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Biomedical subjects

A Gordon

Publications and source records attributed to A Gordon.

At least 289 records · Page 16Linked to original sources
PubMed1977

The effect of triiodothyronine on 2-deoxy-D-(1-3H)glucose uptake in cultured chick embryo heart cells.

The uptake of 2-deoxy-D-[1-3H]glucose ([1-3H]DOG)by cultured chick embryo heart cells was stimulated by exposure to triiodothyronine (T3). The concentration of free T3 for half maximal stimulation of [1-3H]DOG uptake was 8.7 x 10(-10)M. Nuclear binding studies revealed that the Kd for T3 was 4.2 x 10(-10)M. The molar potencies of other thyroactive compounds in stimulating [1-3H]DOG uptake, relative to L-T3, were: 500% for 3'-isopropyl-3,5-diiodo-L-thyronine, 20% for L-thyroxine (T4), 17% for D-T3, 2.2% for D-T4, 0.6% for 3,5-diiodo-L-thyronine and less than 0.1% for 3',5',3-triiodo-L-thyronine and L-thyronine. These data suggest that cultured chick embryo heart cells may serve in the study of the mode of action of thyroid hormones.

Animals↗
PubMed1977

The effects of actinomycin D, puromycin, cycloheximide and hydroxyurea on 3',5,3-triiodo-L-thyronine stimulated 2-deoxy-D-glucose uptake in chick embryo heart cells in vitro.

The uptake of 2-deoxy-D-[1-3H]glucose ([1-3H]DOG) by cultured chick embryo heart cells was stimulated by L-triiodothyronine (T3). This stimulation began with the exposure to T3, rose linearly for about 8 h and reached a plateau around 24h. Actinomycin D, puromycin and cyclohexmide had no effect on the stimulated sugar uptake during the first 6h. These agents prevented the further increase in the rate of [1-3H]DOG uptake in T3-treated cultures that occurred between 6 and 24h. In the presence of hydroxyurea the uptake of [1-3H]DOG in both control and T3-treated cells was unchanged. These results suggest that some of the effects of T3 may not require new synthesis of either RNA, proteins or DNA.

Animals↗
PubMed1977

The effect 3,5,3'-triiodo-L-thyronine on the kinetic parameters of sugar transport in cultured chick embryo heart cells.

The effect of 3,5,3'-triiodo-L-thyronine (T3; 10(-8)M) on sugar transport was studied in cultured chick embryo heart cells. T3 did not increase the uptake of L-glucose, a sugar which enters the cell by simple diffusion. The effect of T3 on the kinetic parameters of the uptake of both 3-0-methyl-D-glucose (3-OMET) and 2-deoxy-D-glucose (2-DOG) was studied after 6 and 24 h exposure to T3. T3 had no effect on the Km for either sugar. T3 increased the Vmax for the first 6 h or exposure for 3-OMET, a sugar which is only transported, and increased the Vmax after 6 and 24 h for 2-DOG, a sugar both transported and phosphorylated. T3 also increased the relative phosphorylation of 2-DOG within the cells in the period between 6 and 24 h. The data show a biphasic effect of T3 on sugar accumulation, an early effect on transport along and a later effect on phosphorylation as well.

Animals↗
PubMed1977

Computer study of thyroid diseases. III. Statistical models.

A binary-variable multiple-regression model is proposed for the computer diagnosis of thyroid disease. The procedure employs a multiple-regression technique in which each variable is assigned a value of either unity or zero. Unlike other current approaches, the proposed model uses only information about the patients themselves; no prior knowledge of the incidence of the disease in the population under study is required. The model was applied to data on 906 patients with suspected thyroid disorders referred to endocrine clinics in Israel. On the basis of simple physical findings and clinical signs and symptoms, the correct diagnosis was obtained in 95% of the cases for males and in 85% for females.

Diagnosis, Computer-Assisted↗
PubMed1977

The effect of renal transplantation on middle molecules in plasma and urine.

The plasma level and urinary excretion of middle molecules were determined in 5 patients with chronic uremia undergoing renal transplantation. The results demonstrate that after successful transplantation, the uremic middle molecules disappear rapidly from plasma while being excreted in the urine. The reduction in plasma level of middle molecules after transplantation is more rapid than the reduction in creatinine concentration.

Adult↗
PubMed1976

Renal transplantation in a Community Hospital.

Eighty renal transplantations were performed at an urban community hospital over a ten-year period. Forty-two transplants were from living related donors and 38 from cadaver donors. The one-year rejection rate for cadaveric transplants was 35% and for transplants between parents and children, 31%, whereas only one of 21 (5%) transplants between siblings was rejected during the first year. These results compare favorably with those reported by others and appear to justify performance of kidney transplantation in the community hospital setting where large numbers of transplant surgeons and nephrologists are involved, and where the number of transplants never has exceeded 15 per year.

Adolescent↗
PubMed1976

An inter-laboratory comparison of total serum triiodothyronine determination.

L-triiodothyronine (T3) standards and an unknown serum were prepared and distributed to 18 different laboratories. T3 was determined on the standards and both T3 and T4 were assayed on the serum. The T3 and T4 results varied widely with a mean variance of 36 and 23%, respectively. There was, however, a positive correlation between the T3 values obtained within each laboratory and results of the unknown serum. Thus, while the data of each laboratory is internally consistent, the data between laboratories cannot be compared without an appropriate reference sera. From this fact, it is concluded that absolute ("true") T3 concentrations in human serum is not yet known. Because of the small number of laboratories involved in this comparison, it was not possible to determine which factors of the various procedures are responsible for the variance of the T3 results.

Evaluation Studies as Topic↗
PubMed1975

Changes in flow and pressure due to rotation of a saphenous vein segment.

The effect of axial rotation on flow through and pressure gradient across saphenous vein segments was studied using 15 cadaver long saphenous veins. A significant reduction in flow occurred at a mean rotation of 25 degrees/cm and a significant increase in head loss across the segments occurred at a mean rotation of 23 degrees/cm. Collapse of the vein segments occurred at a mean rotation of 27 degrees/cm.

Blood Flow Velocity↗
PubMed1975

Optimal length of a saphenous vein segment when used as an arterial substitute.

An in-vitro experiment using 12 cadaver long saphenous veins was performed to determine the optimal length of a saphenous vein segment intended for use as an arterial substitute. This length was found to be 8% greater than the body length, as judged by maximal flow through the veins and 6% greater than body length judged by minimal pressure loss across the vein segments. Extreme extension of the veins resulted in incomplete transverse rupture of the inner layers of three of the veins tested.

Arteries↗
PubMed1975

Triiodothyronine binding in rat anterior pituitary, posterior pituitary, median eminence and brain.

In vivo studies of the exchange of tracer [125-I]-L-triiodothyronine (T3) between plasma (P), and the anterior pituitary (AP), posterior pituitary (PP), median eminence (ME) and the frontal lobes of the brain (B), in the rat show that from 2.5 h onwards the concentration of new [125I]T3 in AP, PP and B were parellel to that of the plasma, with a t1/2 of 7.4 h; the t1/2 for ME was 10.3 h. The extrapolation of these curves to zero time was assumed to indicate the relative concentration of T3 per unit weight in terms of total body T3. T3 content of these tissues was determined by radioimmunoassay. The values obtained validated the steady state parameters derived from the radio-isotopic measurements. As an indicator of the concentration gradient between tissue and plasma the organ/plasma (O/P) ratio was calculated; these data indicate that under steady state conditions, the order of T3 concentration is AP greater than PP greater than ME greater than B. Binding studies have shown that AP and PP contain "specific," saturable binders while ME and B do not. Evaluation of the binding parameters of the high affinity binders in both AP and PP gave similar association constants. These associations constants, when corrected for the binding strength of T3 to plasma proteins, resulted in values similar to those of neuclear T3 binders.

Animals↗