HLA-DR antigens in Kleine-Levin syndrome.
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Adolescent↗
Biomedical subjects
L M Smit
Publications and source records attributed to L M Smit.
A new case of dihydropyrimidine dehydrogenase deficiency.
We present the clinical and biochemical features of a boy with dihydropyrimidine dehydrogenase deficiency, which seem to underline a disease entity of developmental retardation, epilepsy and muscular hypertonia.
Brain↗
The first adult case with 4-hydroxybutyric aciduria.
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Adult↗
A new case of hyperargininaemia: neurological and biochemical findings prior to and during dietary treatment.
We present clinical and biochemical data on a further patient with hyperargininaemia and the results of neurophysiological tests both before and during dietary treatment with an essential amino acid mixture. With normalisation of plasma arginine concentrations, neurological functions improved and brain stem auditory evoked potentials normalized suggesting a partially reversible central conduction disorder. Neuroradiological findings included cerebral cortical atrophy on computed tomography scan and patchy abnormal myelination on magnetic resonance imaging (MRI). The typical clinical picture is discussed with reference to published therapeutical trials.
Amino Acid Metabolism, Inborn Errors↗
Morphological changes in the human end plate with age.
We carried out a light and electron microscopic study on end plates and related structures in external intercostal muscles from subjects aged between 4 and 77 years. Light microscopically end plates maintained the same size, did not increase in number and showed no sprouting of terminal axons, all indicating that major compensatory histological changes to maintain adequate neuromuscular transmission with age were not required. At the ultrastructural level end plates became more complex mainly at the postsynaptic side. The latter included increased length and branching of the postsynaptic membrane with enlargement of the postsynaptic area, and degeneration of junctional folds. However, some neuromuscular junctions (NMJs) showed little branching of the postsynaptic membrane, even in old age. At the presynaptic side nerve terminals with an irregular shape were noted in the aged. Schwann cell processes were seen to intrude into the primary synaptic cleft. From these data we suggest that degeneration of the postsynaptic membrane with consequent focal denervation of NMJs is a primary event in the age-related changes of end plates. The muscle fibres showed a minor degree of type grouping in old age doubtless due to loss of motor neurons with age.
Adult↗
Moyamoya disease associated with renovascular hypertension.
This is a report of a case history of a child with cerebral Moyamoya disease and gradual development of systemic hypertension. Sodium depletion combined with enalapril induced renal failure. A bilateral renal artery stenosis was found. Percutaneous transluminal angioplasty was not successful and was followed by autotransplantation of both kidneys. Histopathological examination of the renal arteries revealed intimal hyperplasia.
Arterial Occlusive Diseases↗
Acute hemiparesis as the presenting sign in a heterozygote for ornithine transcarbamylase deficiency.
Strokes in children occur in conjunction with cardiac disease, hematological disorders, trauma, intracranial infections and migraine. Recently several inborn errors of metabolism have been recognized as possible causes of stroke-like symptoms. We describe a female heterozygote of ornithine transcarbamylase deficiency, who presented with convulsions and right sided hemiplegia. MR-imaging of the brain demonstrated an acute ischemic lesion in the left hemisphere. In addition to other known metabolic causes of stroke like attacks urea cycle defects should be considered in the differential diagnosis of acute hemiplegia in childhood.
Amino Acid Metabolism, Inborn Errors↗
[The Kleine-Levin syndrome].
Two boys, aged 12 and 13 years, showed relapsing periods of somnolence and excessive eating, starting after a viral illness. One of them also showed periodic disturbance of sexual impulse control. The symptomatic periods were followed by symptom-free intervals in a highly characteristic pattern. This gave the clue to the diagnosis Kleine-Levin syndrome. The cause of this syndrome is unknown, in some cases a relationship between infectious disease or traumatic brain damage has been postulated. A dysfunction of the hypothalamus and associated structures is suspected. The syndrome has a rather favourable prognosis. The symptoms can be relieved by amphetamines, methylphenidate and probably also by lithium carbonate.
Adolescent↗
[Spinal muscular atrophy in young infants].
Two congenital anterior horn cell diseases may be responsible for neonatal muscular atrophy. The acute Werdnig-Hoffmann disease (SMA-I) has a progressive course, the anterior horn cell degeneration (AHCD) is non progressive in the postnatal period. In case of Werdnig-Hoffmann disease symptoms of hypotonia and muscle weakness may be present at birth, but become progressive during the first months of live. The full clinical picture of AHCD is present at birth. In the latter clinical symptoms of fetal hypokinesia may be noticed during intrauterine life. Histopathological muscle investigation reveals a more or less characteristic neurogenic pattern in Werdnig-Hoffmann disease, in AHCD neurogenic and myopathic changes are variable. Two examples of these diseases will be discussed.
Arthrogryposis↗
[Infectious sinus thrombosis in children].
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Child↗
A myasthenic syndrome with congenital paucity of secondary synaptic clefts: CPSC syndrome.
Two cases of a newly recognized myasthenic syndrome were investigated (CPSC syndrome). The course of the disease was observed for periods of 6 and 3 years. In infancy, exacerbations of the symptoms occurred during febrile illness, but thereafter the clinical course was stable and the children appeared to be only slightly handicapped. Biopsies were taken from the intercostal muscle in both patients. Microelectrode studies revealed small Mepp amplitudes. Light microscopy demonstrated predominance of type I fibers and focal type-grouping. There was a lowered cholinesterase activity and frequent branching of preterminal axons. Electron microscopy revealed that there were few, if any, folds of the postsynaptic membrane and that there were no signs of degeneration. Methods for localization of acetylcholine receptors (AChR) revealed a deficiency and altered distribution of AChRs at these postsynaptic membranes and the occurrence of extrajunctional AChRs in some muscle fibers. It is concluded that the syndrome is a clinicopathological entity, characterized morphologically by a congenital paucity of secondary synaptic clefts (CPSC syndrome).
Child↗
Karyotyping urine sediment cells confirms trisomy 12 mosaicism detected at amniocentesis.
A newborn is described in whom trisomy 12 mosaicism was detected prenatally at third trimester amniocentesis during the fourth pregnancy of a 34-year-old woman. After birth, trisomy 12 cells were found in placental tissue and in cultured urine sediment cells. A sample of cord blood and a skin biopsy revealed only normal (46,XX) cells. Both parents had a normal karyotype. After a difficult start with unexplained hypoglycaemias and convulsion equivalents, the girl is doing well at the age of 9 months: there are no signs of central motor disturbance. The importance of the use of cultured urine sediment cells in confirming chromosomal mosaicism is stressed.
Adult↗
Junctional plasticity in hereditary myasthenia.
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Humans↗
A congenital myasthenic disorder with paucity of secondary synaptic clefts: deficiency and altered distribution of acetylcholine receptors.
Congenital myasthenia (CM) constitutes a heterogeneous group of disorders with different underlying defects. The authors investigated a case of CM, presenting with congenital contractures. Endplate studies in the first year of life showed a developmental disorder of postsynaptic membranes. Clinical follow-up demonstrated a beneficial effect of pyridostigmine, resulting in normal motor development. Results of a second biopsy at age 4 are reported in this paper. Microelectrode study showed small Mepp amplitudes, which returned to nearly normal in the presence of neostigmine. In the electronmicroscope the postsynaptic membranes showed a paucity of infoldings, as in the first biopsy. These membranes showed only scanty, patchy enhancement with two different methods for localization of AChR. The extrajunctional membranes showed evidence of local presence of AChR. Our results show a developmental disorder of postsynaptic membranes with a deficiency and altered distribution of AChRs.
Biopsy↗
Immunohistochemical localization of acetylcholine receptors at human endplates using a monoclonal antibody.
We describe a simple indirect immunohistochemical method for localization of acetylcholine receptors (AChR) in motor endplates at the light and electron microscopic level. This method involves the use of a monoclonal antibody directed against the main immunogenic region (MIR) of AChRs and is applicable to periodate-lysine-paraformaldehyde (PLP)-fixed tissue. We discuss the advantages of this method, as compared with the alpha-bungarotoxin-immunoperoxidase technique, and stress its value for diagnostic investigations of motor point biopsies from patients with neuromuscular transmission disorders.
Adolescent↗
Progressive dystonia with marked diurnal fluctuation. Report of a case.
A 9-year-old girl suffering from progressive fluctuating dystonia is reported. Some problems of diagnosis are discussed. The differential diagnosis is described and a comparison is made with cases from the literature.
Carbidopa↗
Familial porencephalic white matter disease in two generations.
We report the pedigree of a family in which a mother and her two children, a boy and a girl, all suffer from a similar, though variably expressed cerebral disorder, seen on CT as uni- or bilateral cavities within the supratentorial white matter in communication with the ventricular system. Additional white matter hypodensity around the lateral ventricles without ventricular widening provides preliminary evidence of a primary disease of myelination, in the absence of histopathological confirmation. This is probably the first report of "porencephaly" which shows a pattern of autosomal dominant inheritance.
Adult↗
Paucity of secondary synaptic clefts in a case of congenital myasthenia with multiple contractures: ultrastructural morphology of a developmental disorder.
A new form of congenital myasthenia is described. An infant whose foetal movements during pregnancy had been weak presented at birth with muscle weakness and multiple contractures of the lower limbs. The clinical course was characterised by myasthenic crises during febrile illnesses. Neurophysiological studies demonstrated a decremental response at 2-3 HZ stimulation; this effect was reversed by edrophonium iv. At the age of eight months, a biopsy from the soleus muscle showed a predominance of type I fibres and variation in fibre diameters was slightly increased. Ultrastructural studies of the motor endplates revealed a marked reduction of post-synaptic membrane lengths with paucity of secondary clefts. Signs of focal degeneration were absent. The picture was reminiscent of foetal neuromuscular junctions. A developmental disorder of the postsynaptic membrane was considered to be the basic cause of the neuromuscular transmission defect.
Axons↗