Robert T. Leshner

Remyelination in the Human Central Nervous System

Abstract. Remyelination, albeit incomplete, has been demonstrated in human central nervous system (CNS). However, information about the initial stage and the final extent of such remyelination is not available. We describe the morphologic findings of a demyelinating lesion with evidence of early remyelination in a biopsy obtained from a 15-year-old boy about two weeks after the onset of neurologic symptoms. The demyelinated area appeared hypercellular with a relatively large number of oligodendrocytes frequently seen in the process of new myelin formation. In addition to the usual reactive changes, the astrocytes were often seen to contain otherwise normallooking oligodendrocytes within their cytoplasm. In the ensuing months, the patient made apparently total functional recovery accompanied by nearly complete resolution of the white matter lesions demonstrated by the subsequent magnetic resonance studies. These observations suggested that the initial remyelination seen in the biopsy eventually succeeded in producing extensive remyelination in the lesion. Although the exact nature of the demyelinating disorder in our patient remains undetermined, this study indicates that clinically significant remyelination is possible in human CNS. Also, our findings appeared strikingly similar to those described in certain experimental animal models in which widespread remyelination is known to occur.

NEUTROPENIA IN A PATIENT RECEIVING INTRAVENOUS IMMUNE GLOBULIN

A child with Guillain-Barre syndrome treated with intravenous immune globulin (IVIG) developed neutropenia (absolute neutrophil count = 390), which resolved 3 days after completion of the therapy. Potential mechanisms for the development of neutropenia during the use of IVIG therapy are discussed. In this case, testing of the IVIG used revealed the presence of a high concentration of anti-neutrophil antibodies compared to other samples. It is recommended that white blood cell and neutrophil counts be monitored daily during the use of such therapy.

Stroke in purine nucleoside phosphorylase deficiency

The first documented case of cerebrovascular disease occurring in a 13-year-old girl with purine nucleoside phosphorylase deficiency is reported. This patient, the oldest known survivor with purine nucleoside phosphorylase deficiency, had previously experienced multiple sequential neurologic problems. She presented with episodes of transient left hemiparesis, followed shortly thereafter by dense left hemiplegia. Magnetic resonance imaging revealed a right internal capsule infarct; cerebral angiography revealed vasculopathy of the proximal vessels. Proposed mechanisms for neurologic dysfunction and cerebrovascular disease in purine nucleoside phosphorylase deficiency are discussed.

Possible radiation-induced dural fibrosarcoma with an unusually short latent period: case report.

We report a case of radiation-induced dural fibrosarcoma in a 9.5-year-old male patient who was treated with radiation for medulloblastoma. He received a total dose of 53.2-Gy radiation, delivered at 1.6 and 1.8 Gy per fraction with a 6 MV linear accelerator using the standard cranial-spinal technique. A sequential magnetic resonance image at 15 months after the completion of radiation therapy showed a mass above the cerebral convexity that increased two-fold in size within a period of 4 months. The tumor showed characteristics of a low-grade fibrosarcoma. This case emphasizes the potential risk of early development of a second neoplasm after therapeutic radiation, especially in children, and also documents what is to our knowledge the shortest latent period between the administration of radiation therapy and the development of an intracranial fibrosarcoma that has been reported.

INFORMATION PROCESSING SPEED OF CHILDREN WITH FRIEDREICH'S ATAXIA

Two children with Friedreichs ataxia and six controls matched for age and Verbal IQ were administered a measure of short‐term memory scanning and tests of attention, memory, language and abstraction. The patients demonstrated a deficit in information processing speed, decreased sustained attention and variable memory performance. The findings suggest that a deficit in information processing speed occurs early in the clinical course of Friedreichs ataxia and progresses as neurological status deteriorates.

Nocardia asteroides brain abscess following mastoidectomy

Nocardia asteroides brain abscess occurred after mastoidectomy and tympanoplasty in a previously healthy 10-year-old boy. Combined surgical excision and trimethoprim/sulfamethoxazole therapy resulted in significant improvement.