Biomedical subjects
Publications and source records attributed to J Gardner.
Charcoal and magnetisable ferric oxide were entrapped in a polyacrylamide gel and, after lyophilisation and micronisation, empolyed for the uptake of free antigen in a radioimmunoassay for digoxin. The results obtained were similar to those using a conventional charcoal separation method.
Tumor cells introduced into the rabbit vitreous produced a form of retinal neovascularization, but only when the tumor cells were in direct contact with the vascularized retina. This contrasted with the production of neovascularization at a distance of several millimeters in other angiogenesis models. An extract of adult rabbit vitreous was found to inhibit the growth of limbal neovascularization induced by tumors implanted in the rabbit corneal stroma. The experimental model of retrolental fibroplasia provides a bioassay to investigate further the apparent inhibitory substances in the vitreous.
This study was designed to compare the outcomes achieved in a series of acute care episodes by different levels of family practice providers working in the clinic setting. The study utilizes a method which depends upon the provider to estimate level of function expected and earliest date of recovery for each episode. When the patients are viewed as a single group, those patients treated by the medex appear to fare considerably better and those seen by a faculty member do worse; however, when each functional status group is examined separately, only the asymptomatic but clinically ill patients (45 cases) show a statistically significant difference in outcomes among the providers, with the medex having good results and the faculty poor results.
The acetylcholine receptor in skeletal muscle is an integral plasma membrane glycoprotein. Its biosynthesis and incorporation into plasma membrane and its degradation are being studied with the use of biochemical, biophysical, and microscopic techniques. In this report, previously published data are combined with new information to yield a consistent and fairly detailed description ofthe mechanisms involved in receptor metabolism. It is proposed that the biosynthesis, transport, and incorporation of the receptor into plasma membranes involve a mechanism similar, or identical, to that used by the cell for production and secretion of secretory proteins. The receptor is degraded by a random-hit process, which involves internalization, transport to secondary lysosomes, and hydrolysis. Sites of regulation of receptor metabolism are discussed in the context of regulation of the number and distribution of receptors in plasma membranes, particularly with respect to the formation and stability of neuromuscular junctions.
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The ability of Friend erythroleukemic cells to bind transferrin and take up its iron increases substantially as a result of dimethyl sulfoxide-stimulated differentiation. Although transferrin-binding activity is also demonstrable in another mouse cell line of hematopoietic origin, the lymphoma cell, it does not increase on exposure to dimethyl sulfoxide. Gel filtration studies corroborate that the binding of transferrin to the erythroleukemic cells is due to the formation of a specific complex of transferrin and a membrane receptor. Thus, the specific interaction of transferrin with its receptor is another expression of dimethyl sulfoxide-induced differentiation in the Friend cell.
The head position of 95 infants, born between 30 and 37 weeks gestational age, was observed every 15 min for 2 hr weekly from birth until 39 weeks conceptional age. At 35 weeks and increasingly thereafter, significantly more time was spent with the head to the right than to the left. By 39 weeks the infants were similar to term infants: almost 90% spent 80% or more time with their heads to the right. The increase appeared independent of intra- or extrauterine experience; neither age at birth nor time since birth was consistently related to head position. Unlike term infants, prematures were equally likely to turn left as right and have their heads left as right 15 min after release from a midline position. These findings suggest complex determinants of asymmetry including factors intrinsic to the fetus and those contributed by the uterine environment.
Organotypic cultures of dorsal root ganglion cells revealed neuronal toxicity when exposed to myoinositol at doses of 1090 to 109 micrometer (500 to 50 microgram/ml). The ultrastructural changes consisted of membranous cytoplasmic bodies at high concentrations and dense bodies at lower concentrations. There were no changes at 0 to 22 micrometer (0 to 10 microgram/ml). This range of neurotoxicity parallels the levels of myoinositol found in the serum of uremic patients. Myelin loss occurred in a pattern suggesting "secondary demyelination," similar to the pattern seen in uremic neuropathy. The relevance as a possible model for uremic neuropathy is discussed.
The outcomes of a series of some 410 acute episodes from two family practice centers were rated on the degree to which the patient regained his usual functional status and his satisfaction with the outcome and the process of care. A portion of outcomes (251) were then compared to process scores obtained using explicit criteria and the rest to implicit process ratings based on the problem-oriented record. In both instances those cases with good outcomes had better process scores than those with bad outcomes; neither measure of satisfaction had a consistent relationship with either process measure.
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Some 1,700 acute care episodes were studied to assess the outcomes in terms of the extent to which patients regained their usual functional status. Involving active follow-up of each patient, the study serves as a prototype for measuring several components of quality of care including actual outcomes, patient expectation of outcome, physician expectation of outcome, and patient satisfaction with outcome and care. Because this study was conducted in a family practice residency training setting, we hope that it will serve as a model of how such information may be used to increase residents' sensitivity to the course of illness commonly seen in primary care, and to encourage the residents to set expectations for the care they give.
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A detailed comparative assessment was made of the use of solid-phase-coupled antibodies in radioimmunoassay, by using an assay for human placental lactogen as a model system. The major advantages of the solid-phase technique are: (1) in common with the use of a second antibody, it is universally applicable; (2) separation can be carried out rapidly; (3) in contrast with some other techniques, the separation of antibody-bound and free antigen is virtually complete. The disadvantages when compared with other procedures are: (1) a considerable proportion of the antibody may be lost during the initial coupling reaction; (2) the tubes must be continuously mixed during incubation, and much effort is expended in removing and replacing the caps; (3) there is a decrease in the apparent affinity constant of the antibody after coupling, which is reflected in a lower sensitivity of the assay system. It is concluded that solid-phase antibodies are of greatest value in those systems in which the supply of antiserum is abundant, and in which the achievement of high sensitivity is not a requirement.
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Late after infection of cultured human cells (KB) with adenovirus type 2, the nucleus contains heterogeneous viral RNA species ranging in size from 10 to 43 S. Four viral RNA species found in the nucleus (36, 38, 40, and 43 S) are synthesized predominantly during a 15-min labeling period with [(3)H]uridine, while smaller RNA species accumulate when labeling is continued for longer periods. In contrast, 6-8 viral RNA species, of sedimentation coefficient from 10 to 29 S, are found in the cytoplasm after a 30-min pulse label and a 2-hr chase. DNA-RNA hybridization-competition experiments demonstrate that viral RNA sequences present in nuclear 36-43S RNA are also present in cytoplasmic and polyribosomal RNA, suggesting that at least some of the cytoplasmic viral-specific RNA molecules are derived by cleavage of high molecular weight precursors from the nucleus.