Structural features of thyroid hormone response elements that increase susceptibility to inhibition by an RTH mutant thyroid hormone receptor

The chicken lysozyme silencer F2 (F2) thyroid hormone response element (TRE) contains an unusual everted palindromic arrangement, has a high affinity for thyroid hormone receptor (TR) homodimers, and is especially sensitive to dominant negative inhibition by, the T3 resistance (RTH) mutant TR beta P453H. We used various TREs and TR mutations to determine the mechanisms for this sensitivity. Changing the F2 orientation from an everted palindrome to a direct repeat with a 4-bp gap (DR+4) (F2-DR) decreased the sensitivity to inhibition at high T3 concentrations, while a loss of this sensitivity occurred with a palindromic arrangement of these same half-sites. F2 contains the dinucleotide TG 5' to each consensus half-site conforming to the optimal TR-binding octamer, YRRGGTCA. A T to A change in position 1 of both F2 half-sites markedly reduced T3-induction, yet only slightly reduced TR homodimer or TR-retinoid X receptor (RXR) heterodimer binding. The TR beta ninth heptad mutation, L428R, prevents TR heterodimerization with RXR and eliminates the inhibitory effect of the P453H mutant TR on the F2-DR, but not the F2 element. Structural features of a TRE that favor strong TR binding of both TR homodimers and TR-RXR heterodimers containing the mutant TR, such as the everted palindromic conformation or the optimal TR-binding consensus octamer, enhance the sensitivity of a TRE to inhibition by the mutant TR. Thus, both half-site orientation and sequence contribute to the sensitivity of a given TRE to dominant negative inhibition by a mutant TR.     

Readmission discount factors in program evaluation. An output value analysis of an adult psychiatry program

The application of output value analysis, a type of benefit/cost analysis, to a psychiatric patient population is reported. A method for discounting the value of the program if a patient was readmitted within a year after discharge was introduced. The application of this discount factor reduces the value produced by the program and thereby reduces both productivity and effectiveness indices. When applied to groups known to differ in readmission rates, such as first admissions and readmissions or voluntary and involuntary admissions, the discount factor can accentuate group differences markedly. When selected diagnostic groups were compared, the discount factor could even reverse the relative standing of the groups.     

Growth of clinical isolates of anaerobic bacteria on agar media: effects of media composition, storage conditions, and reduction under anaerobic conditions

The quantitative growth, the colony size, and the rate of growth of 47 clinical anaerobic isolates were compared on five different media, namely Brucella agar, brain heart infusion agar, Columbia agar, Schaedler agar, and tryptic soy agar. There was no significant difference in the quantitative growth of the anaerobes inoculated onto the five media. Although no single medium was superior for the growth of all isolates, 12 of 22 isolates, inoculated onto media stored for 4 weeks or less, grew best on Schaedler agar. The effects of supplementation of the media with reducing agents and reduction of the media before use were also analyzed and were found to be affected by the composition and length of storage of the media, as well as the bacteria tested.     

Cytogenetic studies of the Australian rodent, Uromys caudimaculatus, a species showing extensive heterochromatin variation

The Australian rodent, Uromys caudimaculatus, consists of two chromosome races. a) The Southern Race is characterized by the possession of two to twelve B-chromosomes. These vary considerably in size, morphology, and C- and G-banding characteristics, they behave as univalent at meiosis and are inherited in a random manner. b) The Northern Race lacks B-chromosomes, but possesses large blocks of distal C-positive heterochromatin on between 18 and 28 of the 46 chromosomes. The C-blocks may be entirely G-positive entirely G-negative, or G-banded, suggesting heterogeneity with the C-blocks. There is extensive variation both between and within populations of the northern race in the number and size of the distal heterochromatic blocks. There is no apparent difference between the races in chiasma frequency. The northern race does have much higher proportion of interstitial versus distal chiasmata, although it is probable that this is merely a reflection of lack of crossing over in the heterochromatic blocks rather than an actual shift of chiasma localisation within the euchromatin. Despite the extensive differences between the races in the amount and organization of constitutive heterochromatin, hybrids show no abnormalities at meiosis and they are fully fertile.     

Investigation of the piroxicam/hydroxypropyl-β-cyclodextrin inclusion complexation by means of a supercritical solvent in the presence of auxiliary agents

The complexation of piroxicam and 2-hydroxypropyl-β-cyclodextrin by means of supercritical CO₂ has been investigated. The experiments were carried out by varying the temperature, pressure and contact time and introducing two different auxiliary agents: polyvinyl pyrrolidone or l-lysine.Cyclodextrins, which are widely used to solubilize a large variety of poorly soluble drugs, are often used in combination with some auxiliary agents to enhance the complexation efficiency of the conventional techniques. While many recent literature works report that supercritical carbon dioxide is a clean, non-toxic alternative to organic solvents, the use of auxiliary agents in the supercritical complexation process has been scarcely examined and still needs to be investigated.The inclusion complexes obtained in this work were analysed by means of the ‘differential solubility method’, differential scanning calorimetry and Fourier transform infrared spectroscopy. The results showed that the supercritical treatment could be successfully employed below 140-150 °C without incurring thermal degradation of the samples. While 66% inclusion efficiency could be obtained at 140 °C and 30 MPa for a mixture of piroxicam/2-hydroxypropyl-β-cyclodextrin (1:2 molar ratio), higher percentages of complexation (95% in the ternary samples with polyvinyl pyrrolidone and 89-91% in those with l-lysine) could be obtained at a lower temperature (130 °C) when auxiliary agents were employed.     

High dielectric response of cobalt aluminate mullite (CAM) nanocomposite over cobalt aluminate mullite polymer (CAMP) nanocomposite in PVDF matrix

In this communication we have compared the dielectric behavior of cobalt aluminate mullite (CAM) nanocomposite and cobalt aluminate mullite polymer (CAMP) nanocomposite with different molar concentration of Co ⁺² ions. The study of dielectric property of the CAM samples as well as that of the CAMP samples at room temperature shows that at all concentrations the dielectric constant is higher than pure mullite and there is a critical concentration of Co ⁺², where maximum enhancement of dielectric property occurs. This paper demonstrates that the loading of a conductive component into a highly insulating matrix is an effective way to fabricate composites with high permittivity as well as a charge storage material. We have designed a device using CAM as the electrode material and CAMP as the separator to compare it with a commercial Li-polymer ion mobile battery. We observed that the charge storage ability of the composite system is better than the commercial Li-polymer ion mobile battery. Our device persists for more than 24 h while the maximum voltage recorded by the device is 0.885 V, whereas the maximum voltage recorded by the conventional commercial Li-polymer ion mobile battery is 0.566 V.     

颗粒增强纯铝基复合材料的磨损特性

研究了Ａｌ２Ｏ３及ＳｉＣ颗粒增强纯铝基复合材料的磨损特性，结果表明，Ａｌ２Ｏ３或ＳｉＣ颗粒的加入，提高了复合材料的耐磨粒磨损性能，随着颗粒含量的增加，复合材料的耐磨性增大；ＳｉＣ与Ａｌ２Ｏ３复合材料的耐磨性相近；复合材料孔隙率较大时耐磨性降低；复合材料的耐磨性不随硬度升高而增加；颗粒增强纯铝基复合材料干摩擦的磨损机理以磨粒磨损为主；润滑摩擦的磨损机理为氧化磨损．