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K L Carpenter

Publications and source records attributed to K L Carpenter.

49 records · Page 3Linked to original sources
PubMed1990

Ceroid accumulation by murine peritoneal macrophages exposed to artificial lipid-containing particles: the role of the hydrophilic component.

Murine resident peritoneal macrophages were maintained in cell culture in a medium containing 10% lipoprotein-deficient foetal calf serum to which various artificial lipid-containing particles were added. These had a core of oxidizable lipid, generally cholesteryl linoleate, and were stabilized in aqueous suspension by one of a variety of poly-L-amino acids, proteins or polysaccharides. Most particles, except those containing poly-L-lysine or poly-L-arginine (both strongly basic), were readily taken up by the macrophages to form typical ceroid inclusions, the morphological form of which was determined by the nature of the core lipid. The hydrophilic stabilizing component seemed largely irrelevant in this respect. The role of the latter appears largely to be to allow the cellular uptake of lipid, although it may also participate in ceroid formation.

Animals↗
PubMed1989

Modulation of ceroid accumulation in macrophages in vitro.

Mouse resident peritoneal macrophages (MPM) cultured with artificial lipoprotein consisting of cholesteryl linoleate complexed with bovine serum albumin (CL/BSA) rapidly accumulate ceroid in the form of rings. Experiments with various phenolic radical scavenger antioxidants and derivatives showed that the radical scavengers which are strongly lipophilic, and possess a free (i.e. non-esterified) phenolic hydroxyl group are inhibitors of ceroid ring formation. Time-course experiments with MPM and CL/BSA in which either or both of the components of the artificial lipoprotein have been oxidised before feeding showed that such oxidation accelerated ceroid accumulation, and suggested that oxidation of the lipoprotein is rate-determining in ceroid accumulation. Copper appeared to be a good catalyst for this. Agents able to activate the respiratory burst production of reactive oxygen species appeared to have no accelerating effect on ceroid accumulation from CL/BSA by MPM in a time-course. A novel method has been attempted for quantitating ceroid in MPM by means of its autofluorescence, using a Fluorescence-activated Cell Sorter (FACS). The results from FACS agree qualitatively with those from alcohol-xylene treatment followed by oil-red-o staining (AX/ORO). MPM cultured with CL/BSA for up to 4 days showed a 2.7-4.6-fold increase in mean fluorescence (at wavelengths greater than 490 nm) over MPM cultured with cholesteryl oleate/BSA (CO/BSA), with CL/BSA/butylated hydroxytoluene (CL/BSA/BHT), with CL/BSA/probucol, and with no artificial lipoprotein. The implications of the findings with respect to human atherosclerosis are discussed.

Animals↗
PubMed1989

On children's uses of from, by and with in oblique noun phrases.

This study was designed to follow up children's early spontaneous uses of from to mark oblique agents by giving 40 children (aged 2;5-6;1), and 10 adults, grammatical and ungrammatical sentences containing from, with, and by to imitate and to repair. As predicted, children's imitations and repairs showed that (a) 2-year-olds produce from for agents, and with for instruments in imitation; and (b) as children get older, they shift to by for agents in their repairs, and keep from to mark locative sources. These findings support the hypothesis that when children first try to express oblique agents, before acquisition of conventional by, they choose from for this purpose because agents, as instigators of actions, are conceived of as the source of the action and its result.

Child↗
PubMed1988

Ceroid accumulation by murine peritoneal macrophages exposed to artificial lipoproteins: ultrastructural observations.

Murine resident peritoneal macrophages were maintained in cell culture in a medium containing 10% lipoprotein-deficient fetal calf serum to which various artificial lipoprotein particles (coacervates of lipid and bovine serum albumin) had been added. The uptake and intracellular fate of these particles was studied by electron microscopy. The appearance of material accumulating within the cells varied according to the nature of the lipid component of the ingested particles. Lipids which are readily oxidised (cholesteryl linoleate, cholesteryl arachidonate, trilinolein) were associated with the formation of ceroid within membrane-bound structures. Less readily oxidized lipids (cholesteryl oleate, triolein) were not associated with ceroid accumulation but instead the cells contained numerous nonmembrane-bound lipid inclusions. The appearances of the ceroid within the murine peritoneal macrophages are similar to those of ceroid in macrophages in human atherosclerotic lesions.

Animals↗
PubMed1987

What is the significance of ceroid in human atherosclerosis?

This review of the significance of ceroid within the atherosclerotic intima proposes that the macrophages have a central role to play in its production. Ceroid is more than merely an "age pigment." It marks the site of previous oxidative events, possibly including the release of biologically active or toxic, soluble oxidized molecules. This being so, this activity of macrophages may have a significant role in the progression of the lesions. The interactions of macrophages and oxidizable unsaturated lipids therefore merit further investigation.

Animals↗
PubMed1987

Ceroid accumulation by murine peritoneal macrophages exposed to artificial lipoproteins.

Murine resident peritoneal macrophages were maintained in cell culture in a medium containing 10% lipoprotein-deficient fetal calf serum to which various artificial lipoproteins (lipid-bovine serum albumin complexes) had been added. Ceroid accumulated in cells exposed to artificial lipoproteins containing cholesteryl esters or acylglycerols possessing polyunsaturated fatty acid residues, but not in cells exposed to lipoproteins containing less readily oxidized lipids. Oxidation of cholesteryl linoleate before its incorporation into artificial lipoprotein accelerated ceroid production. Incorporation of free radical scavengers into cholesteryl linoleate-containing artificial lipoproteins impaired ceroid formation. The results are discussed in terms of the mechanisms by which the ceroid might have been produced and its significance for human atherogenesis.

Animals↗
PubMed1986

Oxidized low density lipoprotein induces ceroid accumulation by murine peritoneal macrophages in vitro.

The presence of ceroid pigment inclusions within macrophage foam cells is a well-recognized phenomenon in human atherosclerosis but its significance is unclear. Murine peritoneal macrophages, maintained in a medium containing 10% lipoprotein-deficient fetal calf serum to which oxidized low density lipoprotein (LDL) has been added, rapidly accumulate similar ceroid inclusions. However, cells exposed to LDL, acetyl--LDL or dextran sulphate--LDL complexes fail to develop ceroid under the same culture conditions. Oxidation of LDL results in considerable physico-chemical changes to both protein and lipid moieties, and these may be important in the uptake of the particles by macrophages and, subsequently, the accumulation of intracellular ceroid.

Animals↗
PubMed1983

Plasma platelet products and exercise-induced myocardial ischemia.

Peripheral plasma concentrations of PF-4 and TxB2 were measured by RIA in 26 patients who underwent exercise stress testing. In group A (n = 15; age 50 +/- 16, mean +/- S.D.) in whom blood sampling was performed by venipuncture, seven patients had a positive stress test associated with an increase in PF-4 concentrations from 3.3 +/- 1.6 ng/ml to 6.9 +/- 3.6 (mean +/- S.D.); six of them demonstrated a greater than 50% increase in PF-4; and only one of eight with a negative stress test had such an increase. In group B (n = 11; 49 +/- 10 yr), patients also underwent postexercise thallium-201 scanning and blood samples were obtained through an intravenous catheter. These patients consistently demonstrated higher PF-4 values (before exercise 7.5 +/- 3.9 ng/ml; after exercise 11.9 +/- 7.1), regardless of the results of the exercise and thallium studies. TxB2 concentrations were unchanged in both groups. To further evaluate the effect of catheter-collected samples on PF-4, five healthy males had serial concurrent blood sampling in opposite arms via both venipuncture and catheter. Although PF-4 concentrations in venipuncture samples were constant, those collected through the catheter increased as a function of time. On the basis of the findings in group A, enhanced platelet activation appears to be associated with exercise-induced ischemia. The observations in group B and the healthy controls indicated that catheter-collection of samples artifactually increased PF-4 concentrations.

Adult↗
PubMed1979

Experimental studies on hemopoiesis in the pronephros of Rana pipiens.

Embryogenesis of hemopoietic cell populations in the pronephros of Rana pipiens was examined during embryonic and early larval development. Differential cell counts of Wright-Giemsa-stained cell suspensions demonstrated that granulopoiesis is the predominant hemopoietic activity in the pronephros, erythropoiesis accounts for a minor component of the hemopoietic activity (less than 10%), and lymphopoiesis within the organ is negligible. Microdensitometric analysis of Feulgen-DNA stained granulocyte populations in pronephroses from larvae that had received chromosomally labeled pronephric analgen transplants between 84 and 96 h of development demonstrated that hemopoiesis in this organ is dependent on colonization by an extrinsic hemopoietic stem cell. A similar analysis of pronephric hemopoiesis in larvae which had received chromosomally labeled, presumptive ventral blood island transplants between 62 and 67 h of development, indicates that granulopoietic cells are not derived from the embryonic blood islands. It is proposed that the pronephros may be the initial site of granulocyte differentiation during early embryogenesis. Although the embryonic origin of the hemopoietic stem cell is unknown, indirect evidence from this study indicates a dorsal stem cell compartment.

Animals↗