Search results for "AEM"
showing 10 items of 1006 documents
A survey of the function of the lethal kettle traps of Arisaema (Araceae), with records of pollinating fungus gnats from Nepal
2000
Abstract Evidence from recent research combined with an evaluation of the literature indicates that Arisaema is adapted to pollination by fungus gnats. It apparently shares this peculiarity among aroids only with the distantly related genus Arisarum . In addition to previous records from Japan and North America, systematic collections from nine Arisaema species during several expeditions in the Himalayas in Nepal showed that, although other less efficient insect groups may participate, the nematoceran families Mycetophilidae and Sciaridae are the principal pollen vectors; they best fit the pollination apparatus of the mainly (para)dioecious kettle trap blossoms. A total of 16 fungus gnat ge…
The Cell Cycle-Specific Growth-Inhibitory Factor Produced by Actinobacillus actinomycetemcomitans Is a Cytolethal Distending Toxin
1998
ABSTRACT Actinobacillus actinomycetemcomitans has been shown to produce a soluble cytotoxic factor(s) distinct from leukotoxin. We have identified in A. actinomycetemcomitans Y4 a cluster of genes encoding a cytolethal distending toxin (CDT). This new member of the CDT family is similar to the CDT produced by Haemophilus ducreyi . The CDT from A. actinomycetemcomitans was produced in Escherichia coli and was able to induce cell distension, growth arrest in G 2 /M phase, nucleus swelling, and chromatin fragmentation in HeLa cells. The three proteins, CDTA, -B and -C, encoded by the cdt locus were all required for toxin activity. Antiserum raised against recombinant CDTC completely inhibited …
Proliferation of gastrointestinal carcinoma cells by T lymphocyte factors interleukin-3 and granulocyte-macrophage colony-stimulating factor
1991
Hematopoietic growth factors have been well characterized by cDNA cloning in recent years. In order to determine the influence of rhGM-CSF and rhIL-3 on epithelial cells of the gastrointestinal tract, their influence on in vitro cultured gastric and pancreas cancer cells was determined. A more than two-fold enhancement of proliferation was observed by IL-3 and GM-CSF in Mz-Sto-1 gastric and 818-4 pancreas carcinoma cells, applying a sensitive microculture system which allows precise quantification. The highest growth rates were obtained adding 1-10 ng/ml of the growth factors, but even picogram amounts were effective. Expression of mRNA for GM-CSF and IL-3 remained undetectable in the cell …
Prenatal low-level exposure to CO alters postnatal development of hippocampal nitric oxide synthase and haem-oxygenase activities in rats.
2001
The effects of prenatal CO exposure (150 ppm from days 0 to 20 of pregnancy) on the postnatal development of hippocampal neuronal NO synthase (nNOS) and haem-oxygenase (HO-2) isoform activities in 15-, 30- and 90-d-old rats were investigated. Unlike HO-2, hippocampal nNOS activity increased from postnatal days 15-90 in controls. Prenatal CO produced a long-lasting decrease in either nNOS or HO-2. The results suggest that the altered developmental profile of hippocampal nNOS and HO-2 activities could be involved in cognitive deficits and long-term potentiation dysfunction exhibited by rats prenatally exposed to CO levels resulting in carboxyhaemoglobin (HbCO) levels equivalent to those obser…
Introduction to stem cell biology in vitro. Threshold to the future.
1999
Abstract: Transplantable hematopoietic cells with multilineage reconstituting ability can be quantitated in suspensions of human or murine cells using similar assay procedures. The incorporation into these assays of stringently defined functional endpoints ensures a high degree of specificity for the cells detected. Application of these assays to stem cell-containing suspensions after they have been stimulated for several days with defined cytokines in vitro, or by a mixture of defined and/or undefined factors in vivo, has shown that net amplifications in these populations can be obtained under both circumstances. Such studies have allowed cytokine conditions that support stem cell self-ren…
HLA antigens in Sicilian patients affected by chronic myelogenous leukaemia.
1987
SUMMARY HLA antigens were investigated in Sicilian patients with chronic myelogenous leukaemia (CML) and in Sicilian healthy controls. The frequency of the HLA-DRw6 antigen was significantly decreased in the group of patients. These results suggest that DRw6 may be a marker for decreased susceptibility to the etiological or pathogenic mechanism(s) which produce CMLs.
The function of the soluble IL-6 receptor in vivo.
1996
Interleukin-6 (IL-6) is considered an important mediator of acute inflammatory responses. Moreover, IL-6 functions as a differentiation and growth factor of hematopoietic precursor cells, B-cells, T-cells, keratinocytes, neuronal cells, osteoclasts and endothelial cells. IL-6 exhibits its action via a receptor complex consisting of a specific IL-6 receptor (IL-6R) and a signal-transducing subunit (gp130). Soluble forms of both receptor components are generated by shedding and are found in patients with various diseases such as AIDS, rheumatoid arthritis and others. The function of the soluble IL-6R in vivo is unknown. To discriminate between the biologic function of hIL-6 alone and that of …
Cdc42 in osterix-expressing cells alters osteoblast behavior and myeloid lineage commitment
2021
Osteoblasts are not only responsible for bone formation. They also support hematopoiesis. This requires responding to cues originating from several signaling pathways, a task performed by Rho GTPases. We therefore examined several transgenic mouse models and used inhibitors of Cdc42 in vitro. Deletion of Cdc42 in vivo using the Osterix promoter suppressed osteoblast function, while its deletion in differentiating osteoblasts using the Collagen-a1(I) promoter decreased osteoblast numbers. In both cases, bone mineral density diminished confirming the importance of Cdc42. Evaluation of hematopoiesis revealed that deletion of Cdc42 using the Osterix, but not the Collagen-a1(I) promoter increase…