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Biomedical subjects

J Virolainen

Publications and source records attributed to J Virolainen.

16 recordsLinked to original sources
PubMed2006

Lameness and fertility of sows and gilts in randomly selected loose-housed herds in Finland.

The prevalence of lameness among 646 sows and gilts in 21 selected herds was determined; 8.8 per cent of the animals were lame and the most common clinical diagnoses were osteochondrosis, infected skin lesions and claw lesions. The lame animals had higher serum concentrations of haptoglobin and C-reactive protein than the sound animals. Animals housed on slatted floors had twice the odds of being lame and 3.7 times the odds of being severely lame than animals housed on solid floors. Yorkshire pigs had 2.7 times the odds of being lame than Landrace or crossbred animals. Higher parity and the use of roughage decreased the odds of the sows not becoming pregnant; however, lameness was not a risk factor for non-pregnancy.

Animals↗
PubMed2000

Baroreflex sensitivity and variants of the renin angiotensin system genes.

OBJECTIVES: Because the renin-angiotensin-aldosterone system (RAS) modifies cardiovascular autonomic regulation, we studied the possible associations between baroreflex sensitivity (BRS) and polymorphism in the RAS genes. BACKGROUND: Wide intersubject variability in BRS is not well explained by cardiovascular risk factors or life style, suggesting a genetic component responsible for the variation of BRS. METHODS: Baroreflex sensitivity as measured from the overshoot phase of the Valsalva maneuver and genetic polymorphisms were examined in a random sample of 161 women and 154 men aged 41 to 61 years and then in an independent random cohort of 29 men and 37 women aged 36 to 37 years. An insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE), M235T variants of angiotensinogen (AGT) and two diallelic polymorphisms in the gene encoding aldosterone synthase (CYP11B2), one in the promoter (-344C/T) and the other in the second intron, were identified by polymerase chain reaction. RESULTS: In the older population, BRS differed significantly across CYP11B2 genotype groups in women (10.1 +/- 4.5, 8.7 +/- 3.8 and 7.1 +/- 3.2 ms x mm Hg(-1) in genotypes -344TT, CT and CC, respectively, p = 0.003 and 11.1 +/- 4.4, 8.9 +/- 4.1 and 7.5 +/- 3.4 ms x mm Hg(-1) in intron 2 genotypes 1/1, 1/2 and 2/2, respectively, p = 0.002), but not in men. No comparable associations were found for BRS with the I/D polymorphism of ACE or the M235T variant of AGT. In the younger population, BRS was even more strongly related to the CYP11B2 promoter genotype (p = 0.0003). The association was statistically significant both in men (p = 0.015) and in women (p = 0.03). CONCLUSIONS: Common genetic polymorphisms in the aldosterone synthase (CYP11B2) gene is associated with interindividual variation in BRS.

Adult↗
PubMed1998

Associations between human aldosterone synthase (CYP11B2) gene polymorphisms and left ventricular size, mass, and function.

BACKGROUND: Aldosterone has direct and indirect effects on the heart, and genetic variations in aldosterone synthesis could therefore influence cardiac structure and function. Such variations might be associated with polymorphisms in the gene encoding aldosterone synthase (CYP11B2), the enzyme catalyzing the last steps of aldosterone biosynthesis. METHODS AND RESULTS: A Finnish population sample of 84 persons (44 women) aged 36 to 37 years was studied by M-mode and Doppler echocardiography to assess left ventricular size, mass, and function. Subjects were genotyped through the use of the polymerase chain reaction for two diallelic polymorphisms in CYP11B2: one in the transcriptional regulatory region (promoter) and the other in the second intron. In multiple regression analyses, the CYP11B2 promoter genotype predicted statistically significant variations in left ventricular end-diastolic diameter (beta=.40, P<.0001), end-systolic diameter (beta=.33, P=.0009), and mass (beta=.17, P=.023). These effects were independent of potentially confounding factors, including sex, body size, blood pressure, physical activity, smoking, and ethanol consumption. Genotype groups also differed in a measure of left ventricular diastolic function, the heart rate-adjusted atrial filling fraction (P=.018). Increased dietary salt, which is known to predict increased left ventricular mass, had this effect only in association with certain CYP11B2 genotypes (P<.001). CONCLUSIONS: Genetic variations in or near the aldosterone synthase (CYP11B2) gene strongly affect left ventricular size and mass in young adults free of clinical heart disease. These polymorphisms may also influence the response of the left ventricle to increases in dietary salt.

Adult↗
PubMed1996

Evolution of heart rate variability in cardiac transplant recipients: a clinical study.

OBJECTIVES: To investigate in cardiac transplant patients whether post-transplantation time, graft arteriosclerosis, allograft rejection, or earlier cytomegalovirus infection affect the neural regulatory mechanisms of the donor heart. DESIGN: A consecutive series of heart transplant patients during a 12-month period. SETTING: A university hospital in Finland. SUBJECTS: Consecutive cardiac transplant recipients (n = 38) attending the hospital for their annual clinical examination were studied. Their mean (SD) age was 45.4 (11.5) years, 37 were male, and the median (range) time since transplantation was 36 (12-72) months. INTERVENTIONS: Power spectral analysis of R-R intervals (during 5 min of controlled breathing, the Valsalva manoeuvre, and deep breathing), routine coronary arteriography, cytomegalovirus serology. RESULTS: R-R interval (r = 0.67; P < 0.001), the root mean square difference of successive R-R intervals (r = 0.38; P < 0.05), the total R-R interval power (r = 0.45; P < 0.01), the power of the very low frequency (0.0-0.07 Hz) component (r = 0.53; P < 0.01), and the power of the nonrespiratory (0.0-0.15 Hz) component (r = 0.49; P < 0.01) were related to the length of time since the operation. Patients having had a transplantation 3 years ago or more had significantly greater median (range) total R-R interval power than those having had the operation less than 3 years ago (59 [10-265] vs. 20 [3-113] ms2; P = 0.02). There was also a difference between the two groups in the very low frequency component (18 [1-226] vs. 5 [0-45] ms2; P = 0.01), in the nonrespiratory component (30[1-227] vs. 9 [0-53]ms2; P = 0.02), and in the Valsalva ratio (0.995 [0.955-1.065] vs. 1.020 [0.975-1.155]; P = 0.03). Patients with and without graft arteriosclerosis, episodes of rejection, or earlier cytomegalovirus infection showed no difference in the power spectral measures. CONCLUSIONS: The donor heart rate variability increases with post-transplantation time. Heart rate variability in transplant recipients is not related to the extent of graft arteriosclerosis, episodes of allograft rejection, or earlier cytomegalovirus infection.

Adult↗
PubMed1995

Influence of negative intrathoracic pressure on right atrial and systemic venous dynamics.

To investigate the effect of a sustained fall in intrathoracic pressure (Mueller manoeuvre) on blood flow through the right heart and on systemic venous dynamics, 16 patients were studied using thermodilution, cinevenograms and simultaneous pressure recordings with two micromanometric transducers. The reductions in airway pressure (median [range]) during two graded Mueller manoeuvres were 25 (20-30) and 42 (22-52) mmHg. Right atrial mean pressure decreased by 17 (2-25) mmHg during the former and 38 (0-49) mmHg during the latter, and simultaneously, pressure gradients of 23 (1-32) and 45 (1-82) mmHg developed between the inferior vena cava and right atrium (P < 0.003 for all). Internal jugular venous pressure decreased by 16 (4-25) and 24 (4-43) mmHg (P < 0.03 for both), respectively, and no pressure gradient developed between internal jugular and superior caval veins. The minimum diameter of the proximal inferior vena cava decreased by 69 (-49-84)% (P = 0.002) during the greater manoeuvre. Cardiac index tended to increase by 26 (-17-40)% (P < 0.066) during the lesser manoeuvre but did not change statistically significantly during the greater. In conclusion, during negative intrathoracic pressure caused acutely by the Mueller manoeuvre, right atrial pressure decreases and the inferior vena cava collapses partially at or below the diaphragm. Despite a significant venous obstruction between the lower body and right atrium, blood flow through the right heart increases or remains constant.

Adult↗
PubMed1995

Heart rate and blood pressure variability and baroreflex sensitivity in hypercholesterolaemia.

To evaluate cardiovascular autonomic function in hypercholesterolaemia, we studied 16 age-matched pairs of healthy males with elevated serum cholesterol and normocholesterolaemic control subjects (altogether 37 men, aged 27-56 years). We used power spectral analysis to measure short-term heart rate and blood pressure variability, and the phenylephrine method to determine baroreceptor reflex sensitivity. The mean (SD) serum cholesterol concentration was 6.43 (1.22) among the hypercholesterolaemic subjects and 4.30 (0.44) mmol/l among the control men (P < 0.001). The respective low density lipoprotein (LDL) cholesterol concentrations were 4.44 (1.22) and 2.46 (0.38) mmol/l (P < 0.001). The total power (0.0-0.5 Hz) of heart rate and blood pressure variability did not differ between the groups, and neither did the high-frequency (0.15-0.5 Hz) and medium-frequency components (0.07-0.15 Hz). Mean (SD) baroreceptor reflex sensitivity was 18.1 (7.9) in hypercholesterolaemic and 19.4 (6.3) ms mmHg-1 in normocholesterolaemic subjects (P = 0.352). when all the subjects were analysed together, we observed a slight inverse trend between serum LDL cholesterol and baroreceptor reflex sensitivity (r = -0.235, P = 0.161). In conclusion, hypercholesterolaemia does not alter autonomic neural regulation of the cardiovascular system as assessed heart rate and blood pressure variability and baroreflex sensitivity.

Baroreflex↗
PubMed1995

Effect of negative intrathoracic pressure on left ventricular pressure dynamics and relaxation.

To investigate the effect of a fall of intrathoracic pressure on left ventricular (LV) hemodynamics and relaxation, simultaneous micromanometric recordings of LV and aortic pressures were performed at rest and during two graded Mueller maneuvers in 16 patients undergoing cardiac catheterization for aortic valve stenosis (n = 8) or chest pain (n = 8). The reductions (means +/- SE) of airway pressure during the lesser and greater maneuvers were 26 +/- 1 and 42 +/- 1 mmHg, respectively. Simultaneously, LV isovolumic-developed pressure increased by 9 +/- 3 and 21 +/- 4 mmHg, respectively (P < 0.03 for both). During the greater maneuver, the individual changes of the time constant of LV isovolumic relaxation (tau) correlated with the changes of LV isovolumic-developed pressure (r = 0.73; P = 0.002). In patients with a > 20-mmHg rise in isovolumic-developed pressure, tau increased by 10.3 +/- 4.6 ms. By multiple-regression analysis, the change of tau was related directly to the change of isovolumic-developed pressure (standardized coefficient beta = 0.80; P = 0.001) and inversely related to the resting systolic LV-aortic pressure gradient (beta = -0.37; P = 0.050). The other hemodynamic changes were independent of aortic valve stenosis. In conclusion, during the Mueller maneuver, the LV isovolumic contraction load increases and tau lengthens, particularly with higher elevations of LV systolic load.

Adult↗
PubMed1994

Acute alcohol intake decreases short-term heart rate variability in healthy subjects.

1. The acute effects of a moderate dose of ethanol (1g/kg body weight) on heart rate and blood pressure variability and baroreflex sensitivity were studied in 12 healthy male subjects in a juice-controlled experiment. Electrocardiographic and finger blood pressure data were recorded and stored in a minicomputer during 5 min of controlled breathing (15 cycles/min) and during deep breathing (5 s inspiration, 5 s expiration, four cycles) before drinking and hourly thereafter for 3 h. 2. Mean breath alcohol concentration rose to 18.9 mg/100 ml. In the time domain analysis, the root mean square difference of successive R-R interval decreased significantly with ethanol as compared with the juice experiment. The difference remained statistically significant even after adjustment for the shorter R-R interval after alcohol. In the frequency domain analysis the high-frequency (0.15-0.5 Hz) spectral power showed a significant decrease after alcohol intake. Also, the index of sensitivity of the baroreceptor reflex (square root of R-R interval power/systolic blood pressure power) decreased significantly in the high-frequency component. Ethanol did not change finger systolic blood pressure, and power spectral analysis did not show significant variability in blood pressure. 3. These data indicate that acute intake of moderate amounts of alcohol causes a significant decrease in heart rate variability owing to diminished vagal modulation of the heart rate.

Adult↗
PubMed1994

Left ventricular size, mass, and function in relation to angiotensin-converting enzyme gene polymorphism in humans.

Angiotensin-converting enzyme (ACE) exhibits genetic variation related to insertion/deletion (I/D) polymorphism in intron 16 of the ACE gene. The DD genotype results in high ACE activity and is overrepresented in diseases characterized by left ventricular (LV) hypertrophy and dysfunction. We studied whether the ACE gene polymorphism predicts LV mass or function in the absence of heart disease. Polymerase chain reaction of leukocyte DNA was used to determine the I/D genotype, and M-mode and Doppler echocardiography were used to quantify LV mass and function in 86 human subjects, 36-37 yr of age. All were free of clinical heart disease. The LV mass-to-body height ratio averaged 99 +/- 19 (SD) g/m in subjects with the II genotype (n = 25), 99 +/- 30 g/m in those with the ID genotype (n = 35), and 94 +/- 24 g/m in those with the DD genotype (n = 26; P = 0.790). The indexes of LV systolic and diastolic function were also unrelated to the ACE genotype. We conclude that in the absence of heart disease the ACE gene variation has no major influence on LV mass or function that is detectable at echocardiography.

Adult↗
PubMed1994

Atrial septal defect blunts the impairment of left ventricular function during the Mueller maneuver.

To investigate whether atrial septal defect (ASD) modifies the left ventricular (LV) hemodynamic response to a fall of intrathoracic pressure (Mueller maneuver), we studied 15 patients with an uncomplicated ASD and 16 healthy control subjects. LV function was measured by M-mode and Doppler echocardiography at rest and during the maneuver. Indicator-dilution technique was used to quantify the pulmonary-to-systemic flow ratio. During comparable changes (means +/- SE) of intrathoracic pressure (-33 +/- 2 mmHg in persons with ASD vs. -34 +/- 2 mmHg in those without), LV systolic function and filling diminished in both groups but patients with ASD showed smaller reductions in LV stroke dimension (-0.9 +/- 0.5 vs. -2.5 +/- 0.4 mm; P = 0.016), peak diameter shortening rate (-4 +/- 2 vs. -12 +/- 2 mm/s; P = 0.007), transmitral velocity-time integral (-1.0 +/- 0.3 vs. -2.2 +/- 0.4 cm; P = 0.022), and cardiac output (-6 +/- 3 vs. -18 +/- 3%; P = 0.029). The pulmonary-to-systemic flow ratio increased from 2.1 +/- 0.1 to 2.6 +/- 0.2 in the ASD group (P = 0.014). In conclusion, LV function diminishes significantly in healthy persons during the Mueller maneuver. In patients with ASD, the changes are directionally similar but quantitatively smaller. An interatrial communication mitigates the impairment of LV function after an acute and sustained drop of intrathoracic pressure.

Adult↗
PubMed1994

Correlates of left ventricular mass in a population sample aged 36 to 37 years. Focus on lifestyle and salt intake.

BACKGROUND: Echocardiographically determined left ventricular (LV) mass predicts adverse cardiovascular events in the general population. We have assessed the correlates of LV mass in a population-based study focusing on lifestyle and salt intake. METHODS AND RESULTS: A random sample of 120 persons born in 1954 was invited; 93 (42 men) entered the study. The subjects' physical activity and alcohol, tobacco, and coffee consumption were quantified by 2-month dairy follow-up, and sodium intake was quantified by 7-day food records. Blood pressure was averaged for casual cuff measurements made 2 months apart. LV mass was determined by M-mode echocardiography, and stroke volume was determined by Doppler. Hematocrit and serum insulin were measured. In multiple linear regression analysis, LV mass was related positively and independently (P < .05) to body weight, systolic blood pressure, stroke volume, sodium intake, hematocrit, and energy expenditure in leisure-time physical activity. Additional analyses showed that the relation of LV mass to daily sodium intake depended on blood pressure (P < .001 for the interaction); the multiple regression coefficient (+/- SE) was 0.41 +/- 0.11 g.mEq-1 x d-1 (P = .001) in subjects with systolic blood pressure above the population median but statistically nonsignificant (-0.15 +/- 0.10 g.mEq-1 x d-1) in those with lower blood pressure. LV mass was clearly elevated only in persons with both blood pressure and sodium intake above the population medians. CONCLUSIONS: Body weight, blood pressure, stroke volume, sodium intake, physical activity, and hematocrit are independent predictors of LV mass among unselected persons aged 36 to 37 years. The synergistic interaction of dietary salt with blood pressure suggests that high sodium intake may sensitize the heart to the hypertrophic stimulus of pressure load. Prospective studies are needed to confirm these cross-sectional associations.

Adult↗
PubMed1994

Prevalence and predictors of audible physiological third heart sound in a population sample aged 36 to 37 years.

BACKGROUND: A physiological third heart sound (S3) is common in youth but allegedly very rare after the age of 40 years. The mechanism of its disappearance is not known. The aim of this work was to study the prevalence and predictors of physiological S3 in a population-based sample of persons approaching 40 years of age. METHODS AND RESULTS: A random sample of 120 persons born in 1954 was invited; 93 (42 men) entered the study. Their physical activity, alcohol and tobacco consumption, and salt intake were quantified by diary follow-up. The presence of an S3 was determined by auscultation and confirmed by phonocardiography. Left ventricular (LV) size, mass, and systolic function were assessed by M-mode echocardiography and LV filling by Doppler velocimetry of transmitral flow. An audible S3 was detected in 22 subjects, 1 of whom had heart disease. The prevalence of physiological S3 was 23.1%. Subjects with physiological S3 had a lower body mass index (22.3 +/- 2.8 versus 24.6 +/- 4.1 kg/m2 [mean +/- SD], P = .005), lower heart rate (63 +/- 7 versus 68 +/- 10 beats per minute, P = .015), higher peak early diastolic transmitral velocity (67 +/- 10 versus 58 +/- 8 cm/s, P = .002), and higher acceleration of early diastolic velocity (717 +/- 148 versus 622 +/- 122 cm/s2, P = .012) than those without S3. No differences were noted in the lifestyle characteristics, blood pressure, or LV mass and systolic function. Body mass index and peak early diastolic transmitral velocity were independent predictors of physiological S3 in logistic regression analysis. CONCLUSIONS: Nearly one fourth of persons approaching their forties still have an audible physiological S3. The presence of S3 is predicted by leanness and a high early diastolic LV inflow velocity; the disappearance of S3 is unlikely to be secondary to increasing blood pressure and relative LV hypertrophy, as is widely presented, but reflects a more primary age-related alteration of LV early diastolic function.

Adult↗
PubMed1993

Short-term heart rate variability and factors modifying the risk of coronary artery disease in a population sample.

Heart rate (HR) variability is impaired in chronic coronary artery disease (CAD), but the mechanism is not fully resolved. This study was aimed at assessing whether HR variability is influenced by the risk factors of CAD. Of a random sample of 120 subjects born in 1954, 88 (41 men and 47 women) could be included in the analyses. No subject had clinical heart disease. The subjects' physical activity, alcohol consumption and smoking were quantified by 2-month diary follow-up. Serum lipids and insulin were measured. The tests of HR variability included power spectral analysis and calculation of the root-mean-square difference of RR intervals at rest under controlled respiration. HR variability indexes were asymmetrically distributed and strongly HR-dependent, and therefore, all statistical tests were performed on log-transformed data adjusted to the population mean HR. Multiple regression analyses showed independent inverse relations between the root-mean-square RR difference and low-density lipoprotein (LDL) cholesterol (beta = -0.22; p = 0.008), and between the total RR-interval power and LDL cholesterol (beta = -0.25; p = 0.007), as well as smoking (beta = -0.19; p = 0.035). In women, alcohol use influenced the RR-interval root-mean-square difference (beta = 0.31; p = 0.015), total power (beta = 0.33; p = 0.017) and high-frequency power (beta = 0.26; p = 0.056). It is concluded that short-term HR variability is related inversely to LDL cholesterol and smoking in the population, and directly to alcohol use in women.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗
PubMed1992

Use of non-invasive finger blood pressure monitoring in the estimation of aortic pressure at rest and during the Mueller manoeuvre.

The aim of this investigation was to evaluate whether reliable estimates of aortic pressure can be derived using non-invasive finger blood pressure monitoring. Finger blood pressure (Ohmeda 2300 Finapres device; Finapres, Englewood, CO) was compared with simultaneous ascending aortic pressure measured with a catheter-transducer system both at rest and during acute negative intrathoracic pressure (the Mueller manoeuvre). Thirty-eight patients aged 17-73 years were studied. All were undergoing routine diagnostic or therapeutic cardiac catheterization. Beat-to-beat values of systolic, diastolic and mean non-invasive finger and invasive aortic blood pressure were measured at rest and factors which might have an influence on the difference between methods were examined. The mean finger-aortic difference was +5 +/- 14 mmHg for systolic, -2 +/- 7 mmHg for diastolic, -5 +/- 8 mmHg for mean and +6 +/- 13 mmHg for pulse pressure. In multivariate linear regression analysis, the difference in systolic pressure was related to aortic systolic pressure (standardized coefficient beta = -0.33, P = 0.01), heart rate (beta = 0.49, P < 0.000), age (beta = -0.29, P < 0.025) and height (beta = 0.40, P < 0.005). The linear regression equations to derive resting aortic pressures from the non-invasive finger pressure readings had correlation coefficients between 0.83 and 0.87 and standard errors of estimate between 6 and 14 mmHg. During the Mueller manoeuvre, Finapres reproduced average pressure changes reliably compared with intra-aortic pressure. Due to moderate inter-individual variation in the finger-aortic differences the correlation coefficients ranged from 0.83 to 0.93 and the standard errors of estimate from 3 to 6 mmHg. Non-invasive finger blood pressure monitoring could be used to estimate central aortic mean and diastolic blood pressure fairly reliably at rest, but with respect to systolic pressure the variance in finger-aortic difference was marked. The average intra-aortic pressure changes caused by the Mueller manoeuvre were reliably reproduced by the Finapres device.

Adolescent↗