Fatal tracheo-innominate artery fistula after tracheostomy in a patient with Pelizaeus-Merzbacher disease.

Tracheo-innominate artery fistula (TIF) is a serious, life-threatening complication following tracheostomy. We report a fatal TIF in a 15-year-old girl with Pelizaeus-Merzbacher disease. She received a tracheostomy for prolonged translaryngeal intubation due to acute respiratory failure without a trial of noninvasive ventilatory support before intubation. Severe hemorrhage from the TIF occurred 6 months after tracheostomy; immediate resuscitation failed. Antemortem fiberoptic bronchoscopy showed tracheal stenosis accompanied by granulation tissue, and postmortem examination revealed TIF with ulcerative granulation. Preventive intervention is required to avoid catastrophic TIF due to its high mortality rate. Moreover, to avoid prolonged translaryngeal intubation leading to tracheostomy, noninvasive ventilatory support before translaryngeal intubation, if applicable, is beneficial.

Clinical findings in Pelizaeus-Merzbacher disease.

Pelizaeus-Merzbacher disease is a rare X-linked disease characterized by defective central nervous system myelination owing to a mutation in the proteolipid protein 1 gene. Few studies report detailed clinical findings in children with genetic confirmation of mutations in the proteolipid protein 1 gene. We reviewed the records of 10 boys with Pelizaeus-Merzbacher disease and one symptomatic carrier girl. Their median age was 2 1/2 years (range 10 months to 20 years). Nine had proteolipid protein 1 gene duplications, one had a point mutation, and one had a single codon deletion. The families of eight patients reported perinatal complications, including maternal hypertension (three patients) and meconium aspiration (three patients). All of the patients were social and interactive, but all had difficulty with expressive speech. All patients presented with nystagmus and had hypotonia that progressed to spasticity, affecting the legs more than the arms; ataxia also contributed to motor impairment. Additional problems reported regarded feeding (eight patients) and sleep (three patients). Further work is needed to clarify the variations in disease course and the relationship of genotype to phenotype.

Selective specification of CNS stem cells into oligodendroglial or neuronal cell lineage: cell culture and transplant studies.

Neural stem cells (NSCs) were isolated from embryonic day 16 Sprague-Dawley rats and cultured in a novel serum-free stem cell medium that selected for the growth of NSCs and against the growth of GFAP(+) cells (astrocytes). NSCs maintained in culture for extended periods of time retained immunoreactivity for both nestin and PSA-NCAM, two markers characteristic of the stem cell phenotype. Moreover, using an oligodendrocyte (OL) specification medium, NSCs differentiated into OL as evidenced by their morphology and expression of multiple oligodendrocyte/myelin-specific markers. In addition, NSCs are capable of acquiring a neuronal phenotype as evidenced by expressing neuronal markers, such as neurofilament (NF) and NeuN when cultured in a defined medium for neurons indicating that these cells are also a good source of neuroblasts, which could be used to replace neuronal populations in the brain. We also showed successful propagation and differentiation of NSCs into OL after cryostorage, allowing for the later use of stored NSCs. The long-term goal of culturing NSCs and committed oligodendrocyte progenitors (OLP) is to obtain homogeneous populations for transplantation with the goal of remyelinating the myelin-deficient CNS. Our preliminary experiments carried out on normal and myelin deficient rats demonstrate that these cells survive and migrate extensively in both types of hosts. NSCs grafted as such, as well as cells derived from NSCs exposed to selective specification before grafting, are able to differentiate within the host brain. As expected, NSCs are capable of giving rise to astrocytes in a medium favoring this phenotype.