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D Dowd

Publications and source records attributed to D Dowd.

5 recordsLinked to original sources
PubMed1998

Assessment of interlaboratory performance in external proficiency testing programs with a direct HDL-cholesterol assay.

Direct assays for the determination of HDL-cholesterol (HDL-C) have recently become available. The methods are precise, require small sample volume, and appear to be less affected by increased triglycerides than traditional precipitation methods. In this study, we describe the inter- and intralaboratory variability of the Boehringer Mannheim Corporation direct HDL-C assay and its performance in external proficiency testing surveys. A comparison study among three laboratories, using different analyzers and 85 serum specimens, showed a correlation coefficient (r) of 0.99. The direct HDL-C assay also showed good agreement with the ultracentrifugation-dextran sulfate-Mg2+ method (r = 0.98) and the Cholesterol Reference Method Laboratory Network-Designated Comparison Method (a = 0.98x + 4.75 mg/L, r = 0.98). Total error at medical decision levels ranged from -0.8% to +11.1%. Furthermore, this assay performed adequately in the College of American Pathologists and the ALERT surveys as well as the CDC Lipid Standardization Program and met all performance criteria of regulatory agencies.

Centers for Disease Control and Prevention, U.S.↗
PubMed1992

Dissociation between linguistic and nonlinguistic gestural systems: a case for compositionality.

This paper addresses the issue of the separability of disorders of sign language from disorders of gesture and pantomime. The study of a left-lesioned deaf signer presents one of the most striking examples to date of the cleavage between linguistic signs and manual pantomime. The left-hemisphere lesion produced a marked sign language aphasia disrupting both the production and the comprehension of sign language. However, in sharp contrast to the breakdown of sign language, the ability to communicate in nonlinguistic gesture was remarkably spared. This case has important implications for our understanding of the neural mediation of language and gesture. We argue that the differences observed in the fractionation of linguistic versus nonlinguistic gesture reflect differing degrees of compositionality of systems underlying language and gesture. The compositionality hypothesis receives support for the existence of phonemic paraphasias in sign language production, illustrating structural dissolution which is absent in the production of pantomimic gesture. Understanding the neural encoding of compositional motoric systems may lead to a principled anatomical account of the neural separability of language and gesture. This case provides a powerful indication of the left hemisphere's specialization for language-specific functions.

Aphasia↗