PubMed Health⌕ Search

Biomedical subjects

S Gutman

Publications and source records attributed to S Gutman.

8 recordsLinked to original sources
PubMed1996

Food and Drug Administration (FDA)'s impact on laboratory performance: FDA's perspective.

The Division of Clinical Laboratory Devices is responsible for the premarket review of in vitro diagnostic devices (laboratory tests). We currently process >1000 diverse applications per year. New versions of old devices are handled as premarket notifications, so-called 510(k) submissions. The review objective is to establish that the new product is "substantially equivalent" to its predicate. Fundamentally new devices are handled as premarket applications. The review objective is to establish de novo that the product is ¿safe and effective.¿ A central regulatory issue over the past several years has been the development of a standardized model for scientific review. The Food and Drug Administration contributes to the quality of in vitro diagnostic devices by providing oversight and objective review, by setting thresholds for product safety and effectiveness, and by ensuring that organized data and appropriate labeling is present in support of a device's intended use.

Chemistry, Clinical↗
PubMed1985

The effect of in vivo glucose administration on human erythrocyte Ca2+-ATPase activity and on enzyme responsiveness in vitro to thyroid hormone and calmodulin.

To characterize endogenous control mechanisms for human erythrocyte membrane Ca2+-ATPase ("calcium pump") activity, we studied the effect of changes in blood glucose concentration in vivo within the physiologic range on Ca2+-ATPase activity in red cells. Red cells obtained in the course of induced hyperglycemia were also studied to determine susceptibility of membrane Ca2+-ATPase to stimulation in vitro by thyroid hormone and calmodulin, both of which have been shown previously to enhance Ca2+-ATPase activity. Oral glucose administration (75 g) to eight healthy, adult subjects induced predictable increases in concentrations of blood glucose and immunoreactive insulin. Basal levels of activity of Ca2+-ATPase in red cells obtained after glucose ingestion fell 55% (P less than 0.025) by 30 min after glucose with recovery of enzyme activity to levels not significantly different from basal by 60 min. Activity of red cell Ca2+-ATPase at time zero was significantly stimulated in vitro by thyroxine (T4, 10(-10) M), triiodo-L-thyronine (T3, 10(-10) M), and calmodulin (100 ng/mg membrane protein). In vivo glucose administration led to depression of red cell enzyme responsiveness in vitro to T4 and T3; recovery from this effect did not occur by 120 min after oral administration of glucose. Calmodulin responsiveness of the enzyme in vitro was less significantly reduced in red cells obtained after glucose ingestion. Intravenous (i.v.) glucose administration (20 g) to five subjects also led to decreased basal enzyme activity (61% of fasting level at 20 min). A significant decrease in response of enzyme to T4 was achieved by 8 min after glucose administration (P less than 0.02), with recovery by 60 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Effect of end-stage renal disease on responsiveness to calmodulin and thyroid hormone of calcium-ATPase in human red blood cells.

Red blood cell membrane Ca2+-ATPase, a calcium-pump-associated enzyme, has been studied in a series of 10 patients with ESRD and in a group of normal volunteers. Basal enzyme activity was significantly reduced in cells from ESRD patients (0.189 +/- 0.018 vs. controls, 0.274 +/- 0.021 mumoles of Pi per milligram of membrane protein per 90 min; P less than 0.001). Calcium efflux from intact red cells, a functional correlate of Ca2+-ATPase activity, was also decreased in ESRD patients. Normal erythrocytes have recently been shown to have membrane Ca2+-ATPase activity that can be stimulated in vitro by physiologic concentrations of thyroid hormone (10(-10) M). In the present studies, ESRD red cell membrane Ca2+-ATPase activity was found to be unresponsive to thyroid hormone. In addition, calcium efflux from intact ESRD cells, in contrast to normal red cells, could not be stimulated by thyroid hormone. ESRD membrane Ca2+-ATPase was also poorly-responsive in vitro to purified calmodulin, the activator protein of the enzyme. This reduction in activity of Ca2+-ATPase in ESRD red cells is similar to previously described alterations in sodium-potassium-ATPase, another membrane-linked cation pump.

Animals↗