[Hopkins syndrome: oral prednisolone was effective for the paralysis].

We describe here a 5-year-old girl who presented flaccid paralysis of the left upper limb after recovery from bronchial asthma. T2-weighted magnetic resonance imaging of the cervical cord revealed a focal high intensity area in the left anterior horn at the C6-C7 level. She was treated with oral prednisolone, and paralysis resolved within two months. Thirty cases of Hopkins syndrome have been reported so far, but its cause remains unknown. Early administration of prednisolone might ameliorate paralysis in this syndrome.

[Brain lesion in congenital myotonic dystrophy].

Congenital myotonic dystrophy (CMyD) affects the brain, causing mental changes and psychomotor retardation. However, the pathophysiology of the brain dysfunctions in CMyD remain to be clarified. We described two cases of CMyD with brain abnormalities. Case 1 was diagnosed as having ventricular dilation at 17 days after birth, and died at 3 years and 6 months. Case 2 was diagnosed as having ventricular dilation at birth, and died at 1 year and 3 months. Pathologically, both cases showed remote hypoxic ischemic brain damage and leptomeningeal glioneuronal heterotopia (LGH). In our patients, the white matter changes may have been caused by perinatal asphyxia, and LGH by embryological abnormalities. Taken our data and those of previous reports together, it is suggested that cerebral abnormalities in CMyD are ascribed to both hypoxic ischemic changes and histogenetic abnormalities.

Magnetic resonance imaging of the cauda equina in two patients with Guillain-Barré syndrome.

The results are presented of magnetic resonance imaging (MRI) of the spine in two cases of childhood Guillain-Barré syndrome. After injection of gadolinium-diethylenetriamine pentaacetic acid, MRI showed enhancement of the cauda equina in these patients. These MRI observations may help confirm the diagnosis of Guillain-Barré syndrome. The nerve root enhancement resolved as the clinical symptoms improved. Serial imaging may be useful in monitoring the response to therapy and assessing new treatment regimens. It may also yield a better understanding of the disease process.

Dissociation between upper and lower neck N13 potentials following paired median nerve stimuli.

Cervical N13 potential in response to the median nerve stimulation can be recorded either from upper (Cv2) or lower (Cv6) neck with almost equal amplitudes and latencies. It has long been debated whether they represent the same or different generator sources. Using a conditioning-test paired stimuli paradigm, we examined the differences of recovery function of Cv2- and Cv6-N13, anterior neck (AN)-P13, and scalp recorded P13/P14 in 6 healthy subjects. All cervical electrodes were referenced to the non-cephalic site. Scalp response was recorded with linked ear reference. The inter-stimulus intervals ranged from 4 to 20 ms with 2 ms increments. Throughout 4 to 18 ms ISI, Cv6-N13, AN-P13 and scalp P13/P14 were suppressed, whereas Cv2-N13 was facilitated. All but scalp P13/P14 returned close to the control at 20 ms ISI. The findings indicate that Cv2-N13, Cv6-N13 and scalp P13/P14 are independent each other and arise from different generator sources. The suppression of Cv6-N13 is consistent with a postsynaptic nature of this potential and may indeed be mediated through dorsal horn interneurons creating a current field orientation in the posterior-anterior direction. The facilitation of Cv2-N13 suggests that this is a presynaptic potential and may travel through the dorsal column with vertical orientation. The longer period of suppression of scalp P13/P14 suggests it to be of polysynaptic origin and to arise at least rostral to the cuneate nucleus.

Developmental changes in P300 wave elicited during two different experimental conditions.

Age-related correlations on auditory event-related potentials were studied using a task-relevant oddball paradigm in 175 normal subjects aged 4-21 years and age-related correlations in the "ignore" condition were studied in 108 normal subjects aged 1-21 years. In the ignore condition, subjects more than 4 years of age were instructed to read a book to divert attention from the auditory stimulus. From 4 to about 17 years of age, the latencies of task-relevant P300 in event-related potentials (ERPs) gradually shortened. In the ignore condition experiment, the P300 latency shortened progressively, but stabilized at about 12 years of age. Whereas P300 in the ignore condition likely corresponds to P3a described previously (passive attention), the conventional P300 wave corresponds to P3b (active attention). The findings indicate a developmental difference between the P3a and P3b potential.

Neonatal glutamate can destroy the hippocampal CA1 structure and impair discrimination learning in rats.

Neonatal Wistar rats were subcutaneously injected with 0.1, 1, or 2 mg/g b.wt. of monosodium glutamate (MSG) at 1, 3, 5, 7, and 9 days after birth. The animals were observed for degeneration of pyramidal cells in the hippocampus. The histological change disappeared when the animals were concurrently injected with glutamate diethyl ester (GDEE), an antagonist of the glutamate receptor. When light-dark discrimination learning was carried out at 10 weeks old, the correct response in the acquisition period was impaired in the animals given 1 and 2 mg/g of neonatal MSG. Their retention scores were also impaired in comparison with the control animal. The behavioral impairment recovered with pre-treatment with GDEE. No significant changes were observed in the concentrations of transmitter substances, including amino acids and monoamines. These results suggest that neonatal MSG destroys the hippocampus and impairs acquisition and retention of discrimination learning through the mechanism of glutamate receptors.