Biomedical subjects

M I Mackness

Publications and source records attributed to M I Mackness.

At least 73 records · Page 4Linked to original sources

PubMed1995

Effect of low-dose cyclosporin on plasma lipoproteins and markers of cholestasis in patients with psoriasis.

The benefits of using cyclosporin in organ transplantation to prevent graft rejection outweigh its potential disadvantages, but with the use of low-dose cyclosporin in relatively healthy individuals, such as those with psoriasis, the risk:benefit ratio is altered. The effects of low-dose cyclosporin (< 5 mg/kg body weight) on liver function and serum lipids and lipoproteins were examined in 40 normolipidaemic, normotensive psoriasis patients with normal renal function. After 3 months of treatment, serum cholesterol and bilirubin concentrations and alkaline phosphatase activity increased significantly (p = 0.001), and glomerular filtration rate (GFR) declined from 107 to 96 ml/min/1.73 m2 (p = 0.05). All these values returned to pretreatment levels 3 months after cessation of cyclosporin. In 15 patients in whom lipoproteins were isolated by ultracentrifugation, there was an increase in plasma low-density lipoprotein (LDL) cholesterol (p = 0.05), but very-low-density lipoprotein cholesterol, high-density lipoprotein (HDL) and HDL2 and HDL3 cholesterol concentrations did not change. The increases in serum bilirubin, alkaline phosphatase activity and LDL cholesterol, seen in individuals with normal baseline liver and renal function, which reverted to baseline following cessation of cyclosporin, suggest that cyclosporin-induced hypercholesterolaemia may be due to either decreased biliary excretion of cholesterol or impaired catabolism of LDL.

Biomarkers↗

PubMed1994

Serum Lp(a) lipoprotein concentration and outcome of thrombolytic treatment for myocardial infarction.

BACKGROUND: Lp(a) lipoprotein has structural homology with plasminogen and has been shown to inhibit plasminogen activation in vitro. OBJECTIVE: To determine whether the serum concentration of Lp(a) lipoprotein present when streptokinase was given in acute myocardial infarction influenced the outcome as judged by electrocardiographic methods. PATIENTS AND DESIGN: Serum Lp(a) lipoprotein concentration was measured in 135 consecutive patients admitted with a diagnosis of acute myocardial infarction who received streptokinase treatment. Recovery from myocardial injury was assessed by the reduction in the sum of ST segment elevation measured from the J point (STJ) in the electrocardiogram immediately before streptokinase was given compared with that three hours later. RESULTS: The serum Lp(a) lipoprotein concentrations were measured within 12 hours of the onset of symptoms of myocardial infarction and were higher than in healthy reference populations. Recovery from myocardial infarction could be assessed from the STJ in 116 patients (86% of the series). Those in whom it could not had bundle branch block, left ventricular hypertrophy, did not survive three hours, or had started intravenous nitrate treatment or some other clinical procedure before or at the time the second electrocardiogram was to be recorded. Patients with reductions in STJ after streptokinase that were > 4 mm (the median decrease) had mean (range) serum Lp(a) lipoprotein concentrations of 41.0 (0.8-220) mg/dl and those with a smaller reduction in STJ had concentrations of 29.1 (1.7-151) mg/dl. The difference was not statistically significant. CONCLUSION: In this study Lp(a) lipoprotein concentration did not significantly influence the outcome of thrombolytic treatment with streptokinase.

Adult↗

PubMed1994

Effects of a new fish oil concentrate on plasma lipids and lipoproteins in patients with hypertriglyceridaemia.

OBJECTIVES: The effect of a fish oil preparation, K-85, in which the omega-3 fatty acid content was concentrated to 92% of total fat, on serum lipid and lipoprotein concentrations was investigated in patients with primary hypertriglyceridaemia. DESIGN: The study was a randomized, double-blind, placebo-controlled study. SETTING: Seven centres participated in the study, five secondary referral centres and two general practices. SUBJECTS: Men and women aged 18-70 years with fasting serum triglyceride concentrations between 2 and 10 mmol/l and fasting serum cholesterol concentrations > 5.2 mmol/l were studied. Patients with diabetes mellitus, hypothyroidism, serious illness in the previous 3 months or severe concurrent illness were excluded from the study, as were drug or alcohol abusers and pregnant and lactating women. Ninety-five subjects entered the study, 79 completed the study. INTERVENTIONS: Patients were randomized to receive K-85 2 g twice daily or corn oil 2 g twice daily for 14 weeks. MAIN OUTCOME MEASUREMENTS: The serum concentrations of triglycerides and cholesterol, very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and lipoprotein (a). Fasting blood glucose and blood pressure. RESULTS: Serum triglycerides and VLDL-cholesterol were significantly lower in the group treated with K-85 than in the placebo group after 6, 10 and 14 weeks (all P < 0.01) and there was a decrease in the serum triglyceride concentration from 3.99 (2.94-9.47) to 2.87 (1.2-9.93) mmol/l (P < 0.001) and in VLDL-cholesterol from 1.47 (0.77-3.63) to 1.12 (0.21-3.67) mmol/l (P < 0.01) in patients receiving K-85. Serum HDL-cholesterol increased from 0.98 (0.95-1.01) to 1.11 (1.07-1.15) mmol/l (P < 0.01) in the patients with type IV hyperlipoproteinaemia but did not change in those with type IIb. Serum LDL-cholesterol, lipoprotein (a) and fasting blood glucose were unaffected by K-85. Diastolic blood pressure decreased from 86 +/- 11 to 80 +/- 12 mmHg (P < 0.02) and was also lower than in the placebo group (P < 0.05). The corn oil placebo did not affect any of the parameters. CONCLUSION: K-85 is effective in lowering serum triglycerides and VLDL in patients with primary hypertriglyceridaemia and may have utility as a triglyceride-lowering agent.

Adult↗

PubMed1994

A prospective study of serum lipoproteins after coronary artery bypass surgery.

We examined the acute and long-term effects of coronary artery bypass (CABG) surgery on serum lipid, lipoprotein and apolipoprotein levels. One series of 34 patients having CABG surgery was studied pre-operatively and for six weeks afterwards, and another 22 patients were investigated before and two years after CABG surgery. None of the patients studied received any lipid-lowering drug therapy or specific dietary advice. In both groups, pre-operative serum lipoprotein (a) (Lp(a)) and serum triglyceride concentrations were raised and serum high-density lipoprotein (HDL) cholesterol and apolipoprotein AI (apo AI) were low compared to healthy people. Acutely, there were profound decreases of 40-60% in the serum levels of cholesterol (p < 0.001), low-density lipoprotein cholesterol (p < 0.05), triglycerides (p < 0.01), Lp(a) (p < 0.05) and apolipoprotein B (apo B) (p < 0.05). There was a small decrease in serum apo A1 (p < 0.05), and serum HDL cholesterol showed no change. All these variables regained their pre-operative values within six weeks. Two years postoperatively, serum Lpa was 40% less than its pre-operative concentration (p < 0.001) and HDL cholesterol had increased (p < 0.001). Triglyceride levels decreased (p < 0.02) when beta-blockade was withdrawn. The long-term decrease in Lp(a) following surgery is unlikely to be due either to stopping beta-blockers or to life-style changes. Myocardial ischaemia relieved by the operation may have been partially responsible for its previously raised concentration.

Adult↗

PubMed1993

The role of high-density lipoprotein and lipid-soluble antioxidant vitamins in inhibiting low-density lipoprotein oxidation.

1. The oxidation of low-density lipoprotein (LDL) is believed to play a central role in atherogenesis. We have compared the effect of antioxidant vitamins and high-density lipoprotein (HDL) on the Cu(2+)-catalysed oxidation of LDL. 2. Antioxidant vitamin supplementation significantly reduced conjugated diene formation but did not affect the formation of lipid peroxides. 3. Conversely, HDL did not affect conjugated diene formation but inhibited the formation of lipid peroxides by up to 90%. 4. The inhibition by HDL of lipid peroxide formation in oxidized LDL was dependent on the concentration of HDL and was not due to HDL chelating Cu2+. 5. Large interindividual variations in the inhibition of lipid peroxide formation by autologous HDL were evident, which were related to the rate of lipid peroxide generation in the LDL. 6. We conclude that HDL is a powerful antioxidant or more probably inhibitor of LDL oxidation in vitro and may play an important role in vivo in preventing atherosclerosis by inhibiting LDL oxidation in the artery wall.

Adult↗

PubMed1993

Purification and immunological characterization of pigeon serum butyrylcholinesterase. Implications on environmental monitoring and toxicological testing of birds.

Butyrylcholinesterase (EC 3.1.1.8) (BChE) was purified from pigeon serum to electrophoretic homogeneity by a four-step procedure involving blue sepharose CL-6B chromatography, ion exchange chromatography, procainamide affinity chromatography and gel filtration. An overall 2789-fold purification was achieved, with a final specific activity of 61.35 mumol/min/mg. The purified enzyme separated into two peaks when filtered through a column of Sephacryl S-300, a smaller peak containing the tetrameric form of BChE (C4) and a larger peak containing the monomeric form of BChE (C1). Native polyacrylamide gel electrophoresis (PAGE) of both peaks revealed single protein bands which coincided with esterase activity, with approximate M(r) values of 84,000 and 340,000, respectively. The C1 monomer represented 85-90% of the activity found in the pigeon serum. It is not clear whether this polymorphism of BChE in vertebrates contributes to the wider inter-individual variations observed in xenobiotics elimination kinetics and in the response to the pharmacological and toxic effects of pesticides. PAGE of the monomeric form of the enzyme in the presence of sodium dodecyl sulphate showed only one protein band with a M(r) of 84,000, while that of the tetrameric form revealed two bands, a major protein band (84,000) and a minor band (170,000), representing the monomer and the dimer of the dissociated tetrameric BChE enzyme under reducing conditions. Highly specific polyclonal antibodies were raised in rabbits against the purified enzyme. These antibodies cross-reacted with other avian BChEs, a criterion which make them useful for the immunopurification of other BChEs from different species as well as for biomonitoring and toxicological studies on the role of esterases as an indicator of avian exposure to organophosphorous pesticides.

Animals↗

PubMed1993

Increased transfer of cholesteryl esters from high density lipoproteins to low density and very low density lipoproteins in patients with angiographic evidence of coronary artery disease.

Cholesterol esterification, transfer of cholesteryl esters from high density lipoproteins to very low density and low density lipoproteins (VLDL/LDL) and the composition of lipoproteins isolated by density gradient ultracentrifugation have been investigated in 18 men with angiographic evidence of severe coronary artery disease and in 27 healthy men without coronary artery disease. Patients had significantly higher serum cholesterol (P < 0.001), serum triglycerides (P < 0.02) and lower high density lipoprotein cholesterol (HDL) (P < 0.04) compared with healthy men. The transfer of cholesteryl ester from HDL to VLDL and LDL was 27.8 +/- 12.2 nmol/ml per h (mean +/- S.D.) in patients and was significantly higher than the value of 17.8 +/- 6.5 nmol/ml per h obtained in healthy men (P < 0.003) or 17.1 +/- 7.6 nmol/ml per h) in 16 controls (P < 0.03) with similar serum cholesterol and triglyceride concentrations. Lipoprotein protein concentrations were significantly higher in LDL (P < 0.05) and small VLDL (P < 0.01) in patients. In addition, patient LDL and large VLDL contained more free cholesterol than matched controls (P < 0.01, P < 0.05, respectively). This was reflected in the increased free cholesterol/phospholipid ratio (a measure of lipoprotein surface composition) in LDL (P < 0.002). These findings indicate that patients with established coronary artery disease have increased transfer of cholesteryl ester from HDL to VLDL and LDL, which is independent of serum triglyceride concentrations. This increased transfer of cholesteryl ester may be a result of the increased free cholesterol content of very low density lipoproteins.

Adult↗

PubMed1993

Is paraoxonase related to atherosclerosis.

Human serum paraoxonase is responsible for the hydrolysis of organophosphate anticholinesterases, however, whether the enzyme has a physiological role other than the detoxication of insecticides and nerve gases has remained uncertain. Recently, evidence has begun to accumulate of a relationship between the serum activity of paraoxonase and atherosclerosis. Paraoxonase may a fundamental role in lipoprotein metabolism, preventing oxidative changes to low-density lipoprotein which render the particle atherogenic.

Arteriosclerosis↗

PubMed1993

The immediate effect of streptokinase on serum lipoprotein(a) concentration and the effect of myocardial infarction on serum lipoprotein(a), apolipoproteins A1 and B, lipids and C-reactive protein.

Lipoprotein(a) (Lp(a)) has close structural homology with plasminogen and, at least in vitro, may interfere with fibrinolysis. Any changes in the serum Lp(a) concentration during and following myocardial infarction (MI) and whether the serum Lp(a) level is affected by streptokinase (SK) are therefore of interest. Serum Lp(a) levels immediately before and 3 h after completion of an intravenous infusion of SK in 39 patients with acute MI were not significantly different (median 31.3 mg/dl before and 35.9 mg/dl after). Furthermore, SK added during the serum Lp(a) assay did not affect the result, except at very high concentrations of SK (1000 units/ml). Serum Lp(a) and fasting lipids were measured daily for 3 days following definite MI in 13 patients and then after 14 and 42 days. There was no significant change in serum Lp(a) following MI. In marked contrast, C-reactive protein levels in these patients increased steeply immediately following MI. Thus, there was no early 'acute-phase response' in serum Lp(a) levels after MI. However, greater variation in its concentration was observed at day 14 than at other times. Serum cholesterol, apolipoprotein B and apolipoprotein A1 concentrations decreased significantly following MI, whereas a significant transient increase in serum triglycerides occurred. Forty-two days after MI all lipid and lipoprotein values had regained their day 1 levels, except for apo A1, which remained depressed.

Aged↗

PubMed1993

Protection of low-density lipoprotein against oxidative modification by high-density lipoprotein associated paraoxonase.

We have investigated the Cu2+ induced generation of lipid peroxides in low density lipoprotein (LDL) incubated with high density lipoprotein (HDL) and with purified paraoxonase, an enzyme normally resident on HDL. HDL (1.5 mg) and paraoxonase (20 micrograms) inhibited lipid peroxide generation in LDL by 32% and 25%, respectively after 24 h of incubation (both P < 0.01). The decrease in LDL lipid peroxides both with HDL and with paraoxonase were concentration dependent. The degree of protection offered by HDL tended to relate to its paraoxonase activity (R = 0.47; P < 0.06). Neither purified paraoxonase nor HDL chelated Cu2+ sufficiently to account for the decrease in LDL oxidation. Purified paraoxonase did not affect LDL oxidation when it had been heat inactivated. Mass transfer of lipid peroxides from LDL to HDL did not explain the protection of LDL against oxidation: the total lipid peroxides accumulating during incubation was decreased both by HDL and by paraoxonase. These results suggest a direct role for HDL in preventing atherosclerosis probably by an enzymic process which prevents the accumulation of lipid peroxides on LDL. Paraoxonase is an example of an enzyme which might possibly be involved.

Aryldialkylphosphatase↗

PubMed1993

Relationship between serum butyrylcholinesterase activity, hypertriglyceridaemia and insulin sensitivity in diabetes mellitus.

1. The activity of serum butyrylcholinesterase ('pseudocholinesterase', EC3.1.1.8) was investigated in 56 patients with type 1 diabetes mellitus, 51 patients with type 2 diabetes mellitus and 101 healthy control subjects. 2. Butyrylcholinesterase activity was significantly elevated in both type 1 (8.10 +/- 3.35 units/ml) and type 2 (7.22 +/- 1.95 units/ml) diabetes compared with the control subjects (4.23 +/- 1.89 units/ml) (P < 0.001). 3. In the patients with type 1 and type 2 diabetes, serum butyrylcholinesterase activity was correlated with log serum fasting triacylglycerol concentration (r = 0.41 and r = 0.43, respectively, P < 0.001). In the type 2 population serum butyrylcholinesterase activity was also correlated with insulin sensitivity (r = -0.51, P < 0.001). 4. Serum butyrylcholinesterase activity was unrelated to age, gender, serum gamma-glutamyltranspeptidase activity, body mass index, or treatment for diabetes in both the diabetic populations. 5. In 37 non-diabetic patients with butyrylcholinesterase deficiency serum triacylglycerol levels were in the normal range. 6. These results are consistent with the view that butyrylcholinesterase may have a role in the altered lipoprotein metabolism in hypertriglyceridaemia associated with insulin insensitivity or insulin deficiency in diabetes mellitus.

Butyrylcholinesterase↗

PubMed1993

Serum lipoprotein (a) concentrations in patients undergoing continuous ambulatory peritoneal dialysis.

Lipoprotein (a) is a subspecies of low-density lipoprotein which possesses as part of its protein moiety a mutant form of plasminogen termed apolipoprotein (a), and which may be closely related to the risk of ischaemic heart disease and cerebral infarction. We have investigated the serum concentrations of lipoprotein (a) and other lipoproteins in 24 male patients on CAPD and compared them to healthy men (n = 100) and to age-matched healthy controls (n = 38). The most striking finding was a substantial elevation of serum lipoprotein (a) in CAPD patients in whom it was 46.9 (2.2-168) mg/dl (median and range) compared to 9.0 (< 0.6-87.4) mg/dl in healthy control group and 6.7 (< 0.6-84.2) mg/dl in age-matched controls (both P < 0.001). Patients, when compared to healthy men, also had significantly increased serum triglycerides (median and range, 1.94 (0.55-8.00) versus 1.24 (0.36-4.40) mmol/l; P < 0.001), very-low-density lipoprotein cholesterol (median and range, 0.98 (0.10-3.71) versus 0.46 (0.10-1.17) mmol/l; P < 0.001), and lower-high-density lipoprotein cholesterol (mean +/- 1 SD, 1.26 +/- 0.29 versus 1.35 +/- 0.31 mmol/l). Of these, however, only the difference in very-low-density lipoprotein cholesterol remained statistically significant (P < 0.001) in comparison to age-matched controls. The marked elevation of serum lipoprotein (a) in patients on CAPD may be due to increased hepatic synthesis as a consequence of the substantial amounts of plasma proteins lost in the dialysate. Elevated serum lipoprotein (a) concentrations in CAPD patients may contribute to their risk of coronary artery disease.

Adult↗

PubMed1993

Serum lipoprotein (a) in renal transplant recipients receiving cyclosporin monotherapy.

Coronary heart disease is more common in patients with chronic renal failure and is a major cause of death after renal transplantation. Elevated serum lipoprotein (a) (Lp(a)) is a known risk factor for coronary heart disease in the general population. We measured the serum concentration of Lp(a) in 58 renal transplant recipients (40 male, 18 female) on cyclosporin monotherapy, and in 58 age- and sex-matched controls. Serum Lp(a) was significantly elevated in the transplant patients with a median of 27.5 (range < 0.8-140.3) mg/dl compared to 7.6 (range < 0.8-87.4) mg/dl in controls (P < 0.001). Total serum cholesterol, low-density lipoprotein cholesterol, and total triglyceride concentrations were also significantly raised (P < 0.001) in the transplant recipients. The increased serum Lp(a) may contribute to the increased cardiovascular morbidity associated with renal transplantation.

Adult↗

PubMed1992

Effects of treatment of hypertriglyceridaemia with gemfibrozil on serum lipoproteins and the transfer of cholesteryl ester from high density lipoproteins to low density lipoproteins.

Lipoprotein composition and cholesterol esterification, before and after treatment with gemfibrozil, have been examined in the fasting and postprandial state in nine patients with primary hypertriglyceridaemia who participated in a double-blind, placebo controlled study. After 8 weeks of treatment fasting serum triglycerides were reduced significantly from 6.05 mmol/l (range 2.48-10.99 mmol/l) to 1.76 mmol/l (range 1.16-11.90 mmol/l) (P less than 0.001). This was mainly due to a decrease in the triglyceride content of the Sf 12-20, 60-400 and Sf greater than 400 lipoprotein fractions (P less than 0.05). The Sf 0-12 fraction showed an increase in cholesteryl ester, free cholesterol, phospholipids and protein. Consistent with these findings there was a net increase in the mass concentration of the Sf 0-12 fraction (P less than 0.05) and a decrease in that of small very low density lipoproteins (Sf 20-60) (P less than 0.05). In the 8 patients in whom it was measured there was a 40% reduction in the rate at which cholesteryl esters derived from radiolabelled-free cholesterol appeared in very low density lipoprotein (VLDL) and low density lipoprotein (LDL) measured in an in vitro system (P less than 0.02), but serum lecithin:cholesterol acyl transferase (LCAT) activity was unchanged. At the end of each treatment phase (placebo or gemfibrozil) patients were given a mixed meal containing 100 g of fat. Treatment with gemfibrozil resulted in a reduction in serum triglyceride concentrations at all time points for at least 5 h after the meal (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Non-enzymatic glycation of apolipoprotein B in the sera of diabetic and non-diabetic subjects.

Utilising a combination of m-aminophenyl-borate affinity chromatography and an immunoradiometric assay for apolipoprotein B (apo B), we have developed a specific and highly sensitive (6 ng/ml) procedure for the assay of glycated apo B. We studied 52 diabetic patients, 50 non-diabetic control subjects and 12 patients heterozygous for familial hypercholesterolaemia (FH). Both insulin-dependent and non-insulin dependent diabetics were included in our study. Total apo B in the diabetics (108 +/- 5 mg/dl; mean +/- S.E.M) was increased (controls: 95 +/- 4 mg/dl; P less than 0.05). In the FH group the serum apo B concentration (216 +/- 24 mg/dl) was significantly higher (P less than 0.001) than both the other groups studied. Both the serum glycated apo B concentration (9.3 +/- 0.8 mg/dl versus 4.8 +/- 0.7 mg/dl) and the percentage glycated apo B (7.9 +/- 0.4% compared to 3.9 +/- 0.2%) were significantly higher in the diabetics than in non-diabetic controls (P less than 0.001). A positive correlation was found between the percentage of glycated apo B and glycated haemoglobin (r = 0.65; P less than 0.001) and fasting glucose concentration (r = 0.52; P less than 0.001) in diabetics. The percentage of glycated apo B in FH patients was not significantly different from controls, but the serum concentration of glycated apo B, because of the greatly increased total level of apo B was raised (8.2 +/- 1.4 mg/dl) to a similar extent to that of the diabetics.

Adult↗

PubMed1991

Lipoprotein secretion by the human hepatoma cell line Hep G2: differential rates of accumulation of apolipoprotein B and lipoprotein lipids in tissue culture media in response to albumin, glucose and oleate.

Serum low-density lipoprotein (LDL) concentration is a major determinant of susceptibility to the development of atherosclerosis. A major component of the protein moiety of LDL and its precursor very-low-density lipoprotein is apolipoprotein B (apo B). The human hepatoma cell line, Hep G2, was used as a model for the investigation of mechanisms which control hepatic secretion of the apo B and lipid components of lipoproteins. Using a sensitive immunoradiometric assay for apo B developed in this laboratory, we showed that bovine serum albumin inhibited and glucose, and fatty acids enhanced the rate of accumulation of apo B in the culture medium of Hep G2 cells. However, these substances did not necessarily affect LDL lipids in the same way as apo B. This finding appeared to be due to Hep G2 cells expressing lipase activities which led to triacylglycerol and phospholipid hydrolysis and lipid reuptake. Reuptake of apo B also occurred, but its rate of accumulation in the culture medium suggested it was a closer reflection of its true secretory rate.

Apolipoproteins B↗

PubMed1991

Paraoxonase prevents accumulation of lipoperoxides in low-density lipoprotein.

Oxidative modification of low-density lipoprotein (LDL) enhances its uptake by macrophages in tissue culture and in vivo may underly the formation of arterial fatty streaks, the progenitors of atheroma. We investigated the possible protection which high-density lipoprotein (HDL) affords against LDL oxidation. The formation of lipoperoxides and thiobarbituric acid reactive substances when LDL was incubated with copper ions was significantly decreased by HDL. The enzyme, paraoxonase (E.C. 3.1.8.1), purified from human HDL, had a similar effect and thus may be the component of HDL responsible for decreasing the accumulation of lipid peroxidation products.

Aryldialkylphosphatase↗

PubMed1991

Species differences in avian serum B esterases revealed by chromatofocusing and possible relationships of esterase activity to pesticide toxicity.

Serum cholinesterase (BChE) and carboxylesterase (CbE) activities were investigated in ten species of birds. Multiple forms of serum BChE and CbE were also separated by chromatofocusing. Higher CbE activity and a wider range of CbE and BChE forms were present in the sera of omnivorous/herbivorous birds than carnivores. Omnivores/herbivores studied were the starling, house sparrow, tree sparrow, pigeon, partridge and magpie. Serum CbE activities of these species ranged from 0.46 to 2.93 mumol/min/mL with 2-6 forms separated by chromatofocusing. 0-6 forms of BChE were separated by the same method. The serum CbE activities of the little owl, tawny owl, barn owl and razorbill ranged from 0.19 to 0.58 mumoles/min/mL with 0-2 forms separated by chromatofocusing. No ChE forms were present within the pH gradient. These results may be significant in contributing to the understanding of the selective toxicity of organophosphorus and carbamate pesticides.

Animals↗