In vitro formation of thyroid hormones from 3,5-diiodothyronine by supernatant of submaxillary gland

Cell-free extracts of submaxillary glands from rat and goat iodinate exogenously added 3,5-diiodothyronine to form 3,5,3’-triidothyronine and thyroxine. This capacity was elevated after either thyroidectomy or exposure of rats to cold (3 ±1 ‡C) for 5 h. However, there was no further increase of iodination of 3,5-diiodothyronine when the thyroidectomized rats were exposed to cold stress. The submaxillary extracts have the ability to incorporate radioactive iodide into 3,5-diiodothyronine, 3,5,3’-triiodothyronine and thyroxine. The presence of 3,5-diiodothyronine was also detected in the soluble supernatant of submaxillary extract.     

Histochemical studies on glycogen synthetase activity by autoradiographic method

Summary Glycogen synthetase (uridine diphosphate glucose-glycogen glucosyl transferase) was studied in different organs by a histoautoradiographic method and by usual staining methods. This activity was found to be present in muscles and liver of different animals. Human skin also showed some activity. Human liver and myocardium showed the highest activity.In the present study, it was found that the glucose-6-phosphate dependent form (D-form) of the glycogen synthetase predominates over the glucose-6-phosphate independent form (I-form) in all the organs except hamster liver where the I-form predominates.Addition of calcium chloride in the incubation medium, to prevent phosphorolytic breakdown of the newly synthesized glycogen, does not improve the reaction. No glucose is incorporated into glycogen from ¹⁴C-glucose-6-phosphate of the incubation medium for glycogen synthetase. Fixation in absolute alcohol at –20° is recommended for tissues where cytolysis is caused by the incubation medium.     

Non-coordinate regulation of RNA synthesis in escherichia coli exposed to 0°C

A non-coordinate mode of regulation of RNA synthesis is observed inEscherichia coli cells during exposure to 0°C. The stable RNA synthesis is preferentially inhibited with simultaneous accumulation of messenger RNA. The species of RNA synthesized at 0°C was determined by several criteria such as sedimentation value in sucrose gradients, DNA-RNA hybridization, half life measurements, protein synthesizing capacity and its functional rate of decay. The mode of regulation of RNA synthesis at 0°C is unique and is distinct from the non-coordinate regulation observed during amino acid starvation under stringent control.     

Comparison of normal distribution–based and nonparametric decision limits on the GH‐2000 score for detecting growth hormone misuse (doping) in sport

This paper is motivated by the GH‐2000 biomarker test, though the discussion is applicable to other diagnostic tests. The GH‐2000 biomarker test has been developed as a powerful technique to detect growth hormone misuse by athletes, based on the GH‐2000 score. Decision limits on the GH‐2000 score have been developed and incorporated into the guidelines of the World Anti‐Doping Agency (WADA). These decision limits are constructed, however, under the assumption that the GH‐2000 score follows a normal distribution. As it is difficult to affirm the normality of a distribution based on a finite sample, nonparametric decision limits, readily available in the statistical literature, are viable alternatives. In this paper, we compare the normal distribution–based and nonparametric decision limits. We show that the decision limit based on the normal distribution may deviate significantly from the nominal confidence level or nominal FPR when the distribution of the GH‐2000 score departs only slightly from the normal distribution. While a nonparametric decision limit does not assume any specific distribution of the GH‐2000 score and always guarantees the nominal confidence level and FPR, it requires a much larger sample size than the normal distribution–based decision limit. Due to the stringent FPR of the GH‐2000 biomarker test used by WADA, the sample sizes currently available are much too small, and it will take many years of testing to have the minimum sample size required, in order to use the nonparametric decision limits. Large sample theory about the normal distribution–based and nonparametric decision limits is also developed in this paper to help understanding their behaviours when the sample size is large.     

Improved plasmids containing the Escherichia coli dam gene under the control of the tac promoter.

We report the construction of a series of plasmids containing the dam gene under the control of the tac promoter. Cells containing these plasmids produce about 8 to 10-fold more Dam methyltransferase (Mtase) than the previously used plasmid pTP166 and avoid the use of a high temperature step necessary for the expression of Dam Mtase in the plasmid pDOX1 and thus allow its use for the study of thermosensitive mutants.