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Biomedical subjects

R B Johnson

Publications and source records attributed to R B Johnson.

At least 181 records · Page 10Linked to original sources
PubMed1976

Establishment of erythropoiesis following bone marrow transplantation in a patient with congenital hypoplastic anemia (Diamond-Blackfan syndrome).

Marrow transplantation was attempted in a 13-yr-old boy with congenital hypoplastic anemia who had never responded to corticosteroid therapy. Prior to the transplant, he had received 238 transfusions, at least 12 of which were from his father. He was prepared for grafting with antilymphocyte globulin, procarbazine, and total body irradiation (1000 rads). The patient, whose red cells were Group B, then received marrow cells from his Group O, histocompatible, sister. Thereafter, reticulocytes, Group O erythrocytes, and female leukocytes appeared in the peripheral blood. Erythroid precursors were seen in the patient's marrow for the first time in his life, and all lacked fluorescent Y chromosomes. Dividing cells were all female. After initially progressing well, the patient developed interstitial pneumonia and died 55 days after the transplant. The successful erythroid graft suggested that this patient's failure to produce red blood cells was due to a defective stem cell rather than to a humoral defect, plasma inhibitor, or abnormal marrow microenvironment. It suggested further that sibling marrow may be engrafted in patients who have received multiple transfusions, even from a parent.

Adolescent↗
PubMed1975

Coffee treat or trick?

The popularity of coffee is due not only to its pleasant taste and aroma but also to its physiologic and psychologic effects. These effects are caused mainly by the caffeine provided in the beverage. However, caffeine may have adverse effects as well, including stimulation of gastric acid secretion. A relationship between heavy coffee ingestion and myocardial infarction has not yet been established but it is a bothersome possibility.

Adult↗
PubMed1975

The self-instructional materials project: progress and prospects.

Faculty members in the Health Sciences Consortium have developed replicable, exportable units of instruction under the direction of the Self-Instructional Materials Project. The project distributes currently 350 packages and lists 570 in it's Directory of Self-Instructional Materials. Published evaluation studies indicate improvement on national board exams with greater efficiency and savings in time when compared with other forms of instruction. One study shows similarity of results with students who use the materials in hospitals away from the university. Four basic activities are necessary to initiate and enlarge the collection of units available on each campus: training, production, tryout/revision and sharing. Analysis of trends for each set of activities is projected over a five-year period. As training activities decline, greater emphasis is placed on quality control and procedures for sharing materials that are under development.

Evaluation Studies as Topic↗
PubMed1975

Simplified Scatchard-plot assay for estrogen receptor in human breast tumor.

In this two-point Scatchard-plot assay, with which a test of competitive inhibition is combined, the sample is mechanically homogenized in a buffer containing dithiothreitol, ultracentrifuged to obtain a fat-free cytosol, the protein content of which is then adjusted, and free and bound labeled estradiol are separated with dextran-coated charcoal after overnight incubation. We tested the method for precision and reliability by assaying such cytosols from pregnant rabbit uteri before and after dilution with kidney cytosol, and by assaying several other target and nontarget animal and human tissues. The Scatchard plot data were more reliable than tests for percent inhibition of binding by a competitor (diethylstilbestrol). For a tumor tissue to be judged positive it must bind at least 8 fmol of estradiol per milligram of protein and have a Kd of 0.1 to 5 X 10(-10) mol/liter. Some non-target tissues showed less than 70% inhibition by 10(4)-fold concentrations (over labeled estradiol) of inhibitor. Of 19 breast-tumor specimens, seven were found to be positive.

Binding Sites↗