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K L Knight

Publications and source records attributed to K L Knight.

187 records · Page 11Linked to original sources
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Rabbit major histocompatibility complex. IV. Expression of major histocompatibility complex class II genes.

The rabbit MHC class II DP, DQ, and DR alpha and beta chain genes were transfected into murine B lymphoma cells. The transfected cells expressed R-DQ and R-DR molecules on the cell surface but they did not express the R-DP genes either on the cell surface or at the level of mRNA. Northern blot analyses showed that the R-DP genes were expressed, albeit at low levels, in rabbit spleen. Similar analyses showed that the R-DQ and R-DR genes were expressed at high levels in rabbit spleen. A new monoclonal anti-rabbit class II antibody, RDR34, has been developed and shown to react with the R-DR transfected cells and not with the R-DQ transfected cells. The previously described monoclonal anti-rabbit class II antibody, 2C4, reacted with the R-DQ transfected cells and not with the R-DR transfected cells. Thus, 2C4 and RDR34 MAb's are specific for the R-DQ and R-DR molecules, respectively. Each of the antibodies reacted with approximately 50% of rabbit spleen cells as shown by immunofluorescent antibody studies.

Animals↗
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Use of power Doppler in pediatric neurosonography: a pictorial essay.

In pediatric neurosonography, conventional color Doppler imaging has been the primary adjunct to routine gray-scale imaging. Power Doppler sonography is a relatively recent development that does not have the limitations of conventional color Doppler ultrasound. The power Doppler technique measures the energy of moving red blood cells instead of the velocity and direction of flow. Advantages of this technique include increased sensitivity for identifying flow in slow-flow states, more complete evaluation of a vessel, and more accurate evaluation of the course of the vessel. Power Doppler sonography is helpful in evaluation of the neonatal brain in a variety of clinical situations: identifying the exact locations of extraaxial fluid collections, differentiating intraventricular clot from normal choroid plexus, detecting intraventricular hemorrhage, and demonstrating asymmetries in cerebral perfusion. However, in certain difficult cases, use of both conventional color Doppler sonography and power Doppler sonography produces increased diagnostic accuracy because these techniques furnish complementary information.

Adolescent↗
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[Kinetics of reappearance of suppressed allotypes in multiheterozygous rabbits (author's transl)].

Heterozygous rabbits of genotype a1n81f73g74/a2n82f71g75 were injected at birth with anti-al antiserum. The suppression of the VHa1 allotype resulted in a similar concommitant suppression of the constant region allotypes coded by genes of the same allogroup as a1. After 3 to 4 months the suppressed allotypes were re-expressed in measurable amounts. At 6 months in the 3 suppressed animals, the proportion of suppressed allotypes (S) to the non-suppressed ones (NS) was higher among colostrum and serum IgA (50% S, 50% NS) than among IgG for IgM. Among these two latter classes the proportion S/(S + NS) remained low (about 15% S, 85% NS) over an 18 month period in two out of three suppressed rabbits. In the third one, the proportion S/(S + NS) among IgG molecules increased to increasing concentration of S allotypes is not compensated by a decrease in concentrations of NS allotypes. The study of these phenomena could bring a better understanding of mechanisms involved in regulation of Ig synthesis and in allotype suppression.

Animals↗