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Biomedical subjects

R Parkman

Publications and source records attributed to R Parkman.

143 records · Page 8Linked to original sources
PubMed1975

Attempted immunologic reconstitution of patients with combined immune deficiency syndrome with bone marrow transplantation from histoincompatible donors.

The immunologic reconstitution from patients with combined immune deficiency syndrome was attempted with bone marrow transplantation from histoincompatible donors. None of the patients achieved long-term immunologic reconstitution. In all cases, the incompatible bone marrow was treated before transplantation. Physical separation of the stem and immunocompetent cells was attempted in 2 cases with the use of enhancing antibody in one of the attempts. The selective destruction of the immunocompetent bone marrow cells after specific stimulation was attempted in the last 2 cases.

Antibody-Producing Cells↗
PubMed1975

Lymphocytotoxins and immunologic unresponsiveness.

A 14-year-old boy with a lifelong history of recurrnet infections and debilitating bronchiectasis was found to lack any evidence of humoral or cellular immunity. His serum contained a high titer of IgM antibody to the heavy chain of IgG and this antibody was also cytotoxic for peripheral lymphocytes. Complement-dependent lymphocytotoxicity could be blocked by IgG or Fc fragment. In this patient, immunosuppression may have been due to an autoantibody against both autologous IgG and lymphocyte plasma membrane.

Adolescent↗
PubMed1970

Murine sarcoma virus: the question of defectiveness.

Infection of mouse and rat cells by the murine sarcoma virus (Moloney isolate) showed two-hit kinetics for focus production in mouse cells but one-hit kinetics in rat cells. Antiserum added to cultures after infection suppressed focus formation in mouse cells but not in rat cells. These studies suggest that, in rat cells infected with murine sarcoma virus, leukemina virus is not needed for focus formation and that these foci result from proliferation of the transformed rat cell; in mouse cells, on the other hand, leukemia virus is needed as "helper," and focus formation requires spread of virus. The term "defectiveness" then, if used, should not be applied to RNA tumor viruses without qualification for the viral function studied and the cell system employed.

Animals↗
PubMedDate not supplied

Surface protein abnormalities in lymphocytes and platelets from patients with Wiskott-Aldrich syndrome.

Lymphocytes from three patients with the Wiskott-Aldrich syndrome were subjected to surface radioiodination and their 125I-labelled surface proteins were analysed by SDS-polyacrylamide gel electrophoresis and autoradiography. Autoradiographs demonstrated the absence in all three patients of an 125I-labelled protein, molecular weight of 115 000, that was present in normal individuals. In addition, one patient had an additional labelled protein, molecular weight 135 000, not found in normal individuals. The platelets from one patient were radioiodinated and the 125I-labelled membrane proteins were analysed. Glycoproteins Ia and Ib were reduced in amount and restricted in heterogeneity while glycoproteins IIb and IIIa were normal. These results suggest that the primary defect in the Wiskott-Aldrich syndrome may be abnormalities of (glyco)proteins normally present on the surface of lymphocytes and platelets.

Blood Platelets↗
PubMedDate not supplied

An in vitro evaluation of a new plasticizer for polyvinylchloride medical devices.

The rate of Hatcol-200 (H-200) leaching from polyvinylchloride (PVC) by serum is one-hundredth that of di-2-ethylhexyl phthalate (DEHP) as determined by radioassay. There is a proportional decrease in leachability of DEHP but not of H-200 as the plasma proteins are diluted. Saline extracts of DEHP demonstrated a low but progressive rate of leaching with an accumulation of 11 microgram/ml after seven weeks whereas H-200 showed only a constant residue of 0.35 microgram/ml. Normal human serum incubated for three weeks at 37 C with PVC strips plasticized with DEHP produced significant growth-inhibition of human diploid fibroblasts. Human serum incubated in an identical manner with PVC plasticized with H-200 for up to four weeks demonstrated no effect on tissue culture. These studies indicate that H-200 deserves further evaluation as a replacement for DEHP in PVC biomedical devices.

Diethylhexyl Phthalate↗