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Biomedical subjects

L M Dubowitz

Publications and source records attributed to L M Dubowitz.

At least 37 records · Page 2Linked to original sources
PubMed1992

Low cerebrospinal fluid concentration of free gamma-aminobutyric acid in startle disease.

The pathophysiology of startle disease (hyperekplexia) is unknown. Hyperactivity of the brainstem reticular formation has been suggested as a cause. We report a newborn infant with classic features of startle disease in whom cerebrospinal fluid (CSF) concentrations of gamma-aminobutyric acid (GABA) were substantially lower than normal during the first weeks of life. She improved greatly on clonazepam treatment. We suggest that the signs of this disorder may be due to a genetic defect or to delayed maturation resulting in low CSF GABA.

Clonazepam↗
PubMed1992

Athetoid cerebral palsy with cysts in the putamen after hypoxic-ischaemic encephalopathy.

Three cases of athetoid cerebral palsy after hypoxic-ischaemic encephalopathy (HIE) are reported. All three neonates had haemorrhagic lesions in the basal ganglia and thalami on magnetic resonance imaging (MRI). Prior cranial ultrasound had detected the lesions in only two cases. In all three children athetoid movements began within the first year of life. Follow up MRI scans showed bilateral symmetrical cystic lesions in the posterior putamen. Although haemorrhagic lesions within the basal ganglia are a common MRI finding in neonates with HIE, few of these babies develop athetoid cerebral palsy. We believe this to be the first report of discrete cystic lesions found in the basal ganglia of children with athetoid cerebral palsy.

Basal Ganglia Diseases↗
PubMed1991

A new system for cotside display and analysis of the preterm neonatal electroencephalogram.

Continuous EEG monitoring is considered to be a sensitive indicator of changes in cerebral function. This paper describes a system for cotside display and analysis of EEG discontinuity and amplitude in one-minute epochs, with provision for simultaneous recording of the EEG. It has been successfully used to monitor continuously the EEGs of more than 30 babies in a neonatal intensive care unit for periods of up to nine days. This system rapidly provides indications of changes in cerebral function, which can allow early intervention and possible prevention of morbidity.

Brain Damage, Chronic↗
PubMed1990

31P magnetic resonance spectroscopy of the human paediatric liver.

Localized 31P NMR spectroscopy was used to study the developing human liver in three neonates and one infant, all with neonatal intracranial problems, but normal liver function. A prominent resonance was present in the phosphomonoester (PME) region of the spectrum of the neonates; the PME/ATP ratio was 1.0 +/- 0.4 (repetition time 1 s), compared to the mean adult liver value of 0.2 +/- 0.1. The saturation factor of PME in the neonates was large, indicating that the increase in PME/ATP reflected an increase in relative PME concentration. The chemical shift of the PME peak in the neonatal liver (6.8 +/- 0.1) was similar to that found in neonatal brain, suggesting that phosphorylethanolamine may be a major constituent. The phosphodiester (PDE)/ATP ratio in these patients (0.4 +/- 0.1) was decreased compared with the mean adult value (1.3 +/- 0.2), and the saturation factor of PDE was small. The results from the infant were different from both the neonates and adults; PME/ATP was decreased compared to the neonates, but increased compared to adults. The saturation factor of PDE was increased compared to neonates. The biochemical implications of the observed changes in PME and PDE in paediatric liver are discussed in relation to membrane turnover.

Brain Diseases↗
PubMed1989

Extensive cystic leucomalacia: correlation of cranial ultrasound, magnetic resonance imaging and clinical findings in sequential studies.

Cranial ultrasound (US) was used in 14 neonates to define three categories of extensive cystic leucomalacia, namely periventricular, mixed, and subcortical. The initial US findings were compared with serial magnetic resonance imaging (MRI) and the neurodevelopmental outcome of the children. In the infants with periventricular leucomalacia, MRI showed a decrease in the size of the cystic areas with age. Six of these seven children showed an increase in the level of myelination upon follow-up examination, although white matter development was slower in the vicinity of the cysts. The lateral ventricles of these children were slightly enlarged and the occipital horns showed an irregular angular outline. In the infants with mixed leucomalacia, MRI showed cystic areas which remained obvious at the final examination. Myelination was grossly delayed in these patients. The lateral ventricles were enlarged and remained unchanged, with the exception of one infant whose ventricles collapsed after shunt revision. In the three children with subcortical leucomalacia, MRI confirmed shrinkage of the cysts in two of the three infants upon the first follow-up examination but thereafter the cysts remained unchanged. No supratentorial myelination was demonstrated in these patients. The ventricles were enlarged and the cortical sulci were prominent in all these infants. A strong correlation was shown between the MRI appearances and the clinical outcome in these children. MRI may be most useful for making the diagnosis of cystic leucomalacia in children not submitted to US examination as neonates or in whom only some of the classical US features have been identified.

Brain↗
PubMed1989

Auditory brain stem responses in infants with posthaemorrhagic ventricular dilatation.

Nineteen infants with posthaemorrhagic ventricular dilatation had auditory brain stem responses measured during the period of maximal ventricular dilatation. These showed various patterns ranging from normal, through various abnormalities, to complete absence of responses. When serial auditory brain stem responses were studied in parallel with the evolution of posthaemorrhagic ventricular dilatation it was seen that the abnormalities of auditory brain stem response usually resolved irrespective of the persistence or progression of ventricular dilatation. No correlation was found between cerebrospinal fluid pressure and prolonged interpeak intervals on the auditory brain stem response. In three patients with posthaemorrhagic ventricular dilatation improvement in the auditory brain stem response occurred when cerebrospinal fluid was withdrawn. Intermittent withdrawal of cerebrospinal fluid (by ventricular tap or lumbar puncture) in two of these infants was followed by improvement in the auditory brain stem response after a period of 24 hours (but not sooner). In one infant born at full term improvement in the auditory brain stem response was noted one week after shunting.

Brain Stem↗
PubMed1989

Continuous EEG monitoring of neonatal seizures: diagnostic and prognostic considerations.

We recruited 275 full term and preterm infants into a prospective evaluation of continuous four channel electroencephalographic (EEG) monitoring in the diagnosis and prognosis of neonatal seizures. EEG seizure activity was found in 55 infants; clinical signs were completely simultaneous in only 12 of these, they were present but limited in another 20, and were completely absent in the remaining 23. EEG seizure activity, with or without clinical signs, were equally associated with serious cerebral lesions and with adverse clinical outcome. The four channel EEG recording provided sufficient data on abnormality to be prognostically specific in 79% of the 43 infants who either died or had serious neurological impairment.

Brain Ischemia↗
PubMed1989

Clinical and EEG response to anticonvulsants in neonatal seizures.

During a two year period prospective continuous electroencephalographic (EEG) monitoring of 275 infants identified seizure activity in 55 cases, 31 of whom were treated with anticonvulsant drugs on clinical grounds. EEG and clinical response was complete in only two and equivocal in another six. Clinical response with persistent EEG seizures occurred in 13 and neither clinical nor EEG response in 10. There was no significant improvement in the generally poor neurological outcome compared with that in 24 infants whose seizures were not treated because of limited or absent clinical manifestations. Background EEG abnormality (as an index of associated cerebral dysfunction) was a guide to potential lack of response to anticonvulsant drugs; it was also predictive of subsequent clinical outcome irrespective of treatment. This study shows that commonly used anticonvulsant drugs (phenobarbitone, paraldehyde, phenytoin, and diazepam) have little effect on seizure control or neurological outcome in neonatal seizures associated with haemorrhagic, hypoxic, or ischaemic cerebral lesions. In view of the variable clinical appearance of EEG seizure activity, continuous EEG monitoring should be an essential feature of further study of neonatal anticonvulsant treatment.

Anticonvulsants↗
PubMed1989

Blood pressure fluctuation and intraventricular hemorrhage in the preterm infant of less than 31 weeks' gestation.

A total of 22 infants of less than 31 weeks' gestation who were mechanically ventilated for a minimum of 12 hours for respiratory distress syndrome were studied. The coefficient of variation of direct systolic pressure was measured each minute from six to 36 hours of age and averaged per hour after birth with a microcomputer-based system of data collection. At the start of recording, the ultrasound scan appeared normal in each infant, but intraventricular hemorrhage developed in ten infants less than 36 hours of age. Twelve infants remained free of intraventricular hemorrhages. BP fluctuation was greater for a longer proportion of measured time in infants in whom intraventricular hemorrhage did not develop compared with those in whom it did develop P less than .05). These findings do not support a causal relationship between BP fluctuation and intraventricular hemorrhage within the range of coefficient of variation studied.

Blood Pressure↗
PubMed1988

Perinatal risk factors for the development of extensive cystic leukomalacia.

Seventeen infants with extensive cystic leukomalacia without associated intraventricular hemorrhages were compared with 34 infants with normal cranial ultrasound findings and 34 infants with large intraventricular hemorrhages to establish whether different risk factors could be elicited for these lesions. Adverse obstetric factors that were associated with extensive leukomalacia were the place of birth (outborn [ie, not born at our hospital but transferred here after delivery]) and the need for emergency cesarean section. Neonatal risk factors, with the exception of gestational age, were equally distributed between the infants with the two types of lesions. The results of this study suggest that extensive cystic leukomalacia and large hemorrhages have similar predisposing factors, but the type of lesion that develops depends on the maturity of the infant.

Birth Weight↗
PubMed1988

MRI of intracerebral haematoma at low field (0.15T) using T2 dependent partial saturation sequences.

Results of MRI at 0.15T in twelve successive patients with intracerebral haematoma are reviewed. Using T2 weighted spin echo (SE) and partial saturation (PS without a refocussing 180 degree pulse) sequences, low intensity areas were seen in eleven of the twelve cases. These included central regions (three cases), a peripheral rim (seven cases) and more diffuse patterns involving the brainstem and cerebral hemispheres (two cases). One case initially displayed a peripheral rim and later a central low intensity region. Central low intensity regions were seen in acute, subacute, and chronic cases. Follow up in five cases displayed an increase in signal within the haematoma in three cases and a decrease in signal intensity in two cases. Low signal intensity areas can be seen within and around intracerebral haematomas imaged with T2 weighted sequences at low field strength.

Adult↗
PubMed1988

Ultrasound evolution and later outcome of infants with periventricular densities.

The evolution of ultrasound findings in 59 infants with transient periventricular densities is described and the neurodevelopmental outcome of 53 of these infants was compared with 92 of 107 infants with normal ultrasound scans, born during the same 24-month period. Four of the 53 infants with transient periventricular densities developed spastic diplegia and 24 developed transient dystonia, whereas only 8 of the 92 children with normal ultrasound scans demonstrated this finding (P less than 0.001). Persistence of the densities for more than 10 days and the presence of densities in the trigone were especially related with subsequent problems. Postmortem findings in two infants and MRI studies in six infants also suggested that transient periventricular densities represent the milder end of the spectrum of periventricular leukomalacia.

Cerebral Palsy↗