Little is known about the mechanisms of lipopolysaccharide (LPS) signaling in immature cells that do not express the LPS receptor CD14 yet. Bone marrow granulocytes do not constitutively express CD14 but can be stimulated by low doses of LPS in the absence of serum and then express an inducible form of LPS receptor (iLpsR). We show that in addition to LPS, cholera toxin (CT) and various cyclic ...

Wether sheep were fitted with rumen fistulas and polyethylene tubes to the abomasum and were given all nutrients by intragastric infusion. In Expt 1 volatile fatty acids (VFA) were given at 340, 450 and 630 kJ gross energy (GE)/kg metabolic weight (W0-75) and protein at 0, 150, 300, 600, 900 and 1500 mg nitrogen/kg W0-75. In Expt 2 VFA were infused at 450 kJ GE/kg W0-75 and protein at 0 and 300...

To clarify the contributions of amidophosphoribosyltransferase (ATase) and its feedback regulation to the rates of purine de novo synthesis, DNA synthesis, protein synthesis, and cell growth, mutated human ATase (mhATase) resistant to feedback inhibition by purine ribonucleotides was engineered by site-directed mutagenesis and expressed in CHO ade (-)A cells (an ATase-deficient cell line of Chi...

Geometric and position isomers of zeatin and of ribosylzeatin and other compounds closely related to zeatin have been tested in the tobacco (Nicotiana tabacum var. Wisconsin No. 38) bioassay. None was more active than zeatin itself. There was a much greater difference in activity (> 50-fold) between trans- and cis-zeatin than between trans-isozeatin [6-(4-hydroxy-2-methyl-trans-2-butenylamino) ...

The feasibility of the hypothesis that rate of cell division might be controlled by a balance between anabolic events leading to nucleic acids and catabolic events which degrade potential nucleic acid precursors has been studied in both in vivo and in vitro systems. Rapidly growing Sarcoma 180 appears to conserve essentially all its cellular purine derivatives (DNA, RNA, and acid-soluble nucleo...

Fifteen purine nucleosides and their O-acetylated ester derivatives were examined for in vitro antitrypanosomal activity against the LAB 110 EATRO isolate of Trypanosoma brucei brucei and two clinical isolates of Trypanosoma brucei rhodesiense. Initial comparisons of activity were made for the LAB 110 EATRO isolate. Three nucleoside analogs exhibited no significant activity (50% inhibitory conc...

Chronic kidney diseases are based on uncontrolled immunological and inflammatory responses to pathophysiological renal circumstances such as glomerulonephritis, which is caused by immunological mechanisms of glomerular inflammation with increased production of renal pro-inflammatory cytokines. Pentoxifylline (PTX) exhibits anti-inflammatory properties by inhibiting cytokine and chemokine produc...

The physiological function of organic anion transporter OAT2 (SLC22A7) remains unclear, but since OAT2 transports purine derivatives, it may be involved in renal handling of uric acid, the final metabolite of purine derivatives. In the present study, we studied uric acid transport in stably OAT2-expressing HEK293 cells (HEK293/OAT2). OAT2 mediated uptake, but not efflux, of [(14)C]uric acid. Ur...

Rapamycin inhibits TOR (target of rapamycin) kinase, and is being used clinically to treat various diseases ranging from cancers to fibrodysplasia ossificans progressiva. To understand rapamycin mechanisms of action more comprehensively, 1014 temperature-sensitive (ts) fission yeast (Schizosaccharomyces pombe) mutants were screened in order to isolate strains in which the ts phenotype was rescu...

The saliva of sheep was shown to contain significant concentrations of uric acid (16(SD 4.5) mumol/l) and allantoin (120(SD 16.4) mumol/l), sufficient to recycle purine derivatives equivalent to about 0.10 of the normal urinary excretion. When allantoin was incubated in vitro in rumen fluid, it was degraded at a rate sufficient to ensure complete destruction of recycled allantoin. In a series o...