, and reasonable limits for salt intake should therefore be established during childhood.

Adult↗
PubMed1997

Transcephalic electrical impedance provides a means for quantifying pulsatile cerebral blood volume changes following head-up tilt.

Transcephalic electrical impedance (delta Z) was used to assess pulsatile cerebral blood volume changes while tilting nine premature (30-34 weeks) infants 20 degrees head up. High-frequency (1.50-4.00 Hz) delta Z variability decreased 27% while heart rate did not show any change. We would like to suggest that the variability of transcephalic electrical impedance analysed with spectral estimation seems to provide a means for quantifying alterations in cerebral circulation.

Blood Volume↗