Mapping the Research Domain Criteria Social Processes Constructs to the Social Responsiveness Scale

OBJECTIVE

Research Domain Criteria (RDoC) operationalizes a set of basic social dimensions that can be used to deconstruct sources of variation in social impairments across affected individuals, regardless of their diagnostic status. This is a necessary step toward the development of etiologically based and individualized treatments. The main objective of this investigation was to derive estimations of the RDoC social constructs from the Social Responsiveness Scale (SRS-2).

METHOD

Exploratory structural equation modeling and confirmatory factor analysis were conducted using individual SRS-2 items from six distinct databases ( N = 27,953; mean age = 9.55 years, SD = 3.79; 71.7% male participants) spanning normative (33.8%) and atypical (66.2%) development. The following models were estimated: a one-factor model; a three-factor model with separate attachment and affiliation, social communication, and understanding of mental states factors; and a four-factor model where social communication was further split into production of facial and non-facial communication.

RESULTS

The one-factor solution showed poor fit. The three-factor solution had adequate fit (comparative fit index = 0.952, Tucker Lewis Index = 0.937, root mean square error of approximation = 0.054). However, the four-factor solution had superior fit (comparative fit index = 0.973, Tucker Lewis Index = 0.961, root mean square error of approximation = 0.042) and was robust across age, sex, and clinical status.

CONCLUSION

To our knowledge, this is the first study examining estimations of the RDoC social constructs from an existing measure. Reported findings show promise for capturing important RDoC social constructs using the SRS-2 and highlight crucial areas for the development of novel dimensional social processing measures.

Quantifying Research Domain Criteria Social Communication Subconstructs Using the Social Communication Questionnaire in Youth

Research Domain Criteria (RDoC) has posited a set of social dimensions that could be useful in identifying sources of individual variation in social impairments across neurodevelopmental disorders. The current investigation aimed to derive estimates of the RDoC social constructs from the Social Communication Questionnaire (SCQ) and examine whether RDoC social processes, as captured by the SCQ, are best represented by a dimensional, categorical, or hybrid model. Individual SCQ items from 4 databases were combined resulting in a total of 26,407 individuals (M_age = 8.13 years, SD_age = 4.19; 69.1% male). The sample consisted of 60.0% of individuals with autism spectrum disorder (ASD), 6.8% with a range of neurodevelopmental disorders and 33.2% of siblings of individuals with ASD. Comparison of a range of factor solutions through the use of exploratory structural equation modeling and confirmatory factor analysis indicated that a 3-factor structure with separate attachment and affiliation, production of nonfacial and facial communication factors provided excellent fit to the data (comparative fit index = .989, Tucker-Lewis index = .984, root mean square error of approximation = .045). and robustness across clinical groups, age, sex, and verbal status. Comparison between the best-fitting factor analysis, latent class analysis, and factor mixture analysis solutions demonstrated that the RDoC social processes domain is best represented as dimensional. Our findings show promise for capturing some of the important RDoC social constructs using the SCQ but also highlight crucial areas for the development of new, dedicated dimensional measures.

Production of rat monoclonal antibody from rat x mouse hybridoma cell lines using microencapsulation technology

The cell growth and monoclonal antibody production characteristics of two rat x mouse heterohybridoma cell lines, designated 187.1 and M1/9.3, were investigated using a biocompatible microencapsulation technology. Both cell lines, derived from the fusion of immunized rat spleen cells with either the NS1 or X63Ag8.653 myeloma cell lines, were found to reach a maximum intracapsular cell density of 1.3 to 1.5 X 10(7) cells/ml during a 27-d culture period. During this period, rat monoclonal antibody accumulated in the intracapsular space of both cultures to a final concentration of 2.0 to 2.8 mg/ml. Comparison of the concentration of rat monoclonal antibody in the extracapsular vs. the intracapsular space of both cultures indicated that significantly less than 1% of the antibody produced by the encapsulated hybridoma cells was capable of transiting the microcapsule membrane during the culture period. Due to the partition of the rat monoclonal antibody within the intracapsular space, the initial purity of the antibody harvested from 21-d microcapsule cultures of 187.1 and M1/9.3 cells was approximately 48 and 75% by weight, respectively. Analysis of the intracapsular protein by sodium dodecyl sulfoxide gel electrophoresis at different times during the culture period demonstrated that the principal contaminant associated with the unpurified antibody was bovine serum albumin.