A network approach for provisional assay recognition of a Hendra virus antibody ELISA: test validation with low sample numbers from infected horses.

Obtaining statistically sound numbers of sera from Hendra virus (HeV)-infected horses is problematic because affected individuals usually die or are euthanized before developing a serum antibody response. As a consequence, test validation becomes a challenge. Our approach is an extension of OIE principles for provisional recognition and included 7 validation panels tested across multiple laboratories that provided estimates for test performance characteristics. At a 0.4 S/P cutoff, 16 of 19 sera from HeV-infected horses gave positive results in the HeV soluble G, indirect ELISA (HeVsG iELISA; DSe 84.2% [95% CI: 60.4-96.6%]); 463 of 477 non-infected horse sera tested negative (DSp 97.1% [95% CI: 95.1-98.4%]). The HeVsG iELISA eliminated almost all false-positive results from the previously used HeV iELISA, with marginally decreased relative sensitivity. Assay robustness was evaluated in inter-laboratory and proficiency testing panels. The HeVsG iELISA is considered to be fit for purpose for serosurveillance and international movement of horses when virus neutralization is used for follow-up testing of positive or inconclusive serum samples.

Muscarinic M1 receptor sequence: preliminary studies on its effects on cognition and expression.

It has been reported that people with schizophrenia who are homozygous at the c.267C>A single nucleotide polymorphism of the cholinergic muscarinic M1 receptor (CHRM1) perform less well on the Wisconsin Card Sorting Test than those who are heterozygous. We investigated whether CHRM1 sequence is associated with impaired executive function, a common problem in schizophrenia. We sequenced the CHRM1 using peripheral DNA from 97 people with schizophrenia who completed the Wisconsin Card Sorting Test, a verbal fluency test and the National Adult Reading Test. Clinical severity was assessed using the Positive and Negative Syndrome Scale. To determine whether CHRM1 sequence affected receptor expression, we used post-mortem data, from another cohort, to investigate associations between CHRM1 sequence and mRNA levels. On the Wisconsin Card Sorting Test, 267C/C participants with schizophrenia made more perseverative errors (p<0.05) and perseverative responses (p<0.05) than 267C/A participants. Genotype had no effect on verbal fluency (p=0.8) or National Adult Reading test (p=0.62). Cortical CHRM1 mRNA levels did not vary with gene sequence (p=0.409). The clinical study supports the proposal that CHRM1 sequence is associated with alterations in some aspects of executive function. However, the post-mortem study indicates this is not simply due to altered expression at the level of mRNA, suggesting this sequence alteration may affect the functionality of the CHRM1.