Operational definitions improve reliability of the age-related white matter changes scale

BACKGROUND AND PURPOSE

Although the age-related white matter changes (ARWMC) scale has been advocated to be applicable to both MRI and CT for assessing the severity of WMC, its inter-rater reliability on CT is only fair. We aimed to operationalize the ARWMC scale and investigate the effect of this operationalization on the reliability and validity on MRI and CT.

METHODS

Operational definitions of the ARWMC scale were derived from Erkinjuntti research criteria for subcortical vascular dementia and Scheltens scale. Using original and operationalized ARWMC scale, eight observers recorded the time for rating per MRI and per CT. We investigated the inter-rater and intrarater reliability as well as validity against volume using data from 97 stroke patients.

RESULTS

Inter-rater reliability of the operationalized scale on CT (0.874, 95% confidence interval [0.780-0.934]) was better than the original scale (0.569, 95% confidence interval [0.247-0.775]). Its intrarater reliability on CT (0.869) and reliability on MRI (inter-rater: 0.860; intrarater: 0.838) was comparable with the original scale (CT intrarater: 0.750 and on MRI inter-rater: 0.845; intrarater: 0.853). The time required to administer the operationalized scale (4'2″ for MRI and 1'18″ for CT) was similar to that of the original scale (3'56″ for MRI and 1'16″ for CT). The original scale and operationalized scale also significantly correlated with WMC volume (operationalized scale ρ = 0.613, P < 0.001, original scale ρ = 0.638, P < 0.001).

CONCLUSION

Operational definitions improve the inter-rater reliability of ARWMC scale on CT, and it correlates with volumetric measurement.

Nasopharygeal carcinoma in Queensland, Australia: a review of 10 years experience

The purpose of this study was to compare the treatment outcomes of patients with nasopharyngeal carcinoma in Queensland in a 10-year period during which synchronous chemoradiotherapy has come into use and to compare characteristics of patients of different racial origins and their prognostic factors. Eighty-one patients treated between 1991 and 2001 at the Queensland Radium Institute, Brisbane, Queensland for histologically confirmed nasopharyngeal carcinoma were included. Seventeen patients were treated using the Intergroup protocol, 32 patients with miscellaneous synchronized chemoradiotherapy, 6 patients with neoadjuvant regimens and 26 patients with radiotherapy only. Asian patients were found to present earlier than White Australian patients (P < 0.02). No significant difference was identified in the histological presentation between the two ethnic groups. Asian patients were more likely to have a relapse and poor loco-regional control. Overall survival, however, was not different. Patients treated according to the Intergroup protocol had better disease-specific survival and relapse-free survival than the other groups. The median follow up was 36 months. Twenty-five patients (30%) developed recurrent disease. The 5-year salvage survival or survival after relapse was 15%. Our experience with the Intergroup protocol in our population is similar to other studies, with likelihood of improved results.

Generation of recombinant influenza A virus without M2 ion-channel protein by introduction of a point mutation at the 5' end of the viral intron

The aim of this study was to inhibit influenza virus M2 protein expression by mutating the splicing signal of the M gene. Mutations were introduced into the GU dinucleotide sequence at the 5'-proximal splicing site of the M gene (corresponding to nt 52-53 of M cRNA). Transfected cells expressing mutated M viral ribonucleoproteins failed to generate M2 mRNA. Interestingly, recombinant viruses with mutations at the dinucleotide sequence were viable, albeit attenuated, in cell culture. These recombinants failed to express M2 mRNA and M2 protein. These observations demonstrated that the GU invariant dinucleotide sequence at the 5'-proximal splicing site of M gene is essential for M2 mRNA synthesis. These results also indicated that the M2 ion-channel protein is critical, but not essential, for virus replication in cell culture. This approach may provide a new way of producing attenuated influenza A virus.