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Biomedical subjects

I Cartwright

Publications and source records attributed to I Cartwright.

8 recordsLinked to original sources
PubMed1999

Separation of the intracellular secretory compartment of rat liver and isolated rat hepatocytes in a single step using self-generating gradients of iodixanol.

A novel method is described for the separation on a single gradient of the major intracellular organelles of the secretory pathway, the Golgi, the smooth endoplasmic reticulum, and the rough endoplasmic reticulum. Total microsomes were prepared from rat liver by differential centrifugation and resuspended in 20% iodixanol. The microsomal suspension was then layered between a 30% iodixanol cushion and a layer of 15% iodixanol and centrifuged in a vertical rotor for 2 h. The microsomes distributed in four visible bands. The gradients were collected by upward displacement and were characterized (i) by determination of UDP galactose-galactosyltransferase (Golgi marker) NADPH-cytochrome c reductase (endoplasmic reticulum marker) and RNA (rough endoplasmic reticulum marker); (ii) by immunoblotting for TGN38 (trans-Golgi marker) and GS28 (cis-Golgi marker) and for protein disulfide isomerase (endoplasmic reticulum lumenal marker); (iii) by determination of the lipid composition; and (iv) by electron microscopy. The results suggest that the top band (density 1.045-1. 090 g/ml), which contains 68% of the galactosyltransferase activity, consists of vesicles derived from the Golgi. The second broad band in the middle of the tube (density 1.130-1.160 g/ml), which contains 54% of the NADPH-cytochrome c reductase activity, consists mainly of vesicles derived from the smooth endoplasmic reticulum, overlapped at the top by a small band of Golgi-derived lamellae. The two bands at the bottom of the tube (density 1.130-1.160 and density 1.180-1. 220 g/ml) appear to contain two subfractions of vesicles derived from the rough endoplasmic reticulum.

Animals↗
PubMed1999

Lipid composition of seven APTT reagents in relation to heparin sensitivity.

The phospholipid content of different activated partial thromboplastin time (APTT) reagents was determined and compared to heparin sensitivity. The seven reagents included were those most widely used amongst participants of the U.K. National External Quality Assessment Scheme (NEQAS) at the time of study. Heparin sensitivity was assessed using the APTT ratios obtained by more than 300 NEQAS participants on five plasmas prepared from patients receiving unfractionated heparin. The concentrations of three neutral lipids and six phospholipids present in the seven APTT reagents were determined by high-performance thin-layer chromatography (HPTLC) and densitometry. Both the concentrations and the relative percentages of individual phospholipid components varied markedly between reagents. The total phospholipid concentration included a 12-fold range from 16 to 205 microgram/ml. Phosphatidylserine (PS) was completely lacking from one reagent prepared from vegetable material and ranged from 3 to 22 microgram/ml in the other six reagents containing extracts from animal tissue. The concentration of phosphatidylcholine ranged from 3 to 109 microgram/ml. There was no demonstrable relationship between the concentration of any individual lipid components and heparin sensitivity. However, the relative percentage phospholipid composition was important since a lower % of PS or phosphatidylinositol (PI) correlated with increasing heparin sensitivity.

Anticoagulants↗
PubMed1990

A placebo-controlled, double-blind study of eicosapentaenoic acid-rich fish oil in patients with stable angina pectoris.

A study was carried out to evaluate the clinical and haematological effects of dietary supplementation with eicosapentaenoic acid (EPA)-rich fish oil (MaxEPA', 2.8 g EPA daily) compared to placebo (olive oil) in 10 patients with stable angina pectoris. After 3 months, there was a significant increase in red cell deformability (p less than 0.001), reduced whole blood viscosity (p less than 0.02), and prolonged skin bleeding time (p less than 0.001) in the fish oil group compared to the placebo group. Haematocrit, plasma viscosity, fibrinogen concentration, platelet count, and in vitro platelet aggregation were unaltered. No significant symptomatic or objective improvement was noted in angina pectoris in either group despite the significant rheological changes produced in the patients receiving fish oil.

Adult↗
PubMed1988

A double-blind, randomised, placebo-controlled trial of fish oil in psoriasis.

28 patients with stable chronic psoriasis completed a trial in which they were randomly allocated to receive either 10 fish-oil capsules ('MaxEPA') or 10 placebo capsules (olive oil) daily. Patients were specifically instructed not to change their normal diet. After 8 weeks' treatment there was a significant lessening of itching, erythema, and scaling in the active treatment group, with a trend towards an overall decrease in body surface area affected. No change occurred in the placebo group.

Administration, Oral↗
PubMed1987

A new familial 'giant platelet syndrome' with structural, metabolic and functional abnormalities of platelets due to a primary megakaryocyte defect.

We have investigated platelet morphology, function and biochemistry in a family affected by dominantly inherited congenital thrombocytopenia with giant platelets. A defect of aggregation was defined with evidence of disturbed fatty acid distribution in platelet membrane phospholipids and impaired arachidonic acid mobilization. Release of 5-hydroxytryptamine was normal. Platelet ultrastructure was grossly abnormal and volume analysis revealed small as well as giant forms. Bone marrow megakaryocytes were morphologically abnormal and the distribution of mean nuclear ploidy atypical, suggesting the production of abnormal platelets due to a primary megakaryocyte disorder. The features of this condition are distinct from those previously described in familial thrombocytopenia and constitute a new "giant platelet syndrome". The qualitative and quantitative platelet defects may be secondary to a disturbance of megakaryocyte cytoplasmic fragmentation.

Adult↗