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Biomedical subjects

R Spector

Publications and source records attributed to R Spector.

At least 163 records · Page 9Linked to original sources
PubMed1978

Does intervention by a nurse improve medication compliance?

A random sample of patients taking two or more drugs, at least one of which was digoxin or methyldopa, was drawn from a medical clinic population. After giving informed consent, the patients were randomized into control and experimental groups. The experimental group was seen by a specially prepared nurse interventionist who attempted to improve medication compliance. The levels of the drugs in the blood were taken as indicators of medication compliance. Our results document that patients exposed to nurse intervention were more compliant than the general clinic population, but were not more compliant than a nonintervention control group. Problems encountered in the collection and interpretation of compliance study data were identified and discussed.

Aged↗
PubMed1977

Ascorbic acid transport by a clonal line of pheochromocytoma cells.

A clonal line of rat pheochromocytoma cells was used as a model of noradrenergic tissue to study ascorbic acid transport. These cells were used because, like sympathetic neurons, they synthesize large amounts of noradrenaline in the presence of ascorbate, they respond to nerve growth factor with the production of neurites and they release, store and take up catecholamines. In these cells, both with and without nerve growth factor (NGF) treatment, [14C]ascorbic acid was concentrated by a stereospecific saturable, energy dependent transport system that could be described by a Michaelis-Menten transport model. The Kt and Vmax for ascorbic acid were approximately 0.03 mM and 0.3 nmole per min per mg protein respectively for both untreated and NGF-treated cells. The ability of the cells to concentrate ascorbic acid was not due to intracellular binding. Cells untreated with NGF and loaded with [14C]ascorbic acid to a concentration of 5.6 nmoles per mg protein retained only 6% of the initial intracellular [14C]ascorbic acid after the 24 h in normal growth medium. Thus, although pheochromocytoma cells contain an ascorbate concentrating system, optimal production of noradrenaline requires ascorbate in the medium.

Adrenal Gland Neoplasms↗
PubMed1977

Identification of folate binding macromolecule in rabbit choroid plexus.

A macromolecular binder of folic acid and folic acid derivatives has been identified in the particulate fraction of homogenates of rabbit choroid plexus. Within the choroid plexus, there are 2.3 nmol of folate-binding activity (binder) per g of tissue. The molecular weight of the folate binder complex, separated from the particulate fraction after solubilization with Triton X-100, was 340,000 to 400,000 by Sephadex gel filtration. The partially purified binder, when freed of endogenous folates, bound equivalent amounts of both [3H]folic acid and [methyl-14C]methyltetrahydrofolic acid per mg of protein. Folic acid, homofolic acid, 5-methyltetrahydrofolic acid, and to a lesser degree, methotrexate, inhibited the binding of both [3H]folic acid and [14C]methyltetrahydrofolic acid. Binding activity, which decreased below pH = 7.0, was unaffected by pretreatment with ribonuclease but was eliminated completely by papain and a protease (Streptomyces griseus). Although dihydrofolate reductase was present in choroid plexus, the binder was distinct from dihydrofolate reductase as judged by gel filtration and methotrexate sensitivity. This high affinity binder of folates may be responsible, in part, for the rapid, saturable uptake of folic acid and methyltetrahydrofolic acid by rabbit choroid plexus in vitro.

Animals↗