2 A prebiotic RNA apparatus functions within the contemporary ribosome

Ribosomes, the universal cellular machines, possess spectacular architecture accompanied by inherent mobility, allowing for their smooth performance as polymerases that translate the genetic code into proteins. The site for peptide bond formation is located within a universal internal semi-symmetrical region, which was identified within all contemporary ribosomes. The high conservation of this region implies its existence irrespective of environmental conditions and indicates that it may represent an ancient RNA molecular apparatus. Hence, we named it the “proto-ribosome”. This prebiotic pocket-like RNA entity is suggested to be capable to accommodate substrates whose stereochemistry enables the creation of chemical bonds. It could have evolved from an earlier catalytic RNA entity that we named the “pre-proto-ribosome”, presumed to be a molecular machine capable of performing various essential tasks in the RNA world, which was snatched by the amino acid invaders for producing proteins.     

Microenvironment created by stromal cells is essential for a rapid expansion of erythroid cells in mouse fetal liver

Mouse stromal cell lines (FLS lines), established from the livers of 13-day gestation mouse fetus, supported the proliferation and differentiation of the erythroid progenitor cells from mouse fetal livers and bone marrow in a semisolid medium in the presence of erythropoietin. A large erythroid colony of over 1000 benzidine-positive erythroid cells was developed from a single erythroid progenitor cell on the FLS cell layer after 4 days of culture. When in close contact with the layer, the erythroid progenitor cells divided rapidly with an average generation time of 9.6 h and mature erythroid cells, including enucleated erythrocytes, were produced. The present studies demonstrate that the microenvironment created by the stromal cells can support the rapid expansion of erythropoietic cell population in the fetal liver of mice.     

Autoradiographic Analysis of [3H]Imipramine Binding in the Human Brain Postmortem: Effects of Age and Alcohol

In vitro quantitative autoradiography of high-affinity [3H]imipramine binding sites was performed on 16 human brains postmortem. The densities of binding sites were highest in the hypothalamus. Next, in descending order, were the basal and lateral nuclei of the amygdala; substantia innominata; insular cortex; the central nucleus of the amygdala; the anterior nucleus of the thalamus; the head of the caudate nucleus; portions of the frontal, parietal, and temporal cortex; claustrum; the granular layer of the dentate gyrus; substantia nigra; the pyramidal layer of CA fields; globus pallidus; red nucleus; and white matter. Imipramine binding was found to increase with age in a region-specific manner. The presence of alcohol had a similar effect, which was most pronounced in the hippocampus. Sex and time from death to autopsy did not affect imipramine binding, in our sample.     

Our method of correcting cryptotia

Our technique for the correction of cryptotia using both Z-plasty and the advancement flap is described. The main advantages are the simple design of the skin incision and the possibility of its application to cryptotia other than severe cartilage deformity and extreme lack of skin.     

Induction of interdigitating reticulum cell-like differentiation in human monocytic leukemia cells by conditioned medium from IL-2-stimulated helper T-cells

Monocytic leukemia (MoL) cells were obtained from the peripheral blood of a patient in whom the leukemic cells infiltrating various lymphoreticular organs exhibited features intermediate between interdigitating reticulum cells (IDC) and ordinary phagocytic macrophages, whereas the leukemic cells in the peripheral blood were essentially monocytic and lacked such features. Peripheral blood CD4+ T-cells were established as an interleukin-2-dependent T-cell line. When the MoL cells were exposed for a few days to conditioned medium from the T-cell line, they extended several dendritic cytoplasmic projections and became intensely positive for HLA-DR antigen, cytoplasmic S-100β protein, and CD1 antigen. Functionally, the conditioned medium significantly down-regulated Fc-mediated and Fc-independent phagocytic activities, and the levels of lysosomal enzymes such as lysozyme and nonspecific esterase in the MoL cells. Moreover, the conditioned medium significantly up-regulated the accessory cell function of the MoL cells as measured by the primary allogenic mixed leukocyte reaction (MLR). Furthermore, the conditioned medium significantly down-regulated the expression of CD14 antigen. Biochemical analysis indicated that the factor responsible for these changes is a protein which is distinct from known human cytokines and whose molecular weight is approximately 31 kDa. These findings suggest that IDC are closely related the monocytic lineage and that helper T-cells play an important role in constructing the microenvironment of T-lymphoid tissues which is necessary for the differentiation and maturation of IDC.     

Effect of Chronic Desipramine Treatment on Dihydroalprenolol, Imipramine, and Desipramine Binding Sites: A Quantitative Autoradiographic Study in the Rat Brain

Desmethylimipramine (DMI) administered once daily for 10 days caused a significant decrease in beta-adrenergic receptor binding, as measured by quantitative autoradiography in discrete brain regions. The decrease was observed 72 h after the last injection throughout the cortex and in hippocampus but not in other regions, much richer in beta-receptors, such as the caudate, olfactory tubercle, superior colliculus, dorsomedial thalamus, substantia nigra, or pineal. The same paradigm did not affect imipramine (IMI) binding in the cortex or in regions with high concentrations of IMI binding sites. DMI binding was not decreased, either. Significant increases in DMI binding were observed in frontal cortex and in the ventral aspect of the bed nucleus of the stria terminalis. We conclude that a reduction in tricyclic binding is not a general phenomenon following chronic treatment with tricyclic antidepressants, and changes in binding, when they do occur, are not correlated with areas of high binding site density.     

Effect of a previous voluntary deep breath on laryngeal resistance in normal and asthmatic subjects

We studied changes in both laryngeal resistance (Rla) and respiratory resistance (Rrs) after a voluntary deep breath in 7 normal and 20 asthmatic subjects. Rla was measured using a low-frequency sound method (Sekizawa et al. J. Appl. Physiol. 55: 591-597, 1983) and Rrs by forced oscillation at 3 Hz. In normal subjects, both Rla and Rrs significantly decreased after a voluntary deep breath (0.05 less than P less than 0.01). During methacholine provocation in the normal subjects, a voluntary deep breath significantly decreased Rrs (0.05 less than P less than 0.01, but Rla was significantly increased (0.05 less than P less than 0.01). In 10 asthmatic subjects in remission, a voluntary deep breath significantly increased Rrs (0.05 less than P less than 0.01) but significantly decreased Rla (0.05 less than P less than 0.01). In another 10 asthmatic subjects during spontaneous mild attacks, a voluntary deep breath significantly increased both Rrs and Rla (0.05 less than P less than 0.01). The present study showed that without obvious bronchoconstriction, Rla decreased after a voluntary deep breath in both normal and asthmatic subjects but, with bronchoconstriction, Rla increased in both groups. Subtraction of the change in Rla from Rrs gives the change in Rrs below the larynx (Rlow). Rlow changed little or decreased in normal subjects and increased in asthmatic subjects, irrespective of base-line bronchomotor tone. These results suggest that airway response below the larynx after a voluntary deep breath differentiates patients with bronchial asthma from normal subjects.     

Genetic factors influencing neurosensitivity to early phenobarbital administration in mice

This study was designed to assess the possible genetic determinants of neurosensitivity to early (neonatal) phenobarbital (PhB) administration and to conduct a strain comparison for the cerebellar histology of both inbred and outbred mice. HS/Ibg, C57BL/10 and DBA/1 pups were injected with 50 mg PhB/kg daily on neonatal days 2-21. On day 50, treated animals (B) of all strains had smaller brains than controls (C). Moreover, the cerebellar area was decreased in HS and C57 B mice but not in DBA mice, suggesting genotype-environment interaction. B mice from all strains had similar Purkinje cell losses. Strain comparison showed that control C57 mice had smaller brains than control HS, and DBA had smaller brains than both HS and C57. Similarly, C57 had smaller cerebellar layers than HS and DBA had smaller cerebellar layers than both HS and C57. DBA and C57 mice had fewer Purkinje cells than HS but did not differ from each other.