Assignment of the gene encoding the human thyrotropin-releasing hormone receptor to 8q23 by fluorescence in situ hybridization

A cDNA for human thyrotropin-releasing hormone (TRH) receptor has been isolated from a human pituitary cDNA library. By using this cDNA as a biotinylated probe, the gene encoding the TRH receptor has been localized to chromosome 8q23 by in situ hybridization.     

Cyclooxygenase and 5-lipoxygenase inhibitory activity of 2,6 di-t-butylphenols linked by a sulfur atom to 1,3,4-thiadiazoles and 1,3,4-oxadiazoles

The preparation of a series of 1,3,4-thiadiazoles and 1,3,4-oxadizoles linked by a thioether to 2,6-di-t-butylphenol and the inhibition of cyclooxygenase (CO) and 5-lipoxygenase (5-LO) by these compounds is dicussed.     

Quantitation of chloramphenicol acetyl transferase (CAT) messenger RNA by filter hybridisation using a digoxigenin label

Summary Slot- and dot-blotting are commonly used to evaluate levels of messenger ribonucleic acid (mRNA). Quantitation of bacterially-expressed chloramphenicol acetyl transferase (CAT) mRNA by this method is highly dependent on total RNA immobilised onto the solid support as well as mRNA concentration. mRNA quantitation by comparison with a pure standard results in underestimation. An improved protocol for CAT mRNA detection is described.     

Iron Regulation in the Developing Rat Brain: Effect of In Utero Ethanol Exposure

Abstract: Fetal alcohol syndrome produces defects that parallel abnormalities associated with early iron deficiency. Hence, we examined the effects of prenatal exposure to ethanol on iron, transferrin, and ferritin concentrations. The subjects were the offspring of pregnant rats fed an ethanol-containing diet (Et), pair-fed an isocaloric control diet (Ct), or fed chow and water. The amounts of iron, transferrin, and ferritin were assessed in three CNS regions (cerebral cortex, subcortical forebrain, and brain-stem). In all three segments of the control rats, iron, transferrin, and ferritin levels decreased during the first 2 postnatal weeks, reached a minimum during week 3, and then rose to adult levels. This pattern was delayed by ethanol treatment, e.g., the minimal concentrations in iron, transferrin, and ferritin in the Et-treated rats were achieved later (3 days, 7 days, and 2 weeks, respectively) than they were in the Ct-treated rats. Ethanol-induced alterations in iron homeostasis persisted into adulthood; iron concentration was reduced, transferrin concentration was unaffected, and ferritin concentration was increased. The net result was that the timely delivery and bioavailability of iron were compromised by ethanol exposure. The defects in iron regulation are permanent and may underlie ethanol-induced abnormalities in iron-dependent growth processes such as myelination.     

Stoichiometry and apparent dissociation constant of the calcium-arsenazo III reaction under physiological conditions.

In vitro and in situ tests have been run to characterize the reaction of the mettalochromic indicator, arsenazo III, with calcium. Job plots as well as plots of indicator absorbance vs. [Ca2+] at different indicator concentrations show a 1:1 reaction stoichiometry. Equilibrium analysis and analysis using Adair's equation are also consistent with 1:1 complexes being formed and give estimates of 34 and 45 muM for the apparent dissociation constant. In situ tests were carried out using giant neurons from Archidoris monteryensis, a marine gastropod mollusc. Dye absorbance changes were measured during voltage clamp pulses which produced a fixed calcium influx. The dependence of absorbance change on total dye concentration is consistent with the formation of a 1:1 complex of Ca with ArIII if measurements are made during the initial period of the loading pulse, less than 300 ms, although the apparent dependency changes with longer delay in measurements from the onset of the pulse.     

The cholesterol turnover, synthesis, and absorption in two sisters with familial hypercholesterolemia (type IIa).

To explore the mechanisms of the profound plasma cholesterol elevations in familial homozygous hypercholesterolemia (type IIa), cholesterol turnover, sterol balance, cholesterol absorption, and low density lipoprotein studies were carried out under controlled dietary conditions in two sisters (aged 13 and 16). Cholesterol turnover was prolonged. The half-life of the first exponential of the plasma cholesterol specific activity decay curve was double that of normal adults. The rate constants for the removal of cholesterol from pool A (KAA = 0.0652) and for the excretion of cholesterol from the system (Kaa = 0.0197) were less than half of normal. The production rates of cholesterol were low, only 6.30 and 6.86 mg/kg per day as measured by cholesterol turnover and sterol balance techniques, respectively. Fecal neutral steroid and bile acid excretion were 5.22 and 1.64 mg/kg per day, which is remarkably low in comparison to those of normal and heterozygous children. Cholesterol absorption was within the upper limit of the values reported for normal adults. THE HDL cholesterol values were extremely low (27 mg/dl) in contrast to profoundly elevated LDL levels. The fractional catabolic rate of LDL (0.127 per day) and the rate of synthesis and catabolism of apo-LDL (15 mg/kg per day) were low in comparison to previously reported values in homozygotes. These composite data indicated that the definable metabolic defects of these two sisters with homozygous familial hypercholesterolemia were the sluggish clearance of cholesterol from the body coupled with low total body synthesis of cholesterol.