Lipoprotein (a) levels in those with high molecular weight apo (a) isoforms may remain low in a significant proportion of patients with end-stage renal disease.

Background: Studies have reported an increase in median Lipoprotein (Lp) (a) in patients with high molecular weight (HMW) apolipoprotein (apo) (a) isoforms and renal impairment. Some studies identify Lp (a) levels as a risk factor for vascular disease in renal failure whilst others have demonstrated an association with apo (a) isoform type and vascular disease.

Methods: A total of 239 patients at end-stage renal failure (ESRF) were studied prior to the initiation of dialysis.

Relationship of renal function to homocysteine and lipoprotein(a) levels: the frequency of the combination of both risk factors in chronic renal impairment.

Background: Total homocysteine (tHcy) and lipoprotein(a) [Lp(a)] levels have been recognized as risk factors for vascular disease. The combination of elevated tHcy and Lp(a) levels may be particularly atherogenic, although no study has examined the prevalence of the combination of both risk factors in patients with chronic renal impairment.

Methods: One hundred ninety-seven patients with renal impairment were studied.

Effects of xanthine oxidase inhibition with allopurinol on endothelial function and peripheral blood flow in hyperuricemic patients with chronic heart failure: results from 2 placebo-controlled studies.

Background: In patients with chronic heart failure (CHF), hyperuricemia is a common finding and is associated with reduced vasodilator capacity and impaired peripheral blood flow. It has been suggested that the causal link of this association is increased xanthine oxidase (XO)-derived oxygen free radical production and endothelial dysfunction. We therefore studied the effects of XO inhibition with allopurinol on endothelial function and peripheral blood flow in CHF patients after intra-arterial infusion and after oral administration in 2 independent placebo-controlled studies.

Assay of serum allantoin in humans by gas chromatography-mass spectrometry.

Background: The small amount of allantoin present in human serum results from free radical (FR) action on urate and may provide a stable marker of free radical activity in vivo. We describe a gas chromatography-mass spectrometry (GC-MS) assay for serum allantoin and report a reference range in healthy individuals.

Methods: Fasting blood samples were obtained from 134 healthy middle-aged volunteers (56 men, mean age 55, range 45-72; 78 women, mean age 55, range 50-72) Allantoin was assayed using 15N(2) allantoin as an internal standard.

Mechanism for elevated plasma lipoprotein(a) concentrations in patients on dialysis: turnover studies.

Plasma concentrations of lipoprotein (a) [Lp(a)] are increased in patients on renal replacement therapy. Lipoprotein (a) is increasingly being recognized as an independent cardiovascular risk factor. In an effort to explore the mechanism for elevation of Lp(a) in patients on dialysis we have performed turnover studies of Lp(a) with radioactive iodine.

Six-month prospective cross-over study to determine the effects of 1.1% amino acid dialysate on lipid metabolism in patients on continuous ambulatory peritoneal dialysis.

Objective: To evaluate the effect of 1.1% amino acid dialysate (AAD) (Nutrineal, Baxter, Castlebar, Ireland) on lipid metabolism in hyperlipidemic patients on continuous ambulatory peritoneal dialysis (CAPD).

Design: Patients were alternately assigned to receive AAD in the first (group A), or the second (group B), 6 months of a prospective cross-over study.

The effect of change of renal replacement therapy on serum lipoprotein (a) concentration.

Lipoprotein (a) [Lp(a)] is an independent atherogenic risk factor. Lp(a) levels are elevated in patients on renal replacement therapy (RRT). This study looked at the effect of change of RRT on serum lipid and Lp(a) levels.

Energy balance in asymptomatic HIV infection.

Objectives: Body weight is regulated by the balance between energy intake and energy expenditure, but the influence of HIV infection on energy balance has not been fully examined. The main objectives of this study were (1) to assess the effect of HIV on energy balance, (2) to examine the relationship of parameters of immunodeficiency to energy balance, and (3) to examine the interrelationship of different components of energy balance in asymptomatic HIV-seropositive men.

Design: A cross-sectional study of nutrition and metabolism in asymptomatic HIV-seropositive men

Methods: Components of energy balance were examined in 104 asymptomatic HIV-seropositive men (CD4 count 4-482 x 10(6)/l) and 57 age-matched HIV-seronegative male controls.

L-arginine depletion inhibits glomerular nitric oxide synthesis and exacerbates rat nephrotoxic nephritis.

Nitric oxide (NO) synthesis is induced in glomeruli in glomerulonephritis; its role in the pathogenesis of glomerular injury is unknown. Interpretation of its role using the currently available analogues of L-arginine as in vivo inhibitors of NO is complicated by their lack of specificity for inducible NO synthase (iNOS). As NO synthesis by iNOS depends on extracellular L-arginine, we have here examined effects of L-arginine depletion on glomerular NO synthesis and the course of accelerated nephrotoxic nephritis (NTN).

Nutritional effects of amino acid dialysate (Nutrineal) in CAPD patients.

The use of amino acid dialysate (AAD) has been shown to improve the nutritional status of malnourished continuous ambulatory peritoneal dialysis (CAPD) patients. We report on a randomized, prospective, cross-over study evaluating the effects of a single, daily, postprandial 2-L exchange of 1.1% AAD (Nutrineal) on a nutritionally unselected group of 18 stable CAPD patients.

Lipids and lipoprotein(a) as risk factors for vascular disease in patients on renal replacement therapy.

A large cohort of patients on renal replacement therapy were screened for the presence of symptomatic arterial disease affecting the coronary, cerebral or peripheral circulations. Ninety-two of 325 patients were found to have vascular disease. Those with vascular disease had significantly higher median lipoprotein(a) [Lp(a)] levels than those without (38.

Arginine metabolism in experimental glomerulonephritis: interaction between nitric oxide synthase and arginase.

L-Arginine is metabolized by two pathways: 1) by nitric oxide synthase (NOS) to nitric oxide (NO) and 2) by arginase forming urea and L-ornithine. Inflammatory responses may involve a balance between the pathways, as NO is cytotoxic and vasodilatory and L-ornithine is a promoter of cell proliferation and matrix synthesis. In experimental glomerulonephritis we have previously shown that NOS is activated in nephritic glomeruli.

Risk factors for cardiovascular disease in IDDM. A study of identical twins.

Patients with insulin-dependent diabetes mellitus (IDDM) have an excess mortality, predominantly attributable to cardiovascular disease. To determine the effect of IDDM on potential risk factors for cardiovascular mortality, we studied subjects from the British Diabetic Twin Study Group. Forty-five identical twin pairs discordant for IDDM were recruited in addition to 45 matched nondiabetic singleton control subjects.

Prevalence of intermittent claudication and risk factors for its development in patients on renal replacement therapy.

The prevalence of symptomatic intermittent claudication (IC) was assessed using a standard cardiovascular questionnaire in a cohort of 325 patients on renal replacement therapy (RRT). IC was found in 19% of patients, 77% of whom were smokers and 22% diabetic. It was more common in men than women and in smokers than non-smokers (p < 0.

The effect of nicotinic acid and acipimox on lipoprotein(a) concentration and turnover.

This study examines the effect of nicotinic acid (1 g t.d.s.

Effect of insulin-dependent diabetes mellitus on lipids and lipoproteins: a study of identical twins.

1. Forty-five identical twin pairs, discordant for insulin-dependent diabetes mellitus, were studied with respect to their serum lipid (high-density lipoprotein, low-density lipoprotein, total cholesterol and triacyl-glycerol) and apoprotein [apoprotein A-I, apoprotein B and lipoprotein (a)] concentrations and apoprotein (a) phenotypes. The twins were compared with an age- and sex-matched non-diabetic control group.

Does cyclosporin increase lipoprotein(a) concentrations in renal transplant recipients?

Cyclosporin, the immunosuppressant of choice for renal transplant recipients, has been implicated as the cause of abnormalities in serum lipid concentrations in these patients. We have measured serum lipoprotein(a) concentrations and analysed the distribution of apoprotein(a) isoforms in 90 renal transplant recipients receiving cyclosporin and prednisolone (with or without azathioprine), 59 patients receiving azathioprine and prednisolone alone, and 146 non-hyperlipidaemic controls. Cyclosporin-treated patients had significantly higher lipoprotein(a) concentrations (median 170 [interquartile range 55-382] mg/L) than those receiving azathioprine and prednisolone (64 [10-204] mg/L, p = 0.

Lipoprotein (a) in patients on maintenance haemodialysis and continuous ambulatory peritoneal dialysis.

Lipoprotein (a) concentrations and apoprotein (a) isoforms were measured in 99 haemodialysis and 79 peritoneal dialysis patients and compared with a normal population. Peritoneal dialysis patients demonstrated a threefold and haemodialysis a twofold increase in median Lp(a) values compared to controls (P < or = 0.001).

Lipid and lipoprotein (a) concentrations in renal transplant patients.

Lipid and lipoprotein concentrations, including lipoprotein (a), were measured in 67 clinically stable renal allograft recipients and compared with age- and sex-matched controls. Median lipoprotein (a) concentrations were significantly elevated in the transplant group (P = 0.048), with the distribution of apoprotein (a) isoforms being similar between the two groups.

Amino acid clearances and daily losses in patients with acute renal failure treated by continuous arteriovenous hemodialysis.

Objective: To determine daily amino acid and total protein losses in patients with acute renal failure receiving total parenteral nutrition (TPN) during treatment by continuous arteriovenous hemofiltration with hemodialysis (CAVHD).

Design: Prospective, nonrandomized study.

Setting: Patients in the ICU of a regional nephrology referral center.

Relation of serum lipoprotein(a) concentration and apolipoprotein(a) phenotype to coronary heart disease in patients with familial hypercholesterolemia.

Familial hypercholesterolemia carries a marked increase in the risk of coronary heart disease (CHD), but there is considerable variation between individuals in susceptibility to CHD. To investigate the possible role of lipoprotein(a) as a risk factor for CHD, we studied the association between serum lipoprotein(a) levels, genetic types of apolipoprotein(a) (which influence lipoprotein(a) levels), and CHD in 115 patients with heterozygous familial hypercholesterolemia. The median lipoprotein(a) level in the 54 patients with CHD was 57 mg per deciliter, which is significantly higher than the corresponding value of 18 mg per deciliter in the 61 patients without CHD.

High lipid parenteral nutrition improves portasystemic encephalopathy.

We have conducted a randomized double crossover study over 4 days in six parenterally fed patients with portasystemic encephalopathy (PSE) in which the nonprotein energy source of otherwise identical feeds was alternately all glucose or predominantly fat. Concentrations of plasma branched chain amino acids (BCAA), plasma insulin, and blood glucose were measured after an initial fast and subsequently after each of the four 24-hr periods of isonitrogenous feeding. The grade of PSE was assessed clinically and by the number connection test, BCAA concentrations were significantly lower during the glucose infusion than during fasting or the lipid infusion.

Psychological stress and silent myocardial ischemia.

Episodes of transient myocardial ischemia during daily life were investigated in 30 patients on two separate occasions, by ambulatory Holter ST monitoring. The first occasion was at a time of uncertainty in the patients' lives, when the results of coronary angiography and the need for surgery were to be discussed. The second was at a later date, when there had been time to adjust to the decision-making process.

High lipid parenteral feeds raise plasma branched chain amino acid concentrations--a possible therapeutic approach to portasystemic encephalopathy?

The effect of varying the calorie source of parenteral feeding from an all glucose source to a high fat source has been studied in seven patients with normal liver function by randomised crossover trial. 'Intralipid' used as the major non-nitrogen calorie source (except for 400 kcal as glucose) was associated with significantly lower plasma concentrations of insulin and glucose, significantly higher plasma concentrations of the three branched chain amino acids, and a significantly higher urinary excretion of sodium. If these effects of a high fat parenteral feed were repeatable in patients with liver failure and portasystemic encephalopathy they might be of therapeutic benefit.