In the fruit fly optic lobe, T4 and T5 cells represent the first direction-selective neurons, with T4 cells responding selectively to moving brightness increments (ON) and T5 cells to brightness decrements (OFF). Both T4 and T5 cells comprise four subtypes with directional tuning to one of the four cardinal directions. We had previously found that upward-sensitive T4 cells implement both prefer...

The well known effect of T4 administration is suppression of TSH level in plasma; with small doses of T4 has been shown to potentiate goitrogenesis induced by goitrogenic drugs. The effects of hort term treatment with sm3.11doses of T4 on plasma and pituitary TSH levels were studied in mice, Very sm3.11doses of T4 caused an increase in circulating TSH while larger dose produced the usual decrea...

Studies of the rate of extrathyroidal conversion of thyroxine (T4) to 3,5,3'-triiodo-L-thyronine (T3) were carried out in rats. Total body homogenates were prepared and extracted with ethanol 48, 72, and 96 hr after the intravenous injection of (125)I-T4. (131)I-T3 was added, and the paper chromatographic purification of T3 was effected by serial elution and rechromatography in three paper and ...

Development of bacteriophage T4 depends on the physiological state of its host cell. Based on previous studies performed under laboratory conditions with different media determining various growth rates of Escherichia coli, a mathematical model was developed which suggested that phage T4 development cannot proceed efficiently in bacteria growing with a doubling time longer than 160 min. Contrar...

Numerous studies have suggested a marked correlation between thyroid functionality indices and lipid metabolism. In this trial we assessed the functional parameters of 165 individuals over 70, 87 women and 78 men, correlating the serum values of T3, T4, FT4, TSH with cholesterol, triglycerides, HDL, Apo-A and Apo-B levels. The correlation was performed over the whole population studied and subs...

UNLABELLED In order to examine the significance of differences in the triiodothyronine/thyroxine (T3/T4) ratio in the achievement of euthyroidism and in different thyroidal diseases, we studied 1050 subjects: 233 were euthyroid (Eu), 239 hypothyroid (Hypo) with initial TSH levels >15 mU/L, 273 hypothyroid on substitution therapy with L-thyroxine alone and TSH values of 0.35-3.5 mU/L, (hypoRx), ...

It is known that some nutrients can have both negative and positive effects on some populations of insects. To test this, the Logrank test and the Interval Overlap Test were evaluated for two crop cycles (February-May and May-August) of the 7705 tomato hybrid, and the effect on the psyllid, Bactericera cockerelli (Sulc.) (Hemiptera: Triozidae), was examined under greenhouse conditions. Tomato p...

The present study was undertaken to define the source of endogenous triiodothyronine (T3) production responsible for maintaining serum T3 levels in euthyroid subjects with depressed serum thyroxine (T4) values. After withdrawal from 4 wk of exogenous T3 administration, a 22% decline in serum T3 values (from 129 +/- 6 to 99 +/- 4 ng/dl) was observed in six euthyroid subjects, despite a twofold r...