Immunocytochemical techniques in stereotactic biopsy

A SNaPshot assay for genotyping 44 individual identification single nucleotide polymorphisms

Single nucleotide polymorphisms (SNPs), which have relatively low mutation rates and can be genotyped after PCR with shorter amplicons compared with short tandem repeats (STRs), are being considered as potentially useful markers in forensic DNA analysis. Those SNPs with high heterozygosity and low Fst (F-statistics) in human populations are described as individual identification SNPs, which perform the same function as STRs used in forensic routine work. In the present study, we developed a multiplex typing method for analyzing 44 selected individual identification SNPs simultaneously by using multiplex PCR reaction in association with fluorescent labeled single base extension (SBE) technique. PCR primers were designed and the lengths of the amplicons ranged from 69 to 125 bp. The population genetics data of 79 unrelated Chinese individuals for the 44 SNP loci were investigated and a series of experiments were performed to validate the characteristic of the SNP multiplex typing assay, such as sensitivity, species specificity and the performance in paternity testing and analysis of highly degraded samples. The results showed that the 44-SNPs multiplex typing assay could be applied in forensic routine work and provide supplementary data when STRs analysis was partial or failed.

Brain stem glioma: the role of a biopsy

A retrospective review of the clinical and histopathological features of 31 patients with brain stem gliomas treated between 1965 and 1990 at Kyushu University Hospital was performed to determine the role of biopsy on these lesions. These 16 male and 15 female patients ranged in age from 3 to 50 years at diagnosis (average: 18.1 years). The primary site of the tumour was the pons in 20 patients, followed by the medulla oblongata and midbrain, and the final histological diagnoses of the lesions based on either the biopsy or autopsy materials were grade I astrocytomas in five patients, grade II in nine, grade III in 10, grade IV in five, and ependymoma in two patients. No consistent correlation could be obtained between the CT findings and histological diagnoses. Open surgical posterior fossa exploration was performed on 17 patients (diagnostic biopsy: 10; volume reduction by tumour removal with or without cyst evacuation: 7) and stereotaxic biopsy on three patients, without any mortality related to these procedures. In our biopsy series, half of the patients with grade II astrocytoma died within 12 months after diagnosis, whereas three out of four patients with grade I astrocytoma survived more than 10 years after diagnosis. Because of the relative safety of the tissue sampling technique, and the importance of an accurate diagnosis in order to select appropriate treatment modalities, histological verification of the lesion should be considered for all patients harbouring a brain stem mass lesion.