Murine adult hematopoietic cells produce adult erythrocytes in fetal recipients

Bone marrow cells from normal adult mice were introduced by microinjection via the placenta into W/W^v genetically anemic fetuses of 11 days' gestation. After birth, erythrocytes were fractionated by fluorescence-activated cell sorting on the basis of antibody binding to a fetal-specific antigen (Ft). Lysates of Ft-positive, i.e., fetal, erythrocytes did not detectably contain hemoglobin of the donor type, as judged from electrophoresis of strain-specific hemoglobin variants. Thus, adult hematopoietic bone marrow cells did not resume fetal differentiation despite their post-transplant maturation in a fetal environment.     

Creatine kinase, myokinase, and acetylcholinesterase activities in muscle-forming primary cultures of mouse teratocarcinoma cells.

Multipotential mouse teratocarcinoma cells in embryoid bodies were explanted on plastic or collagen substrates. Various modes of cell determination, including myogenesis, occurred. The predominant avenue of differentiation soon became myogenesis: many multinucleated myotubes formed and yielded an extensive network of skeletal muscle fibers. The process does not proceed to normal completion, as the fibers have a paucity of striations and are not contractile. Activities of several enzymes ordinarily associated with muscle differentiation were examined. Acetylcholinesterase activity increases, especially during myotube formation, as in normal myogenesis. However, creatine kinase activity rises during myotube formation and then drops abnormally, and myokinase activity fails to increase appreciably. The fetal isozymic form of creatine kinase is expressed in the cultures, although well differentiated solid tumors taken from mice show attainment of the adult muscle isozyme type if skeletal muscle is demonstrably present. The results are consistent with the interpretation that coordinately regulated changes in gene expressions controlling these functions may be required for later stages of myogenesis.     

Brain and ganglion development from two genotypic classes of cells in allophenic mice.

Several strain-specific markers were found to be histochemically visualizable in parts of the central nervous system in allophenic mice. These markers therefore provide a new basis for mapping the normal developmental lineages of major parts of the nervous system, and for identifying the focus of mutant gene action in some neurological mutations. Cell strains in mosaic animals were visualized on the basis of a quantitative difference in β-galactosidase activity (Bgs-locus), in the Purkinje zone of the cerebellum, and in the hippocampal pyramidal zone of the cerebrum. The differential between strains was increased if the beige ($\text{bg}{}^{\mathrm{J}}\text{bg}{}^{\mathrm{J}}$) mutation was included in the high-activity strain. (β-galactosidase is lysosomal, and enhanced visualization in beige results from its enlarged and aggregated lysosomes.) Purkinje cell-strain visualization was also obtained by an indirect fluorescent antibody technique, in sections treated with antisera containing antibodies against strain-type histocompatibility alloantigens, including H-2. The above markers reveal considerable interspersion of cells from separate lineages in short sequences of each genotype. Purkinje and pyramidal cells of the same brain sometimes differ appreciably in genotypic composition. The enzyme glucosephosphate isomerase was found histochemically to be localized in nerve fibers rather than cell bodies in the brain. However, it was prominent in the cell bodies of the spinal ganglia, so that biochemical determination of ganglion strain-types is possible by means of strain-specific isozymes (Gpi-1-locus). Individual ganglia contained both cell strains and thus are not individually derived as clones from the neural crest.     

Protein patterns of developmentally totipotent mouse teratocarcinoma cells and normal early embryo cells

Protein patterns of mouse teratocarcinoma stem cells were compared, by two-dimensional gel electrophoresis, with those of early embryo cells. These malignant cells were known from previous experiments (B. Mintz and K. Illmensee, 1975, Proc. Nat. Acad. Sci. USA72, 3585–3589) to be capable of conversion to normalcy and of contributing to embryogenesis when introduced into a blastocyst. The protein comparisons were intended to reveal whether totipotent teratocarcinoma cells most nearly resemble normal totipotent cells of a specific stage, as a possible clue to their developmental origins. A simple method was devised for the purpose of generally facilitating comparisons of two-dimensional gels, among which technical variations commonly alter the absolute positions of individual proteins. This variation was normalized by the use of a reference constellation, or a network of lines connecting shared landmark proteins identified in all the gels. Whereas the network may undergo topological change from one gel to another, it continues to provide a readily recognized standard of reference. Protein patterns displayed many similarities and some differences, hence nonidentity, between teratocarcinoma cells and all normal preimplantation embryo stages tested, as well as between the various embryo stages themselves. The results also unexpectedly disclosed, however, that changed physiological states or posttranslational alterations may contribute significantly to some of the protein differences irrespective of the developmental status or potentialities of the cells. For example, in the OTT 6050 teratocarcinoma transplant line, pure teratocarcinoma cell groups (“cores”) found in the ascites fluid synthesized several proteins not expressed when the cores were enveloped (in embryoid bodies) by a yolk saclike epithelium; yet the core cells from both sources form comparable tumors if injected subcutaneously and are able to undergo differentiation if injected into blastocysts. In another comparison, some proteins that were present in inner cell masses isolated from blastocysts were absent in intact blastocysts, possibly because of their modification by the surrounding trophoblast in the latter case. These observations imply that protein differences between embryo regions or stages, however real, are not necessarily relevant for an evaluation of their developmental prospects.     

The isolation and properties of a second glycoprotein (LGP-II) from the articular lubricating fraction from bovine synovial fluid.

A high-molecular-weight glycoprotein (LGP-I) was shown [Swann, Sotman, Dixon & Brooks (1977) Biochem. J. 161, 473--485] to be the major constituent in the articular lubricating fraction from bovine synovial fluid. In addition to the LGP-I component, a second glycoprotein (LGP-II) was also present. After fractionation of bovine synovial fluid by sequential sedimentation in CsCl density gradients, the LGP-I and LGP-II components were separated by gel-permeation chromatography. The LGP-II component was then purified by chromatography on DEAE Bio-Gel A and Bio-Gel P-150. The molecular weight of the LGP-II component was 48,800 calculated from sedimentation-equilibrium measurements. Amino acids represented 53% (w/w) and carbohydrate constituents 36% (w/w) of the molecule. Glutamic acid and lysine (144 and 100 residues/1000 residues) were the major amino acids. Glucosamine, mannose, galactose and N-acetylneuraminic acid [representing 8.0, 6.6, 9.5 and 11.9% (w/w) respectively] were the only carbohydrate constituents detected. Immunodiffusion analysis showed that LGP-II component did not form a detectable precipitin line with antiserum to bovine serum. It appears likely, therefore, that this glycoprotein is synthesized by the joint tissues and is not derived from serum.     

Radiosynthesis and evaluation of [11C]CMP,a high affinity GSK3 ligand

Dysfunction of GSK3 is implicated in the etiology of many brain, inflammatory, cardiac diseases, and cancer. PET imaging would enable in vivo detection and quantification of GSK3 and can impact the choice of therapy, allow non-invasive monitoring of disease progression and treatment effects. In this report, the synthesis and evaluation of a high affinity GSK3 ligand, [¹¹C]2-(cyclopropanecarboxamido)-N-(4-methoxypyridin-3-yl)isonicotinamide, ([¹¹C]CMP, (3), (IC₅₀?=?3.4?nM, LogP?=?1.1) is described. [¹¹C]CMP was synthesized in 25?±?5% yield by radiomethylating the corresponding phenolate using [¹¹C]CH₃I. The radioligand exhibited modest uptake in U251 human glioblastoma cell lines with ～50% specific binding. MicroPET studies in rats indicated negligible blood–brain barrier (BBB) penetration of [¹¹C]CMP, despite its high affinity and suitable logP value for BBB penetration. However, administration of cyclosporine prior to [¹¹C]CMP injection showed significant improvement in brain radioactivity uptake and the tracer binding. This finding indicates that [¹¹C]CMP might be a P-gp efflux substrate and therefore has some limitations for routine in vivo PET evaluations in brain.     

Early Isoflurane Exposure Impairs Synaptic Development in Fmr1 KO Mice via the mTOR Pathway

Neurochemical Research - General anesthetics (GAs) may cause disruptions in brain development, and the effect of GA exposure in the setting of pre-existing neurodevelopmental disease is unknown. We...     

Global Echoes in the Caribbean Playground

Becoming West Indian: Culture, Self and Nation in St. Vincent . Virginia Heyer Young
Global Culture, Island Identity: Continuity and Change in the Afro-Caribbean Community of Nevis . Karen Fog Olivig
Us and Them in Modern Societies . Thomas Hylland Eriksen
Women and Change in the Caribbean . Janet H. Momsen , ed.