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Biomedical subjects

W C Mentzer

Publications and source records attributed to W C Mentzer.

86 records · Page 5Linked to original sources
PubMed1975

Dimethyl adipimidate: a new antisickling agent.

A new approach to the prevention of sickling in vitro by use of the bifunctional crosslinking reagent, dimethyl adipimidate, is described. Prior treatment of sickle erythrocytes with dimethyl adipimidate will inhibit sickling in completely deoxygenated erythrocytes. Treated erythrocytes do not demonstrate the potassium loss and viscosity increase that usually accompany sickling. The oxygen affinity of hemoglobin in these cells is increased independently from changes in the concentration of 2,3-diphosphoglycerate. The hemoglobin obtained from treated erythrocytes contains a high-molecular-weight component as well as additional positively charged components. The relative degree to which chemical modification and/or crosslinking is an essential part of the antisickling properties of the material is not known.

Adipates↗
PubMed1975

Hereditary stomatocytosis: membrane and metabolism studies.

A defect in the protein kinase-mediated phosphorylation of erythrocyte membrane proteins, previously unrecognized in stomatocytosis, was discovered in a boy with hereditary stomatocytosis and severe hemolytic anemia. The high-sodium, low-potassium erythrocytes of this patient were remarkably permeable to both sodium and potassium. The rate of ouabain-inhibitable active cation transport was more than ten times normal and was sustained by an increase of similar magnitude in glycolysis. The deformability in vitro of fresh stomatocytes was reduced and deteriorated further after a brief period of incubation with glucose. Ferrokinetic studies showed that these rigid cells were sequestered by the spleen. When stomatocytes were deprived of glucose in vitro, ATP depletion and ATPase cation pump failure rapidly ensued. Because of their permeability defect, such depleted cells rapidly became swollen and lysed. Prolonged entrapment in acidic, hypoglycemic regions of the spleen would recapitulate these unfavorable events in vivo. In this regard, splenectomy was followed by an improvement in erythrocyte survival, although evidence of continuing hemolysis was obtained.

Abnormalities, Multiple↗
PubMed1971

Selective reticulocyte destruction in erythrocyte pyruvate kinase deficiency.

Radioisotope studies of bilirubin turnover, ferrokinetics, and red cell survival ((51)Cr) in a patient with erythrocyte PK deficiency have provided evidence for prompt reticulocyte sequestration and destruction by the reticuloendothelial system. More mature erythrocytes appeared to survive well despite their deficiency of PK. PK-deficient reticulocytes, dependent upon oxidative phosphorylation for ATP production, are exquisitely sensitive to cyanide- or nitrogen-induced mitochondrial inhibition. If oxidative phosphorylation is unavailable, ATP levels decline rapidly, producing alterations in the cell membrane which allow massive losses of potassium and water. The result is a shrunken, spiculated, viscous cell whose rheologic properties would favor its sequestration by the reticuloendothelial system. Those reticulocytes with particularly low levels of PK exhibit very low glycolytic rates and thus are uniquely reliant upon oxidative phosphorylation. Other reticulocytes, better endowed with PK activity, can meet the increased ATP requirements of young erythrocytes. Upon reaching maturity, such cells have diminished ATP needs and can, therefore, survive despite their enzyme deficiency.

Adenosine Triphosphate↗
PubMedDate not supplied

Bone marrow transplantation for beta-thalassemia: the University of California San Francisco experience.

We report the results of allogeneic HLA-matched family donor stem cell transplantation in 17 North American children with beta-thalassemia major or hemoglobin E/beta-thalassemia who received transplants at the University of California San Francisco. Pretransplantation conditioning was with busulfan, cyclophosphamide, and antithymocyte globulin and graft-versus-host prophylaxis used cyclosporine, usually with added methotrexate. Twelve children are alive, well, and free of the clinical manifestations of thalassemia. Four experienced graft rejection and autologous recovery, and one died from complications shortly after transplantation. Overall survival was 94% and event-free survival 71%, results similar to those obtained by other transplantation centers. Improved conditioning regimes and enlargement of the donor pool will be needed to improve the outcome of transplantation and to make this treatment available to more children with thalassemia.

Adolescent↗