Biomedical subjects
Publications and source records attributed to M Nork.
This report describes a patient with intracranial Aspergillus flavus infection in whom it was impossible to remove the fungal mass surgically. Progressive fungal infiltration of the optic nerves was reversed and the extensive intracranial fungal burden was managed successfully with combination antifungal-immunomodulatory therapy alone.
PURPOSE: To report features of mycetomas (actino- and eumycetoma infection), which belong to the so-called rare bone infections, as evaluated by MR and other imaging methods and to assess chemotherapy treatment. MATERIAL AND METHODS: Twenty patients (average age 57 years) were diagnosed by different modalities. Analyses of 57 plain films, 31 three-phase bone scans, 28 CT and 35 MR examinations were performed. The MR protocol included T1-weighting without and with contrast, T2-weighted, proton density and fat suppressing sequences. RESULTS: Signs of chronic osteomyelitis were seen in plain films of 10 patients (50%), but the healing process was difficult to assess. Bone scintigraphy was positive in 12 patients (60%). In 14 patients (70%), CT could demonstrate bone lesions, but the healing process was difficult to estimate in 4 patients. MR imaging provided accurate diagnostic information in 15 cases (75%). In 16 patients (80%), small lesions could be identified due to grains, which seemed to differentiate mycetoma from other infections and tumorous lesions. MR examination gave definitive answer about the healing process in 18 cases (90%). CONCLUSION: MR investigation was superior to the other imaging techniques in the evaluation of mycetoma and the assessment of therapy.
Two patients with bilateral frontoparietal polymicrogyria are reported. Severe developmental delay, mental retardation, spastic tetraplegia, and seizures were the main clinical features. Magnetic resonance imaging revealed a bilateral thick cortex with irregular gyri and a festoonlike gray-white matter junction. Bilateral frontoparietal polymicrogyria may represent a further form of the bilateral polymicrogyria syndromes in addition to perisylvian and parasagittal parieto-occipital polymicrogyria.
The case of a Yemeni girl with isolated peroxisomal acyl-CoA:dihydroxyacetonephosphate acyltransferase (DHAPAT) deficiency is reported. She had rhizomelic chondrodysplasia punctata, microcephaly, failure to thrive, delayed motor and mental development, and spastic quadriplegia. Deficient de novo plasmalogen synthesis in her fibroblasts as a result of low DHAPAT activity was found, while her very-long-chain fatty acid profile, phytanic acid concentration, alkyl-dihydroxyacetonephosphate synthase (alkyl-DHAP synthase) activity, and peroxisomal 3-ketoacyl-CoA thiolase protein were normal. A mutation in her DHAPAT complementary DNA resulted in the substitution of an arginine residue in the protein at position 211 by a histidine (R211H). Magnetic resonance imaging showed abnormal white matter signal in the centrum semiovale involving the arcuate fibers, while the corpus callosum was normal. DHAPAT and alkyl-DHAP synthase initiate the synthesis of plasmalogens, which are major constituents of myelin phospholipids. The reported girl's abnormal formation of myelin is probably related to the inadequacy of plasmalogen biosynthesis, which is likely to be due to deficient DHAPAT activity.
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Corpus callosum agenesis, retardation, adducted thumbs, spastic paraparesis, and hydrocephalus (CRASH syndrome) is an X-linked recessive disorder caused by mutations in the neuronal cell adhesion molecule L1 (LICAM) gene. L1 plays a key role in axon outgrowth and pathfinding during the development of the nervous system. We describe the case of a boy from the United Arab Emirates who presented with CRASH syndrome. Scanning the L1 gene of the patient resulted in the discovery of a novel missense mutation: transition of a G (guanine) to T (thymine) at position 604 (G604-->T), which results in conversion of aspartic acid to tyrosine at position 202 (D202Y) of the L1 protein. It is very likely that the cerebral dysgenesis is due to the abnormal structure and function of L1.
The authors report on seven patients, six males and one female, with Joubert's syndrome who underwent developmental evaluation, neurologic and ophthalmologic examinations, and magnetic resonance imaging of the brain. All patients had severe developmental delay, hypotonia, impairment of smooth visual pursuit, and saccadic eye movements. Six had jerky eye movements and ptosis was observed in two patients and retinal dystrophy in one. The posterior lobe of the vermis was absent in all patients and the small rudimentary anterior lobe lacked fusion in the midline, with cleft formation in five patients. Malformation of the pontomesencephalic junction, with prominent superior cerebellar peduncles and deep interpeduncular fossa, was observed in all patients. Abnormal cerebellar-brainstem and cerebellocortical connections because of the lack of the posterior vermis and dysplasia of the deep cerebellar nuclei might be responsible for the abnormal eye movements and retarded development in Joubert's syndrome. Correlation between radiologic findings and clinical symptoms and the possible role of abnormal patterning of the midbrain-hindbrain by homeotic genes during embryonic development are reviewed.
The clinical courses, neuroimaging and muscle biopsy findings of two infants born to an inbred Arab family are described. They had a syndrome of micrencephaly with simplified gyral pattern, abnormal myelin formation and arthrogryposis. Increased variation of fiber size was seen in the muscle biopsy, creatine kinase, however was normal. Large areas of muscle were replaced by adipofibrous tissue. The infants had dysmorphic features consistent with the fetal akinesia/hypokinesia sequence. The abnormalities were suggestive of microlissencephaly probably associated with a dysgenetic process in the muscles. The syndrome showed an autosomal recessive inheritance.
We report two sibs with features overlapping those of orofaciodigital syndrome type VI (Varadi syndrome). Both presented at birth with oculomotor abnormalities, dysmorphic facial features, and dysgenesis of the cerebellar vermis. There were minimal oral manifestations (high arched palate) in both of them and one had postaxial polydactyly of both hands and one foot. In addition, there was evidence of aplasia of the pituitary gland on MRI scan in both of them with evidence of hypopituitarism. Both responded well to hormone replacement therapy with improvement in their linear growth and mental ability. These cases may represent a new autosomal recessive midline defect syndrome with features overlapping OFDS VI. Alternatively the features in these children could represent variability within OFDS VI.
An inbred Arab family with three neonates affected by microlissencephaly syndrome is reported. Brain magnetic resonance imaging in the index case revealed very thin brain mantle with agyria-pachygyria, agenesis of the corpus callosum, and hypoplasia of the brainstem and cerebellum. All three neonates had microcephaly, arthrogryposis multiplex congenita, and micropenis. The presence of three affected newborn infants in a consanguineous family suggests an autosomal-recessive mode of inheritance of this syndrome. The spectrum of microlissencephaly syndrome is reviewed.
An infant is described who had a combination of lobar holoprosencephaly and open-lip schizencephaly. Midline fusion of the basal ganglia was associated with bilateral absence of abundant parts of the brain mantle. Agenesis of the corpus callosum, hypoplasia of the optic nerves and chiasm, absence of the septum pellucidum, posterior pituitary and olfactory bulbs were further components of the malformation. Blindness, intractable seizures, spastic tetraplegia, somatomental retardation and diabetes insipidus were the main clinical features. A defect in the induction of the mediobasal part of the prosencephalon and failure of cell proliferation can be responsible for this complex malformation. Recent results of homeobox gene research relevant to the development of the prosencephalon are discussed.
Cerebral perfusion was investigated in three patients with agyria-pachygyria by using 99mTc-HMPAO SPECT in order to study the distribution of blood flow. Diffuse cortical hypoperfusion was found in all three infants. The visual cortex was not identifiable in two of the cases. The basal ganglia and cerebellum were prominent by their normal high activity, while tracer uptake was very low in the thalamus. The possible role of improper development of interneuronal connections and abnormal vascular pattern in background of the perfusion defect is discussed.
Nevo syndrome is an autosomal recessive syndrome characterised by prenatal overgrowth, joint laxity, kyphosis, wrist drop, spindle shaped fingers, and volar oedema. Four children from two families have been reported previously. We report two further children from two unrelated Arab families from two different tribes. Both presented at birth with hypotonia, joint laxity, kyphosis, wrist drop, spindle shaped fingers, and volar oedema. Both have delayed motor development at the ages of 2 years 10 months and 3 months respectively. Cognitive development is normal in one, and the other case appears to be developing normally at 3 months of age. One has, in addition, a wide spinal canal on MRI of the spine indicating some degree of dural ectasia. This report brings the total number of children reported with this syndrome to six from four families; three of these families are Arab. This indicates that the gene for this syndrome is probably commoner in Arabs than in other populations.
Fourteen children with spastic hemiplegia of various etiology: cerebral palsy (seven cases, five with porencephalic cyst); stroke with small deep infarcts (two); hemiconvulsion-hemiplegia-epilepsy syndrome (three); traumatic brain injury (two), were investigated by 99mTc-HMPAO SPECT. Localized and remote perfusion abnormalities were studied. Hypoperfusion corresponding to CT abnormalities was found in each group, but the perfusion deficit extended beyond the boundaries of anatomical defects, most prominently in cases with widespread unilateral epileptic discharges. Ipsilateral cerebellar diaschisis was observed in patients with early cerebral insult (who had porencephalic cyst of pre- or perinatal onset) and crossed cerebellar diaschisis was noted in a patient who sustained traumatic brain injury at a later age. Diaschisis in the overlying cortex, thalamus and basal ganglia was noticed in several cases. Although clinical symptoms or signs could not be unequivocally attributed either to the size of the perfusion defects beyond the boundaries of lesions shown by CT or to the diaschisis, the findings may contribute to reveal age-related abnormal perfusion patterns.