The role of clonal deletion and anergy in oral tolerance.
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Biomedical subjects
C C Whitacre
Publications and source records attributed to C C Whitacre.
A technique for separation of canine lymphocytes and their use in the lymphocytotoxic, blastogenic, and rosette assys.
When the techniques established for preparing lymphocytes from human blood were applied to canine blood, the resulting preparations were contaminated with significant numbers of other blood cells. A three-step technique is described here for the separation of canine lymphocytes from blood which eliminates most granulocytes, platelets, and erythrocytes. Defibrinated blood is incubated with iron particles to allow phagocytosis by granulocytes. When mixed with Plasmagel, erythrocytes and iron-containing granulocytes sediment rapidly, leaving a lymphocyte-rich supernate plasma which is recovered and banded by centrifugation on a Ficoll-Hypaque gradient. Any erythrocytes remaining in the lymphocyte suspension aspirated from the gradient are eliminated by hypotonic lysis and centrifugation. The resulting preparation, representing 30 per cent recovery of the circulating lymphocytes, contained 85 to 94 per cent lymphocytes with a cell viability of 99 per cent. The functional capacity of the lymphocyte preparation was tested in three assays: 1) lymphoblastic transformation using phytohemagglutinin and pokeweed mitogen, 2) E rosette formation with human erythrocytes showed a mean 5 per cent rosette forming lymphocytes, 3) antibody-mediated lymphocytotoxicity using a canine anti-lymphocyte serum showed titers reproducible within one tube dilution.
Animals↗
MR of head and neck adenopathy in asymptomatic HIV-seropositive men.
PURPOSE: Adenopathy is a well-known component of AIDS-related complex. Our goal was to determine whether asymptomatic HIV-infected persons have characteristic findings of head and neck adenopathy on MR imaging and whether there is an association between the MR findings and the CD4 lymphocyte counts. METHODS: We blindly and retrospectively evaluated the distribution and size of lymphadenopathy seen on screening MR examinations that were performed on 50 asymptomatic HIV-positive male subjects and 50 age-matched HIV-negative control subjects. We also correlated the imaging findings in HIV-seropositive and -seronegative subjects with their CD4 counts. RESULTS: The HIV-positive subjects had a higher incidence of adenopathy compared with the controls. Statistically significant differences were found between the groups in size and number of neck lymph nodes, thickness of the adenoids, size of high, deep cervical-retropharyngeal lymph nodes, and presence of parotid abnormalities. We found a correlation between increasing lymph node size and decreasing CD4 levels. CONCLUSION: We conclude that HIV-positive asymptomatic patients have a high incidence of head and neck abnormalities including lymphadenopathy, and alteration in their CD4 counts not commonly seen in seronegative control subjects.
Adult↗