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Biomedical subjects

R Morrison

Publications and source records attributed to R Morrison.

At least 73 records · Page 4Linked to original sources

Immunofixation of complement component C3 phenotypes in bloodstains after cellulose acetate electrophoresis.

The determination of the polymorphic C3 phenotypes was accomplished by electrophoresis on cellulose acetate followed by immunofixation. The three common phenotypes resulting from the two common codominant alleles C3S and C3F were clearly distinguishable in blood and bloodstain samples. Storage and degradation of C3 in blood samples as well as the stability of C3 in dried bloodstains is discussed.

Blood Stains↗

Biochemical and x-ray diffraction analysis of concanavalin B crystals from jack bean.

Parallel biochemical and crystallographic studies have been carried out on the protein concanavalin B from Jack Bean (Canavalis ensiformis). The studies show the protein to be a monomer of 33,000 daltons with unexceptional amino acid composition and no covalently bound carbohydrate. The molecule contains a single, firmly bound zinc ion and we present evidence that the protein specifically binds nucleotide coenzymes including at least NADPH and flavin mononucleotide. An electron density map of the concanavalin B crystals (space group P6(1), a = b = 80.9 A, c = 102.2 A) has been calculated from phases based on six isomorphous heavy atom derivatives. A description of the structure of the protein based on the 5.0 A resolution x-ray diffraction study is provided. The structure appears to contain a substantial amount of alpha-helix as well as an extensive beta-sheet and these are organized into two domains of unequal size. The position of the bound zinc is indicated by anomalous difference Fouriers and the nucleotide binding site by conventional difference Fourier maps.

Journal Article↗

Epidermal growth factor binding and mitogenic activity on purified populations of cells from the central nervous system.

Binding of 125I-epidermal growth factor (EGF) to purified populations of rat astrocytes, oligodendrocytes, and neurons was measured. Astrocytes bound 40,000-100,000 EGF molecules per cell, while oligodendrocytes bound only 6,000-10,000 EGF molecules per cell. In contrast, neurons had little or no capacity to bind 125I-EGF. EGF alone was able to stimulate incorporation of tritiated thymidine fivefold in purified astrocyte cultures incubated in serum-free medium. When EGF was added to the previously described chemically defined medium for astrocytes, incorporation of tritiated thymidine in purified astrocytes was equivalent to that observed in medium containing 10% fetal calf serum. Addition of EGF to this chemically defined medium also doubled the proliferative capability of the medium for cultured astrocytes. EGF was maximally effective in stimulating 3H-thymidine incorporation at concentrations between 1-10 ng/ml.

Animals↗

Evaluation of the Tamari-Kaplitt LVAD.

Experience with a modern inexpensive, unichambered heparinized "left ventricular assist device" in the closed chest unheparinized dog is described. The pumps were driven with EKG activated air drives. These functioned well. The major physiologic problems were absolute limitation of inflow and late mural and valve disk thrombus formation at pump times approaching 5 to 6 hrs, under the limitations of the experiment. The inexpensiveness of this LVAD, its obvious practicality in terms of application as a counter pulsator in human open heart surgery and now in experimental animals, provides some hope that an inexpensive, practical, functional preanticoagulated LVAD of this type may ultimately result in a significant improvement in the utility and cost effectiveness of this approach to left ventricular failure.

Animals↗

Carcinoma of the bladder - radiotherapy.

Differentiated transitional cell carcinoma responded better to radiotherapy than anaplastic or squamous cell carcinoma. Five year survival was higher in low stage than in high stage carcinoma, and higher in papillary than in solid carcinoma. Tumour control, but also complication rate, increased with higher radiation dose. With the introduction of a two volume irradiation technique, a large tumour dose can be given with a minimum of complications.

Carcinoma↗

Calcium metabolism in cancer. Studies using calcium isotopes and immunoassays for parathyroid hormone and calcitonin.

Studies of calcium metabolism in 38 patients with cancer indicated that: 1) intestinal absorption of calcium was reduced in patients with skeletal metastases and in those with hypercalcemia; 2) calcium-47 space (a measurement of bone turnover rate) was high in the patients with skeletal metastases; 3) hypercalcemic patients had higher urinary and endogenous fecal excretion of calcium than those who were normocalcemic; 4) levels of plasma immunoreactive parathyroid hormone were similar in normo- and hypercalcemic patients, but the levels for a given serum calcium in malignant disease were lower than those in primary hyperparathyroidism; and 5) some patients had elevated calcitonin levels. Hypercalcemia complicating malignant disease is therefore not due to hyperabsorption or diminished excretion of calcium, and a low calcium diet is unlikely to benefit these patients. Measurement of 47Ca space could be of use in monitoring therapy of patients with skeletal metastases, and measurement of plasma parathyroid hormone could be useful in the differential diagnosis of hypercalcemia.

Adult↗