Juha Laakso

Risk of acute coronary events and serum concentration of asymmetrical dimethylarginine

Asymmetrical dimethylarginine (ADMA) is an endogenous nitric oxide synthase inhibitor, which has been suggested to be a novel independent risk factor for endothelial dysfunction and coronary heart disease. We investigated the association of ADMA concentration in serum with risk of acute coronary events. We did a prospective, nested, case-control study in middle-aged men from eastern Finland. In an analysis of men who did not smoke, those who were in the highest quartile for ADMA (>0.62 micromol/L) had a 3.9-fold (95% CI 1.25-12.3, p=0.02) increase in risk of acute coronary events compared with the other quartiles. Our findings suggest that ADMA is a predictor of acute coronary events.

High-dose statins and skeletal muscle metabolism in humans: A randomized, controlled trial

Myopathy, probably caused by 3‐hydroxy‐3‐methylglutaryl‐coenzyme A reductase inhibition in skeletal muscle, rarely occurs in patients taking statins. This study was designed to assess the effect of high‐dose statin treatment on cholesterol and ubiquinone metabolism and mitochondrial function in human skeletal muscle.

The effect of Simvastatin treatment on natural antioxidants in low-density lipoproteins and high-energy phosphates and ubiquinone in skeletal muscle*

It has been hypothesized that treating hypercholesterolemic patients with statins will lead not only to a reduction in cholesterol, but also to inhibited synthesis of other compounds which derive from the synthetic pathway of cholesterol. In theory, this could further lead to ubiquinone deficiency in muscle cell mitochondria, disturbing normal cellular respiration and causing adverse effects such as rhabdomyolysis. Furthermore, ubiquinone is one of the lipophilic antioxidants in low-density lipoprotein (LDL), and therefore it has also been hypothesized that statin treatment will reduce the antioxidant capacity of LDL. We investigated the effect of 6 months of simvastatin treatment (20 mg/day) on skeletal muscle concentrations of high-energy phosphates and ubiquinone by performing biopsies in 19 hypercholesterolemic patients. Parallel assays were performed in untreated control subjects. The muscle high-energy phosphate and ubiquinone concentrations assayed after simvastatin treatment were similar to those observed at baseline and did not differ from the values obtained in control subjects at the beginning and end of follow-up. These results do not support the hypothesis of diminished isoprenoid synthesis or energy generation in muscle cells during simvastatin treatment. Furthermore, the results of analysis of antioxidant concentrations in LDL before and after simvastatin treatment indicate that the antioxidant capacity of LDL is maintained in simvastatin-treated patients.

Boron neutron capture therapy of brain tumors: clinical trials at the Finnish facility using boronophenylalanine

SummaryTwo clinical trials are currently running at the Finnish dedicated boron neutron capture therapy (BNCT) facility. Between May 1999 and December 2001, 18 patients with supratentorial glioblastoma were treated with boronophenylalanine (BPA)-based BNCT within a context of a prospective clinical trial (protocol P-01). All patients underwent prior surgery, but none had received conventional radiotherapy or cancer chemotherapy before BNCT. BPA-fructose was given as 2-h infusion at BPA-dosages ranging from 290 to 400 mg/kg prior to neutron beam irradiation, which was given as a single fraction from two fields. The average planning target volume dose ranged from 30 to 61 Gy (W), and the average normal brain dose from 3 to 6 Gy (W). The treatment was generally well tolerated, and none of the patients have died during the first months following BNCT. The estimated 1-year overall survival is 61%. In another trial (protocol P-03), three patients with recurring or progressing glioblastoma following surgery and conventional cranial radiotherapy to 50–60 Gy, were treated with BPA-based BNCT using the BPA dosage of 290 mg/kg. The average planning target dose in these patients was 25–29 Gy (W), and the average whole brain dose 2–3 Gy (W). All three patients tolerated brain reirradiation with BNCT, and none died during the first three months following BNCT. We conclude that BPA-based BNCT has been relatively well tolerated both in previously irradiated and unirradiated glioblastoma patients. Efficacy comparisons with conventional photo radiation are difficult due to patient selection and confounding factors such as other treatments given, but the results support continuation of clinical research on BPA-based BNCT.

Effect of high-dose statin treatment on plasma concentrations of endogenous nitric oxide synthase inhibitors.

Asymmetric dimethylarginine (ADMA) and monomethylarginine (LMMA) are endogenous inhibitors of nitric oxide synthase. A high level of ADMA in plasma has shown to be a significant risk factor for acute coronary syndromes and elevated plasma ADMA levels are prevalent in patients with hypercholesterolemia. It was therefore hypothesized that lowering plasma cholesterol levels with statin treatment would also lower ADMA concentrations. This double-blind study addressed the effect of high-dose statin treatment on plasma levels of ADMA and LMMA. Forty-eight subjects with mild hypercholesterolemia were randomly assigned to receive simvastatin 80 mg/d, atorvastatin 40 mg/d, or placebo for 8 weeks. Both statins decreased low-density lipoprotein cholesterol effectively (simvastatin 54% and atorvastatin 49%). However, concentrations of arginine derivatives remained unchanged during statin treatment and did not correlate with cholesterol levels. This study indicates that statin treatment has no clear influence on plasma ADMA or LMMA concentrations.

Asymmetrical dimethylarginine (ADMA) and risk of acute coronary events: Does statin treatment influence plasma ADMA levels?

The purpose of this study was to evaluate the hypothesis that high serum levels of ADMA, an indicator of endothelial dysfunction, are associated with an elevated risk of acute coronary events in middle-aged men. To test the hypothesis that lipid lowering medication with statins lowers circulating ADMA levels, we also investigated the effect of simvastatin and atorvastatin treatment on plasma ADMA concentration. In a prospective nested case-control study in 150 middle-aged non-smoking men from Eastern Finland, those who were in the highest quartile for serum ADMA (>0.62 micromol/l) had a 3.9-fold (95% CI: 1.25-12.3, P=0.02) increase in risk of acute coronary events compared with other quartiles. In an 8-week randomised double-blind placebo-controlled trial, plasma ADMA concentrations remained unchanged in simvastatin 80 mg/day (n=16), atorvastatin 40 mg/day (n=16) and placebo (n=16) groups over the study period. Our findings indicate that high serum levels of ADMA, a potential marker for endothelial dysfunction, may increase the risk of acute coronary syndromes. However, aggressive treatment with either simvastatin or atorvastatin did not reduce plasma ADMA levels.

Effects of Dietary Sodium and Magnesium on Cyclosporin A–Induced Hypertension and Nephrotoxicity in Spontaneously Hypertensive Rats

Arterial hypertension, nephrotoxicity, and magnesium loss are common side effects of the immunosuppressive agent cyclosporin A (CsA). In the present study, the effects of dietary sodium and magnesium on CsA toxicity were examined in spontaneously hypertensive rats. A 6-week treatment with CsA during a moderately low-sodium diet (Na 0.3%, Mg 0.2% of the dry weight of the chow) raised blood pressure only slightly, without evidence of nephrotoxicity. By contrast, CsA during a high-sodium diet (Na 2.6%) produced a pronounced rise in blood pressure as well as marked nephrotoxicity, comprising decreased creatinine clearance, increased levels of serum creatinine and urea, and increased urinary protein excretion. During the high-sodium diet, CsA decreased myocardial and bone magnesium concentration and increased myocardial and renal calcium concentration. Magnesium supplementation (Mg 0.6%) protected against the CsA-induced hypertension and nephrotoxicity during the high-sodium diet. Magnesium supplementation also completely prevented the CsA-induced myocardial magnesium depletion and calcium accumulation in the heart and kidney during the high-sodium diet. Our findings indicate a detrimental interaction between increased sodium intake and CsA treatment and a marked protection by concomitant oral magnesium supplementation.

Ubiquinone supplementation and exercise capacity in trained young and older men

AbstractIt has been suggested that ubiquinone improves exercise performance and antioxidant capacity. We studied the effects of ubiquinone supplementation (120 mg · day−1 for 6 weeks) on aerobic capacity and lipid peroxidation during exercise in 11 young (aged 22–38 years) and 8 older (aged 60–74 years), trained men. The cross-over study was double-blind and placebo-controlled. Serum ubiquinone concentration increased after supplementation (P < 0.0001 for treatment) in both age groups. The maximal oxygen uptake (

Plasma Asymmetric Dimethylarginine and Hyperemic Myocardial Blood Flow in Young Subjects With Borderline Hypertension or Familial Hypercholesterolemia

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