Biomedical subjects
R A Wilson
Publications and source records attributed to R A Wilson.
Historical perspectives of the United States Air Force, Army, Navy, Public Health Service, and Veterans Administration Nursing Services.
Explore the source record for details and available documents.
The formation and turnover of the membranocalyx on the tegument of Schistosoma mansoni.
The multilaminate vesicles present in the tegument cytoplasm appear to fuse with side channels projecting out into the cytoplasm from the base of the surface pits. Their lamellate contents then unroll and spread out to form a trilaminate membranocalyx lining the pits and covering the tegument surface. The plant lectin concanavalin A appears to stabilize the process of vesicle fusion leading to an aggregation of multilaminate vesicles trapped in the lumen of the surface pits. The membranocalyx can be labelled with cationized ferritin. Chase incubations in normal medium indicate that by 4 h most of the label and the membranocalyx to which it is bound have been lost to the medium. This suggests that under the conditions of these experiments the membranocalyx has a half-life of 2-3 h.
Public health and the Podiatric Health Section of the American Public Health Association.
Explore the source record for details and available documents.
The tegument of Schistosoma mansoni: a histochemical investigation.
The main components of the schistome tegument were found to be neutral glycoprotein and phospholipid; a small quantity of glycolipid was observed in the male dorsal tegument. The tegument can be differentiated from other schisotsome tissues on the basis of enzyme content; three hydrolytic enzymes were shown to be specifically localized in the tegument: alkaline phosphatase, adenosine triphosphatase and indoxyl esterase. It is suggested that these enzymes could be used as intrinsic markers for tegument structures. The subtegumental cells appear to be the major sites of biosynthetic activity since they contain large amounts of RNA and mitochondrial enzymes.
The stimulation of daughter redia production during the larval development of Fasciola hepatica.
In snails maintained at 20 degrees C rediae of Fasciola hepatica merge from sporocysts from 11 days after infection onwards. The number of mother rediae rises steadily thereafter until at least 40 days after infection. Daughter rediae are seldom observed in mother rediae dissected from snails maintained at 20 degrees C. Their production can, however, be stimulated by subjecting the snail host to starvation, to low, and to high temperature shocks. The parasite is susceptible to stress from immediately after infection for about 16 days, when maintained at 20 degrees C. In general, the more extreme the shock, the greater is daughter redial production. Increasing the length of the period of stress from 12 h up to 9 days does not increase the production of daughter rediae, nor does repeated on/off cold shocks or continuous maintenance at 10 degrees C. Daughter rediae develop more rapidly than cercariae and leave the mother rediae several days earlier. There is no evidence that presence of daughter rediae coincides with the suppression of cercarial production. The findings are discussed with reference to possible mechanisms by which parasite development might be controlled.
Experimental neonatal colibacillosis in cows: immunoglobin classes involved in protection.
Pregnant cows were vaccinated with one of four vaccine preparations to induce passive immunity in their offspring against a homologous oral challenge with Escherichia coli strain B-44. Quantitative assays of specific antibody in colostral whey from both immunized and nonimmunized dams revealed that immunoglobulin G, immunoglobulin A (IgA), and immunoglobulin M (IgM) with anti-O (somatic) activity were present in whey of all dams tested, whereas a marked deficiency of IgA and IgM anti-K immunoglobulin was noted in the whey from control dams only. The degree of scours (neonatal colibacillosis) induced by oral challenge was evaluated clinically and reported by a semiquantitative scour index as 0 to 4+. Calf scour indexes showed an inverse relationship to the frequency of occurrence and to the levels of IgA and IgM in whey of dams vaccinated with killed vaccine, live vaccine, and culture supernatant, and from nonvaccinated controls. The data strongly suggested that IgA and colostral IgM anti-K immunoglobulins were important in passive immunity in experimental neonatal bovine colibacillosis.
Experimental neonatal colibacillosis in cows: serological studies.
Serological studies of passive immunity in experimentally induced bovine colibacillosis was studied in a 41-cow university herd. Pregnant dams were antigenized prepartum with two injections administered by the subcutaneous and intrammamary routes with one of four vaccine preparations (killed bacteria, live bacteria, culture supernatant, or heart infusion broth [control]). The data indicate that 77% of the neonates born to vaccinated dams were strongly protected against oral challenge with Escherichia coli strain B-44. Bacterial agglutinin and passive hemagglutination titers of colostral whey directly reflected the efficacy of the vaccines. A notable decrease in the whey titers to somatic and capsular antigens occurred after heat treatment at 56 C for 30 min. Complicity of heat-liable immune factor(s) in protection from scouring was suggested. The nature of the protective antigen is not clearly defined by these studies but there is some evidence that the K antigen may play a vital role in this regard.
Fetal mummification associated with porcine parvovirus infection.
A crossbred gilt farrowed 2 mummified fetuses at term, but subsequently developed uterine inertia and became listless. The remaining 5 fetuses of the litter (4 mummified and 1 normal appearing) were collected by hysterectomy. Porcine parvovirus (PPV) was isolated from tissues of the mummified fetuses, and masses of viral antigen were detected throughout the same tissues when cryostat sections were examined by immunofluorescence microscopy. Serum from the normal-appearing fetus of this litter had a hemagglutination inhibition (HI) titer for PPV of 320. The finding of antibody (HI titer of 1,280) in serum collected from the gilt on the day of farrowing, but not in serum collected 67 days before, indicated initial exposure to PPV during gestation.
Determination of zinc phosphide in range vegetation by gas chromatography.
Explore the source record for details and available documents.
Cell-mediated immunity in the uremic rat.
The popliteal node assay of the graft-versus-host reaction in the inbred rat provides a sensitive measure of cell-mediated immunity. Spleen cells from uremic Lewis rats as well as normal cells cultured in uremic serum demonstrated significant immunosuppression which was proportional to the severity of the uremia.
Current concepts in cavity design for amalgam restorations.
Explore the source record for details and available documents.
A study on cataplexy.
Explore the source record for details and available documents.
Differential conditioning of electrodermal responses: effects of performing a masking task during the interstimulus and intertrial intervals.
Explore the source record for details and available documents.
A study of the effect of temperature on the growth of Fasciola hepatica in Lymnaea truncatula.
Explore the source record for details and available documents.
An in vitro investigation of dynamic processes occurring in the schistosome tegument, using compounds known to disrupt secretory processes.
Explore the source record for details and available documents.