Antigenic variability of foot-and-mouth disease virus serotype O during serial cytolytic passage.

The emergence and disappearance of antigenic variants of foot-and-mouth disease virus (FMDV) during a field outbreak occurs periodically due to the volatile nature of its genome. In the present analysis, change in antigenic behavior of serotype O FMDV during the serial cytolytic passage in the absence of immune pressure was observed. Initially, the isolate showed a poor antigenic match (relationship value <0.3) with the serotype O vaccine strain and upon serial passage increase in relationship value was observed. Comparison of capsid sequence revealed substitution at four positions (VP3:K58 â†’ E and P158 â†’ S, VP1:E83 â†’ K and R172 â†’ Q) acquired during the serial passage. Examination of passage level and amino acid substitution revealed the critical role of position VP3-58 that was identified earlier as crucial for antigenic site IV, in the observed antigenic variability. The role of position VP3-58 was further confirmed using reverse genetics approach.

The role of the third occipital nerve in surgical treatment of occipital migraine headaches.

BACKGROUND: The third occipital nerve is often encountered during the occipital migraine surgery, however its contribution to migraine headaches is unclear. The objective of this study was to determine whether removing the third occipital nerve plays any role in the clinical outcomes of occipital migraine surgery. METHODS: A retrospective comparative review was conducted on all occipital migraine headache (Site IV) patients from 1/2000 to 12/2010. Inclusion criteria were: 1) completion of migraine questionnaire, 2) migraine Site IV decompression, and 3) minimum 6 months of follow-up. Patients were divided into those who had the third occipital nerve removed and those who did not. Outcome variables included overall Migraine Headache Index reduction and Site IV pain elimination. RESULTS: 229 patients met the study inclusion criteria. The third occipital nerve removed group (111 patients) and the third occipital nerve not removed group (118 patients) were comparable in terms of age, gender, number of surgical sites, and statistically well matched regarding preoperative headache characteristics. Comparing the third occipital nerve removed to the third occipital nerve not removed group, Migraine headache index reduction was 63% vs. 64%. Patients experiencing migraine headache elimination (third occipital nerve removed 26% vs. third occipital nerve not removed 29%; p=0.45) and surgery success with at least 50% reduction in migraine headache (third occipital nerve removed 80% vs. third occipital nerve not removed 81%; p=0.82) were also similar. There was also no difference between the two groups in symptomatic neuroma formation. Site IV specific pain elimination was similar between the two groups (third occipital nerve removed 58% vs. third occipital nerve not removed 64%; p=0.54). CONCLUSIONS: Removal of the third occipital nerve did not alter migraine surgery success.