Effects of retinoid beta-glucuronides and N-retinoyl amines on the differentiation of HL-60 cells in vitro

Retinoyl beta-glucuronide and retinyl beta-glucuronide, which are naturally occurring water-soluble metabolites of vitamin A, induce the granulocytic differentiation of HL-60 cells in vitro, as evidenced by an increased reduction of nitroblue tetrazolium. The relative effectiveness of various retinoids in differentiation is retinoic acid greater than retinoyl beta-glucuronide greater than retinyl beta-glucuronide. Under the selected assay conditions, retinol, hydroxyphenyl-retinamide, retinamide, and N-retinoyl-phenylalanine are essentially inactive in differentiation. At concentrations of retinoids from 10(-9) to 10(-5) M, cell viability was best with the retinoid beta-glucuronides and retinamide, less with retinoic acid and retinol, and poorest with the N-retinoyl aromatic amines. Cellular growth was depressed only slightly by retinyl beta-glucuronide and retinamide, but to a greater degree by the other derivatives. Retinoyl beta-glucuronide was hydrolyzed in part to retinoic acid, whereas retinyl beta-glucuronide was cleaved to retinol, if at all, at a very slow rate. Under the selected assay conditions, retinoic acid and the retinoid beta-glucuronides primarily induce the differentiation of HL-60 cells, whereas the N-retinoyl aromatic amines show cytotoxicity.     

Open-field behaviour in chickens: A replication revisited

In an attempt to show that the open field can still be used as a valid measure of fear, Jones (1983) has reported a failure to replicate some of our findings. The present studies show that this was due to procedural and methodological differences. For instance, we found that birds tested in a novel environment behaved quite differently from those, as in Jones' case, which were placed in one resembling the home cage. Moreover, birds housed in isolation for two days prior to testing reacted differently than those, as again in Jones' case, which were reared in isolation from hatching to the time of testing. The results were interpreted as being consistent with our view that open-field behaviour reflects a conflict between the need to reinstate contact with conspecifics on the one hand, and evade predation on the other.     

血红细胞超氧化物歧化酶(SOD)制备工艺的研究初报

本文报告了本实验室设计的由血红细胞自溶液60℃热变性, 乙醇——氯仿法除血红蛋白,旋转蒸发法减压浓缩抽去氯仿、乙醇,硫酸铵分级盐析法沉降SOD,Sepbadex G-75层析提纯SOD等步骤构成的一条成本低、设计合理、简便实用的分离纯化SOD的工艺路线。     

An ethological analysis of open-field behaviour in chickens

Two salient but previously unacknowledged aspects of open-field testing involve contact with a potential predator, as a consequence of placement in the open field by a human, and separation from imprinted companions. As a result we propose that open-field behaviour in chickens (Gallus gallus) represents a compromise between opposing tendencies to reinstate contact with conspecifics and minimize detection in the face of possible predation. Five experiments were conducted to test various implications of this model. Manipulations designed to enhance the predatory overtones of open-field testing were found to postpone reinstatement behaviours (e.g. distress calling and escape attempts) and prolong behaviours that serve to minimize detection (e.g freezing). Unlike the more traditional view of open-field behaviour as an index of general emotionality, our model suggests that the principal reason for movement is based on attempts to reinstate social contact. In support of the model, birds tested in the presence of cagemates showed significantly longer durations of freezing than those tested individually. The same was true for birds maintained in social isolation for two days prior to testing. The applicability of this approach to conceptualizing the behaviour of chickens in the open field is discussed, and the supposed relationship between fear and distress calling is critically evaluated.     

Affinity of Ionic Species of Nucleoside Transport Protein Inhibitors

Abstract

A class of very potent nucleoside transport inhibitors is present in two molecular forms around physiological pH. We investigated whether the monoprotonated or the unionized species of these molecules binds to this camer protein with higher affinity.     

Effects of Formalin-Inactivated Respiratory Syncytial Virus (FI-RSV) in the Perinatal Lamb Model of RSV

Respiratory syncytial virus (RSV) is the most frequent cause of bronchiolitis in infants and children worldwide. There are currently no licensed vaccines or effective antivirals. The lack of a vaccine is partly due to increased caution following the aftermath of a failed clinical trial of a formalin-inactivated RSV vaccine (FI-RSV) conducted in the 1960’s that led to enhanced disease, necessitating hospitalization of 80% of vaccine recipients and resulting in two fatalities. Perinatal lamb lungs are similar in size, structure and physiology to those of human infants and are susceptible to human strains of RSV that induce similar lesions as those observed in infected human infants. We sought to determine if perinatal lambs immunized with FI-RSV would develop key features of vaccine-enhanced disease. This was tested in colostrum-deprived lambs immunized at 3–5 days of age with FI-RSV followed two weeks later by RSV infection. The FI-RSV-vaccinated lambs exhibited several key features of RSV vaccine-enhanced disease, including reduced RSV titers in bronchoalveolar lavage fluid and lung, and increased infiltration of peribronchiolar and perivascular lymphocytes compared to lambs either undergoing an acute RSV infection or naïve controls; all features of RSV vaccine-enhanced disease. These results represent a first step proof-of-principle demonstration that the lamb can develop altered responses to RSV following FI-RSV vaccination. The lamb model may be useful for future mechanistic studies as well as the assessment of RSV vaccines designed for infants.