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Biomedical subjects

J Shepherd

Publications and source records attributed to J Shepherd.

At least 55 records · Page 3Linked to original sources
PubMed2000

The role of small, dense low density lipoprotein (LDL): a new look.

Plasma low density lipoprotein (LDL) plays a central role in atherogenesis, and elevated levels of LDL are associated with an increased risk of coronary heart disease (CHD). Studies have now revealed that LDL is structurally heterogeneous, based on its size and density. Patients with combined hyperlipidemia exhibit a lipid profile - the so-called atherogenic lipoprotein phenotype - that is associated with elevated triglyceride levels, low levels of high density lipoprotein and a preponderance of atherogenic, small, dense LDL particles. Such individuals are at an increased risk of CHD events, regardless of their total LDL circulating mass. Evidence suggests that when plasma triglycerides exceed a critical threshold of approximately 133 mg/dl (1.5 mmol/l), this favours the formation of small, dense LDL from larger, less dense species. Lipid-lowering agents that are capable of lowering triglyceride levels below this threshold value will cause a shift to a less dense and, therefore, less atherogenic LDL profile. This effect has been demonstrated for the HMG-CoA reductase inhibitor atorvastatin which, in addition to its ability to markedly decrease the total LDL circulating mass, can also shift the LDL profile towards less dense, larger species. This suggests that atorvastatin may also affect the atherogenic lipoprotein phenotype found in patients with combined hyperlipidemia.

Atorvastatin↗
PubMed2000

The cardiovascular event reduction tool (CERT)--a simplified cardiac risk prediction model developed from the West of Scotland Coronary Prevention Study (WOSCOPS).

The clinical decision to treat hypercholesterolemia is premised on an awareness of patient risk, and cardiac risk prediction models offer a practical means of determining such risk. However, these models are based on observational cohorts where estimates of the treatment benefit are largely inferred. The West of Scotland Coronary Prevention Study (WOSCOPS) provides an opportunity to develop a risk-benefit prediction model from the actual observed primary event reduction seen in the trial. Five-year Cox model risk estimates were derived from all WOSCOPS subjects (n = 6,595 men, aged 45 to 64 years old at baseline) using factors previously shown to be predictive of definite fatal coronary heart disease or nonfatal myocardial infarction. Model risk factors included age, diastolic blood pressure, total cholesterol/ high-density lipoprotein ratio (TC/HDL), current smoking, diabetes, family history of fatal coronary heart disease, nitrate use or angina, and treatment (placebo/ 40-mg pravastatin). All risk factors were expressed as categorical variables to facilitate risk assessment. Risk estimates were incorporated into a simple, hand-held slide rule or risk tool. Risk estimates were identified for 5-year age bands (45 to 65 years), 4 categories of TC/HDL ratio (<5.5, 5.5 to <6.5, 6.5 to <7.5, > or = 7.5), 2 levels of diastolic blood pressure (<90, > or = 90 mm Hg), from 0 to 3 additional risk factors (current smoking, diabetes, family history of premature fatal coronary heart disease, nitrate use or angina), and pravastatin treatment. Five-year risk estimates ranged from 2% in very low-risk subjects to 61% in the very high-risk subjects. Risk reduction due to pravastatin treatment averaged 31%. Thus, the Cardiovascular Event Reduction Tool (CERT) is a risk prediction model derived from the WOSCOPS trial. Its use will help physicians identify patients who will benefit from cholesterol reduction.

Age Factors↗
PubMed2000

Interventions for encouraging sexual lifestyles and behaviours intended to prevent cervical cancer.

BACKGROUND: Cervical cancer is one of the most common cancers affecting women world-wide. Prevention falls into two main categories - primary and secondary. Primary prevention is characterised by health promotion to promote lifestyles and behaviours minimising risk of cervical cancer. Interventions to promote the use of condoms for sexual intercourse (especially early intercourse amongst young women), sexual partner reduction, and negotiated safer sex strategies has been recommended as one approach to limit the spread of Human Papilloma Virus (HPV), one of the major risk factors for cervical cancer. OBJECTIVES: To determine the effectiveness of health education interventions to promote sexual risk reduction behaviours amongst women in order to reduce transmission of HPV. SEARCH STRATEGY: Electronic searching of EMBASE, ERIC, MEDLINE, PsycLIT, Social Science Citation Index and the CCTR were undertaken using a highly sensitive search strategy. Hand-searching took place of selected journals and reference lists. SELECTION CRITERIA: Studies were included if they evaluated educational interventions targeting women only, and measured the impact on : either a behavioural outcome such as condom use for sexual intercourse, partner reduction, or abstinence; or a clinical outcome such as incidence of a sexually transmitted disease (STD). DATA COLLECTION AND ANALYSIS: Data were extracted and methodological quality was assessed independently by two reviewers and any discrepancies were resolved between them. Ten per cent of the total number of studies were reviewed additionally by a third reviewer as a quality check and differences in judgement were resolved accordingly. MAIN RESULTS: Thirty trials met the inclusion criteria for the review. All of them had the primary aim of preventing HIV and other STDs rather than cervical cancer. Four core methodological qualities were present in 10 of the 30 studies and constitute the subset from which potentially reliable conclusions may be drawn. Each of the 10 studies showed a statistically significant positive effect on sexual risk reduction, typically with increased use of condoms for vaginal intercourse. This positive effect was generally sustained up to three months after intervention. REVIEWER'S CONCLUSIONS: Educational interventions targeting socially and economically disadvantaged women in which information provision is complemented by sexual negotiation skill development can encourage at least short-term sexual risk reduction behaviour. This has the potential to reduce the transmission of HPV, thus possibly reduce the incidence of cervical carcinoma.

Female↗
PubMed2000

Lipoprotein (a) levels in normal pregnancy and in pregnancy complicated with pre-eclampsia.

Lipoprotein (a) (Lp(a)) is recognised as a risk factor for arterial and venous thrombosis, a property which may relate to its structural similarity to plasminogen. Pregnancy is associated with a hypofibrinolytic state. Elevated Lp(a) may influence fibrinolysis and have an unfavourable role in pregnancy outcome. In this study alterations in plasma Lp(a) concentrations during normal pregnancy was examined, in a detailed longitudinal investigation, in ten women together with changes in other lipid parameters. In addition, Lp(a) concentrations were examined in subjects with pre-eclampsia (n=10) relative to matched controls (n=10), since it has recently been reported that a substantial increase in circulating Lp(a) occurs in this disorder. Lp(a) concentration increased steadily in normal pregnancy between 10 and 35 weeks with a doubling of the median value from 14.5 to 27.0 mg/dl (P=0.01). A significant increase in Lp(a) values was observed in all subjects with increasing gestation (median rise 190%, range 117-340%). This increase was intermediate to those seen in plasma triglyceride and cholesterol. No significant difference in Lp(a) values was observed in subjects with pre-eclampsia, compared with matched normal pregnancy controls (median 14 mg/dl [IQR 4.7-69.0] in pre-eclampsia vs 20 mg/dl [9.0-56. 3] in controls; P=0.57), at a median gestation of 32 weeks. In conclusion, there is a 2-fold increase in Lp(a) during normal pregnancy, which may influence fibrinolysis. Circulating Lp(a) is not significantly elevated in women with pre-eclampsia, and thus is unlikely to play a role in the pathophysiology of this disorder.

Adult↗
PubMed2000

Eye movement desensitization and reprocessing in the treatment of post-traumatic stress disorder: a review of an emerging therapy.

BACKGROUND: Eye Movement Desensitization and Reprocessing (EMDR) is a relatively new form of psychotherapy for post-traumatic stress disorder. We critically reviewed randomized controlled trials of EMDR. METHODS: A wide range of electronic databases and reference lists of articles obtained were searched and relevant experts were consulted. Studies were critically appraised according to established criteria. RESULTS: We found 16 published randomized controlled trials (RCTs) comparing EMDR with alternative psychotherapy treatments, variants of EMDR and with delayed treatment groups. Studies were generally small (mean number of patients = 35) and of variable methodological quality, with only five reporting blinding of outcome assessors to treatment allocation, and in some cases with high loss to follow-up. In most cases EMDR was shown to be effective at reducing symptoms up to 3 months after treatment. In one case benefit was maintained up to 9 months and in another (uncontrolled) follow-up treatment effect was present at 15 months. Two studies suggest that EMDR is as effective as exposure therapies, three claim greater effectiveness in comparison to relaxation training, and three claim superiority over delayed treatment groups. Of the studies examining specific treatment components, two found that treatment with eyes moving was more effective than eyes fixed, while three studies found the two procedures to be of equal effectiveness. CONCLUSION: The evidence in support of EMDR is of limited quality but results are encouraging for this inexpensive, simple therapy. Further research is warranted in larger samples with longer periods of follow-up.

Desensitization, Psychologic↗
PubMed2000

Identification of MEN1 gene mutations in families with MEN 1 and related disorders.

Following identification of the MEN1 gene, we analysed patients from 12 MEN 1 families, 8 sporadic cases of MEN 1, and 13 patients with MEN 1-like symptoms (e.g. cases of familial isolated hyperparathyroidism (FIHPT), familial acromegaly, or atypical MEN 1 cases) for the presence of germline MEN1 mutations. The entire coding region of the MEN1 gene was sequenced, and mutations were detected in 11 MEN 1 families; one sporadic MEN 1 patient, one case of FIHPT and one MEN 1-like case. Constitutional DNA samples from individuals without MEN1 mutations were digested with several restriction enzymes, Southern blotted and probed with MEN1 cDNA to analyse for the presence of larger deletions of the MEN1 gene unable to be detected by PCR. One MEN 1 patient was found to carry such a deletion. This patient was heterozygous for the D418D polymorphism, however sequence analysis of RT-PCR products showed that only the variant allele was transcribed, thus confirming the result obtained by Southern analysis, which indicated loss of a region containing the initiation codon of one allele.

Acromegaly↗
PubMed2000

Identification of somatic mutations of the MEN1 gene in sporadic endocrine tumours.

Endocrine tumours of the pancreas, anterior pituitary or parathyroids arise either sporadically in the general population, or as a part of inherited syndromes such as multiple endocrine neoplasia type 1 (MEN 1). The mechanisms responsible for the development of sporadic endocrine lesions are not well understood, although loss of heterozygosity (LOH) of the MEN1 locus on chromosome 11q13 and somatic mutation of the MEN1 gene have been frequently associated with the development of MEN 1-type sporadic endocrine lesions. To further investigate the role of the MEN1 gene in sporadic endocrine tumorigenesis, we analysed DNA from 14 primary parathyroid lesions, 8 anterior pituitary tumours and 3 pancreatic tumours for the presence of somatic MEN1 gene mutations and LOH of seven microsatellite markers flanking the MEN1 locus. In addition, we similarly analysed 8 secondary parathyroid lesions which arose in patients with chronic renal failure. None of the patients studied had a family history of MEN 1. Three primary parathyroid lesions and one pancreatic tumour (glucagonoma) were found to have lost one allele at the MEN1 locus. Somatic mutations were identified by SSCP and sequence analysis in one of these parathyroid lesions (P320L) and in the glucagonoma (E179V). These results support previous findings that inactivation of the MEN1 tumour suppressor gene contributes to the development of sporadic MEN 1-type endocrine lesions but is not associated with the development of parathyroid hyperplasia seen in some renal failure patients.

Adenoma↗
PubMed2000

Cervical cancer and sexual lifestyle: a systematic review of health education interventions targeted at women.

A systematic review was conducted to determine the effectiveness of health education interventions to promote sexual risk reduction behaviours amongst women in order to reduce transmission of human papillomavirus (HPV), a leading agent in the development of cervical cancer. A comprehensive search was conducted to identify relevant studies. Studies were included in the review if they evaluated educational interventions targeting women only and measured the impact on either a behavioural outcome such as condom use for sexual intercourse, partner reduction or abstinence, or a clinical outcome such as incidence of a STD. Thirty studies met the inclusion criteria for the review; all had the primary aim of preventing HIV and other STDs rather than cervical cancer. Ten of the 30 studies were considered to provide the strongest evidence for a causal relationship between the intervention and the change in outcomes measured. Each of these 10 most rigorous studies showed a statistically significant positive effect on sexual risk reduction, typically with increased use of condoms for vaginal intercourse. This positive effect was generally sustained up to 3 months after intervention. It was concluded that educational interventions targeting socially and economically disadvantaged women in which information provision is complemented by sexual negotiation skill development can encourage at least short-term sexual risk reduction behaviour. This effect has the potential to reduce the transmission of HPV and thus possibly reduce the incidence of cervical carcinoma.

Female↗
PubMed2000

Apolipoprotein E polymorphism and serum concentration in Alzheimer's disease in nine European centres: the ApoEurope study. ApoEurope group.

As part of the ApoEurope Project, apolipoprotein E (apo E) common polymorphism and serum concentration were determined in 489 Alzheimer's disease patients and 429 controls. Patients and controls were recruited through nine centres in eight European countries. Age, sex ratios and education levels of both case and control populations were similar, although discrete differences appeared between centres. The prevalence of the epsilon4 allele was higher in Alzheimer's disease than in controls (increased by 140%), while serum apo E concentration was lower by 11.2% (p<0.001). In addition, serum total cholesterol and triglyceride concentrations were lower in Alzheimer's disease (p<0.001), while that of apo Al was not affected. The decrease in serum apo E concentration was not accounted for by the epsilon4 allele, age or gender, suggesting that apo E concentration might represent an additional risk factor for Alzheimer's disease, complementary and independent of the epsilon4 allele. Further analysis will be aimed at determining whether the quantitative link between apo E concentration and Alzheimer's disease occurs through the effect of apo E genotype on lipid parameters or by other mechanisms.

Age Factors↗
PubMed2000

Apolipoprotein B metabolism and the distribution of VLDL and LDL subfractions.

Apolipoprotein B (apoB) metabolism was investigated in 20 men with plasma triglyceride 0.66-2.40 mmol/l and plasma cholesterol 3.95-6. 95 mmol/l. Kinetics of VLDL(1) (S(f) 60-400), VLDL(2) (S(f) 20-60), IDL (S(f) 12-20), and LDL (S(f) 0;-12) apoB were analyzed using a trideuterated leucine tracer and a multicompartmental model which allowed input into each fraction. VLDL(1) apoB production varied widely (from 5.4 to 26.6 mg/kg/d) as did VLDL(2) apoB production (from 0.18 to 8.4 mg/kg/d) but the two were not correlated. IDL plus LDL apoB direct production accounted for up to half of total apoB production and was inversely related to plasma triglyceride (r = -0.54, P = 0.009). Percent of direct apoB production into the IDL/LDL density range (r = 0.50, P < 0.02) was positively related to the LDL apoB fractional catabolic rate (FCR). Plasma triglyceride in these subjects was determined principally by VLDL(1) and VLDL(2) apoB fractional transfer rates (FTR), i.e., lipolysis. IDL apoB concentration was regulated mainly by the IDL to LDL FTR (r = -0.71, P < 0.0001). LDL apoB concentration correlated with VLDL(2) apoB production (r = 0.48, P = 0.018) and the LDL FCR (r = -0.77, P < 0. 001) but not with VLDL(1), IDL, or LDL apoB production. Subjects with predominantly small, dense LDL (pattern B) had lower VLDL(1) and VLDL(2) apoB FTRs, higher VLDL(2) apoB production, and a lower LDL apoB FCR than those with large LDL (pattern A). Thus, the metabolic conditions that favored appearance of small, dense LDL were diminished lipolysis of VLDL, resulting in a raised plasma triglyceride above the putative threshold of 1.5 mmol/l, and a prolonged residence time for LDL. This latter condition presumably permitted sufficient time for the processes of lipid exchange and lipolysis to generate small LDL particles.

Adult↗
PubMed2000

Blood rheology, cardiovascular risk factors, and cardiovascular disease: the West of Scotland Coronary Prevention Study.

The West of Scotland Coronary Prevention Study (WOSCOPS) showed that pravastatin reduced the risk of coronary heart disease (CHD) events in 6,595 middle-aged hypercholesterolaemic men aged 45-64 years without prior myocardial infarction followed for an average of 4.9 years. We hypothesised prospectively (a) that baseline levels of haemorheological variables were related to baseline and incident CHD and to mortality; and (b) that reduction in lipoproteins by pravastatin would lower plasma and blood viscosity, a potential contributory mechanism to CHD events. We therefore studied plasma and blood viscosity, fibrinogen, haematocrit, and blood cell counts at baseline and 1 year. At baseline, plasma and blood viscosity were related to risk factors, CHD measures, and claudication. On univariate analysis, baseline levels of all rheological variables (except platelet count) were related to incident CHD; CHD mortality; and total mortality. On multivariate analysis including baseline CHD and risk factors, plasma and blood viscosity, haematocrit and white cell count each remained significantly associated with incident CHD; while fibrinogen remained an independent predictor of mortality (all p < 0.03). After one year, lipoprotein reduction by pravastatin was associated with significant reductions (about one quarter of a standard deviation) in plasma viscosity (mean difference 0.02 mPa.s, p <0.001) and in blood viscosity (mean difference 0.06 mPa.s, p<0.001), but was not associated with significant changes in other rheological variables. We therefore suggest that pravastatin therapy, which reduces elevated lipoproteins in hypercholesterolaemic men, may lower risks of CHD and mortality partly by lowering plasma and blood viscosity. Further studies are required to test this hypothesis.

Anticholesteremic Agents↗
PubMed2000

Combination therapy (interferon alfa and ribavirin) in the treatment of chronic hepatitis C: a rapid and systematic review.

BACKGROUND: Hepatitis C is a viral disease of the liver, which frequently causes few or no symptoms at first infection but has a high probability of becoming an insidious chronic disease. Treatment has traditionally been with interferon alfa but only a small proportion of patients have been cured by this method. The recent introduction of ribavirin, given in combination, has led to a re-appraisal of the management of chronic hepatitis C. The current report considers the additional benefit of combination therapy (interferon alfa and ribavirin) compared with monotherapy (interferon alfa alone) for the treatment of patients with chronic hepatitis C. It supersedes two reports of combination therapy conducted by the Scottish Health Purchasing Information Centre and the Wessex Institute for Health Research and Development. OBJECTIVE: To review the clinical effectiveness and cost-effectiveness of combination therapy with interferon alfa and ribavirin in patients with chronic hepatitis C. METHODS - EFFECTIVENESS: Electronic databases were searched from 1993 to the end of 1999, to identify randomised controlled trials (RCTs) or systematic reviews of RCTs that evaluated interferon alfa in combination with ribavirin compared with interferon alfa alone (or placebo) in patients with chronic hepatitis C. Bibliographies from previous studies were also examined. METHODS - ECONOMIC ANALYSIS: The economic evaluation is based on the three largest RCTs of combination therapy, and a pooled analysis of two of these trials. Sustained virological response rates were entered into a spreadsheet model incorporating a hypothetical cohort of 1000 patients who were followed over a 30-year period. RESULTS - EFFECTIVENESS: Nineteen RCTs and two meta-analyses were identified. The methodological quality of the included studies was variable, though the larger RCTs and meta-analyses were considered to be of high quality. Results of these trials indicate that combination therapy produces larger sustained response rates than monotherapy. For patients naive to interferon treatment, sustained virological response rates were: 33% (95% confidence interval (CI), 29 to 37) for combination therapy compared with 6% (95% CI, 3 to 10) for monotherapy, based on 24 weeks of treatment; and 41% (95% CI, 36 to 45) compared with 16% (95% CI, 13 to 19), respectively, for 48 weeks of treatment. For patients who had relapsed following a previous course of interferon, sustained virological response rates were 49% (95% CI, 42 to 57) compared with 5% (95% CI, 2 to 9), respectively, based on 24 weeks of treatment. Two groups of chronic hepatitis C patients are expected to benefit from combination therapy: interferon-naive patients and relapse patients. RESULTS - ECONOMIC ANALYSIS: A 4-week cycle of interferon alfa at 3 mU three times a week costs pound 194; ribavirin costs pound 543. Thus, ribavirin substantially increases drug costs compared with interferon monotherapy. Six months of combination therapy will cost pound 4422 (excluding monitoring costs). For interferon alfa-naive patients, the additional discounted cost per quality-adjusted life-year (QALY) gained from treatment with combination therapy for 6 months compared with no active treatment is pound 7578. For patients who have relapsed after a previous course of interferon alfa, the additional discounted cost per QALY gained from treatment with combination therapy for 6 months compared with monotherapy for 6 months is pound 3503. A subgroup analysis was conducted to examine the sensitivity of the cost per QALY based on the response rates of different patient subgroups (chronic hepatitis C patients with between none and five favourable response factors). This shows it is worth treating all patients with combination therapy as first-line treatment for 6 months, but only worth treating those with one or two response factors for a further 6 months. Those with three or four factors do well by 6 months, but gain very little from furt

Antiviral Agents↗
PubMed1999

The design of a prospective study of Pravastatin in the Elderly at Risk (PROSPER). PROSPER Study Group. PROspective Study of Pravastatin in the Elderly at Risk.

The PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) is a randomized, double-blind, placebo-controlled trial designed to test the hypothesis that treatment with pravastatin will diminish risk of subsequent major vascular events in a cohort of men and women (70 to 82 years old) with preexisting vascular disease or significant risk of developing this condition. Five thousand eight hundred four men and women in addition to receiving advice on diet and smoking, have been randomized equally to treatment with 40 mg pravastatin/day or matching placebo in 3 centers (Cork, Ireland, Glasgow, Scotland, and Leiden, The Netherlands). Following an average 3.5-year intervention period, a primary assessment will be made of the influence of this therapy on major vascular events (a combination of coronary heart disease, death, nonfatal myocardial infarction, and fatal and nonfatal stroke). A number of additional analyses will also be conducted on the individual components of the primary end point, on men, on women, and on subjects with and without previous evidence of vascular disease. Finally, an assessment will be made of the effects of treatment on cognitive function, disability, hospitalization or institutionalization, vascular mortality, and all-cause mortality.

Aged↗
PubMed1999

From best evidence to best practice - what are the obstacles?

There are numerous obstacles to overcome when implementing measures resulting from new evidence in clinical practice - some relate to practitioners in hospitals and primary care, others to patients, their relatives and public opinion. Many post-myocardial infarction (MI) patients are still discharged from hospital without any specific recommendations for risk-factor management, despite the fact that the hospital stay provides an excellent window of opportunity for treatment. Conversely, the primary-care physician may assume that as these measures were not implemented in hospital, they are unimportant. Even if recommendations for risk modification are made, the patient's attitude towards risk reduction can reduce its effectiveness. The HELP study found that the public had a reasonable knowledge of coronary heart disease (CHD) and the risks involved. However, their attitude was remarkably indifferent; even in post-MI patients, 24% were aware of lipid-lowering treatments, but did not take them, while 38% were not even aware of this form of therapy. Despite this, the medical profession was found to be the most credible source of information about CHD. Healthcare professionals, therefore, have an obligation to ensure patients receive the maximum benefit from medical advances by working together to overcome the barriers.

Coronary Disease↗
PubMed1999

Sialic acid-containing components of lipoproteins influence lipoprotein-proteoglycan interactions.

Sialic acid is a negatively charged sugar associated with the protein and lipid portions of lipoproteins. Sialic acid has been hypothesised to play an anti-atherogenic role in lipoprotein metabolism through the electrostatic inhibition of lipoprotein interactions with chondroitin-6-sulphate-rich arterial proteoglycans (APG). We conducted a series of studies using native and modified lipoproteins (VLDL1 Sf 60-400, VLDL2 Sf 20-60, IDL1 Sf 16-20, IDL2 Sf 12-16, LDL(A) Sf 8-12, and LDL(B) Sf0-8) that vary in their sialic acid content to examine the relationship between lipoprotein sialic acid content and its interaction with APG. Lipoprotein sialic acid was greatest in VLDL1 and decreased progressively with particle density until the IDL2 fraction (VLDL1 > VLDL2 > IDL1 > IDL2 = LDL(A) = LDL(B)). The pattern of reactivity of each fraction with APG was different from the pattern observed for lipoprotein sialic acid content (IDL2 > LDL(A) > LDL(B) > IDL1 > VLDL2 > VLDL1). Levels of sialic acid were lower in subjects with CHD as compared to control subjects but the presence of CHD had no effect on lipoprotein-APG complex formation when sex and plasma triglyceride levels were taken into account. There was also no significant relationship between the lipoprotein sialic acid content and the reactivity with APG within each lipoprotein fraction. Treatment of hypertriglyceridaemic subjects with ciprofibrate decreased lipoprotein-APG complex formation in all lipoprotein fractions. This was associated with a decrease in the total sialic acid content of apo B100-containing lipoproteins suggesting that the total sialic acid content of apo B100-containing lipoproteins has no influence on lipoprotein-APG complex formation. We next conducted in vitro experiments to manipulate LDL sialic acid content. Enzymatic removal of sialic acid from LDL with neuraminidase resulted in an increase in LDL-APG complex formation. This was accompanied by an increase in the exposure of free amino groups on LDL possibly due to disruption of interactions between free amino groups and sialic acid-containing components on LDL. Increasing LDL sialic acid content through incubation with ganglioside resulted in a decrease in lipoprotein-APG complex formation without any changes in the exposure of free amino groups on LDL. We conclude that total sialic acid content of lipoproteins is not a major determinant of their binding to APG. However, specific sialic acid-containing components on lipoproteins can affect their interaction with APG.

Apolipoprotein B-100↗