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Biomedical subjects

R Merrell

Publications and source records attributed to R Merrell.

6 recordsLinked to original sources
PubMed1991

Parathyroid adenoma in a cancer center patient population.

The association of parathyroid adenoma and antecedent events or relationships was examined retrospectively in 103 patients with parathyroid adenoma drawn from a cancer institute patient population. Patients were divided into two study groups by the referral pattern-intramural or community. The major contrast between the two groups was that the intramural patients had cancer diagnoses. The factors of advanced age, female gender, and prior regional irradiation appeared to be associated with the development of parathyroid adenoma. An interrelationship of incidental cancer and parathyroid adenoma, however, was not supported. Breast and differential thyroid cancers were most frequently associated with parathyroid adenoma, but age, gender, and irradiation were bias influences.

Adenoma↗
PubMed1990

Transplantation of adrenal medullary tissue to caudate nucleus using stereotactic techniques.

Stereotactic techniques were used to transplant adrenal medullary tissue to the head of the right caudate nucleus in 12 patients with Parkinson's disease. No significant lasting complications were seen. All patients had an initial improvement. 11 of the 12 patients remain improved over their preoperative condition after 6-18 months, 3 with good results and 9 with only modest improvement. At 6 months, the mean Schwab and England score had improved from 59.2 +/- 18.8 preoperatively to 75.8 +/- 15.1 (p less than or equal to 0.01) and the mean Hoehn and Yahr scale had improved from 3.42 +/- 0.90 to 2.92 +/- 0.63 (p less than or equal to 0.01).

Adrenal Medulla↗
PubMed1977

Studies on cell recognition in the developing brain.

Several lines of evidence demonstrate cell-cell receptors on the surface of developing brain cells. Plasma membrane vesicles with regional and temporal binding specificities can be prepared. Active factors that block cell aggregation can be extracted from these membranes and partially purified. Quantitative studies of cell-cell adhesion demonstrate a gradient of adhesive specificity along the dorsoventral axis of the developing retina.

Animals↗
PubMed1975

Embryonal cell surface recognition. Extraction of an active plasma membrane component.

Plasma membranes obtained from different neural regions of the chicken embryo have previously been shown to specifically bind to homotypic cells and prevent cell aggregation (Merrell, R., and Glaser, L. (1973) Proc. Natl. Acad. Sci. U. S. A. 70, 2794-2798). Proteins responsible for the specific inhibition of cell aggregation have been solubilized from the plasma membrane of neural retina and optic tectum by delipidation with acetone followed by extraction with lithium diiodosalicylate. The extracts show the same regional and temporal specificity as previously shown for plasma membrane recognition by the same cells (Gottlieb, D. I., Merrell, R., and Glaser, L. (1974) Proc. Natl. Acad. Sci. U. S. A. 71, 1800-1802). Two micrograms of the most purified protein fraction inhibits the aggregation of 2.5 times 10(-4) cells under standard assay conditions. This represents a 20-fold increase in specific activity compared to whole membranes.

Animals↗
PubMed1975

Temporal changes in tectal cell surface specificity induced by nerve growth factor.

The change in cell surface adhesive specificity previously shown to occur between day 7 and 8 of development in the chick optic tectum ]Gottlieb et al. (1974), Proc. Nat. Acad. Sci. USA 71, 1800-1802] can be induced in rotating cultures of tectal cells by the addition of 10(-7) M mouse submaxillary gland nerve growth factor. Insulin, proinsulin, dexamethasone, and performic-acid-oxidized nerve growth factor are individually inactive in this system, but nerve growth factor in which the three tryptophan residues/subunit have been oxidized with N-bromosuccinimide is active. Thus, the specificity of this system for nerve growth factor is different than that observed with embryonic dorsal root or sympathetic ganglia, where the oxidized tryptophan derivative is inactive in stimulating neurite production. It is possible that in this system nerve growth factor serves as an analog of another specific trophic factor, presumably structurally related to nerve growth factor, may be active at much lower concentrations.

Age Factors↗