Biomedical subjects

Riikka Rontu

Publications and source records attributed to Riikka Rontu.

32 records · Page 2Linked to original sources

PubMed2005

Epidermal growth factor A61G polymorphism and cardiac autonomic control in adults.

The authors examined the relationship between functional epidermal growth factor gene A61G polymorphism and cardiac autonomic control in a sample of 75 young adults. Heart rate, preejection period, and respiratory sinus arrhythmia were measured continuously during rest and a set of challenging tasks. The functional G allele of the epidermal growth factor gene was associated with lower heart rate F(5,32), 6.92, p = 0.014, eta2 = 0.19, and higher respiratory sinus arrhythmia F(5,32), 4.71, p = 0.038, eta2 = 0.14, among women during the rest, but was not related to with cardiovascular reactivity for challenges in women or in men. The present findings suggest that epidermal growth factor A61G polymorphism is associated with cardiac control in women.

Acoustic Stimulation↗

PubMed2005

The apolipoprotein E polymorphism is not associated with response to electroconvulsive therapy in major depressive disorder.

The apolipoprotein E (APOE) polymorphism is associated with neurodegenerative diseases. Its role regarding psychiatric disorders is controversial. It has been suggested to affect antidepressant treatment response and response to electroconvulsive therapy (ECT). In the present study, the association between APOE polymorphism and response to ECT in 119 patients with major depressive disorder was investigated. Moreover, a relation between APOE polymorphism and the age of onset of depression as well as the cognitive outcome of ECT was studied. In the whole population, no association was found between APOE polymorphism and response to ECT. However, in nonpsychotic patients, the epsilon2 allele tended to be more frequent in responders than nonresponders. Earlier onset of depression was observed in the patients with epsilon4 allele in late-life depression. There was no association between the APOE genotype and the cognitive change caused by ECT in the population as a whole. In women, however, epsilon2 allele may play a protective and epsilon4 allele a deleterious role in cognition during ECT.

Adult↗

PubMed2005

Interleukin-6 modulates plasma cholesterol and C-reactive protein concentrations in nonagenarians.

OBJECTIVES: To establish whether the relationship between interleukin-6 (IL-6) and plasma lipid and C-reactive protein (CRP) concentrations is different in Finnish nonagenarians than in middle-aged subjects with lower inflammatory status. DESIGN: Cross-sectional. SETTING: Observational cohort study concentrating on the oldest old. PARTICIPANTS: Nonagenarians (n=291, mean age+/-standard deviation 90+/-1; 68 men, 223 women) who lived in the Tampere municipality in southern Finland and a middle-aged control population from the same area (n=227, aged 44+/-8). MEASUREMENTS: Plasma high sensitive CRP and lipid concentrations were analyzed using an automatic analyzer and IL-6 levels using enzyme-linked immunosorbent assay. RESULTS: Plasma concentrations of IL-6 (4.39+/-5.25 vs 1.88+/-1.98 pg/mL) and CRP (3.54+/-4.98 vs 1.53+/-1.91 mg/L) were significantly higher in nonagenarians than in middle-aged subjects (P<.001). In nonagenarians, plasma CRP levels increased (P<.001) and plasma total cholesterol (P=.006), low-density lipoprotein cholesterol (P=.02), and high-density lipoprotein cholesterol (P=.002) levels decreased according to IL-6 quartiles. In middle-aged subjects, similar associations were not found. CONCLUSION: The relationship between IL-6 and plasma CRP and cholesterol levels in nonagenarians with enhanced systemic inflammation differs from that of middle-aged subjects.

Adult↗

PubMed2005

Microcrystalline chitosan is ineffective to decrease plasma lipids in both apolipoprotein E epsilon 4 carriers and non-carriers: a long-term placebo-controlled trial in hypercholesterolaemic volunteers.

Chitosan is a deacetylated product of chitin. Microcrystalline form of chitosan has a large adsorption area claimed to decrease gastrointestinal absorption of cholesterol. However, the long-term effect of chitosan on plasma lipids is variable, the averaged influence being negligible or lacking in mildly-to-moderately hypercholesterolaemic (4.8-6.8 mmol/l) subjects. We evaluated whether this variation and inefficacy depend on apolipoprotein E genotype. 130 middle-aged, otherwise healthy men (n=55) and women (n=75) were randomized into two treatment groups for a 7 month trial. During a 1 month run-in period all participants received placebo. Subsequently, one half first took placebo twice daily for 3 months and then 1.2 g chitosan twice daily for 3 months, and the other half vice versa in a cross-over way. Altogether 84 participants completed the study. Plasma lipids and glucose were determined at the end of each phase of the study, and all subjects undergone to the cross-over phases were apolipoprotein E genotyped. Chitosan altered plasma total, low- and high density cholesterol, triglycerides, and blood glucose in neither apolipoprotein E epsilon 4 allele carriers (n=29) nor non-carriers (n=55), compared to placebo. In conclusions, chitosan is ineffective to decrease plasma lipids in apolipoprotein E epsilon 4 carrier and non-carrier phenotypes with mildly-to-moderately increased plasma cholesterol.

Adolescent↗

PubMed2005

Antibody titer against malondialdehyde-modified LDL compares with HDL cholesterol concentration in identifying angiographically verified coronary artery disease. Comparison of tests by ROC analysis.

Antibody titer against malondialdehyde (MDA)-modified low-density lipoprotein (LDL) has been found to be associated with atherosclerosis, but it has not been established whether it would detect subjects with coronary artery disease (CAD). In the present study, receiver-operating characteristic (ROC) analysis was used to compare the diagnostic accuracy of the antibody titer against MDA-modified LDL and high-density lipoprotein (HDL) and LDL cholesterol levels in discrimination between subjects with (n = 51) and without (n = 35) angiographically verified 3-vessel CAD. As a result, the antibody titer against MDA-modified LDL was lower in subjects with CAD compared with subjects without CAD (p < 0.0001). The area under the ROC plot was 0.822 (95% CI, 0.727 to 0.918) for the antibody titer and 0.769 (95% CI, 0.661 to 0.876) for the HDL cholesterol concentration. Both the antibody titer and the plasma HDL cholesterol level were more accurate markers of CAD than the LDL cholesterol level. As a conclusion, our results indicate that the antibody titer against MDA-modified LDL discriminates between subjects with widespread CAD and those without CAD similarly as the HDL cholesterol concentration. Moreover, the antibody titer against MDA-modified LDL is inversely correlated with the risk of severe CAD.

Antibodies↗

PubMed2004

Interaction of tumor necrosis alpha - G308A and epidermal growth factor gene polymorphisms in early-onset schizophrenia.

The study population comprised 94 Finnish patients with DSM-IV diagnosis of schizophrenia. The patients were placed into two subgroups according to medication response to conventional neuroleptics. The aim of the study was to examine the frequency of tumor necrosis factor -308 (G > A) polymorphism in these patients and their 98 control subjects who were age- and gender-matched blood donors. Associations between TNFalpha -308 polymorphism alone and between the interaction of TNFalpha and epidermal growth factor gene polymorphisms, and medication response and age at onset of schizophrenia were also studied. The frequencies of TNFalpha A-allele were 11.7 % in patients and 12.8% in controls. The difference was not significant (p = 0.75). TNFalpha -308 polymorphism was not associated with medication response. However, patients with EGF AA and TNFalpha AG/AA genotype had a lower age at onset of schizophrenia compared with the rest of the patients not having this combination (20.0 years, 3.3 vs. 30.2 years, 10.1 mean + SD; p < 0.001). The results support earlier findings according to which TNFalpha polymorphism is not associated with the incidence of schizophrenia. On the other hand, the role of cytokines in schizophrenia may involve genetic interactions predisposing early onset of illness.

Adult↗

PubMed2004

Neuregulin genotype and medication response in Finnish patients with schizophrenia.

Neuregulin 1 is involved both in neurodevelopment and neurotransmitter mechanisms in the brain. There is evidence of an association between neuregulin 1 genotype and schizophrenia. We compared neuregulin 1 genotypes in patients with schizophrenia (n=94) and control subjects (n=395) of Finnish origin by using one SNP (SNP8NRG221533) as a genetic marker. We also analyzed NRG1 genotype with regard to age at onset and between responders and non-responders to conventional antipsychotics. The NRG1 genotype or allele frequencies showed similar distributions between patient and control groups. Age at onset was not associated with NRG1 genotype. The TT genotype was overrepresented in the non-responders group compared with the responders (p=0.013). Further studies are needed to ascertain the significance of neuregulin genotype in medication response to schizophrenia.

Adult↗

PubMed2004

Apolipoprotein E polymorphism is associated with age of onset in schizophrenia.

The aims of the study were to investigate the relationship between Apolipoprotein E (APOE) polymorphism, risk of schizophrenia, treatment response to conventional anti-psychotics, and age of onset in schizophrenia. The sample comprised 94 Finnish patients with a DSM-IV diagnosis of schizophrenia. Forty-three of the patients were good responders to conventional anti-psychotics and 51 were classified as non-responders. The control group consisted of 98 healthy blood donors. The APOE allele frequencies (epsilon 2, epsilon 3, and epsilon 4) were 4.8, 72.3, and 22.9% in patients and 7.1, 75.0, and 17.9 in controls. None of the differences between groups were statistically significant. No association between treatment response and APOE genotype was found. Patients with APOE epsilon 4/epsilon 4 genotype had a markedly lower age of onset compared with rest of the sample (p=0.0015), which remained significant when controlling for gender (p=0.02). There was an increasing linear trend between the number of epsilon 3 alleles (0, 1, or 2) and age of onset in schizophrenia (p=0.08). An inverse trend was found between the number of epsilon 4 alleles and age of onset (p=0.07). No relationship between APOE polymorphism and risk for schizophrenia was found. APOE epsilon 4/epsilon 4 genotype may be associated with early onset schizophrenia. APOE epsilon 3 allele may function protectively in later onset in this disease.

Adult↗

PubMed2004

Endothelial dysfunction and increased arterial intima-media thickness in children with type 1 diabetes.

BACKGROUND: Endothelial dysfunction may play a pathophysiological role in the development of atherosclerosis in subjects with type 1 diabetes. We examined whether alterations in vascular endothelial function exist in children with type 1 diabetes and tested the hypothesis that endothelial dysfunction is associated with early structural atherosclerotic vascular changes in these children. METHODS AND RESULTS: Noninvasive ultrasound was used to measure brachial artery flow-mediated dilation (FMD) responses and carotid artery intima-media thickness (IMT) in 75 children (mean age 11+/-2 years), 45 with type 1 diabetes (diabetes duration 4.4+/-2.9 years) and 30 healthy control children. Children with diabetes had lower peak FMD response (4.4+/-3.4% versus 8.7+/-3.6%, P<0.001) and increased IMT (P<0.001) compared with controls. Sixteen children with diabetes (36%) had endothelial dysfunction defined as total FMD response in the lowest decile for normal children. These children had increased carotid IMT (0.58+/-0.05 versus 0.54+/-0.04 mm, P=0.01) and higher LDL cholesterol concentration (2.63+/-0.76 versus 2.16+/-0.60 mmol/L, P=0.03) compared with diabetic children without endothelial dysfunction. Multivariate correlates of increased IMT included diabetes group (P=0.03), low FMD (P=0.03), and high LDL cholesterol (P=0.08). CONCLUSIONS: Impaired FMD response is a common manifestation in children with type 1 diabetes and is associated with increased carotid artery IMT. These data suggest that endothelial dysfunction in children with type 1 diabetes may predispose them to the development of early atherosclerosis.

Adolescent↗

PubMed2004

Fatty acid and cholesterol composition of the uterine artery intima in relation to menopausal status, age, and serum cholesterol.

OBJECTIVES: Estrogens modulate lipid metabolism and the increased risk of atherosclerosis in postmenopausal women is at least partly due to the reduction of estrogen production after menopause. We studied the effect of menopause on the contents of long-chain fatty acids, free cholesterol (FC) and cholesterol ester (CE) in uterine artery wall. METHODS: The uterine artery intima samples were obtained in connection with surgery of 21 postmenopausal and 51 premenopausal women. The amount of FC, CE and phospholipid fatty acids were measured by gas chromatography after extraction and fractionation and these lipid values were related to menopausal status, age and serum total and low-density lipoprotein (LDL) cholesterol levels. RESULTS: Premenopausal females had significantly less intimal FC (161 +/- 50 vs. 407 +/- 276 microg/100 mg wet weight, P = 0.003) and CE (19 +/- 34 vs. 305 +/- 348 microg/100 mg wet weight, P = 0.050) and smaller proportion of linoleic acid out of all phospholipid fatty acids (4.2 vs. 7.2%, P = 0.002) than postmenopausal women after adjustment with age. The content of CE (r = 0.34, P = 0.025) and the FC-to-CE ratio (r = -0.45, P = 0.002) correlated with age in premenopausal but not in postmenopausal women. Moreover, the intimal content of CE correlated with the percentage of intimal phospholipid linoleic acid in postmenopausal women (r = 0.79, P = 0.020). The same was true for FC (r = 0.73, P < 0.001). CONCLUSIONS: These results indicate that CE and FC accumulation into the wall of uterine artery depends on menopausal status, independently of age, and that the phospholipid long-chain fatty acid composition differs significantly between premenopausal and postmenopausal women. This suggests that estrogens may be involved in the regulation of artery wall lipid composition.

Adult↗

PubMed2004

Impact of long-term hormone replacement therapy on in vivo and in vitro markers of lipid oxidation.

Postmenopausal hormone replacement therapy (HRT) with estrogen has been suggested to inhibit oxidation of low-density lipoprotein (LDL) in vitro, but progestins may oppose this effect. We studied whether estrogen HRT and combined HRT with estrogen and progestin differ in their ability to resist in vivo and in vitro oxidation of lipids. Study group included 15 women on oestradiol valerate (mean age 56 years, treatment duration 10.5 years) and 15 women on combined HRT with oestradiol valerate and levonorgestrel (mean age 58 years, treatment duration 11.3 years). In addition to lipid and apolipoprotein concentrations, the lagtime of LDL to oxidation, the rate of the propagation phase and the maximum concentration of conjugated dienes were recorded as indices of LDL susceptibility to copper-induced oxidation in vitro. As an in vivo marker of oxidative stress we measured 24-h excretion of urinary 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha). All measurements were done after long-term HRT (baseline), after 4 weeks pause and again 3 weeks after reintroduction of HRT. High-density lipoprotein (HDL) cholesterol and apolipoprotein AI concentrations were significantly higher and LDL to HDL ratio significantly lower after long-term oestradiol valerate therapy than after combined therapy. Simultaneously, the triglyceride and lipoprotein (a) levels were higher in the estrogen group. Susceptibility of LDL to oxidation and the level of 8-iso-PGF2alpha were similar in both groups at all measurement points, and treatment group was not a statistically significant determinant of these markers at baseline. According to these results, estrogen and combined HRT do not differ in their abilities to oppose LDL oxidation in vitro or systemic oxidative stress in vivo, but have differential effects on blood lipids.

Apolipoproteins↗

PubMed2004

Association of paraoxonase-1 M55L genotype and alcohol consumption with coronary atherosclerosis: the Helsinki Sudden Death Study.

High-density lipoprotein (HDL) level is inversely correlated with coronary heart disease risk. Paraoxonase-1 (PON1) is an HDL-associated anti-atherogenic enzyme. The activity of PON1 is affected by the methionine for leucine substitution at position 55 (M55L) and increased during regular moderate alcohol consumption, consistent with increased HDL cholesterol concentration. We related the PON1 M55L genotypes to the extent of atherosclerosis in left anterior descending coronary artery (LAD) in alcohol abstainers (0-1 g of alcohol/day), moderate consumers (1-36 g of alcohol/day) and drinkers (> 36 g of alcohol/day). The study subjects included an autopsy series of total of 700 middle-aged Finnish men from the Helsinki Sudden Death Study. The LAD was stained for fat and the areas covered with fatty streaks and fibrotic and complicated plaques were measured. Data on coronary artery disease risk factors were obtained from relatives or close friends of the deceased. Compared to the LL homozygotes, carriers of the M55 allele tended to have larger areas of atherosclerotic lesions, the size of which decreased dose-dependently by reported alcohol consumption. Moderate consumers carrying the M55 allele had significantly larger complicated plaques compared to the LL homozygotes drinking as much (P = 0.009). Among the M55 allele carriers, drinkers showed significantly smaller areas of fatty streaks compared to abstainers (P = 0.042) and moderate consumers (P < 0.001) (for the PON1 genotype by alcohol interaction, P = 0.078). Similarly, drinkers with the M55 allele also had statistically significantly smaller areas of complicated lesions than moderate consumers with the M55 allele (P < 0.0001) (for the PON1 genotype by alcohol interaction, P = 0.009). The areas of atherosclerotic lesions in LAD appear to be dependent on the amount of alcohol consumption, especially in men carrying the PON1 M55 allele.

Adult↗

PubMed2003

Smoking-dependent association between paraoxonase 1 M/L55 genotype and coronary atherosclerosis in males: an autopsy study.

High-density lipoprotein-associated paraoxonase 1 (PON1) enzyme can retard the oxidation of lipids. The methionine for leucine substitution at position 55 (M/L55) of the PON1 protein is associated with lower (MM genotype) or higher (ML or LL genotype) expression of the gene affecting serum level of PON1. We studied the association of the PON1 M/L55 genotype with the extent of atherosclerosis in an autopsy series of Finnish males. Areas of the coronary arteries and the aorta covered with fatty streaks and fibrotic and complicated lesions were measured from a total of 700 cases. Carriers of the MM genotype (14.4% of subjects) had larger percentual areas of fatty streaks in their left anterior descending coronary artery (P=0.014) and right coronary artery (P=0.004), as well as in thoracic (P<0.001) and abdominal aorta (P=0.010) compared to carriers of the LL or ML genotype. A PON1 genotype-by-smoking interaction was observed on the area of fatty streaks in left anterior descending coronary artery (P=0.011) and right coronary artery (P=0.005); the association between fatty streaks and MM genotype was evident only among non-smokers, whereas in smokers this association was abolished. The areas of more advanced atherosclerotic lesions did not vary significantly between the genotype groups. These data suggest that the genetic variation of PON1 affects the formation of early atherosclerotic lesions and that the effect is modified by smoking.

Adult↗

PubMed2003

Effects of long-term estrogen replacement therapy versus combined hormone replacement therapy on nitric oxide-dependent vasomotor function.

Postmenopausal hormone replacement therapy (HRT) with estrogen may increase production of the predominant endothelium-derived vasodilator nitric oxide (NO) and consequently improve vascular reactivity. In contrast, concurrent progestin therapy may oppose this beneficial effect. We studied the effect of long-term estrogen HRT and combined HRT on vasomotor function and on plasma nitrate, which reflects the amount of NO in the circulation. As lipid peroxidation affects NO production and impairs endothelial function, we also measured the amount of the in vivo lipid peroxidation marker urinary 8-iso-prostaglandin F(2 alpha). The study group comprised 15 women receiving estradiol valerate HRT (mean age, 56 yr; treatment duration, 10.5 yr) and 15 women receiving combined HRT with estradiol valerate and levonorgestrel (mean age, 58 yr; treatment duration, 11.3 yr). The peak flow velocity (PFV) and pulsatility index of the common carotid and internal carotid artery and the abdominal aorta were measured by ultrasonography after long-term HRT (baseline), after a 4-wk pause and again 3 wk after reintroducing HRT. A statistically significant interaction between the groups and time points was observed in the PFV of the internal carotid artery (P = 0.011). In women taking estradiol valerate, the PFV values decreased significantly after withdrawal of HRT (P = 0.007) and increased again to the baseline level after reintroduction of therapy (P < 0.001). In women receiving combined HRT, the PFV remained stable over all study periods. At baseline, the PFV of women taking estradiol valerate correlated with the plasma nitrate concentration in the common carotid artery (r = 0.646; P = 0.009) and in the abdominal aorta (r = 0.579; P = 0.024). For pulsatility index and urinary 8-iso-prostaglandin F(2 alpha) excretion, there were no significant differences between the groups. Our results suggest that the favorable effects of long-term estrogen treatment on blood flow are at least partly mediated through NO. The addition of levonorgestrel to the treatment regimen appears to abolish this effect.

Aged↗