Honored guest presentation: contemporary treatment of skull base meningiomas.
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Cavernous Sinus↗
Biomedical subjects
A J Kokkino
Publications and source records attributed to A J Kokkino.
Role of genomic instability in meningioma progression.
Microsatellite length instability, probably resulting from defective DNA mismatch repair mechanisms, has been described in a variety of cancers. Such genetic instability may play a significant role in tumor formation and progression. To investigate the role of microsatellite alterations in meningioma tumorigenesis and progression, we examined 33 microsatellite markers on nine chromosomes for abnormalities in 18 benign, 15 atypical, and 11 malignant meningiomas. In each tumor, at least 15 markers were investigated. Microsatellite instability was not detected in any of the cases examined. However, loss of heterozygosity for markers from various chromosomes was seen frequently among atypical and malignant meningiomas. Although some of these chromosomal losses might represent random events, our data also indicate a role for specific loci on chromosome arms 14q, 1p, 10q, and possibly 9p in the development of malignancy in meningiomas. Our results argue against a significant role for a generalized microsatellite instability phenotype in meningiomas, but they suggest that genomic instability resulting in frequent allelic deletions may contribute to meningioma progression.
Alleles↗
Vertical fracture of the odontoid process: case report.
Fifteen percent of cervical spine fractures involve the odontoid process. Most odontoid fractures can be classified as Types I through III according to the scheme developed by Anderson and D'Alonzo. We report a case of a vertically oriented fracture through the odontoid process that does not fit into any of these categories. Only two such cases have been described in the literature. Our patient is an 18-year-old man who sustained an axial loading injury to his cervical spine. Plain lateral cervical tomography and computed tomography were performed to characterize the fracture and to evaluate the instability. The patient was placed in a rigid orthosis for 12 weeks, and at 6-month follow-up, he had full range of motion and showed no evidence of abnormal movement, as revealed by flexion-extension studies. This case demonstrates the shortcomings of the current classification system for odontoid fractures and value of plain tomography and computed tomography in evaluating odontoid fractures.
Adolescent↗
Mutagenicity evaluation of HC Blue No. 1 and HC Blue No. 2. III. Effects in the Salmonella typhimurium/Escherichia coli reversion assay and the mouse lymphoma L5178Y TK+/- forward mutation assay.
The hair-dye ingredients, HC Blue No. 1 (HCB1) and HC Blue No. 2 (HCB2), were tested for the induction of bacterial mutation using Salmonella typhimurium strains TA1535, TA1537, TA98 and TA100; and Escherichia coli strains WP2uvrA-. In addition, both dyes were evaluated in the mouse lymphoma L5178Y TK+/- assay (MLA) for the potential to induce forward mutation. A liver homogenate (S9) prepared from Aroclor 1254-induced male Fischer 344 rats was used to provide a means for metabolic activation. HCB1 was not mutagenic in the Ames assay, but was weakly mutagenic in the MLA only in the presence of metabolic activation. In contrast, HCB2 was a strong mutagen in the Ames assay in tester strain TA98 both in the presence and absence of metabolic activation. A positive response was also noted with HCB2 in the MLA, both in the presence and absence of metabolic activation. Negative findings from the Ames assay of this study agree with other published results where an identical lot of HCB1 was used. Using the same lot, a weak positive result was observed in the MLA, however, the activation requirements and magnitude of the response were different from that of a lot evaluated by the NTP. In contrast, HCB2 appears to be both a bacterial and mammalian cell mutagen independent of lot variability.
Animals↗
A simplified protocol for the mouse bone marrow micronucleus assay.
Complex and expensive protocols involving multiple sampling times have been proposed and recommended for the in vivo mouse bone marrow micronucleus assay. The purpose of this study was to determine whether a simplified procedure employing two identical exposures and a single sampling time would be equally effective at detecting chemical clastogens. Furthermore, the utility of the protocol was investigated for both intraperitoneal and oral routes of administration. The results obtained from a group of chemicals spanning the known time range for maximum frequency of micronucleus induction prove the effectiveness of this simplified protocol.
9,10-Dimethyl-1,2-benzanthracene↗