Biomedical subjects
Publications and source records attributed to A Niklasson.
All clinical studies of at least 1 week's duration with felodipine in patients with hypertension were included in a safety analysis. The major finding was that felodipine does not increase mortality or the incidence of major cardiovascular events and that the data indicate a favorable effect.
PURPOSE: To determine the influence of gestational age, birth size, perinatal morbidity, and postnatal growth on fundus morphology in preterm children using digital image analysis of fundus photographs. METHODS: Thirty-nine preterm children (mean postmenstrual gestational age, 29.1 weeks; range, 24.6 to 32) were included in the study. Thirty-nine healthy children, born at term, were used as control subjects. Fundus photographs were obtained at a mean age of 4.8 years (preterm) and 6.1 years (control subjects). RESULTS: There was no difference in optic disc, excavation, or peripapillary crescent area between the two groups. In the group of preterm children, a large optic disc size was associated with a low birth weight (rs = -0.29, P = 0.07), duration of assisted ventilation (rs = 0.43, P = 0.006), and number of blood transfusions (rs = 0.33, P = 0.04). The girls born prematurely showed a negative relation between the length of gestation and the area of the optic disc (r2 = 0.28, P = 0.009). No such relation was found in boys. The preterm children had increased tortuosity of retinal vessels (P < 0.001 and P < 0.002 for arteries and veins, respectively) and reduced number of vascular branching points (P < 0.001) compared with those of the control subjects. There were no associations between these vascular abnormalities and the perinatal and postnatal variables studied. CONCLUSIONS: No difference in optic disc morphology between preterm children and control subjects was found. However, preterm birth seems to affect the retinal vascular pattern close to the optic disc, independently of retinopathy of prematurity. Among the girls born preterm, optic disc size was negatively correlated to gestational age.
Low birth weight and high placental weight are associated with increased cardiovascular morbidity and mortality. Children born after hypertensive pregnancies have higher blood pressure than children born after normotensive pregnancies. Hypertension in pregnancy is considered a major risk factor for intrauterine growth retardation. The present study describes size at birth and perinatal characteristics in children born after hypertensive pregnancies. During five consecutive years 17,000 deliveries took place in the well defined geographic area of eastern Göteborg. Hypertension in pregnancy complicated 261 pregnancies. For comparison 260 normotensive pregnancies, matched for maternal age and time of delivery, were used. Standard deviation score for birth weight and length were calculated according to reference standards for birth weight (BWSDS) and length (BLSDS) based on all Swedish births 1977-1981 (n = 475,588). Children born after hypertensive pregnancies had lower birth weight, were shorter and had a shorter gestational period as compared with children born after normotensive pregnancies. Head circumference and placental weight did not differ and there were no significant differences in BWSDS. It is concluded that hypertensive pregnancies are characterized by lower birth weight and shorter gestational period. However, intrauterine growth retardation is not a general characteristic of hypertension in pregnancy.
A new model for evaluating leanness/fatness (LeanSDS) in the newborn infant has been used to examine body weight for length in a group of Swedish infants in whom idiopathic growth hormone deficiency (GHD n = 220) was later diagnosed. These infants have earlier been reported to be significantly shorter (median = -0.87 SDS; SDS; standard deviation scores) and lighter (median = -0.60 SDS) in relation to gestational age, than the most recent reference. A group of infants who later developed GHD due to organic etiologies (n = 92) had normal weight and length for gestational age at birth. Using the LeanSDS model (with intercept 0.0 and regression coefficient 0.7) revealed that these idiopathic GHD infants have weight that is normal for their length (mean LeanSDS = 0.11 +/- 0.08 (SEM); n.s.) why the abnormality is a reduced linear growth. These findings also indicate that birth length (linear growth) should be given increased attention when size at birth is evaluated.
Carbohydrate and fat metabolism during and after anaesthesia and surgery was studied in 14 neonates with major congenital non-cardiac anomalies. They were either given a glucose solution until surgery or starved for at least 4 h before surgery. Ringer-acetate alone or Ringer-acetate plus 10% glucose was used for the intraoperative fluid therapy. After anaesthesia all neonates were given a 10% glucose solution. Concentrations of glucose, free fatty acids, triglycerides, lactate, pyruvate, alanine, glycerol and 3-hydroxybutyrate were measured at predetermined intervals pre-, intra- and postoperatively. Blood glucose concentrations rose during surgery both in neonates given glucose before and during surgery (n = 6) and in neonates not given glucose before and during surgery (n = 6). Increased intraoperative levels of free fatty acids and 3-hydroxybutyrate were found in neonates not given glucose before and during surgery. The triglyceride levels were equal in both groups. In two neonates given glucose before surgery and Ringer-acetate during surgery increased levels of 3-hydroxybutyrate were found, particularly in one patient who became hypoglycaemic. In conclusion, starved neonates without intraoperative glucose supply mobilized fat and maintained blood glucose concentrations.
A new methodology for evaluation of weight in relation to length normalized for sex and gestational age (leanness/fatness) in the newborn infant is presented. Using standard deviation scores (SDS) for weight and length in a linear regression model, a new continuous variable called LEANSDS has been constructed with intercept = zero, regression coefficient = 0.7152, SD = 0.6988 and r2 = 0.51, irrespective of gender and gestational age within the range 34-43 weeks' gestation. The model is based on the Swedish 1986 Medical Birth Register and was tested on the 1985 year cohort. The reference material consisted of live-born, singleton infants considered "healthy". This new variable is independent of length. A chart is presented which simplifies visual evaluation. Using -2 SD as the cut-off limit, approximately one-third of light-for-dates infants are also lean, while two-thirds of the lean infants are not light for dates. Proportions of "not healthy" live-born infants and still births are given. Using another method, based on weight and length, and with some approximations needed for calculation of a comparable BW/BLSDS, the correlation was 0.9974, but this calculation is more elaborate and the comparable chart more complex. This method reveals the influence of gestational age on the relationship between weight and length, indicating a "prenatal puberty". Empirically, the logarithmic relationship found between weight and length indicates a ponderal index exponent of 2.4-2.5 instead of 3. LEANSDS, with its continuous nature, also gives the degree of deviation in each individual and in groups of infants, and can be added together and further analysed with improved sensitivity.
To investigate leukotriene (LT) generation by human colostral macrophages (CM phi), we evaluated calcium ionophore A23187-induced LTB4 and LTC4 production by CM phi obtained from mothers who had had preterm and term deliveries. As a comparison, we also investigated such production of these LTs by blood monocytes (BMo). LTB4 and LTC4 production by preterm CM phi did not significantly differ from that by term CM phi. LTB4 and LTC4 production by both preterm and term CM phi was significantly lower than that by BMo. The ratio of LTC4 to LTB4 did not differ significantly between preterm and term CM phi. The CM phi ratios were significantly lower than that of BMo. These findings suggest that human CM phi can generate LTB4 and LTC4 but that production, especially LTC4 production, is suppressed compared with that of BMo.
Blood concentrations of glucose were measured during surgery and during the first 8 h after operation in 30 neonates undergoing major surgery during the first week of life. Fifteen of the neonates were given Ringer-acetate as the only crystalloid peroperative fluid; to the other 15, 10% glucose i.v. was administered during surgery. In the Ringer-acetate group, mean (SD) blood concentration of glucose increased from 3.1 (2.0) to 4.3 (2.4) mmol litre-1 during surgery. The corresponding increase in the glucose-supplemented group was 3.4 (1.5) to 6.3 (2.2) mmol litre-1. In the Ringer-acetate group, peroperative blood concentrations of glucose were found to be low if a preoperative glucose infusion was interrupted at the start of anaesthesia. Hypoglycaemia occurred in both groups, but more often in the group given Ringer-acetate only (3/15 vs 1/15). Hypoglycaemia was found only in neonates less than 48 h of age and during the first 1 h of anaesthesia only. Monitoring of blood concentrations of glucose and adjustment of the glucose infusion appears to be desirable during and after surgery in neonates.
The effects of carnitine supplementation on fat and glucose metabolism and carnitine balance were studied in 12 preterm neonates receiving full or partial parenteral nutrition (PN) for 5 to 21 days. The gestational age ranged from 27 to 32 weeks and the birth weight from 790 to 2090 g. The neonates were assigned at random to receive either L-carnitine 10 mg/kg (n = 6) or saline (n = 6). In the carnitine group, increased concentrations in plasma of total and free carnitine were observed. Less than 50% of the given dose was recovered in urine. In the placebo group no changes in the total plasma carnitine concentration were seen. In all neonates plasma triglycerides, free fatty acids, glycerol, alanine, 3-hydroxybutyrate (BOB), glucose and lactate were measured at predetermined intervals. The only significant difference between the groups was higher BOB-concentrations in the carnitine group 2 days after the start of parenteral nutrition. Elevated BOB concentrations are an indicator of improved fatty acid oxidation in the carnitine group. In this study, only a temporary effect of the carnitine supplementation was found.
This study analyses gestational age, mode of delivery and size at birth in children who later developed idiopathic or organic growth hormone deficiency (GHD). A data register of children on growth hormone (GH) treatment in Sweden was compared with the Swedish Medical Birth Register during a 14-year period (1973-1986) comprising 1.4 million newborn children. Size at birth was evaluated using a new Swedish reference standard based on data from around 500,000 newborn children. It was found that the children who later develop idiopathic GHD (IGHD) were born with a normal distribution of gestational age. They were more often born with breech delivery (7.1% versus 2.8%) or caesarean section (16.6% versus 10.4%) compared with normal children. The children's condition at birth was poorer than normal, as shown by the frequency of Apgar scores below 7 at 5 minutes (5.2% versus 1.2%). Finally, it was found that children who later develop IGHD (n = 220) had a median birth length of 0.87 SDS below the mean and a median birth weight of 0.60 SDS below the mean of the standard. In contrast, both the birth length and weight of the children who later develop organic GHD (OGHD) (n = 92) did not differ from that of the reference.
Data from the Swedish Medical Birth Registration, 1977-1981 were used to apply methods of constructing reference standards for size at birth. Using clinical information a 'healthy' sub-population was extracted. The conditional distributions of birthweight (BW) and birthlength (BL) for each week of Gestational age, and the conditional distribution of birthweight given birthlength were modelled using truncated Normal distributions, after making use of Box-Cox power transformations. Spline functions were then used in conjunction with a multiplicative method to obtain appropriate percentage point curves. Examples of this analysis are given.
Data from the Swedish Medical Birth Registration, 1977-78, were utilized to develop methods of calculating reference standards for evaluating size at birth. Using the clinical information available, a 'healthy' sub-group was extracted. The individual distributions of birthweight (BW), birth length (BL) and birth headcircumference (BHc) at each week of gestational age (GA) were modelled following some truncation of their ranges. Application of the Box-Cox power family of transformations was generally found to improve the normality of the data. Certain percentages (such as 2.28, 50 and 97.72) were linked through a smoothing device. Features of the results include a positively skewed BW distribution in most GA weeks, a normal positively skewed BW distribution in most GA weeks, a normal distribution of BL and BHc at term, a larger relative variation in BW at lower GA than at term, and a distinct sigmoid shape of the median and other BW curves. Compared with five commonly quoted standards, the present data show the least deceleration in the fullterm region. Disregarding the clinical information, 'primary' sub-groups were also extracted using decomposing techniques. These gave rise to similar BW/GA relationships. Using data from the WHO comparative study, the method just mentioned was applied to standardize BW and BW-specific early neonatal mortality rates. This resulted in an improved description of biological events.
Total plasma carnitine was analysed in 19 women, with uncomplicated pregnancies, who underwent elective caesarean section, and in their neonates. The women were given a balanced glucose (glucose group) or saline (saline group) infusion, group allocation being on a random basis. The carnitine levels in maternal or infant plasma did not differ between these two groups. At delivery, the mean maternal carnitine value, 17.4 +/- 1.25 mumol/l, was lower than the mean infant value, 25.9 mumol/l +/- 2.67 (mean +/- SE, p less than 0.005) and lower than the mean value in non-pregnant, fertile women, i.e. 40.9 +/- 1.22 mumol/l. The mean carnitine value in the unfed neonate had not changed when the infant was 4 hours old. A positive correlation was found between carnitine levels in maternal and infant plasma (p less than 0.01). At delivery, the levels of non-esterified fatty acids and 3-OH-butyrate in infant plasma were different in the two groups, but not at 4 hours of age. The results suggest that the maternal carnitine level is the most important factor governing plasma carnitine levels in the neonate.
In order to assess the importance of pertinent perinatal risk factors in causing hearing loss (HI), a retrospective evaluation was made of the records of 146 affected children born in the city of Göteborg between 1970 and 1979. The incidence among six-year-olds born between 1970 and 1974 was 3.8 per 1000 newborns. If only HI of more severe degree was taken into account (above 40dB in the best ear), the remaining incidence was 1.4/1000. Sensorineural HI (SNHI) accounted for 87 per cent of the cases. A positive hereditary tendency for HI was found in 55 per cent. In 61 per cent the origin of the HI was presumably prenatal, either positive heredity alone or in the form of facio-auricular anomalies, syndromes and toxic influences (infection and alcohol) during early pregnancy. Postnatal infections (meningitis, parotitis and secretory otitis media) could be ascertained as causes in about 20 per cent of the cases. For 12 per cent no aetiology could be determined. Perinatal aetiology was probable or possible in about 10 per cent of the children. The frequency of SNHI was found to be increased among survivors of neonatal intensive care, VLBW, LBW and SFD infants. Caesarean section, ventouse and breech delivery were not associated with increased rates, nor were hyperbilirubinaemia, exchange transfusion or birth asphyxia. No cases could be traced to aminoglycoside treatment. Neonatal sepsis/meningitis may have been the cause in two of the 146 cases. Hypoxia as a consequence of apnoea and respiratory distress syndrome necessitating mechanical ventilation appeared to be the major risk-factor in the neonatal period. However, in comparison with genetic predisposition, potentially damaging perinatal factors appeared to be of minor importance.
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An update of the Swedish reference standards for weight, length, and head circumference at birth, for each week of gestational age, is presented. It is based on the total Swedish cohorts of infants born 1977-1981 (n = 475,588). A "healthy population" (79%) was extracted, using prospectively collected data. Weekly (28-42 weeks) grouped data for length and head circumference were well approximated by the normal distribution, but the distributions for birthweight were positively skewed. The original skewed distributions for birthweight were transformed, using the square root, resulting in distributions close to the Gaussian. For smoothing purposes, the weakly values for the mean and the standard deviation were both fitted by a third degree polynomial function. These functions also make possible the calculation of the continuous variable, standard deviation score, for individual newborn infants as well as a comparison of distributions between groups of infants. The reference values and charts presented here have two major advantages over the current Swedish ones: the sample size used is now sufficiently large at the lower gestational ages, so that empirically found variations can be used, and the skewness of the birth weight distribution has been taken into account. The use of the reference standards presented here improves and facilitates evaluation of size deviation at birth.