Induction of angiogenic response by chemically stable prostacyclin analogs

Angiogenic activities of several chemically stable prostacyclin analogs (isocarbacyclins and 7-fluoro prostacyclin) were evaluated by the chick embryo chorioallantoic membrane assay. These compounds showed potent angiogenic activity at very low concentration (0.1 micrograms/egg 1.0 micrograms/egg), whereas naturally occurring prostaglandins such as prostacyclin and PGE1 were almost ineffective up to 1 microgram/egg. Pretreatment of chorioallantoic membranes with dexamethasone or indomethacin inhibited the angiogenic response induced by these chemically stable prostacyclin analogs. These results indicate that these prostacyclin analogs induce the angiogenic response of chick chorioallantoic membranes via a mechanism involving activation of inflammatory cells, as well as through their direct angiogenic activity.     

Isolation of tetraploid clones with high efficiency from diploid 3Y1 rat fibroblasts treated with sodium butyrate

Summary Sodium butyrate causes proliferation arrest with a G2 (4C) DNA content and induces formation of tetraploid cells upon removal of the inhibitor, in rat 3Y1 diploid fibroblasts. We isolated tetraploid clones from the butyrate-treated 3Y1 cells with high efficiency; among 21 clones randomly isolated, 5 were pure diploid, 7 were mainly tetraploid with a small contaminating diploid population, and 7 were pure tetraploid. Among the pure tetraploid clones, two showed doubled chromosome numbers with slightly broader distributions than that seen in parental 3Y1 cells. Butyrate further induced polyploid formation in the tetraploid cells thus produced, but octaploid cells that resulted could not be maintained for prolongeed, cultivation. We found no difference between the tetraploid and the (parental and parallel isolated) diploid clones in terms of colony-forming ability, proliferation rate, and sensitivity to density-dependent inhibition of proliferation. These results suggest that doubling of chromosome number by itself does not cause a change in proliferation property. The tetraploid clones had lower average saturation densities possibly due to enlargement of cell size represented by higher cellular protein content.     

The production of ethylene by plants determined by means of paper chromatography

Ethylene was collected in methanol solution of mercuric acetate and the addition compound formed was then separated by means of paper chromatography. The spot area and colour intensity after detection were determined using a densitometer. The amount of collected ethylene was calculated from a calibration curve. The ethylene liberated from plant samples was collected during one or two days. During this period the amputation of the whole plant organs did not influence ethylene production. Changes in ethylene production were found after segmentation of the tissue or after the treatment with auxin and Co²⁺ ions. The above-ground parts of investigated herbs released 0.3 to 3.5 μl of ethylene per kg fresh weight per hour. The leaves of investigated trees released 1 to 20 μl of ethylene per kg f.w. per hour. The rate of the production of ethylene seems to be specific for a given species.     

Factors determining the biosynthesis of griseofulvin and similar substances

Была высказана гипотеза, что биосинтез гризеофульвине, цитромицетина, фульвиновой кислоты, фусаeубине, руброфусарина и родствеооых им вешеств протекаеР не путем конденсации линейнон цепочки, а из двух более коротких цепочек, которые возникают конденсацией 4 и 3 ацетатных единп. реакции, осушествляющиеся на уровне этих цапочек (илн прнмежувочных структур) метиляция, редукция, и, возможно, последующая дегидратация или только эноэизация— определяют направление дальнeйшeй кондeнсации в такой стeпeни, что конeчныe продуктыотдичаются своeй структурой.     

Cost of allogeneic and autologous blood transfusion in Canada. Canadian Cost of Transfusion Study Group.

OBJECTIVE: To determine the cost, from a societal perspective, of blood transfusion in Canada. STUDY DESIGN: Cost-structure analysis. SETTING: Data were collected from eight hospitals and from six blood centres operated by the Canadian Red Cross Society in four provinces. OUTCOME MEASURES: Costs associated with four stages of transfusion-- collection, production, distribution and delivery--in 1933 were assessed. Costs were divided into the following categories; personnel, purchases, external services, overhead, donors'' time, patients'' time (for autologous transfusion), wastage and infection. RESULTS: The mean overall cost of a transfusion performed on an inpatient basis was $210 per unit of red blood cells for an allogeneic transfusion and $338 per unit of blood for an autologous transfusion. The mean cost of an allogeneic transfusion performed on an outpatient basis was $280 per unit of red blood cells. CONCLUSION: The costs determined in this study can be used in future studies comparing the cost-effectiveness of allogeneic transfusion with that of alternative methods.     

Organ correlations inchenopodium rabrum l. shoots studied by Means of32P Distribution

21-day old plants ofChenopodium rubrum L. ecotype 374 were used. Organ relationships in the shoots were investigated by³²P distribution, which indicated different organ correlations in plants grown in continuous light and in plants treated with flower-inducing and non-inducing dark periods. Dark periods were associated with a low³²P distribution in young leaves and a high one in axillary buds. In the following light period the high³²P distribution in axillary buds continued whereas the³²P distribution in the leaves on the main axis increased and was similar to that in plants grown in continuous light. The high³²P distribution in axillary buds was brought about by both, flower-inducing and non-inducing dark treatments. Decapitation resulted in a high³²P distribution in buds, in continuous light an increased³²P distribution was also found in leaves. These effects were not fully cancelled by IAA application. The results are discussed with respect to an assumption that decrease of apical dominance represents a step in a sequence of events leading to flowering.     

Suppression of Recombination Losses in Polymer:Nonfullerene Acceptor Organic Solar Cells due to Aggregation Dependence of Acceptor Electron Affinity

Here, it is investigated whether an energetic cascade between mixed and pure regions assists in suppressing recombination losses in non‐fullerene acceptor (NFA)‐based organic solar cells. The impact of polymer‐NFA blend composition upon morphology, energetics, charge carrier recombination kinetics, and photocurrent properties are studied. By changing film composition, morphological structures are varied from consisting of highly intermixed polymer‐NFA phases to consisting of both intermixed and pure phase. Cyclic voltammetry is employed to investigate the impact of blend morphology upon NFA lowest unoccupied molecular orbital (LUMO) level energetics. Transient absorption spectroscopy reveals the importance of an energetic cascade between mixed and pure phases in the electron–hole dynamics in order to well separate spatially localized electron–hole pairs. Raman spectroscopy is used to investigate the origin of energetic shift of NFA LUMO levels. It appears that the increase in NFA electron affinity in pure phases relative to mixed phases is correlated with a transition from a relatively planar backbone structure of NFA in pure, aggregated phases, to a more twisted structure in molecularly mixed phases. The studies focus on addressing whether aggregation‐dependent acceptor LUMO level energetics are a general design requirement for both fullerene and NFAs, and quantifying the magnitude, origin, and impact of such energetic shifts upon device performance.     

Identification of a population of cells with hematopoietic stem cell properties in mouse aorta-gonad-mesonephros cultures

The aorta-gonad-mesonephros (AGM) region is a primary source of definitive hematopoietic cells in the midgestation mouse embryo. In cultures of dispersed AGM regions, adherent cells containing endothelial cells are observed first, and then non-adherent hematopoietic cells are produced. Here we report on the characterization of hematopoietic cells that emerge in the AGM culture. Based on the expression profiles of CD45 and c-Kit, we defined three cell populations: CD45(low) c-Kit(+) cells that had the ability to form hematopoietic cell colonies in methylcellulose media and in co-cultures with stromal cells; CD45(low) c-Kit(-) cells that showed a granulocyte morphology; CD45(high) c-Kit(low/-) that exhibited a macrophage morphology. In co-cultures of OP9 stromal cells and freshly prepared AGM cultures, CD45(low) c-Kit(+) cells from the AGM culture had the abilities to reproduce CD45(low) c-Kit(+) cells and differentiate into CD45(low) c-Kit(-) and CD45(high) c-Kit(low/-) cells, whereas CD45(low) c-Kit(-) and CD45(high) c-Kit(low/-) did not produce CD45(low) c-Kit(+) cells. Furthermore, CD45(low) c-Kit(+) cells displayed a long-term repopulating activity in adult hematopoietic tissue when transplanted into the liver of irradiated newborn mice. These results indicate that CD45(low) c-Kit(+) cells from the AGM culture have the potential to reconstitute multi-lineage hematopoietic cells.     

Aggregation of Expanded Huntingtin in the Brains of Patients With Huntington Disease

Huntingtin containing an expanded polyglutamine causes neuronal death and Huntington disease. Although expanded huntingtin is found in virtually every cell type, its toxicity is limited to neurons of certain areas of the brain, such as cortex and caudate/putamen. In affected areas of the brain, expanded huntingtin is not found in its intact monomeric form. It is found instead in the form of N-terminal fragments, oligomers and polymers, all of which accumulate in the cortex. Whereas the oligomer is mostly soluble, the polymers and the fragments associate with each other and with other proteins to form the insoluble inclusions characteristic of the disease. It is likely that the aggregates containing expanded huntingtin are toxic to neurons, but it remains to be determined whether the oligomer or the inclusion is the toxic species.Key Words: huntingtin, polyglutamine, aggregation, oligomer, polymer, N-terminal fragments, transglutaminase