Neuro-imaging characteristics of sensory impairment in cerebral palsy; a systematic review

Background

Objective: To identify and examine neural reorganization of the sensory network in terms of lesion type, somatotopic organization of the primary somatosensory area, and functional connectivity in relation to sensory function in children and young adults with cerebral palsy (CP).

Methods

Design: systematic review, Prospero registration ID 342570. Data sources: PubMed; Cochrane; Web of Science; Embase; CINAHL and PEDro from inception to March 13, 2021. Eligibility criteria: All types of original studies, concerning sensory connectivity in relation to sensory outcome in patients with spastic CP, <30 years of age. No publication status or date restrictions were applied. Data extraction and synthesis: Two authors independently determined the eligibility of studies. Quality assessment was performed by a third author. Neuro-imaging/neurophysiological techniques, sensory outcomes and patient characteristics were extracted.

Results

Children and young adults with periventricular leucomalacia (PVL) lesions have significantly better hand function and sensation scores than patients with cortical-subcortical/middle cerebral artery (MCA) lesions. Ipsilesional reorganization of the S1 (primary somatosensory cortex) area appears to be the primary compensation mechanism after a unilateral early brain lesion, regardless of the timing of the lesion. Interhemispheric reorganization of the sensory system after early brain lesions is rare and, when it occurs, poorly effective. Diffusion tractography shows a positive correlation between the ascending sensory tract (AST) diffusivity metrics of the more affected hemisphere and sensory test outcomes.

Discussion and conclusions

Because of the large variability in study design, patient characteristics, neuroimaging/neurophysiological techniques and parameters as well as sensory assessment methods used, it is difficult to draw definite inferences on the relationship between the reorganization of the sensory network following early brain damage and sensory function in children and young adults with CP. In general, sensory function seems to be worse in cortical as opposed to white matter tract (PVL) lesions. International consensus on a clinically relevant sensory test battery is needed to enhance understanding of the intriguing compensatory mechanisms of sensory network following early brain damage and potential consequences for rehabilitation strategies.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/.

Lower limb muscle fatigue after uphill walking in children with unilateral spastic cerebral palsy

Fatigue during walking is a common complaint in cerebral palsy (CP). The primary purpose of this study is to investigate muscle fatigue from surface electromyography (sEMG) measurements after a treadmill-based fatigue protocol with increasing incline and speed in children with CP with drop foot. The secondary purpose is to investigate whether changes in sagittal kinematics of hip, knee and ankle occur after fatigue. Eighteen subjects with unilateral spastic CP performed the protocol while wearing their ankle-foot orthosis and scored their fatigue on the OMNI scale of perceived exertion. The median frequency (MF) and root mean square (RMS) were used as sEMG measures for fatigue and linear mixed effects model were applied. The MF was significantly decreased in fatigued condition, especially in the affected leg and in the tibialis anterior and peroneus longus muscle. The RMS did not change significantly in fatigued condition, while the OMNI fatigue score indicated patients felt really fatigued. No changes in sagittal kinematics of hip, knee and ankle were found using statistical non-parametric mapping. In conclusion, the current fatigue protocol seems promising in inducing fatigue in a population with CP with drop foot and it could be used to expand knowledge on muscle fatigue during walking in CP.

A guideline for the clinical management of basal cell nevus syndrome (Gorlin-Goltz syndrome)

The overall objective of this guideline is to provide up-to-date, evidence-based recommendations for the diagnosis and surveillance of all symptoms of children and adults with either basal cell nevus syndrome (BCNS), a clinical suspicion of BCNS, or a parent with BCNS. In the last two groups the guidelines should be followed until the diagnosis of BCNS can be rejected with certainty. The guideline aims to: - Update and expand on the previous guidelines by an appraisal of all relevant literature from January 2011 up to January 2021 - Address important, practical, clinical questions relating to the primary guideline objective - Provide guideline recommendations - Discuss potential developments and future directions.

Additional value of advanced neurosonography and magnetic resonance imaging in fetuses at risk for brain damage

OBJECTIVE

To assess the additional value of fetal multiplanar (axial, coronal and sagittal) neurosonography and magnetic resonance imaging (MRI) to that of the standard axial ultrasound planes in diagnosing brain damage in fetuses at high risk.

METHODS

This was a prospective, multicenter, observational study. Women were eligible for participation if their fetus was at risk for acquired brain anomalies. Risk factors were congenital infection, alloimmune thrombocytopenia, fetal growth restriction, trauma during pregnancy, fetal hydrops, monochorionic twins and prior ultrasound finding suggestive of an acquired brain anomaly. Examinations of the fetal brain before birth comprised axial ultrasound and advanced neurosonography biweekly and MRI once. After birth, neonatal cranial ultrasound was performed at < 24 h and at term-equivalent age. Neonatal brain MRI was performed once at term-equivalent age. An expert panel blinded to medical information, including imaging findings by the other methods, evaluated the presence of periventricular echogenicity (PVE) changes, peri- and intraventricular hemorrhage (IVH) and changes in basal ganglia and/or thalami echogenicity (BGTE) on ultrasound, and the equivalent signal intensity (SI) changes on MRI. Conclusions on imaging findings were generated by consensus. The children were followed up with examinations for psychomotor development at 1 year of age, using the Touwen examination and Alberta Infant Motor Scale, and at 2 years of age using Bayley Scale of Infant Development-III (BSID-III) and behavioral, sensory profile and linguistic questionnaires; scores > 1 SD below the mean were considered suspicious for neurodevelopmental sequelae.

RESULTS

Fifty-six fetuses were examined, and in 39/56 fetuses, all fetal-imaging modalities were available. PVE/SI changes were observed in 6/39, 21/39 and 2/39 fetuses on axial ultrasound planes, multiplanar neurosonography and MRI, respectively. IVH was found in 3/39, 11/39 and 1/39 fetuses, and BGTE/SI changes in 0/39, 12/39 and 0/39 fetuses, respectively. Outcome was suspicious for neurodevelopmental sequelae in 13/46 infants at 1 year, and at 2 years, 41/41 children had scores within 1 SD of the mean on BSID-III and 20 had scores > 1 SD below the mean on the behavioral (5/38), sensory profile (17/37) and/or linguistic (6/39) questionnaires.

CONCLUSIONS

In this cohort of fetuses at risk for brain damage, the severity of acquired brain anomalies was limited. Nevertheless, multiplanar neurosonography detected more fetal PVE changes, IVH and/or BGTE changes compared to the standard axial ultrasound planes and MRI. Fetal MRI did not demonstrate any anomalies that were not seen on neurosonography. Neurodevelopmental outcome at 2 years of age showed no or mild impairment in most cases. © 2019 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Mobility Characteristics of Children with Spastic Paraplegia Due to a Mutation in the KIF1A Gene

Several de novo variants in the KIF1A gene have been reported to cause a complicated form of hereditary spastic paraplegia. Additional symptoms include cognitive impairment and varying degrees of peripheral neuropathy, epilepsy, decreased visual acuity, and ataxia. We describe four patients (ages 10-18 years), focusing on their mobility and gait characteristics. Two patients were not able to walk without assistance and showed a severe abnormal gait pattern, crouch gait. At examination, severe contractures were found.In addition to describing the different phenotypes with specific attention to gait in our cases, we reviewed known KIF1A mutations and summarized their associated phenotypes.We conclude that mobility and cognition are severely affected in children with spastic paraplegia due to de novo KIF1A mutations. Deterioration in mobility is most likely due to progressive spasticity, muscle weakness, and the secondary development of severe contractures, possibly combined with an additional progressive polyneuropathy. Close follow-up and treatment of these patients are warranted.

Placental Histology After Minor Trauma in Pregnancy: A Pilot Study

OBJECTIVE

Trauma in pregnancy may cause placental abruption. Consequences of moderate placental injury on neurodevelopment are unknown. The aim was to evaluate placental histology after maternal trauma.

METHODS

A prospective study was conducted at 2 tertiary medical centers in the Netherlands. Placentas from women exposed to maternal trauma ≥ 20 weeks' gestational age were histologically examined. Neurological follow-up of the infants was performed at 1 year of age by means of Alberta Infant Motor Scale. Histological findings were compared to placentas from pregnancies without trauma.

PRINCIPAL RESULTS

Thirteen placentas were investigated in the trauma group. The control group consisted of 15 placentas. Placental pathology was seen more often in the trauma cases (11 of the 13) than in the controls (6 of the 15), P = .024. Neurological follow-up was normal.

CONCLUSIONS

In this small population, majority of the placentas showed pathology after minor trauma in pregnancy without consequences for neurodevelopment at 1 year.

Neurodevelopmental outcome at 2 years of age in preterm infants with late-onset sepsis

Late-onset sepsis is associated with impaired neurodevelopmental outcome in preterm infants. This prospective cohort study aims to establish the effect of sepsis after 72 h of life on cognitive, psychomotor, and language development of preterm infants (below 32 weeks gestational age and/or below 1500 g). At 2 years corrected age, neurodevelopmental outcome was tested using Bayley's Scales of Infant Development-II, Lexilijst (lexical development questionnaire), and behavior checklists. Of 117 patients included, 85 experienced blood culture-proven infection. Coagulase-negative staphylococci were responsible for 55% of the episodes. No significant differences were found in cognitive, motor, and behavioral scores or lexiquotient comparing patients with versus no proven infection. When comparing three groups (coagulase-negative staphylococci, other, and negative blood culture), a significant difference was found in composite cognitive scores (p = 0.016), in favor of the coagulase-negative staphylococci group versus other causal agent group (p = 0.007). No significant differences were found in other subscales.Conclusion: In this cohort, no differences were found in neurodevelopmental outcome at 2 years corrected age between proven and no proven infection groups; confirmation in larger cohorts with a control group is needed. Patients encountering coagulase-negative staphylococci sepsis showed a significant better cognitive outcome compared to other causal agents. What is Known: • Late-onset sepsis is associated with impaired neurodevelopmental outcome in preterm infants. What is New: • Preterm infants encountering late-onset sepsis by coagulase-negative staphylococci show a better cognitive outcome in comparison to other causal infectious agents in this cohort. • No differences were found in neurodevelopment at 2 years of age in preterm infants with suspected lateonset sepsis, between proven and no proven infection groups. Confirmation is needed in larger cohorts with a substantial control group.

Neurobehavioural outcome in 6-18 year old children after trauma in pregnancy: Case-control study

BACKGROUND

Maternal trauma complicates pregnancy in approximately 7%. Long-term development of children exposed to maternal trauma is unknown.

AIM

To determine neurobehavioural outcome of children (6-18 years) born after maternal trauma in pregnancy compared to a matched control group.

STUDY DESIGN

Case-control study performed at a tertiary medical centre.

SUBJECTS

All consecutive children born after maternal hospitalization for trauma during pregnancy between 1995 and 2005. Controls were children born at the same hospital and period after an uneventful pregnancy.

OUTCOME MEASURES

Trauma type and severity (Injury Severity Score, ≥9: severe); information from medical files at admission (cases). All mothers filled out two questionnaires about the infant; 1. concerning health, motor development and educational level, 2. concerning behavioural development through the validated Dutch version of the Child Behavior Checklist (CBCL).

RESULTS

Questionnaires were returned by 34 cases and 28 controls. The traumas concerned mainly motor vehicle accidents and falls, and 3/34 had severe injuries. No differences in health, motor development, educational level and CBCL was found between the cases and controls, except for more hospitalization in the cases (p = 0.009).

CONCLUSION

Long-term follow-up of a limited population of children 6-18 years after exposure of mainly non-severe trauma before birth is similar to a control population except for unexplained more hospitalization in the cases.

Incidence and outcome of acquired demyelinating syndromes in Dutch children: update of a nationwide and prospective study

INTRODUCTION

Acquired demyelinating syndromes (ADS) are immune-mediated demyelinating disorders of the central nervous system in children. A nationwide, multicentre and prospective cohort study was initiated in the Netherlands in 2006, with a reported ADS incidence of 0.66/100,000 per year and MS incidence of 0.15/100,000 per year in the period between 2007 and 2010. In this study, we provide an update on the incidence and the long-term follow-up of ADS in the Netherlands.

METHODS

Children < 18 years with a first attack of demyelination were included consecutively from January 2006 to December 2016. Diagnoses were based on the International Paediatric MS study group consensus criteria. Outcome data were collected by neurological and neuropsychological assessments, and telephone call assessments.

RESULTS

Between 2011 and 2016, 55/165 of the ADS patients were diagnosed with MS (33%). This resulted in an increased ADS and MS incidence of 0.80/100,000 per year and 0.26/100,000 per year, respectively. Since 2006 a total of 243 ADS patients have been included. During follow-up (median 55 months, IQR 28-84), 137 patients were diagnosed with monophasic disease (56%), 89 with MS (37%) and 17 with multiphasic disease other than MS (7%). At least one form of residual deficit including cognitive impairment was observed in 69% of all ADS patients, even in monophasic ADS. An Expanded Disability Status Scale score of ≥ 5.5 was reached in 3/89 MS patients (3%).

CONCLUSION

The reported incidence of ADS in Dutch children has increased since 2010. Residual deficits are common in this group, even in monophasic patients. Therefore, long-term follow-up in ADS patients is warranted.

Effect of selective dorsal rhizotomy on daily care and comfort in non-walking children and adolescents with severe spasticity

BACKGROUND

In non-walking children with severe spasticity, daily care can be difficult and many patients suffer from pain. Selective dorsal rhizotomy (SDR) reduces spasticity in the legs, and therefore has the potential to improve daily care and comfort.

AIM

To examine effects of SDR on daily care and comfort in non-walking children with severe spasticity due to different underlying neurological conditions.

METHODS

Medical history, changes in daily care and comfort and satisfaction with outcome were assessed retrospectively in non-walking children who underwent SDR in our center, with a mean follow-up of 1y 7m (range 11m-4y 3m). All eligible patients (n = 24, years 2009-2014) were included.

RESULTS

Mean age at SDR was 12y 4m (SD 4y 3m, range 2y 8m-19y 3m). Associated orthopaedic problems were frequent. Seven patients underwent scoliosis correction in the same session. Most improvements were reported in dressing (n = 16), washing (n = 12) and comfort (n = 10). Median score for satisfaction was 7 on a scale of 10 (range 1-9). SDR resulted in reduction of spasticity in leg muscles. In nine patients dystonia was recorded post-operatively, mainly in children with congenital malformations and syndromes.

INTERPRETATION

SDR is a single event intervention that can improve daily care and comfort in non-walking children with severe spasticity, and can safely be combined with scoliosis correction. Despite the improvements, satisfaction is variable. Careful attention is necessary for risk factors for dystonia, which may be unmasked after SDR.

Comparison of psychomotor outcome in patients with perinatal asphyxia with versus without therapeutic hypothermia at 4 years using the Ages and Stages Questionnaire screening tool

INTRODUCTION

Therapeutic hypothermia improves outcome after perinatal asphyxia. The Ages and Stages Questionnaire is a screening tool to detect neurodevelopmental delay. In this study we examined the outcome of patients with perinatal asphyxia (defined as Apgar score <5 at 10 min, or continued need for resuscitation, or pH < 7.00 in umbilical cord or within one hour after birth) with and without therapeutic hypothermia treatment at the age of four years.

METHODS

Cohort study of patients with perinatal asphyxia admitted to the Neonatal Intensive Care Units of the VU University Medical Center, Amsterdam and the Wilhelmina Children's Hospital, Utrecht in the year 2008. Parents were asked to fill out the 48 months Ages and Stages Questionnaire (ASQ). In Wilhelmina Children's Hospital treatment with therapeutic hypothermia was implemented in 2008, in the VU University Medical Center in 2009, providing a historical cohort.

RESULTS/DISCUSSION

Twenty-three questionnaires were evaluated. Response rate of questionnaires for the VU Medical Center was 63% (n = 10) and Wilhelmina's Childrens Hospital 93% (n = 13). No significant differences were found in the mean scores between both groups. However, the untreated group scored more frequently under the -2 SD threshold. In the fine motor skills domain the difference was statistically significant (p = 0.031). In the treated group no patients developed cerebral palsy and in the untreated group two patients developed cerebral palsy.

CONCLUSION

In this study patients treated with hypothermia tend to have a better neurodevelopmental outcome. No significant differences were found between the two groups, apart from the fine motor skills.

Feedback learning and behavior problems after pediatric traumatic brain injury

BACKGROUND

Feedback learning is essential for behavioral development. We investigated feedback learning in relation to behavior problems after pediatric traumatic brain injury (TBI).

METHOD

Children aged 6-13 years diagnosed with TBI (n = 112; 1.7 years post-injury) were compared with children with traumatic control (TC) injury (n = 52). TBI severity was defined as mild TBI without risk factors for complicated TBI (mildRF- TBI, n = 24), mild TBI with ⩾1 risk factor for complicated TBI (mildRF+ TBI, n = 51) and moderate/severe TBI (n = 37). The Probabilistic Learning Test was used to measure feedback learning, assessing the effects of inconsistent feedback on learning and generalization of learning from the learning context to novel contexts. The relation between feedback learning and behavioral functioning rated by parents and teachers was explored.

RESULTS

No evidence was found for an effect of TBI on learning from inconsistent feedback, while the moderate/severe TBI group showed impaired generalization of learning from the learning context to novel contexts (p = 0.03, d = -0.51). Furthermore, the mildRF+ TBI and moderate/severe TBI groups had higher parent and teacher ratings of internalizing problems (p's ⩽ 0.04, d's ⩾ 0.47) than the TC group, while the moderate/severe TBI group also had higher parent ratings of externalizing problems (p = 0.006, d = 0.58). Importantly, poorer generalization of learning predicted higher parent ratings of externalizing problems in children with TBI (p = 0.03, β = -0.21) and had diagnostic utility for the identification of children with TBI and clinically significant externalizing behavior problems (area under the curve = 0.77, p = 0.001).

CONCLUSIONS

Moderate/severe pediatric TBI has a negative impact on generalization of learning, which may contribute to post-injury externalizing problems.

Pediatric neurocysticercosis: three cases presented in the Netherlands with divergent clinical presentations

BACKGROUND

Neurocysticercosis is a helminthic disease that affects the central nervous system by the larvae of the Taenia solium, the pork tapeworm. Because of the growing number of immigrants from endemic areas, its incidence is increasing in Western Europe.

CASES

We describe three children, aged between 2 and 13 years, two of whom have a definite and one a probable diagnosis of neurocysticercosis based on the "Del Brutto criteria." They presented with different symptoms and signs: symptomatic epilepsy, asymmetric cerebral palsy, and headache. Serological evaluation was negative in two of the three cases. All cases showed comparable abnormalities on magnetic resonance imaging of the brain: solitary or multiple, cystic lesions, with surrounding edema. In one of them, the "scolex" (part of the larvae) could be visualized. One case was treated with albendazole, the other two cases did not receive medication.

CONCLUSION

A prompt diagnosis of neurocysticercosis by recognition of its typical brain lesions is important to prevent unnecessary diagnostic tests and treatment.

Clinical and genetic aspects of PCDH19-related epilepsy syndromes and the possible role of PCDH19 mutations in males with autism spectrum disorders

Epilepsy and mental retardation limited to females (EFMR), caused by PCDH19 mutations, has a variable clinical expression that needs further exploration. Onset of epilepsy may be provoked by fever and can resemble Dravet syndrome. Furthermore, transmitting males have no seizures, but are reported to have rigid personalities suggesting possible autism spectrum disorders (ASD). Therefore, this study aimed to determine the phenotypic spectrum associated with PCDH19 mutations in Dravet-like and EFMR female patients and in males with ASD. We screened 120 females suffering from Dravet-like epilepsy, 136 females with EFMR features and 20 males with ASD. Phenotypes and genotypes of the PCDH19 mutation carriers were compared with those of 125 females with EFMR reported in the literature. We report 15 additional patients with a PCDH19 mutation. Review of clinical data of all reported patients showed that the clinical picture of EFMR is heterogeneous, but epilepsy onset in infancy, fever sensitivity and occurrence of seizures in clusters are key features. Seizures remit in the majority of patients during teenage years. Intellectual disability and behavioural disturbances are common. Fifty percent of all mutations are missense mutations, located in the extracellular domains only. Truncating mutations have been identified in all protein domains. One ASD proband carried one missense mutation predicted to have a deleterious effect, suggesting that ASD in males can be associated with PCDH19 mutations.

Incidence of acquired demyelinating syndromes of the CNS in Dutch children: a nationwide study

Acquired demyelinating syndromes (ADS) can be a first presentation of multiple sclerosis (MS) in children. The incidence of these disorders in Europe is currently unknown. Children (<18 years old) living in the Netherlands who presented with ADS were included from January 1, 2007 to December 31, 2010 by the Dutch pediatric MS study group and the Dutch surveillance of rare pediatric disorders. Demographic and clinical data were collected. Eighty-six patients were identified over 4 years, resulting in an incidence of 0.66/1,00,000 per year. Most patients presented with polyfocal ADS without encephalopathy (30%), followed by polyfocal ADS with encephalopathy (24%), optic neuritis (ON, 22%), monofocal ADS (16%), transverse myelitis (3%), and neuromyelitis optica (3%). Patients with polyfocal ADS with encephalopathy were younger (median 3.9 years) than patients with ON (median 14.6 years, p < 0.001) or monofocal ADS (median 16.0 years, p < 0.001). Patients with polyfocal ADS without encephalopathy (median 9.2 years) were also younger than monofocal ADS patients (median 16.0 years, p < 0.001). There was a slight female preponderance in all groups except the ON group, and a relatively large number of ADS patients (29%) reported a non-European ancestry. Familial autoimmune diseases were reported in 23%, more often in patients with relapsing disease than monophasic disease (46 vs. 15%, p = 0.002) and occurring most often in the maternal family (84%, p < 0.001). During the study period, 23% of patients were subsequently diagnosed with MS. The annual incidence of ADS in the Netherlands is 0.66/1,00,000 children/year. A polyfocal disease onset of ADS was most common.

Gaze behaviour during interception in children with spastic unilateral cerebral palsy

Anticipatory gaze behaviour during interceptive movements was investigated in children with Spastic Unilateral Cerebral Palsy (SUCP), and related to the side of the intracerebral lesion. Five children with lesions of the right hemisphere (RHL) and five children with lesions of the left hemisphere (LHL) had to walk towards and intercept a ball that moved perpendicular to the walking path. Interception accuracy and gaze patterns were measured in a no-occlusion and occlusion condition, in which the ball was occluded from view for half of its trajectory. There was a clear support for a relationship between gaze behaviour and success in interception performance, with some evidence for the presence of anticipatory gaze behaviour. There were also differences in gaze behaviour between children with RHL and children with LHL that might be related to planning, but these did not affect interception accuracy. It is concluded that gaze behaviour during interceptive movements is anticipatory, and at least partly dependent on the lesional side.

Familial hemophagocytic lymphohistiocytosis in a pediatric patient diagnosed by brain magnetic resonance imaging

Familial hemophagocytic lymphohistiocytosis (fHLH) is an autosomal recessive disorder characterized by proliferation and infiltration of several organs by activated lymphocytes and macrophages. Without allogeneic stem cell transplantation, fHLH is fatal. We describe a previously healthy 11-month-old boy with a rapidly progressive encephalopathy. An older brother died at 8 months following a subacute encephalopathy diagnosed as meningoencephalitis. The family history led to the suspicion of a metabolic disease, but metabolic studies were unrevealing. MRI showed multiple inhomogeneous signal abnormalities in the cortex and white matter, most prominent in the cerebral hemispheres and around the dentate nucleus. Gadolinium-enhanced T1-weighted images showed a multitude of enhancing foci, suggestive of perivascular enhancement. Based on MRI pattern with multiple lesions, perivascular enhancement and family history, fHLH was suspected. DNA analysis showed that the patient was compound-heterozygous for the c.445 G>A (p.Gly149Ser) mutation in exon 1 and the c.757 G>A (p.Glu253Lys) mutation in exon 2 of the perforin 1 gene. The patient was treated according to the international HLH-2004 protocol (dexamethasone, etoposide, cyclosporine, intrathecal methotrexate and prednisolone) followed by allogeneic cord blood transplantation. He showed a significant neurological and radiological improvement. The reported case demonstrates that MRI pattern recognition can lead to early diagnosis of fHLH, with subsequent adequate treatment.

Fetal origin of brain damage in 2 infants with a COL4A1 mutation: fetal and neonatal MRI

Mutations in the gene COL4A1, encoding collagen IV A1, are associated with familial porencephaly. Previously, COL4A1 mutation-associated antenatal hemorrhages have been suggested by early post-natal imaging. We describe 2 children with fetal intracerebral hemorrhages and a COL4A1 mutation. There was also extensive hemispheric tissue loss in both infants and loss of cerebellar tissue in one infant. This paper show prenatal evidence of fetal hemorrhage in association with a COL4A1 mutation.

Chronological changes of the amplitude-integrated EEG in a neonate with molybdenum cofactor deficiency

Molybdenum cofactor (Moco) deficiency is a rare neurometabolic disorder, characterized by neurological impairment and refractive seizures, due to toxic accumulation of sulfite in the brain. Earlier it was suggested that in Moco-deficient humans maternal clearance of neurotoxic metabolites prevents prenatal brain damage. However, limited data are available about the time profile in which neurophysiologic deterioration occurs after birth. The amplitude-integrated electroencephalography (aEEG) is a bedside method in neonates to monitor cerebral recovery after hypoxic-ischemic insults, detect epileptic activity, and evaluate antiepileptic drug treatment. We describe a chronological series of changes in aEEG tracings in a neonate with Moco deficiency. He presented with myoclonic spasms and hypertonicity a few hours after birth, however, the aEEG pattern was still normal. Within 2 days, the aEEG rapidly changed into a burst suppression pattern with repetitive seizures. After antiepileptic treatment, the aEEG remained abnormal. In this patient, the normal aEEG pattern at birth may have been due to maternal clearance of sulfite in utero. After birth, accumulation of sulfite causes progressive brain damage, reflected by the progressive depression of the aEEG tracings. This is in agreement with the results from a Moco-deficient mouse model, suggesting that maternal sulfite clearance suppresses prenatal brain damage. To our knowledge, this is the first case report describing the chronological changes in the aEEG pattern in a Moco-deficient patient. Insight into the time profile in which neurologic deterioration in Moco-deficient humans occurs is essential, especially when potential treatment strategies are being evaluated.

Effect of selective dorsal rhizotomy on gait in children with bilateral spastic paresis: kinematic and EMG-pattern changes

INTRODUCTION

Selective dorsal rhizotomy (SDR) is an effective treatment for reducing spasticity and improving gait in children with spastic cerebral palsy. Data concerning muscle activity changes after SDR treatment are limited.

PATIENTS AND METHODS

In 30 children who underwent SDR a gait analysis was performed before and 12-24 months postoperatively. Subjects walked on a 10-m walkway at comfortable walking speed. Biplanar video was registered and surface EMG was recorded. Sagittal knee angles were measured from video and observational gait assessments were performed using the Edinburgh gait assessment scale (EGAS).

RESULTS

The EGAS significantly improved after SDR (p<0.001). There were significant improvements of the knee angle kinematics (p<0.001). Only slight changes in EMG activity were observed. The activity of the m. gastrocnemius (GM) decreased and a late peak appeared in stance, the activity of the m. semitendinosus (ST) increased in stance. The activity of the m. rectus femoris (RF) decreased in swing.

CONCLUSION

SDR improved overall gait performance but EMG changes were only slight. Better timing of the GM in stance and reduced activity of RF in swing may have increased knee flexion in swing. Reduced hamstrings spasticity may have led to postural instability in the hip.

Quantitative MR imaging and spectroscopy in congenital cytomegalovirus infection and periventricular leukomalacia suggests a comparable neuropathological substrate of the cerebral white matter lesions

Congenital CYTOMEGALOVIRUS (CMV) infection and periventricular leukomalacia (PVL) both lead to static cerebral white matter lesions. In contrast to PVL, the neuropathologicAL substrate of these lesions in congenital CMV is not clear. By comparing changes in quantitative magnetic resonance (MR) parameters and MR spectroscopy metabolite concentrations we wanted to determine whether the nature of the white matter pathology in congenital CMV infection could be similar to the known pathology of PVL. Diffusion parameters, apparent diffusion coefficient (ADC) and fractional anisotropy (FA), magnetization transfer ratio (MTR) and MR spectroscopy concentrations were studied in white matter lesions in five patients with a congenital CMV infection and six patients with PVL. In both groups ADC values were increased, FA and MTR values were reduced, concentrations of total N-acetylaspartate and choline-containing compounds were reduced; and MYO-inositol concentrations were slightly increased. No differences were found between the two groups, suggesting that the pathology of the white matter lesions in congenital CMV infections is similar to that of PVL and also characterized by axonal losses, lack of myelin deposition due to oligodendrocytic losses, and astrogliosis. Congenital CMV infection and PVL affect the cerebral white matter in the same developmental period when immature oligodendrocytes are particularly vulnerable.

Prognostic factors after a first attack of inflammatory CNS demyelination in children

OBJECTIVE

To identify clinical, radiologic, or CSF factors that predict conversion to multiple sclerosis (MS) after a first attack of inflammatory demyelination in children.

METHODS

In this nationwide retrospective multicenter study in the Netherlands, 117 children below age 16 were included. Fifty-four children presented with a monofocal clinically isolated syndrome (CIS) and 63 children with a polyfocal CIS (PCIS).

RESULTS

A second MS-defining attack occurred in 43% of the CIS cases, compared to 21% of the patients with PCIS onset (p < 0.006). Basal ganglia and thalamic lesions and lesions larger than 2 cm on MRI (considered typical of ADEM) were observed during PCIS, irrespective of the presence of encephalopathy. No significant difference in developing MS was found in children with PCIS with or without encephalopathy. Elevated IgG index and presence of oligoclonal CSF bands were more often observed in children who developed MS. Both Barkhof and KIDMUS MRI criteria shared a high specificity and had a high positive predictive value for conversion to MS. In children under the age of 10, the Barkhof criteria had a higher sensitivity than the KIDMUS criteria, but still lower than in older children.

CONCLUSIONS

Barkhof and KIDMUS MRI criteria share a high specificity and positive prognostic value for conversion to multiple sclerosis (MS). Sensitivity of these criteria is poor, especially in children below 10 years of age. Basal ganglia lesions can occur in patients who later develop MS. A substantial number of patients presenting with polyfocal onset and no encephalopathy remained monophasic.

[Post-mortem MRI in newborns when autopsy is not permitted]

2 newborns, boys weighing 1400 and 950 g, died 2 and 8 hours after birth respectively. Autopsy was not permitted but MRI was possible. In the first newborn, characteristic abnormalities ofa Potter's sequence were found: pulmonary hypoplasia, missing kidneys and ureters and a rudimentary bladder. Clinically, a small chest, low-positioned ears, a flattened nose, a retracted chin, contractures of both knees and a talipes equinus of both feet had already been observed. In the second newborn, an MRI scan of the skull revealed a torn cerebellar tentorium with intracranial bleeding. The cause of death in newborns is often unknown. Autopsy is the gold standard for determining the cause of death. However for a variety of reasons, many parents do not give informed consent for autopsy. In such cases, post-mortem MRI may be an alternative. Abnormalities ofthe central nervous system, muscles and internal organs can usually be clearly visualized using MRI. However, the diagnosis of cardiac abnormalities using this technique is more difficult.

[Limping in toddlers due to disorders of the spine and spinal cord]

Limping is a frequent symptom during childhood and can be caused by a variety ofdiseases, the most common causes being trauma and infections of the bones or joints. The authors describe three cases of limping in toddlers caused by infrequent spinal diseases. The toddlers presented with limping without a preceding trauma. In the first patient, an 18-month-old girl, the limping was caused by spondylodiscitis. She recovered completely after antibiotics. The second patient, a 13-month-old boy, presented with limping caused by neuroblastoma with extensive bone metastasis. Despite chemotherapy and partial resection of the neuroblastoma, the boy did not survive. In the last patient, a 19-month-old girl, the limping was caused by an intraspinal intramedullary astrocytoma. She recovered after partial resection of the tumour. In young children presenting with limping, diagnoses involving the spine should also be considered because early intervention can influence the prognosis favourably.

Motor outcome at the age of one after perinatal hypoxic-ischemic encephalopathy

OBJECTIVE

The aim of this report is to describe the motor outcome in one year-old children who were born at full-term with perinatal hypoxic-ischemic encephalopathy (HIE). Relationships between motor ability tests and neurological examination at one year, and between these tests and neonatal brain magnetic resonance imaging (MRI) were investigated.

PARTICIPANTS AND METHODS

32 surviving children, born full-term with perinatal HIE, are included in this report. All children had a neonatal MRI. At one year, motor ability was assessed with the Alberta Infant Motor Scale and the Bayley Scales of Infant Development (2nd version). Neurological examinations included the neurological optimality score (NOS).

RESULTS

At one year, 14 children (44%) had normal motor ability, nine (28%) had mildly delayed, and nine had significantly delayed motor ability. The NOS ranged from 14.6-27 points. All children with normal motor ability had (near) optimal NOS, however, not all children with high NOS had normal motor ability. Eleven children (34%) had normal neonatal MRI; at one year, six of them had normal, and five had mildly delayed motor ability. Eight children with normal motor ability showed abnormalities on neonatal MRI.

CONCLUSION

Neonatal brain MRI does not predict motor outcome at one year. Motor ability tests and neurological examinations should be used in a complementary manner to describe outcome after HIE.

Neonatal seizure monitoring using non-linear EEG analysis

Birth asphyxia is a major concern in neonatal care. Epileptic seizures are associated with subsequent neurodevelopmental deficits. Eighty-five percent of these seizures remain subclinical and therefore an on-line monitoring device is needed. In an earlier study we showed that the synchronization likelihood was able to distinguish between neonatal EEG epochs with and without epileptic seizures. In this study we investigated whether the synchronization likelihood can be used in complete EEGs, without artifact removal. Twenty complete EEGs from 20 neonatal patients were studied. The synchronization likelihood was calculated and correlated with the visual scoring done by 3 experts. In addition, we determined the influence of seizure length on the likelihood of detection. Using the raw unfiltered EEG data we found a sensitivity of 65.9 % and a specificity of 89.8 % for the detection of seizure activity in each epoch. In addition, the seizure detection rate was 100 % when the seizures lasted for 100 seconds or more. The synchronization likelihood seems to be a useful tool in the automatic monitoring of epileptic seizures in infants on the neonatal ward. Due to the retrospective nature of our study, the consequences for clinical intervention cannot yet be determined and prospective studies are needed. Therefore, we will conduct a prospective study on the neonatal intensive care unit with a recently developed on-line version of the synchronization likelihood analysis.

Predictive value of EEG in neonates with periventricular leukomalacia

The aim of this study was to evaluate whether EEG (i.e. positive Rolandic sharp waves) can be used to predict neurodevelopment in newborn infants with periventricular leukomalacia and compare the predictive value with that of MRI. A sequential cohort of neonates (n=45; 33 males, 12 females; mean gestational age 31.2 weeks, SD 2.7, range 27 to 37.8 weeks; mean birthweight 1592 g, SD 601 g) with periventricular hyperechogenicities on cranial ultrasound was recruited for this study. EEGs were analyzed for positive Rolandic sharp waves. Neurodevelopment was evaluated at the ages of 12 and 18 months. In the whole group the probability of a poor outcome was 24% and the probability of any impairment was 33%. If the number of positive Rolandic sharp waves was no more than 0.1 per minute, the probability of a poor outcome was reduced to 9% (95% confidence interval [95%CI] 2 to 27%) and the probability of any impairment was reduced to 13% (95%CI 4 to 32%). In all infants with more than 0.1 positive Rolandic sharp waves per minute the probability of a poor outcome was 41% (95%CI 23 to 61%) and of any impairment was 55% (95%CI 34 to 73%). In these infants MRI identified infants with a poor outcome with a sensitivity of 1.00 (95%CI 0.70 to 1.00) and a specificity of 0.92 (95%CI 0.67 to 0.99), and infants with any impairment with a sensitivity of 0.83 (95%CI 0.55 to 0.95) and a specificity of 1.00 (95%CI 0.72 to 1.00). Results suggest that if an EEG of an infant with periventricular leukomalacia contains no more than 0.1 positive Rolandic sharp waves per minute the probability of a normal or mildly delayed development is high (0.91, 95%CI 0.73 to 0.98). MRI enhances the accuracy of the outcome prediction slightly; however, owing to a wide confidence interval, this advantage is negligible. However, if the frequency of the positive Rolandic sharp waves exceeds 0.1per minute, MRI can significantly enhance the precision of the prediction of outcome.

Diffusion-weighted MRI in severe neonatal hypoxic ischaemia: the white cerebrum

Presently, prognosis of infants with perinatal hypoxia-ischaemia is estimated using the Sarnat scale, which combines clinical evaluation and electroencephalography, in combination with magnetic resonance imaging (MRI) and or evoked potentials. While the value of conventional MRI is limited during the first week of life, diffusion-weighted MRI demonstrates effects of acute cerebral ischaemia within hours of onset. However, the exact value of diffusion MRI in the prognosis of infants with hypoxia-ischaemia has to be established in larger follow-up studies. In this report we describe 5 term (post-conceptional age 40 1/7 to 41 2/7 week) neonates with severe hypoxia-ischaemia and a characteristic pattern of diffusion changes. T 1 -weighted images showed a hyperintense cortical signal in only one case and extensive hyperintensity in the basal nuclei in all 5 cases. T 2 -weighted images showed nearly complete loss of cortical delineation in three cases. Increased signal on diffusion-weighted images was seen throughout all cortical and subcortical areas while the cerebellum remained normal. This pattern, which we refer to as the "white cerebrum", is most readily apparent on coronal images. The apparent diffusion coefficient (ADC) was calculated and compared to that of four control infants. In the cortex ADC values were lowered (0.70 +/- 0.17 micro m 2/msec [mean +/- standard deviation (SD)]; controls [n = 4]: 1.18 +/- 0.02 micro m 2/msec) as compared to values of ADC in the cerebellum (1.31 +/- 0.06 micro m 2/msec [mean +/- SD]; controls [n = 4]: 1.25 +/- 0.06 micro m 2/msec). All infants died in the perinatal period. In summary, the "white cerebrum" on diffusion-weighted MRI indicates severe neonatal hypoxia-ischaemia and is the counterpart of the white cerebellum on CT.

Visual rating of age-related white matter changes on magnetic resonance imaging: scale comparison, interrater agreement, and correlations with quantitative measurements

BACKGROUND AND PURPOSE

To provide further insight into the MRI assessment of age-related white matter changes (ARWMCs) with visual rating scales, 3 raters with different levels of experience tested the interrater agreement and comparability of 3 widely used rating scales in a cross-sectional and follow-up setting. Furthermore, the correlation between visual ratings and quantitative volumetric measurement was assessed.

METHODS

Three raters from different sites using 3 established rating scales (Manolio, Fazekas and Schmidt, Scheltens) evaluated 74 baseline and follow-up scans from 5 European centers. One investigator also rated baseline scans in a set of 255 participants of the Austrian Stroke Prevention Study (ASPS) and measured the volume of ARWMCs.

RESULTS

The interrater agreement for the baseline investigation was fair to good for all scales (kappa values, 0.59 to 0.78). On the follow-up scans, all 3 raters depicted significant ARWMC progression; however, the direct interrater agreement for this task was poor (kappa, 0.19 to 0.39). Comparison of the interrater reliability between the 3 scales revealed a statistical significant difference between the scale of Manolio and that of Fazekas and Schmidt for the baseline investigation (z value, -2.9676; P=0.003), demonstrating better interrater agreement for the Fazekas and Schmidt scale. The rating results obtained with all 3 scales were highly correlated with each other (Spearman rank correlation, 0.712 to 0.806; P< or =0.01), and there was significant agreement between all 3 visual rating scales and the quantitative volumetric measurement of ARWMC (Kendall W, 0.37, 0.48, and 0.57; P<0.001).

CONCLUSIONS

Our data demonstrate that the 3 rating scales studied reflect the actual volume of ARWMCs well. The 2 scales that provide more detailed information on ARWMCs seemed preferential compared with the 1 that yields more global information. The visual assessment of ARWMC progression remains problematic and may require modifications or extensions of existing rating scales.

Clinical pharmacokinetics of phenobarbital in neonates

Demographic and clinical pharmacokinetic data collected from term and preterm neonates who were treated with intravenous phenobarbital have been analysed to evaluate the role of patient characteristics in pharmacokinetic parameters. Significant relationships between total body weight (TBW) or body surface area (BSA) and volume of distribution (Vd) and total body clearance (CL) were found. Coefficients of determination were: 0.55 and 0.59 for Vd, and 0.76 and 0.72 for CL against TBW and BSA, respectively. In addition, significant relationships between height of the infants and volume of distribution of phenobarbital and total body clearance were observed. Coefficients of determination were 0.58 for Vd and 0.56 for CL. A weaker but significant correlation existed between gestational age and Vd or CL of phenobarbital. Coefficients of determination were 0.43 and 0.64, respectively. There was no correlation between volume of distribution per kg body weight or total body clearance per kg body weight and any patient parameter investigated. However, these latter pharmacokinetic parameters tended to decrease with increasing gestational age and height of the neonates. The results obtained were used to develop new loading and maintenance doses for phenobarbital in neonates based on total body weight and body surface area and based on height and gestational age for cases that weight is not available.

The validity of the pretreated, unilaterally MPTP-treated monkeys as a model of Parkinson's disease: a detailed behavioural analysis of the therapeutic and undesired effects of the D2 agonist quinpirole and the D1 agonist SKF 81297

The goal of this study was to evaluate the validity of the pretreated, unilaterally MPTP-treated monkey as an animal model of Parkinson's disease (PD). For that purpose, a detailed ethogram was developed and assessed in four male rhesus monkeys that had received MPTP (2.5 mg) in the carotid artery contralateral to the dominant limb. Subsequently, the behavioural effects of the dopamine D2 agonist quinpirole and the dopamine D1 agonist SKF 81297 were studied. The ethogram was found to allow a clear-cut and objective separation of drug-induced behaviours into therapeutic and undesired effects in the MPTP-treated monkeys. Saline-treated monkeys predominantly displayed ipsilateral goal-directed fore-limb movements, and distinct types of ipsilaterally directed rotations. Although quinpirole and SKF 81297 increased motor behaviours, such as body displacement, contralateral fore-limb movements and contralateral rotational behaviours, assessment of the new detailed ethogram revealed that this increase was completely due to the activation of abnormal, non-goal-directed behaviours, such as dyskinetic fore-limb movements, pivoting and shuffling. Moreover, the new ethogram made clear that the drug treatments induced not only dyskinesia and dystonia, but also epileptoid behaviour, which was confirmed by EEG analysis. In summary, the detailed behavioural analysis showed that this model does not adequately predict the clinical effects of the D2 agonist. It is concluded that the pretreated, unilaterally MPTP-treated monkey is not a valid model to predict the therapeutic and undesired effects of dopaminergic drugs in humans.

[123I]FP-CIT binds to the dopamine transporter as assessed by biodistribution studies in rats and SPECT studies in MPTP-lesioned monkeys

[123I]FP-CIT (N-omega-fluoropropyl-2 beta-carbomethoxy-3 beta-(4-iodophenyl)-tropane), a radioiodinated cocaine analogue, was evaluated as an agent for the in vivo labeling of dopamine (DA) transporters by biodistribution studies in rats and by single photon emission computed tomography (SPECT) studies in unilateral 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned monkeys. In rats, intravenous injection of [123I]FP-CIT resulted in high accumulation of radioactivity in the striatum. Less pronounced uptake was seen in brain areas with high densities of serotonergic uptake sites. While striatal uptake of radioactivity after injection of [123I]FP-CIT was displaced significantly by GBR12,909 but not by fluvoxamine, the opposite was observed in brain areas known to be rich of serotonin transporters. Monkeys which were unilaterally treated with neurotoxic doses of MPTP showed severe loss of striatal [123I]FP-CIT uptake at the side of treatment. The results of this study indicate that [123I]FP-CIT, although not being a selective radioligand, binds specifically to the striatal DA transporter in vivo and thus suggest that [123I]FP-CIT promises to be a suitable radioligand for SPECT imaging of DA transporters in humans.

In vitro and in vivo characterization of newly developed iodinated 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]piperazine derivatives in rats: limited value as dopamine transporter SPECT ligands

A series of 1-{2-[bis(4-fluorophenyl)methoxy]ethyl}piperazines (CYD1, 2, 3, 5) with a 4-substituent incorporating a 1-hydroxy-3-iodo-2-propenyl moiety, except CYD2 which lacks the hydroxy, was synthesized as potential in vivo imaging ligands for the dopamine transporter. For two of the piperazine derivatives (CYD3 and 5), possible stereoselectivity was considered as well (both E- and Z-form). Their in vitro potency for inhibition of [3H]dopamine uptake in rat striatal synaptosomes was 10-fold lower than that of GBR 12,909 used as a reference. The highest Ki values were 137 and 101 nM for CYD1E and CYD3E, respectively. Inhibition potency was higher for the E- than for the Z-isomers. In vivo distribution of radioactivity in rats injected with the 123I-labeled CYDs showed preferred striatal uptake for CYD1E and CYD3E as compared to the cerebellum and occipital cortex. Although the E-isomer of CYD3 showed the best in vitro and in vivo binding characteristics, its striatal uptake ratios (maximal value: 2.7 for striatum-to-cerebellum at 4 h p.i.) are too low to consider application in human Single Photon Emission Computed Tomography studies.

Evaluation of [123I] beta-CIT binding with SPECT in controls, early and late Parkinson's disease

The main neuropathological feature in Parkinson's disease (PD) is a severe degeneration of the dopaminergic neurons in the substantia nigra resulting in a loss of dopamine in the striatum. Recently, a new radioligand (beta-CIT) for single photon emission computed tomography (SPECT) became available for in vivo imaging of the dopamine transporter on nerve endings of dopaminergic neurons in the striatum. The present results demonstrate that [123I]-beta-CIT SPECT allows a discrimination between early and late PD patients. In our opinion, these preliminary data suggest that [123I]-beta-CIT SPECT should be used from now on in longitudinal studies (such as the DATATOP study) in which the effects of (putative) neuroprotective interventions in PD are monitored.

Morphine and naltrexone modulate D2 but not D1 receptor induced motor behavior in MPTP-lesioned monkeys

Interactions at the behavioral level between dopamine (DA) and opioid receptors in the mammalian brain have been amply demonstrated. Considering the pivotal role for DA receptors in the pharmacotherapy of Parkinson's disease (PD), these interactions might be clinically relevant. Therefore, in the present study the effects of the opioid antagonist naltrexone and agonist morphine on D1 and D2 receptor induced stimulation of motor behavior in the unilateral MPTP monkey model (n = 5) of PD were investigated. The results show that both naltrexone and morphine [0.1-1.0 mg/kg; intramuscular injection (IM)] inhibited D2 receptor stimulated contralateral rotational behavior and hand use induced by administration of quinpirole (LY 171555; 0.01 mg/kg, IM) in a dose-related way. However, no effects of these opioid drugs were observed on D1 receptor stimulated contralateral rotational behavior and hand use induced by administration of SKF 81297 (0.3 mg/kg, IM). Interestingly, the action of the alleged preferential mu-receptor antagonist naltrexone was mimicked by the selective delta-opioid antagonist naltrindole (0.5 mg/kg, IM). From this study it is concluded that in a non-human primate model of PD, alteration of opioid tonus leads to modulation of D2 receptor but not D1 receptor controlled motor behavior. The possible underlying mechanisms and clinical relevance of these findings are discussed.

The dopamine D1 agonist SKF 81297 and the dopamine D2 agonist LY 171555 act synergistically to stimulate motor behavior of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned parkinsonian rhesus monkeys

At present, the pharmacotherapy of Parkinson's disease (PD) consists mainly of L-dihydroxyphenylalanine (L-DOPA) and/or dopamine D2 receptor agonists. However, in general the clinical efficacy of D2 agonists is less than that of L-DOPA. Therefore, attention is being focussed on the role of the D1 receptor as a target for therapeutic intervention in PD. Recently, we reported that SKF 81297 is a selective D1 agonist that stimulates motor behavior of unilaterally MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-lesioned rhesus monkeys. Presently, we studied the effect of coadministration of SKF 81297 and the D2 agonist LY 171555 using the same model of PD. Coadministration of behaviorally active doses of SKF 81297 (0.3 mg/kg) and LY 171555 (0.01 mg/kg) resulted in a prolongation of the motor stimulation induced by either of the drugs alone. Neither administration of SKF 81297, in a dose of 0.03 mg/kg, nor of LY 171555, in a dose of 0.003 mg/kg, were behaviorally active, whereas the combined administration of these compounds induced a significant stimulation of motor behavior. These data suggest that (a) D1 receptor stimulation will prove to be useful in the treatment of PD and (b) better therapeutic results will be obtained by simultaneous stimulation of D1 and D2 receptors as compared with stimulation of both receptors alone.

Dopamine D1 receptor agonists display a different intrinsic activity in rat, monkey and human astrocytes

Measuring dopamine D1 receptor stimulated cyclic AMP production in cultured astrocytes from rat, monkey and human brain, we demonstrate that the 'classical' drug SKF 38393 (7,8-dihydroxy-1- phenyl-2,3,4,5-tetrahydro-1 H-3-benzazepine) is a partial agonist with particularly low intrinsic activity in primates. Furthermore, its analogue SKF 81297 (6-chloro-7,8-dihydroxy-1-phenyl-2,3,4,5- tetrahydro-1 H-3-benzazepine) is shown to be a full agonist in rats but a partial, albeit more efficacious, agonist in primates, whereas the benzopyran A 68930 ((1R,3S)-1-aminomethyl-5,6- dihydroxy-3-phenyl-isochroman HCl) displays full efficacy in both species. The data suggest that cultured astrocytes provide a good model to study species differences in the pharmacological characteristics of dopamine D1 receptor agonists and indicate that SKF 38393 is not suited to study dopamine D1 receptor function in primates.

No direct correlation between behaviorally active doses of the dopamine D2 agonist LY 171555 and displacement of [123I]IBZM as measured with SPECT in MPTP monkeys

Almost no information is available concerning the link between clinical effects of dopamine D2 receptor agonists in the treatment of Parkinson's disease (PD) and the extent of D2 receptor occupancy in the brain. Therefore, we investigated the possible correlation between administration of behaviorally active doses of the selective D2 agonist LY 171555 and in vivo D2 receptor occupancy in the unilateral 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-lesioned rhesus monkey model of PD. Single photon emission computed tomography (SPECT) with the D2 receptor antagonist [123I]IBZM (iodobenzamide) as radioligand was used to estimate the receptor occupancy. The MPTP-lesioned monkeys consistently showed signs of unilateral parkinsonism. LY 171555 (0.01 or 0.3 mg/kg) significantly increased contralateral rotation (away from the lesion), being most effective at the lower dose. In the MPTP-lesioned monkeys [123I]IBZM activity in the left (lesioned) striatum was significantly higher as compared to that in the right striatum. Only upon administration of 0.3 mg/kg LY 171555 a significant amount of receptor occupancy by LY 171555, as measured with [123I]IBZM SPECT, at both lesioned and non-lesioned side, was detected. Using D2 receptor mediated inhibition of the evoked release of [3H]acetylcholine from rat striatal tissue as a functional model, we showed that the lack of effect with 0.01 mg/kg LY 171555 was not due to non-competitive interaction between LY 171555 and IBZM at the D2 receptor. We conclude that the D2 antagonist [123I]IBZM is not a suitable SPECT ligand to study the relationship between behavioral effects of the selective D2 agonist LY 171555 in unilaterally MPTP-lesioned monkeys and the D2 receptor occupancy in vivo in this animal model of PD.

The selective dopamine D1 receptor agonist, SKF 81297, stimulates motor behaviour of MPTP-lesioned monkeys

The alleged selective, high efficacy dopamine D1 receptor agonist, SKF 81297 (0.05-0.3 mg/kg i.m.), induced rotational behaviour away from the lesion and stimulated use of the dominant right hand in unilaterally (left side) 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned rhesus monkeys (Macaca mulatta). The effects of SKF 81297 were completely blocked by the dopamine D1 receptor antagonist, SCH 23390 (0.05 mg/kg), but not by the dopamine D2 receptor antagonist, remoxipride (1 mg/kg), and were similar to those induced by the selective dopamine D2 agonist, LY 171555 (0.01 mg/kg). These results suggest a functional stimulatory role for the dopamine D1 receptor on motor behaviour in a non-human primate model of Parkinson's disease when stimulated with a high efficacy selective dopamine D1 receptor agonist.