Stereoselectivity of induction of the retinoblastoma gene product (pRb) dephosphorylation by D-erythro-sphingosine supports a role for pRb in growth suppression by sphingosine.

Sphingosine has been shown to inhibit cell growth in many cell lines although the mechanism of this effect remains obscure. More recently, D-erythro-sphingosine has been shown to act as an early inducer of dephosphorylation of the retinoblastoma gene product (pRb) in the lymphoblastic leukemia cell line MOLT-4 [Chao, R., Khan, W.

AIDS and malnutrition: dual assaults on the body.

The immune system is impaired by either malnutrition or human immunodeficiency virus infection. When these occur together, their compounding effects promote altered metabolism, inadequate intake, and malabsorption, which further impair immune function and contribute to human immunodeficiency virus wasting. Careful dietary management can help meet nutritional needs without further compromising the immune status of the person living with acquired immune deficiency syndrome.

Integrated light-scattering spectroscopy, a sensitive probe for peptide-vesicle binding: application to the membrane-bound colicin E1 channel peptide.

Integrated light-scattering (ILS) spectroscopy was used to monitor the binding of the colicin E1 channel peptide to POPC:POPG large unilamellar vesicles (LUV; 60:40, mol:mol) at acidic pH (3.5). Binding conditions were chosen such that nearly all of the channel peptide was bound to the vesicles with little free peptide remaining in solution.

Evidence for the modulation of Pseudomonas aeruginosa exotoxin A-induced pore formation by membrane surface charge density.

The lipid requirement for the binding of wild-type Pseudomonas aeruginosa exotoxin A (ETA) to model endosomal membrane vesicles was evaluated using a fluorescence quenching technique. The binding of toxin to monodisperse model membrane vesicles (0.1 micron diameter) composed of various molar ratios of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylserine (POPS) prepared by an extrusion method [Hope, M.

Fumonisin- and AAL-Toxin-Induced Disruption of Sphingolipid Metabolism with Accumulation of Free Sphingoid Bases.

Fumonisins (FB) and AAL-toxin are sphingoid-like compounds produced by several species of fungi associated with plant diseases. In animal cells, both fumonisins produced by Fusarium moniliforme and AAL-toxin produced by Alternaria alternata f. sp.

Rehabilitation of amputees with end-stage renal disease. Functional outcome and cost.

A retrospective chart review was performed on 19 lower extremity amputees with end-stage renal disease (ESRD) on dialysis and 19 controls with peripheral vascular disease (PVD) without ESRD to compare functional outcome with costs of rehabilitation. The groups were similar demographically and by etiology, level and side of amputation. Functional outcome as measured by Functional Independence Measure (FIM) scores did not show a significant difference between the groups on admission (P = 0.

Mechanism of Fumonisin Toxicity and Carcinogenesis.

What are the molecular events that fumonisin-induced porcine pulmonary edema syndrome and equine leucoencephalomalacia have in common? Do these animal diseases relate mechanistically to fumonisin toxicity in laboratory rats? There is considerable data indicating that disruption of sphingolipid metabolism plays an important early role in all of these diseases. studies have revealed that fumonisins and structurally related Alternaria alternata f. sp.

Mechanism of Fumonisin Toxicity and Carcinogenesis.

What are the molecular events that fumonisin-induced porcine pulmonary edema syndrome and equine leucoencephalomalacia have in common? Do these animal diseases relate mechanistically to fumonisin toxicity in laboratory rats? There is considerable data indicating that disruption of sphingolipid metabolism plays an important early role in all of these diseases. studies have revealed that fumonisins and structurally related Alternaria alternata f. sp.

Uptake and metabolism of sphingolipids in isolated intestinal loops of mice.

Sphingolipids are found in all eukaryotic organisms. However, little is known about the digestion, uptake and subsequent metabolism of these constituents of food. In this study, radiolabeled sphingolipids were placed in isolated intestinal segments of female CF1 mice, and the metabolism and distribution of the radiolabel were followed.

Dietary sphingomyelin inhibits 1,2-dimethylhydrazine-induced colon cancer in CF1 mice.

Sphingolipids are in all eukaryotic cells and modulate cell growth, differentiation, and transformation; however, little is known about the physiological effects of their consumption. Mice were fed diets supplemented with milk sphingomyelin to determine effects on colon carcinogenesis. Cancer was initiated in CF1 mice by 1,2-dimethylhydrazine.

Dietary fumonisin B1 induces disruption of sphingolipid metabolism in Sprague-Dawley rats: a new mechanism of nephrotoxicity.

Fumonisins are potent inhibitors of sphingolipid biosynthesis produced by several Fusarium species. Consumption of corn or corn products infected with F. moniliforme, or high levels of fumonisins, is associated with several animal diseases.

Home care of a malnourished AIDS client.

Many HIV positive clients experience malnutrition that may decrease the quality and length of life. The case study in this article includes study questions that provide the home healthcare nurse an opportunity to plan interventions that may increase nutrient intake.

Nutrition interventions for the HIV positive client.

Several factors contribute to malnutrition during HIV infection. These factors can be grouped into three categories: hypermetabolism, inadequate intake, and malabsorption. This article presents a brief overview of these categories and offers suggestions to help the home healthcare nurse manage nutritional interferences.

Mapping the membrane topology of the closed state of the colicin E1 channel.

The membrane-associated closed channel state of the colicin E1 thermolytic peptide was studied by the Parallax Method of depth-dependent fluorescence quenching. A number of single Trp-containing peptides of colicin E1 were prepared to facilitate the use of Trp as a probe for the topography of the channel peptide in the membrane-bound state. The bound form of the channel peptide was studied by binding channel peptide to 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine/1-pal-mitoyl -2-oleoyl-sn- glycero-3-phosphatidylglycerol large unilamellar vesicles (60:40, mol/mol, approximately 0.

The colicin E1 insertion-competent state: detection of structural changes using fluorescence resonance energy transfer.

The single cysteine residue (Cys-505) located in the hydrophobic membrane anchor domain in the colicin E1 COOH-terminal channel peptide was labeled with the thiol-specific fluorescent reagent IAEDANS [5-[[[(iodoacetyl)amino]ethyl]amino]naphthalene-1-sulfonic acid]. The labeling stoichiometry was nearly 1:1 [AEDANS: peptide (mol:mol)]. Eleven single Trp mutants of the channel peptide were prepared, and the FRET efficiency for each Trp residue (donor) and the AEDANS chromophore (acceptor), covalently attached to Cys-505, was measured.

Disruption of sphingolipid metabolism and stimulation of DNA synthesis by fumonisin B1. A molecular mechanism for carcinogenesis associated with Fusarium moniliforme.

Consumption of grains contaminated with Fusarium moniliforme (Sheldon) causes liver cancer in rats and has been correlated with esophageal cancer in humans. The causative agents are believed to be a family of compounds known as fumonisins, which bear remarkable structural resemblances to sphingosine and sphinganine, the long-chain (sphingoid) base backbones of sphingolipids. Recently, fumonisin B1 has been shown to block de novo synthesis of sphingolipids by inhibiting sphingosine (sphinganine) N-acyltransferase, which leads to accumulation of sphingoid bases.

Direct and indirect cost of percutaneous transluminal coronary angioplasty.

A prospective study of 53 patients employed in the 6-month period before coronary angioplasty was performed to determine the direct and indirect costs of lag time in work resumption. The total direct costs calculated were $273,480; indirect costs for this sample were $150,944. When these costs are generalized to all patients in the US undergoing uncomplicated percutaneous transluminal coronary angioplasty, the costs are more than $1.

Fumonisin B1 inhibits sphingosine (sphinganine) N-acyltransferase and de novo sphingolipid biosynthesis in cultured neurons in situ.

Fumonisins, mycotoxins produced by Fusarium moniliforme and a number of other fungi, cause neuronal degeneration, liver and renal toxicity, cancer, and other injury to animals. Recent work with rat hepatocytes (Wang, E., Norred, W.

Apo A-IV: a new satiety signal.

Chylomicrons have a suppressive effect on food consumption, which is attributed to apolipoprotein A-IV (apo A-IV). This protein is found in cerebrospinal fluid in vivo, and its infusion into the third ventricle of the brain reduces food intake. These findings suggest that this apolipoprotein operates through the central nervous system to regulate food intake.

Acrylamide quenching of the intrinsic fluorescence of tryptophan residues genetically engineered into the soluble colicin E1 channel peptide. Structural characterization of the insertion-competent state.

Colicin E1 or any of its COOH-terminal channel peptides can be activated in vitro by acidic (< 4.5) pH or detergents. In its activated or insertion-competent state, the colicin E1 thermolytic (178 residue) channel peptide demonstrated an increased ability to bind and form channels in artificial membranes.

Regulation of phosphatidate phosphatase activity from the yeast Saccharomyces cerevisiae by sphingoid bases.

The regulation of Saccharomyces cerevisiae membrane-associated phosphatidate phosphatase (3-sn-phosphatidate phosphohydrolase, EC 3.1.3.

Overproduction and purification of the colicin E1 immunity protein.

Colicin E1 immunity protein encoded by the plasmid colicin E1 was overproduced in Escherichia coli from an expression plasmid which was constructed by placing the immunity protein-encoding sequence downstream of the tac promoter and by properly positioning the ribosome binding site on a run-away replication vector. The immunity protein was solubilized with 0.5% Brij 58 from the membrane fraction and purified to homogeneity by a simple batch procedure with hydroxyapatite gel and reverse-phase chromatography.

Effects of feeding Fusarium moniliforme culture material, containing known levels of fumonisin B1, on the young broiler chick.

The effects of feeding Fusarium moniliforme culture material, containing known concentrations of fumonisin B1 (FB1), were studied in broiler chicks. Day-old chicks were allotted randomly to dietary treatments containing 0, 1.02, 2.