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Biomedical subjects

H Lagercrantz

Publications and source records attributed to H Lagercrantz.

At least 109 records · Page 6Linked to original sources
PubMed1993

Morbidity and mortality in 262 infants with birth weight below 1500 g born in Stockholm County 1988-1992.

The aim of this study was to examine the relationship between neonatal clinical conditions and the development of senso-motoric handicaps. Two hundred and sixty-two infants with a birth weight < 1500 g, born in or referred to the Karolinska/S:t Göran's Children Hospital from September 1988 to April 1992 were studied prospectively. The total survival was 83%. Preliminary results of the Griffiths' test of these infants showed an average cognitive ability of the same level as for full-terms except for those pre-term infants who had suffered from the combination of chronic lung disease and leukomalacia. The incidence of moderate to severe senso-motoric disability is up to the present time 5%.

Humans↗
PubMed1993

Fetal anaemia and its relation with increased concentrations of adenosine.

Adenosine concentrations were measured in umbilical venous blood obtained by cordocentesis from 14 fetuses of 19-34 weeks' gestation. The concentration did not change significantly with gestational age, but anaemic fetuses showed significantly increased concentrations of adenosine and there was a positive association with blood oxygen tension. These findings suggest that the fetus responds to tissue hypoxia by increasing blood adenosine concentrations from at least 19 weeks' gestation.

Adenosine↗
PubMed1993

Diversity in regulation of adhesion molecules (Mac-1 and L-selectin) in monocytes and neutrophils from neonates and adults.

The surface expression and regulation of the adhesion promoting glycoproteins Mac-1 and L-selectin was measured on monocytes and neutrophils from neonates and adults. A significant decrease in Mac-1 up regulation on both monocytes and neutrophils was found in neonates after both high (10(-7)M) and low (10(-9)M) concentrations of the chemotactic factor N-formyl-methionyl-phenylalanine (FMLP). A significant difference was obtained after incubation for five minutes, which was further enhanced after incubation for 15 minutes. Factors related to bacterial infections, lipopolysaccharides, activated sera (C5a), and aggregated IgG induced an impaired Mac-1 up regulation on both monocytes and neutrophils from neonates compared with adults. The expression of L-selectin was significantly lower on neutrophils from neonates and was less down regulated upon stimulation with a low concentration (10(-12)M) of FMLP. On monocytes from neonates, the expression and down regulation of L-selectin did not differ from monocytes from adults. Mode of delivery did not influence the regulation of Mac-1 and L-selectin in neonates. Diversity in expression and regulation of Mac-1 and L-selectin on monocytes and neutrophils may contribute to the increased susceptibility to infections observed in neonates.

Adolescent↗
PubMed1993

Neonatal adaptation in hypertensive pregnancy--a study of labetalol vs hydralazine treatment.

Twenty mothers with moderate to severe preeclampsia were allocated to labetalol (Trandate) or hydralazine (Apresolin) antihypertensive treatment. Arterial blood gas analysis was performed at delivery from the clamped cord. Neonatal blood pressure, heart rate and axillary temperature were registered 0.5, 2, 6, 12, 24, 36, 48 hours and 3, 4 and 7 days after birth. Respiratory rate was registered at the same intervals until 36 hours after birth. Blood glucose levels were measured 2, 6, 12 and 24 hours after birth. Peripheral blood flow in the calf was measured at 24 hours of age. Gestational age did not differ between the two groups; 36 (27-40) in the labetalol, and 35 (29-37) weeks in the hydralazine group (median and range). Median cord pH was lower, and the number of infants with a cord pH < 7.20 was higher in the hydralazine group. Blood glucose levels were lower in the labetalol group at 6 hours of age (p < 0.05). No other differences were found between the two groups. The conclusion is that no clinical signs of adrenergic blockade have been found at 24 hours of age, and no negative effect of labetalol on the neonatal adaptation compared to hydralazine antihypertensive treatment was found.

Adolescent↗
PubMed1992

Obstructive sleep apnea in Arnold-Chiari malformation treated with acetazolamide.

We studied respiratory patterns and transcutaneous gas pressures in two infants with Arnold-Chiari type II malformation referred to us due to repeated episodes of stridor and cyanosis. During both active and quiet sleep, respiration was irregular and absent or inverse thoracic breathing movements and frequent decreases in oxygen saturation to below 80% were observed. When breathing air with 2% CO2 or when given acetazolamide 10 mg/kg, chest wall movements normalized and oxygenation increased to near normal levels. After three months of treatment with acetazolamide 20 mg/kg/24 h no further episodes of hypoventilation or hypoxemia were observed and further treatment could be discontinued. We conclude that stimulation of respiration by CO2 or by acetazolamide appears to recruit chest wall muscles and promote upper airway patency in Arnold-Chiari malformation. A treatment trial with acetazolamide seems justifiable in these infants when respiratory problems are present.

Acetazolamide↗
PubMed1992

The first breaths of air stimulate noradrenaline turnover in the brain of the newborn rat.

The aim of this study was to analyse the noradrenaline (NA)-turnover in the brain around birth and its significance for neonatal adaptation. NA and its metabolite 3-methoxy-4-hydroxyphenylethylene glycol (MHPG) have been measured by high-pressure liquid chromatography (HPLC) in the pons-medulla and cortex in rat foetuses and pups. The MHPG/NA ratio was used as an index of NA-turnover. Catecholamines were also determined in the adrenals for comparison. The MHPG/NA ratios were found to increase 2.7-fold in the pons-medulla and 2-fold in the cortex during the first day after birth. The surge of NA-turnover occurred after the pups had been breathing air for two hours. The increase of NA-turnover was significantly lower in the cortex of rat pups breathing a hypoxic gas mixture or when they were kept in a cooler environment. The differences were less marked in the pons-medulla. We conclude that breathing air stimulates NA-turnover in the brain of the newborn rat and this stimulatory effect is modulated by environmental factors.

Animals↗
PubMed1992

Ventilatory response to hyperoxia in newborn rats born in hypoxia--possible relationship to carotid body dopamine.

1. The influence of postnatal hypoxia on regulation of breathing and turnover rate of carotid body dopamine was examined in newborn rats. The percentage change in frequency, tidal volume and ventilation elicited by transient hyperoxia was assessed by flow plethysmography in unanaesthetized pups. The alteration in ventilation was taken as an index of peripheral chemoreceptor activity. 2. The rats were born and reared in hypoxia. The inspired oxygen fraction (FI,O2) was 0.12-0.14 until 2 days after delivery when the rats were placed into room air and the ventilatory chemoreflex was tested. At 4 days of age, i.e. 2 days after termination of hypoxia, the rats were tested again. The ventilatory data were compared with those from a previous study in normoxic rats. 3. We found a smaller decrease in ventilation (8.8 +/- 3.9%, mean +/- S.D.) in the hypoxic rats at 2 days of age compared with normoxic rats (22.7 +/- 6.4%; P < 0.001). In contrast, at 4 days of age there was no difference in ventilatory response between the posthypoxic rats (19.2 +/- 4.6%) and normoxic pups (18.6 +/- 4.9%). 4. The turnover rates of dopamine in carotid bodies were determined at 0-6, 6-12, 12-24 h and 2 days after birth in hypoxic rats and in 2-day-old posthypoxic rat pups at different time intervals after termination of hypoxia. Postnatal hypoxia sustained a high turnover rate which decreased after termination of the hypoxia. 5. We propose that the weak chemoreflex in hypoxic rat pups is brought about by a high release of carotid body dopamine.

Animals↗
PubMed1992

Catecholamine abnormalities in transient tachypnoea of the premature newborn.

The aim of the present study was to assess if there was an association between low catecholamine levels at birth in the premature infant and the development of TTN. Blood samples were collected at delivery from the umbilical artery of all preterm infants with a gestational age less than 36 weeks for determination of pH and catecholamine levels (noradrenaline and adrenaline). Amongst non-asphyxiated infants only, cord pH greater than 7.25 and/or Apgar score greater than 7 at five minutes, catecholamine levels were compared between the 10 infants who developed transient tachypnoea of the newborn (TTN) and 13 controls of a similar gestational age range (31-35 weeks) who developed no respiratory distress in the neonatal period. Infants who developed TTN were more often delivered without labour, 8 of 10 compared to 2 of 13 controls (p less than 0.01). There were no significant differences in adrenaline levels between the two groups. Noradrenaline levels, however, were significantly lower in the infants who developed TTN, being a median of 3.1 nmol/l (range 1.07-5.85 nmol/l) compared to a median of 6.4 nmol/l (range 2.38-22.83) in the controls (p less than 0.01). Infants who were delivered following labour had significantly elevated noradrenaline levels compared those delivered without labour (elective delivery) (p less than 0.05). These results suggest that low noradrenaline levels in preterm infants may explain the association in this group of TTN and "elective" delivery.

Apgar Score↗
PubMed1992

Neuropeptide Y and catecholamine release in the piglet during hypoxia: enhancement by theophylline.

Sympathoadrenal activity was studied in 13 young piglets during hypoxia. The piglets were anaesthetized with chloralose/urethane, tracheostomized, paralyzed with gallamine and artificially ventilated. A femoral artery catheter was inserted and used for blood sampling. The piglets were challenged with 6 min of 6% CO2, 10 min of 12% O2 and 6 min of 6% O2 before and after theophylline (an adenosine receptor antagonist) treatment 20 mg/kg (n = 9) or saline (n = 4). Plasma samples were obtained before, during and after each hypercapnic or hypoxic period and analysed for their content of noradrenaline, adrenaline and neuropeptide Y. Hypercapnia with 6% CO2 and moderate hypoxia with 12% O2 did not lead to any significant increase of either noradrenaline (NA), adrenaline (A) or neuropeptide Y (NPY). However, severe hypoxia with 6% O2 increased the NA level from 30 to 66 nmol/l; the A level from 1 to 28 nmol/l and NPY from 140 to 213 pmol/l. After treatment with theophylline the baseline NA increased from 27 to 40 nmol/l, A rom 1.5 to 4.0 and NPY concentration from 65 to 171 pmol/l. Theophylline moderately enhanced the release of NPY, NA and A during the 12% O2 challenge. However, during the severe hypoxia (6%), the increase of NA (from 49 to 333 nmol/l), A (from 8 to 214 nmol/l) and NPY (from 184 to 385 pmol/l) showed considerably enhancement after the theophylline treatment. The results obtained before and after saline were similar showing that the duration of the experiments per se did not change the baseline levels or the effect of the challenges on NA, A or NPY levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Expression and release of neuroregulators during development: monoamines and neuropeptides.

The turnover of catecholamines (CA) was determined in the adrenal medulla and brain of rat fetuses and pups. In general we found a considerable increase soon after birth. The expression of mRNA for CA-synthesizing enzymes was also considerably enhanced in the adrenals shortly after birth. Furthermore, we demonstrated increased expression of neuropeptides after birth, increased synthesis of mRNA encoding for neuropeptide Y in the adrenals 24 h after birth; and considerable activation of the substance P gene in a respiratory nuclei of rabbit pups which had been breathing for 2 h as compared with fetuses at term.

Adrenal Medulla↗