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Biomedical subjects

J K Jackson

Publications and source records attributed to J K Jackson.

45 records · Page 3Linked to original sources
PubMed1990

Role of membrane proteins in monosodium urate crystal-membrane interactions. I. Effect of pretreatment of erythrocyte membranes with glutaraldehyde and neuraminidase.

Intact human erythrocytes were pretreated with glutaraldehyde, neuraminidase or a combination of both treatments, incubated with monosodium urate monohydrate (MSUM) crystals and the percent hemolysis values determined by measuring hemoglobin release from the cells. The binding of MSUM crystals to pretreated erythrocyte membranes was also quantitated. Neuraminidase treated cells gave higher percent hemolysis values than untreated cells due primarily to the increased binding of MSUM to neuraminidase treated erythrocyte membranes. Pretreatment of red cells with glutaraldehyde up to a maximum concentration of 0.015% inhibited MSUM induced hemolysis but the binding of MSUM to glutaraldehyde treated and untreated cell membranes was the same. We propose a "pore" model for MSUM induced hemolysis.

Cross-Linking Reagents↗
PubMed1990

Role of membrane proteins in monosodium urate crystal-membrane interactions. II. Effect of pretreatments of erythrocyte membranes with membrane permeable and impermeable protein crosslinking agents.

Intact, human erythrocytes were pretreated with membrane permeable, dimethyl adipimidate (DMA) and dimethyl suberimidate (DMS) and membrane impermeable 3,3' dithiobis (sulfosuccinimidylpropionate) (DTSSP) protein crosslinking agents and incubated with monosodium urate monohydrate (MSUM) crystals. The percent inhibition of lysis values for pretreated cells relative to untreated cells were determined. All 3 agents caused a concentration dependent inhibition of MSUM induced hemolysis that was not due to a decrease in MSUM binding to the pretreated membranes. It was proposed that the inhibition of lysis was due to crosslinking of integral and cytoskeletal membrane proteins, resulting in a reduced mobility of the proteins, inhibition of lateralization of integral proteins into aggregates and decreased "pore" formation in the membrane.

Cell Membrane Permeability↗
PubMed1989

Calcium pyrophosphate and monosodium urate crystal interactions with neutrophils: effect of crystal size and lipoprotein binding to crystals.

"Small" (between 75-98% of crystals less than or equal to 10 microns) and "large" (between 81-93% of crystals greater than 10 microns) size fractions of monosodium urate monohydrate (MSUM) and calcium pyrophosphate dihydrate triclinic (CPPD) crystals were incubated with human neutrophils and crystal induced neutrophil cytolysis monitored by measuring the release of lactate dehydrogenase. "Small" size fractions of MSUM and CPPD gave higher percent lysis values than "large" crystals. The binding of high density lipoproteins (HDL) and low density lipoproteins (LDL) to the crystals was quantitated. HDL and LDL bound in significant amounts to both CPPD and MSUM and strongly inhibited CPPD and MSUM induced neutrophil cytolysis. We propose that HDL and LDL bound to MSUM and CPPD may play important roles in the regulation of gouty inflammation.

Apolipoproteins↗
PubMed1988

Monosodium urate monohydrate crystal induced changes in membrane fluidity: a fluorescence polarization study.

The hydrophobic fluorophore 1,6-diphenyl-1,3,5-hexatriene was incorporated into erythrocyte ghosts. After incubation of the labelled ghost membranes with monosodium urate monohydrate (MSUM) crystals, low speed centrifugation was used to separate ghosts bound to MSUM from "free" ghosts. The fluorescence anisotropy of ghosts with bound crystals was significantly lower than for free ghosts, indicative of an increased membrane fluidity. Possible mechanisms for the fluidization of ghosts membranes after MSUM binding and the relationship of this to cellular membranolysis are discussed.

Crystallization↗
PubMed1987

Characterization and membranolytic effects of triclinic calcium pyrophosphate dihydrate crystals.

The effects of incubation time and buffers of differing phosphate concentration on the ability of well characterized, synthetic triclinic calcium pyrophosphate dihydrate (CPPD) crystals to cause hemolysis of erythrocytes were determined. Maximum hemolysis was attained between 8-11 h; the percent hemolysis was 79% at a high crystal concentration of 50 mg/ml. The percent hemolysis values decreased with increasing phosphate concentration, which may have been due to adsorbed phosphate ions partially masking or protecting the erythrocyte membrane from a binding interaction with CPPD crystals. CPPD crystals possessed a significant negative surface potential, and we postulate that the CPPD crystal-membrane interaction may be mediated via an electrostatic mechanism.

Calcium Pyrophosphate↗
PubMedDate not supplied

A comparison of the lytic properties of two ether-linked lipids, one with and one without antineoplastic activity.

We have synthesized two ether lipids: 2'-(trimethylammonio)ethyl 4-(hexadecyloxy)-3(S)-methoxybutanephosphonate (compound 1) with antineoplastic activity and a maltosyl derivative (compound 2) without antineoplastic activity. We have compared the antineoplastic activity of these two compounds against WEHI-3B cells with their ability to disrupt the membranes of erythrocytes or neutrophils. Since ether lipids are highly hydrophobic molecules, it is possible that they may exert their cytotoxic action by inducing the nonspecific perturbation of cellular membranes, causing lysis and cell death. Membrane disruption was monitored by the lysis of cells or the change in erythrocyte membrane microviscocity and compared with the effect of detergents (known nonspecific lytic agents). Both compounds 1 and 2 caused the lysis of erythrocytes and neutrophils. The rate of lysis of erythrocytes was comparable to the rate of change of erythrocyte membrane microviscosity caused by both compounds 1 and 2. Both compounds caused the lysis of erythrocytes via a noncolloid osmotic mechanism that displayed features of the lysis caused by detergents at high concentrations.

Antineoplastic Agents↗