Acute toxicity of MPTP and MPP+ in the brain of embryo and newborn mice

1-Methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) causes damage to dopaminergic neurons in the nigrostriatal system, similar to that seen in Parkinson disease (PD). Recently, a few reports have confirmed neuroblastic apoptosis in the subventricular zone (SVZ) of adult C57BL/6J mice by i.p. injection of MPTP, and concluded that MPTP is also toxic to neuroblasts in the SVZ. While there have been many researches on the neurotoxicity of MPTP in adult mice, there have been only a few in fetal mice. In the present study, we assessed the toxicity of MPTP to embryonic and newborn mice after a single injection into pregnant or newborn mice. MPTP and 1-methyl-4-phenylpyridinium (MPP⁺), a metabolite of MPTP, caused loss of tyrosine hydroxylase (TH)-positive cells or fibers and increased apoptotic cells in embryonic and newborn mice. In addition, MPTP and MPP⁺ induced a marked increase of apoptotic cells in the SVZ compared to the nigrostriatal system. The present results may indicate that MPTP and MPP⁺ pass through the placenta and blood–brain barrier (BBB) and that a different mechanism may be involved in MPTP- or MPP⁺-induced toxicity in the SVZ and in the nigrostriatal system of embryonic and newborn mice.     

Correlation of histology and molecular genetic analysis of 1p, 19q, 10q, TP53, EGFR, CDK4, and CDKN2A in 91 astrocytic and oligodendroglial tumors.

PURPOSE: The histological diagnosis of human gliomas is of great importance for estimating patient prognosis and guiding therapy but suffers from being subjective and, therefore, variable. We hypothesized that molecular genetic analysis could provide a more objective means to classify tumors and, thus, reduce diagnostic variability. EXPERIMENTAL DESIGN: We performed molecular genetic analysis on 91 nonselected gliomas for 1p, 19q, 10q, TP53, epidermal growth factor receptor, and cyclin-dependent kinase 4 abnormalities and compared with the consensus diagnoses established among four independent neuropathologists. RESULTS: There were six astrocytomas, seven anaplastic astrocytomas, 45 glioblastomas, 21 oligodendrogliomas, eight anaplastic oligodendrogliomas, three oligoastrocytomas, and one anaplastic oligoastrocytoma. Twenty-nine cases had either 1p or 19qloss of heterozygosity (LOH) while retaining both copies of 10q, of which 25 (86%) were histologically oligodendroglioma, anaplastic oligodendroglioma, oligoastrocytoma, or anaplastic oligoastrocytoma. As for the oligodendroglial tumors, unanimous agreement of the initial diagnoses was almost restricted to those cases with combined 1p/19qLOH, whereas all nine tumors without 1p loss initially received variable diagnoses. Interestingly, TP53 mutation was inversely related to 1pLOH in all gliomas (P = 0.0003) but not 19qLOH (P = 0.15). CONCLUSIONS: These data demonstrate that molecular genetic analysis of 1p/19q/10q/TP53 has significant diagnostic value, especially in detecting oligodendroglial tumors. In addition, 1pLOH and TP53 mutations in gliomas may be markers of oligodendroglial and astrocytic pathways, respectively, which may separate gliomas with the same histological diagnosis, especially oligodendroglial tumors and glioblastomas. Testing for those molecular genetic alterations would be essential to obtain more homogeneous sets of gliomas for the future clinical studies.