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Biomedical subjects

I Kjellmer

Publications and source records attributed to I Kjellmer.

At least 19 recordsLinked to original sources
PubMed1998

Breast-feeding during treatment with cyclosporine.

BACKGROUND: Mothers treated with cyclosporine (CsA) have previously not been allowed to breast-feed due to the reported accumulation of the drug in breast milk. The purpose of this study was to evaluate the consequences of allowing breast-feeding. METHODS: Seven infants were breast-fed by mothers who had undergone kidney transplantation alone (n=5) or simultaneous kidney and pancreas transplants (n=2). In addition to CsA, all mothers received prednisolone at 5-7.5 mg/day and six mothers received azathioprine at 50-100 mg. CsA concentration was measured in the whole blood of mothers and babies and in breast milk. Serum creatinine was measured in babies 1 week after birth and after 4-12 months of breast-feeding. RESULTS: Blood CsA levels ranged from 55 to 130 ng/ml in mothers (12-hr trough), 50 to 227 ng/ml in breast milk (mean for each woman), and was below the detection limit of 30 ng/ml in all infants. Breast milk concentration ranged from 87 to 440 ng/ml in 16 samples obtained at various time points from one mother. Infants' serum creatinine ranged from 25 to 54 micromol/L at 1 week after birth and 23-52 micromol/L after breast-feeding. All babies thrived. CONCLUSIONS: Breast-fed infants of mothers treated with CsA received less than 300 microg per day of CsA and absorbed undetectable amounts. There were no demonstrable nephrotoxic effects or other side effects. Thus, women with kidney transplants could be allowed to breast-feed.

Adult↗
PubMed1998

Free radicals are formed in the brain of fetal sheep during reperfusion after cerebral ischemia.

Free radical production in the brain of acutely anesthetized, exteriorized lamb fetuses (n = 11, gestational age = 135 d) was measured using spin trap methodology. Communications between the vertebral and carotid circulations were tied, producing a two-vessel supply to the brain. Flow probes and occlusion slings were placed around each carotid. The spin trap 2-ethyl-3-hydroxy-2,4,4-trimethyloxazolidine (OXANOH) was infused intermittently into one carotid at a constant rate, and blood samples were taken at intervals from the sagittal sinus. These samples were analyzed for the stable radical OXANO. using electron spin resonance spectrometry. Six animals were subjected to 30 min of complete cerebral ischemia, and five fetuses served as sham-operated control animals. During postischemic reperfusion radical formation increased 2-fold during the first 20 min. However, the elevation of OXANO. in the venous effluent from the brain did not start until the transient hyperemia had passed. It is thus concluded that the increase of OXANO. observed is caused by an augmentation of free radical production during reperfusion. Because the spin trap agent was infused directly into the arterial supply and recovered directly from the venous effluent of the brain, the site of production could be the brain tissue, the endothelial cells of the cerebral circulation, and activated leukocytes. This is the first demonstration of increased radical production from the fetal brain. It is noteworthy that it takes place despite oxygen tension of the reperfusing blood of only 3-3.5 kPa.

Animals↗
PubMed1998

Cerebral Doppler blood flow velocimetry and central hemodynamics in the ovine fetus during hypoxemia-acidemia.

The purpose of this study was to assess the effects of hypocapnic hypoxia, acidemia and the combination of hypoxia/acidemia on blood flow velocity variables in the fetal cerebral circulation. Chronically instrumented fetal sheep were used and the ewes were induced to breathe a hypoxic gas mixture for about 90 min. This caused an initial period of hypoxemia followed by a period of mixed hypoxemia/acidemia. When the ewe was reoxygenated, the fetus experienced a period of normoxic acidemia. The fetal cerebral circulation was assessed by recording Doppler blood flow velocity waveform variables in a cerebral vessel and the umbilical artery, using standard ultrasound equipment. External carotid artery blood flow was maintained during hypoxic and hypoxic/acidotic periods despite a fall in cardiac output. In the cerebral vessel, mean maximum velocity (time-averaged maximum velocity), minimum diastolic velocity and maximum systolic velocity manifested increases during hypoxic and hypoxic-acidotic periods, but pulsatility index did not change due to the effect of reduced heart rate on pulsatility index. Umbilical artery pulsatility index increased in the hypoxic and hypoxic-acidotic periods, despite unchanged mean maximum velocity, minimum diastolic velocity and maximum systolic velocity. With acute hemodynamic changes, the measurement of pulsatility index can yield misleading results. For clinical and experimental research on the fetal cerebral circulation, more attention should be paid to the individual Doppler variables, especially to the mean maximum velocity, than to the pulsatility index alone. Changes in mean maximum velocity recorded from the cerebral artery seem to reflect changes in the cerebral arterial flow.

Acidosis↗
PubMed1997

Formation of free radicals in hypoxic ischemic brain damage in the neonatal rat, assessed by an endogenous spin trap and lipid peroxidation.

The formation of free radicals and lipid peroxidation in the brain after hypoxic ischemia was investigated. Seven-day-old rats were subjected to unilateral (left) carotid artery ligation followed by 70 min of hypoxia with 8% oxygen at 36 degrees C. The animals were randomized into six groups as follows: control animals (no anesthesia, ligation or hypoxia) and animals decapitated at 0, 15, 30, 60 and 180 min into the reoxygenation period. Lipid peroxidation was quantified in brain homogenates using the thiobarbituric acid assay (TBA). The TBA-malondialdehyde (MDA) complex was measured with HPLC. The semi-dehydroascorbate radical was measured using electron spin resonance (ESR) spectroscopy. The semi-dehydroascorbate radical levels increased more than 3-fold in the left HI hemisphere compared to the left control hemisphere 15 min posthypoxic ischemia. The amount of MDA was significantly increased in the hypoxic ischemic (HI) hemisphere ipsilateral to the carotid ligation compared with contralateral hypoxic hemisphere. The MDA level in the left HI hemisphere was also significantly elevated at 0, 15, 30 and 60 min, but not at 180 min into the reoxygenation period. Reoxygenation after hypoxic ischemia thus induced formation of semi-dehydroascorbate radicals and lipid peroxidation.

Animals↗
PubMed1997

Recording non-nutritive sucking in the neonate. Description of an automatized system for analysis.

A new method for automatic analysis of non-nutritive sucking in newborn infants is described, which uses a specially designed computer program that analyses an analogue signal obtained from a pressure transducer inside a pacifier. Validation is done with four independent methods: electromyogram, visual identification, control of the automatic treatment and comparison of inter-observer results. A high degree of correspondence is shown. The system was applied to 58 healthy full-term neonates. Infants less than 24 h old demonstrated a significantly different sucking pattern compared with the 3-day-old infant. The duration of their bursts was longer (3.7 vs 2.8 s), the frequency of their sucking was lower (1.7 vs 2.0 Hz) and the variability of their sucking pattern was greater. These results also testify to the validity of the method inasmuch as the values for the different sucking parameters are similar to corresponding values presented earlier.

Age Factors↗
PubMed1997

Serum levels of magnesium at birth related to complications of immaturity.

Magnesium is a natural calcium channel blocker inhibiting vasoconstriction in numerous vascular beds. Magnesium sulphate given prior to birth to pre-eclamptic mothers and mothers in preterm labour has in retrospect been found to be associated with a decreased incidence of both intraventricular haemorrhage and cerebral palsy. Little is known about the effect of normal variations of serum magnesium in the very preterm baby, where morbidity is closely related to rapid vascular changes. We have analysed the absolute levels and normal variations of magnesium concentration in cord blood and during the first 3 weeks after birth for 69 infants born before 32 gestational weeks of age. The results show an inverse relation between serum magnesium at birth and gestational age. Higher levels of serum magnesium at birth within normal variations were associated with a delayed closure of the ductus arteriosus, and mild but not severe peri- and intraventricular haemorrhage.

Bronchopulmonary Dysplasia↗
PubMed1997

Long-term effects of intrauterine growth retardation.

Intrauterine growth retardation (IUGR) was studied both after experimental induction in rats and spontaneously occurring in man. The growth-retarded rat pups were compared to appropriately grown litter mates with developmental and behavioural tests at 50 and 90 days of age. Female rats exhibited no differences between growth-retarded and control rats but growth-retarded male rats had poor performance at 50 but not at 90 days compared to male controls. In the patient study 25 growth-retarded babies were compared with 21 appropriately grown controls. The growth-retarded babies had delayed latency periods of the visual evoked potentials at term and 6 weeks later, and at follow-up (18 months) demonstrated significantly more developmental and behavioural problems than the control group.

Animals↗
PubMed1997

Can paediatricians benefit from the Internet?

It is likely that many paediatricians will find the Internet useful. The main benefits are probably the ease and speed of communication and immediate access to a few databases such as MEDLINE. It is also practical to integrate the import, processing, storage, and export of data into one's own computer. It is also possible that the Internet in all its forms will become an integrated part of our daily paediatric practice as a result of the increased usage of the Internet by patients, parents, and paediatricians.

Computer Communication Networks↗
PubMed1996

Impact of reoxygenation with oxygen and air on the extent of the brain damage after hypoxia-ischaemia in neonatal rats.

Brain damage after hypoxia-ischaemia develops partly during the state of reoxygenation. The generation of free oxygen radicals is considered to be one possible mechanism. In order to evaluate the role of hyperoxygenation, a comparison was made between reoxygenation with pure oxygen and with air after hypoxia-ischaemia in a rat model of unilateral cerebral hemisphere damage. Brain damage was induced in 7-day-old rats. The animals were treated during reoxygenation with either 100% oxygen for 0.5 h or air. The extent of the brain damage was determined at 3 weeks of age by weighing the left and right hemispheres separately. No significant difference in weight deficit of the hemispheres was seen in the oxygen-treated group (15.5%, median) compared to the air-treated group (25.0%). Reoxygenation with pure oxygen after hypoxia-ischaemia in neonatal rats does not cause increased brain damage compared with reoxygenation with room air.

Air↗
PubMed1996

Posthypoxic cooling of neonatal rats provides protection against brain injury.

AIM: To determine whether moderate hypothermia, applied after a hypoxic-ischaemic insult in neonatal rats, reduces cerebral damage. METHOD: Unilateral hypoxic-ischaemic brain damage was induced in 7 day old rats by left carotid ligation, followed by 120 minutes of normothermic exposure to 8% O2, followed by random selection to three hours of hypothermia (rectal temperature, mean (SD), 32.5 (0.4) degrees C) or normothermia (38.3 (0.4) degrees C). One hundred and one animals were used for brain temperature or blood chemistry studies and 24 for survival studies (7 days) with neuropathology, including cell counting as outcome measures. RESULTS: Thirty sections from each brain were histologically examined with respect to distribution and pattern of damage and given a score from 0 to 4. Animals treated with hypothermia had significantly less damage than normothermic animals (score 0.5 (0.3) vs 1.8 (0.5)). CONCLUSIONS: Posthypoxic hypothermia reduces brain damage in awake, unrestrained 7 day old rats.

Animals↗
PubMed1995

Neuron specific enolase in asphyxiated newborns: association with encephalopathy and cerebral function monitor trace.

Neuron specific enolase (NSE) in serum and cerebrospinal fluid (CSF) and glutamate in CSF were investigated in the immediate postasphyctic period in 22 term newborn infants. The cerebral function monitor (CFM) pattern was also assessed and hypoxic-ischaemic encephalopathy (HIE) was graded. NSE was significantly increased in the CSF of infants with HIE (median value 25.4 micrograms/l) compared with control infants (10.0 micrograms/l). Infants with the highest concentrations died. NSE in CSF correlated with the degree of asphyxial damage. Glutamate and NSE in CSF did not correlate, presumably due to the different time factors of the release after the insult. NSE in CSF corresponded well with the type of CFM pattern, which was also highly predictive of outcome.

Asphyxia Neonatorum↗
PubMed1993

Excitatory amino acids in the cerebrospinal fluid of asphyxiated infants: relationship to hypoxic-ischemic encephalopathy.

Asphyxiated (n = 27) and control infants (n = 25) were subjected to spinal taps. Amino acids were measured with liquid chromatography and the degree of hypoxic-ischemic encephalopathy was determined in each case. In asphyxiated infants, the concentrations of aspartate and glutamate were 286% and 387% (p < or = 0.01 and p < or = 0.05) of the control values, respectively. The cerebrospinal fluid aspartate levels were significantly (p < or = 0.05) higher in the group with severe (3.4 mumol/l) compared with the group with mild hypoxic-ischemic encephalopathy (1.0 mumol/l). Glutamate was also higher in the group with severe (12.3 mumol/l) than in the groups with mild (2.7 mumol/l) or moderate (3.2 mumol/l) hypoxic-ischemic encephalopathy (p < or = 0.05). High concentrations of excitatory amino acids were present in the CSF of asphyxiated infants which may exert excitotoxic effects.

Amino Acids↗