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Biomedical subjects

L Rovamo

Publications and source records attributed to L Rovamo.

16 recordsLinked to original sources

First-trimester diagnosis of imperforate anus.

Imperforate anus or anorectal atresia is often associated with major fetal structural defects but it may also be an isolated abnormality. Prenatal diagnosis is difficult but may be assisted by ultrasound detection of a dilated distal bowel or rectum. We report on a fetus at 12 weeks of gestation in which a dilated colon was detected at ultrasound examination. Dilatation of the colon was clearly seen in the first and third trimesters of pregnancy, but was difficult to detect in the second trimester. At birth, the newborn was diagnosed with a low type of imperforate anus.

Adult↗

Dynamics of the QT interval during and after exercise in healthy children.

The dynamics and homogeneity of the QT interval have been used as indicators of susceptibility to ventricular arrhythmias. We determined the relationship between QT intervals and heart rate during exercise testing and subsequent recovery in 18 healthy children. The QT intervals were measured to the apex (early QT), to the end (total QT), and from the apex to the end of the T wave (late QT) (inhomogeneity of repolarization) at heart rates from 60 by steps of 10 to 180 beats.min-1. Group mean total QT and early QT exhibited better linear correlations with heart rate (r 0.998 and 0.999) than with cardiac cycle length (r 0.954 and 0.959). The slope relating total QT to heart rate was -1.30 during exercise and -1.42 during recovery (P < 0.05). The corresponding slopes relating early QT to heart rate were -1.11 and -1.30 (P < 0.05). Late QT, as a proportion of total QT, increased at high heart rates. Rate correction using Bazett's method gave abnormal total QT values (> 440 ms) in 12 children (67%) whereas linear correction gave values below 440 ms only. In conclusion, the relationship between QT and heart rate is linear and differs during exercise and recovery. Inhomogeneity of repolarization increases at high heart rates. Linear correction of total QT and early QT intervals improves the evaluation of repolarization duration in exercise testing in children.

Adolescent↗

Linkage of the long QT syndrome to the short arm of chromosome 11: use of five highly polymorphic markers towards more detailed localization of the mutant gene.

The long QT syndrome is an autosomally dominantly inherited cardiac disorder characterized by abnormalities of myocardial repolarization, exercise- or stress-related syncopal attacks and risk of sudden death due to cardiac arrhythmias. Genetic linkage studies have defined three LQT loci on chromosomes 11p15.5, 3q21-24 and 7p35-36. We performed linkage analyses in three Finnish LQT families using five amplifiable markers assigned to chromosome 11p15. By multipoint linkage analyses we obtained a maximal lod score of 5.503, suggesting that the LQT1 locus maps between D11S922 and D11S1338 on chromosome 11. Our data provide a step towards closer definition of the exact borderlines of the LQT1 locus in chromosome 11 and demonstrate markers with high utility in identification of gene carriers in the affected families.

Adolescent↗

Fetal and neonatal prostacyclin and thromboxane in relation to mode of delivery.

To study whether prostacyclin and thromboxane A2 might play a role in neonatal adaption pieces of the umbilical arteries of infants born vaginally (n = 18) or by elective caesarean section (n = 11) were superfused in vitro and the release of 6-keto-PGF1a (hydration product of prostacyclin) and thromboxane B2 (metabolite of thromboxane A2) measured by radioimmunoassay. In addition, the capacity of fetal platelets to produce thromboxane A2 and the neonatal urinary concentrations of 6-keto-PGF1a were measured. Infants born by caesarean section had lower diastolic blood pressure, higher heart rate, and smaller differences between rectal and skin temperature compared with infants born vaginally during the first two hours of life. The only difference encountered in the prostanoids between the groups was reduced urinary excretion of 6-keto-PGF1a in infants born by caesarean section, whose release of 6-keto-PGF1a by the umbilical artery was positively correlated with heart rate, respiration frequency, and dermal temperature. Thus prostacyclin may be a regulatory determinant, particularly in infants born by caesarean section.

6-Ketoprostaglandin F1 alpha↗

Plasma beta-endorphin in perinatal asphyxia and respiratory difficulties in newborn infants.

The effects of intrauterine stress and birth asphyxia on the plasma concentration of beta-endorphin (beta-E) in cord blood and in venous blood at the age of 2 h was investigated in newborn infants. Term infants with acute birth asphyxia (n = 11), infants born to mothers with preeclampsia (n = 15), and prematures with respiratory difficulties (n = 4) were entered into the study. Twenty control infants were studied; 12 were born after spontaneous delivery and eight after elective cesarean section. After normal spontaneous delivery, the plasma beta-E level decreased significantly, the median values being 17 pmol/liter at birth and 9.3 pmol/liter at the age of 2 h, whereas after elective cesarean section it remained unchanged (13 and 13 pmol/liter, respectively). In acute asphyxia the plasma beta-E level varied widely at birth, from 9.7 to 108 pmol/liter. At the age of 2 h, the beta-E level was high (26 to 83 pmol/liter) in those asphyctic infants who required prolonged mechanical ventilation, but it fell to the range of 1.6-13 pmol/liter when the infant recovered rapidly. The beta-E level was not increased in the preeclampsia group, not even in small for gestational age infants. In preterm newborn infants with respiratory difficulties, a significant postnatal rise of plasma beta-E level was found, the beta-E value varying from 7.3 to 16 pmol/liter at birth and from 61 to 168 pmol/liter at the age of 2 h. These results indicate that increased beta-E secretion is associated with respiratory difficulties in the newborn infant.

Apgar Score↗

Stress of delivery and plasma endorphins and catecholamines in the newborn infant.

Cord plasma levels of endorphins and catecholamines were correlated with the values of cord blood gas analysis and with hemodynamic parameters in 11 newborns (group A) delivered by elective cesarean section and in 18 newborns (group B) born spontaneously by vaginal route. All infants were in a good condition. No statistically significant differences were found in the mean cord plasma levels of adrenaline (A), noradrenaline (NA) and immunoreactive beta-endorphin (ir beta-E) between groups A and B. After spontaneous labor in group B a highly significant negative correlation was found between plasma NA level and pH and a positive correlation between NA and carbon dioxide tension in cord arterial blood and between NA and the short-term variability of the fetal heart rate before birth. Cord plasma A and ir beta-E did not show such correlations. These findings show that cord plasma level of NA is a sensitive indicator of minor stress during normal labor. After birth, during the first two hours of life, the mean plasma level of ir beta-E decreased in group B after vaginal delivery, but remained at a higher level in group A after elective cesarean section. This shows that the mode of delivery influences the neonatal endorphin secretion.

Blood Gas Analysis↗

Plasma immunoreactive beta-endorphin and cortisol in the newborn infant after elective caesarean section and after spontaneous labour.

The effect of the mode of delivery on the plasma concentration of immunoreactive beta-endorphin (irbeta-E) and cortisol was studied in 27 newborn infants, 10 delivered by caesarean section and 17 by spontaneous vaginal labour. After elective caesarean section, the mean plasma concentration of cortisol rose from 227 +/- 27 nmol/l (S.E.) at birth to 705 +/- 90 nmol/l at the age of 2 h, indicating a significant increase in cortisol secretion, and the mean irbeta-E remained high, being 111 +/- 24 ng/l at birth and 117 +/- 21 ng/l at the age of 2 h. After spontaneous labour, the plasma cortisol level was already high at birth, 735 +/- 78 nmol/l, and remained so to the age of 2 h, 659 +/- 43 nmol/l, whereas the plasma irbeta-E decreased from 181 +/- 29 at birth to 64 +/- 7 ng/l at the age of 2 h. All newborns were in a good condition except one in whom transitory tachypnea developed during the follow-up. In this newborn the plasma level of irbeta-E increased greatly: from 210 ng/l to 705 ng/l. These results show that, irrespective of the route, the delivery is stressfull to the newborn infant. In newborns delivered by caesarean section the stress response comes after birth. Additional stress such as respiratory difficulties seems to increase the secretion of beta-endorphin.

Cesarean Section↗

Morbid obesity, gastric plication and a severe neurological deficit.

A 39-year-old man had protracted vomiting after gastric plication for morbid obesity. Within three months he lost 53 kg in weight and developed neuromuscular weakness, especially in the lower extremities. Clinical and laboratory studies suggested both radicular and peripheral neuropathy. One year later the condition was only marginally improved: he took only few steps unsupported. The apparent etiology is malnutrition but the primary cause remained unknown.

Adult↗

Postheparin plasma lipases and carnitine in infants during parenteral nutrition.

Lipoprotein lipase is the rate-limiting factor for hydrolyzing triglycerides to glycerol and fatty acids. Carnitine is a cofactor in the transport of long-chain fatty acids through the mitochondrial membrane for oxidation. To assess these determinants of fat utilization during total parenteral nutrition, lipoprotein and hepatic lipase activities and carnitine concentrations of nine newborn infants, operated on because of gastrointestinal anomalies during the first day of life, were measured with specific methods. Total parenteral nutrition was built up in 3 days whereafter the infants received 3 g/kg of fat at a constant rate of infusion for 24 h/day. Lipoprotein lipase activity of post-heparin plasma increased from 14 to 35 mumol free fatty acids/ml/h during parenteral nutrition whereas hepatic lipase activity remained unchanged at 40 mumol free fatty acids/ml/h. Serum free carnitine and acylcarnitine levels decreased significantly during parenteral nutrition; urinary excretion of carnitine decreased also. In addition, serum cholesterol and phospholipids increased markedly during parenteral nutrition whereas serum triglycerides, free fatty acids, and blood beta-hydroxybutyrate remained unchanged. Serum apolipoprotein A-I concentrations were unaltered, apolipoprotein A-II underwent a transient increase, and apolipoprotein B increased monotonically during parenteral nutrition. The results suggest that under the present circumstances neither lipoprotein lipase activity nor carnitine resources are rate-limiting for the utilization of fat in newborn infants during total parenteral nutrition.

Apolipoproteins A↗

Analysis of neonatal heart rate variability by a microprocessor-based on-line system.

The effects of different rejection logic limits on the results of analysis of neonatal heart rate variability from electrocardiograms by a microprocessor-based system were studied on fourteen infants after normal labor and on ten infants after elective cesarean section. In addition to the infant's movements and crying, two further main sources of error in the calculation of variability indices were detected: premature beats and problems in the shape of QRS complexes in a neonatal electrocardiogram. No noteworthy problem was observed in the calculation of the interval index (II), which describes the long term variability of heart rate. In the calculation of the differential indices (DI), which describe the short term component of heart rate, distorted QRS complexes created very high DIs when the rejection logic was ten beats per minute (bpm). When stricter rejection limits were used (five bpm), the DI values even in these cases fell within the normal range. The DI values calculated using a rejection limit of five bpm were always lower than those calculated using a rejection limit of ten bpm, but the reference values of neonatal II and DI after normal labor were similar to those presented previously using a rejection limit of ten bpm. In conclusion, the neonatal electrocardiogram appears to be a noisy signal, comparable with the abdominal fetal electrocardiogram, and strict rejection limits are useful in processing it for indices of variability.

Computers↗

Postheparin plasma lipase activities and plasma lipoproteins in newborn infants.

We measured blood glucose, serum insulin and apoprotein A-I and A-II, and triglycerides and cholesterol contained in serum lipoprotein fractions of 24 full-term newborn infants who underwent exchange transfusion with heparinized blood for hematological reasons. The values were similar to those previously reported for healthy newborn infants. We also measure lipoprotein and hepatic lipase activities with specific methods. Fifteen minutes after an intravenous heparin bolus of 100 IU/kg, mean lipoprotein lipase activity in infants (16.0 mumol free fatty acids/ml/h) was as in adults. In contrast, hepatic lipase activity was significantly higher in infants (54.3 mumol free fatty acids/ml/h) than in adults. There was no sex difference in the infant lipase activities. Lipoprotein and hepatic lipase activities were also measured 5 and 15 min after a heparin bolus of 10 and 50 IU/kg: 10 IU/kg released only part of the lipase activities. In addition, the two lipases were measured during the exchange transfusion. Although 92% of the original infant blood was removed, lipoprotein lipase activity remained constant. In contrast, hepatic lipase activity decreased considerably. In infants, postheparin lipolytic activity is a conventional measure of lipoprotein lipase. Lipoprotein and hepatic lipases comprise 95% of postheparin lipolytic activity. In our infants, hepatic lipase activity was 3.4 times higher than lipoprotein lipase activity. Hence, it seems unjustified to use postheparin lipolytic activity as a measure of lipoprotein lipase.

Cholesterol↗

Postheparin plasma lipoprotein and hepatic lipases in preterm neonates.

Postheparin plasma lipoprotein lipase and hepatic lipase activities of 11 preterm infants aged 1 to 4 days were measured 15 min after a heparin bolus of 100 IU/kg and during an exchange transfusion performed with fresh heparinized blood. Each infant had a birth weight (range, 1210-3490 g) appropriate for gestational age (range, 28-36 (wk). Eight of the infants (group 1) were in good clinical condition while three (group 2) suffered from septic shock. After the heparin bolus and during the exchange transfusion, lipoprotein and hepatic lipase activities in group 1 were higher than in term infants. In group 2, both lipase activities were extremely low after the heparin bolus but increased approaching the activities of group 1 during the exchange transfusion. Clearance of fat from the circulation is slower in preterm than term infants. This has been attributed to low lipoprotein lipase activity. Our results, however, indicate that lipoprotein lipase is not the reason for slow clearance of fat from the circulation in preterm infants except in septic shock.

Blood Group Incompatibility↗

Later potentials on signal-averaged electrocardiograms in children after right ventriculotomy.

After corrective surgery for congenital heart defects, scars may create fractionation and delay of the electrical signals in the heart muscle, providing a substrate for arrhythmias. Signal-averaged electrocardiograms (SAECGs) were obtained from 33 children after right ventriculotomy, on average 6 years after surgery, and from 38 healthy controls of the same age. The duration of the filtered QRS complex (fQRS), the duration of the low amplitude signal (< 40 microV) in the terminal QRS complex (LAS40), and the root mean square amplitude of the terminal 40 ms of the QRS complex (RMS40) were determined. The values of fQRS > or = 117 ms, RMS40 < or = 25 microV, and LAS40 > or = 35 ms, which were beyond the mean +/- 2 SD of the healthy controls, were considered abnormal. Most patients had right bundle branch block and therefore a prolonged fQRS. Late potentials were defined as present if both the RMS40 and LAS40 were abnormal. Altogether nine patients (27%) had late potentials. In the patients with late potentials the incidence of serious ventricular arrhythmias was 44% (4 of 9) and in the patients without late potentials 0% (0 of 24). In seven patients with enlargement of the right ventricle, the incidence of arrhythmias was 57% (4 of 7) when late potentials were present and 0% (0 of 7) when they were absent. In the present study late potentials were associated with a history of arrhythmias, especially when the right ventricle was enlarged. Therefore the SAECG may be useful for determining the risk of serious arrhythmia events in children operated for congenital heart defects.

Adolescent↗

Magnetocardiographic localization of ventricular pre-excitation in a child with a congenital heart defect.

Magnetocardiographic mapping was performed on a 2-year-old boy who suffered from the Wolff-Parkinson-White syndrome in association with a complex congenital heart defect. The pre-excitation site was determined noninvasively from the measured cardiac magnetic fields. The location was in the same anatomic region as found by intraoperative epicardial mapping. This result shows that magnetocardiography can be helpful for determining an accessory pathway also in patients with grossly abnormal cardiac anatomy.

Child, Preschool↗