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Biomedical subjects

A Julkunen

Publications and source records attributed to A Julkunen.

16 recordsLinked to original sources
PubMed2004

The effect of mechanical loading on the MyHC synthesis rate and composition in rat plantaris muscle.

The aim of this study was to investigate the response of protein synthesis rate, particularly myosin heavy chain (MyHC) isoforms synthesis and the magnitude of its isoform transformation in fast-twitch plantaris muscle, to different modes of prolonged mechanical loading. Different protocols of mechanical loading were used: resistance training (RT), compensatory hypertrophy (CH) of m. plantaris after tenotomy of m. gastrocnemius and a combination of the two previous loadings (RT + CH). During the different modes of loading, plantaris muscle hypertrophy in RT group was approximately 10 %, CH approximately 40 % and CH + RT approximately 44 %. MyHC I and IID isoform synthesis rate increased in all experimental groups, as well as their relative content. MyHC IIA relative content decreased during RT and RT + CH and increased during CH. MHC IIB isoform relative content decreased in all experimental groups, but compared with CH in CH + RT MyHC IIB isoform content increased in plantaris muscle. These results demonstrate that different modes of mechanical loading resulted in the selective up- and down-regulation of MyHC isoforms in fast-twitch skeletal muscle. The synthesis rate and relative content of the two fastest isoforms of MyHC IIB and IID are regulated to different directions during mechanical loading.

Animals↗
PubMed1998

Effects of gestational exposure to a video display terminal-like magnetic field (20-kHz) on CBA/S mice.

Possible adverse effects of magnetic fields (MFs) on reproduction have been an open question. To verify the embryo-lethal effect of pulsed MF of the type emitted by video display terminals (VDTs) reported previously in CBA/S mice, a developmental toxicity study was conducted in animals of the same origin. Mated CBA/S mice (80-86 pregnant animals per group) were exposed to a 20-kHz MF with sawtooth waveform continuously from gestational day 0-18. The flux density of the vertical MF was 15 microT peak-to-peak (150 mG). This field was previously reported to increase the number of resorptions in CBA/S mice. On gestational day 18, the dams were killed and blood and bone marrow samples were taken for hematology and micronuclei analysis, respectively. The number of corpora lutea was counted and the content of the uterus examined. There were no statistically significant differences in maternal or fetal body weights, number of corpora lutea, implantations, resorptions, dead and live fetuses, or external and skeletal malformations. MF did not alter the number of blood cells or cause micronuclei in bone marrow erythrocytes in the dams. The mean number of resorptions was slightly but not statistically significantly, higher in the MF group than in controls. The results do not indicate marked developmental, hematological, or clastogenic effects of 20-kHz MFs.

Abnormalities, Radiation-Induced↗
PubMed1998

Effects of low-frequency magnetic fields on fetal development in CBA/Ca mice.

Effects of alternating magnetic fields (MFs) on the embryonic and fetal development in CBA/Ca mice were studied. Mated females were exposed continuously to a sinusoidal 50 Hz (13 microT or 0.13 mT root mean square) or a sawtooth 20 kHz (15 microT peak-to-peak) MF from day 0 to day 18 of pregnancy for 24 h/day until necropsied on day 18. Control animals were kept under the same conditions without the MF. MFs did not cause maternal toxicity. No adverse effects were seen in maternal hematology and the frequency of micronuclei in maternal bone marrow erythrocytes did not change. The MFs did not increase the number of resorptions or fetuses with major or minor malformations in any exposure group. The mean number of implantations and living fetuses per litter were similar in all groups. The corrected weight gain (weight gain without uterine content) of dams, pregnancy rates, incidences of resorptions and late fetal deaths, and fetal body weights were similar in all groups. There was, however, a statistically significant increase in the incidence of fetuses with at least three skeletal variations in all groups exposed to MFs. In conclusion, the 50 Hz or 20 kHz MFs did not increase incidences of malformations or resorptions in CBA/Ca mice, but increased skeletal variations consistently in all exposure groups.

Animals↗
PubMed1996

Fish diet, fish oil and docosahexaenoic acid rich oil lower fasting and postprandial plasma lipid levels.

OBJECTIVE: The present study was carried out to clarify the effects of fish diet, fish oil and docosahexaenoic acid (DHA) rich oil on fasting and postprandial lipid levels in healthy male students. DESIGN: The study was a randomized single-blind study with a control and three study groups. SETTING: The study was carried out in the Departments of Physiology and Clinical Nutrition of University of Kuopio. SUBJECTS: Healthy male volunteers were recruited for the study from the university student population. Fifty-nine subjects entered and 55 completed the study. INTERVENTIONS: For 15 weeks the subjects in the fish diet group ate 4.3 +/- 0.5 fish containing meals per week and those in the fish oil and DHA-oil groups ate 4 g oil per day. Fish diet provided 0.38 +/- 0.04 g eicosapentaenoic acid (EPA) and 0.67 +/- 0.09 g DHA, fish oil 1.33 g EPA and 0.95 g DHA and DHA-oil (EPA-free) 1.68 g DHA per day. RESULTS: Fasting plasma triglyceride levels decreased in all test groups in 14 weeks when compared to the control group (P < 0.05). Total plasma cholesterol levels did not change but the HDL2/HDL3-cholesterol ratio increased in all test groups by over 50% (P < 0.05). The postprandial total and chylomicron triglyceride responses, measured as areas under the response curve, were lowered in 15 weeks by the fish diet and fish oil (P < 0.05), the same tendency (P < 0.1) being seen in DHA-oil group. CONCLUSIONS: These results show that both fasting and postprandial triglyceride concentrations can be decreased with moderate intakes of long-chain n-3 fatty acids either from a fish diet or fish oil and that also pure DHA has a hypotriglyceridemic effect.

Adult↗
PubMed1995

Subchronic toxicity of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) in Wistar rats.

The subchronic (14-18 wk) toxicity of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a mutagenic by-product in chlorinated drinking water, was evaluated in Wistar rats. In a range-finding study, MX was administered daily for 14 days by gavage in deionized water to male rats (five animals per group) at doses of 12.5, 25, 50, 100 or 200 mg/kg body weight. The doses above 50 mg/kg were lethal and three out of five animals also died during treatment at 50 mg/kg. The range-finding study was repeated with doses of 5, 10 and 20 mg MX/kg, given on 5 days a week, to both males and females (10 animals per group). These doses were not overtly toxic but caused several changes in plasma clinical chemistry at 10 and 20 mg MX/kg in comparison with the controls. These included increased urea, creatinine and bilirubin and decreased inorganic phosphate and potassium in females and increased cholesterol in males. In the subchronic toxicity study, rats (15 per group, were given MX by gavage, on 5 days a week, at doses of 0 (controls) or 30 md/kg (low dose) for 18 wk, or, in the high-dose group, at doses increasing from 45 to 75 mg/kg over 14 wk. The high dose was finally lethal (two males and one female died) and caused hypersalivation, wheezing respiration, emaciation and tangled fur in animals. The body weights of the high-dose males decreased by 15%, and food consumption was decreased by 15 to 20%, but the water consumption increased by 15% to 60%. Plasma cholesterol and triglycerides were elevated and urine excretion was increased. Urine specific gravity was decreased and the relative weights of the liver and kidneys were increased in both sexes at both doses in comparison with the controls. At both doses, duodenal hyperplasia occurred in males and females, and slight focal epithelial hyperplasia in the forestomach was observed in males. Splenic atrophy and haemosiderosis were seen in two high-dose females, and epithelial cell atypia in the urinary bladder of one high-dose male and female. The frequency of bone marrow polychromatic erythrocytes with micronuclei was slightly increased in low-dose males. The results indicate that repeated administration of MX disturbs the fluid-electrolyte balance and induces diuresis, causes mucosal hyperplasia in the gastro-intestinal tract as a local effect, and affects lipid metabolism.

Animals↗
PubMed1995

Adaptation of the troponin T ELISA test to a microplate immunoassay reader.

Troponin T concentration in serum is usually measured by the automated method developed by Boehringer Mannheim for the ES-series of analysers. These instruments need at least 140 microliters of serum and 700 microliters of reagents for a single analysis, which takes 90 min. We describe an alternative procedure, using streptavidin-coated microtitre plates, troponin T reagents of Boehringer Mannheim and an ELISA-reader to measure the concentration of troponin T. The present assay needs only 30 microliters of sample and 200 microliters of reagents, and it takes 75 min; the detection limit is 0.10 microgram/l. We also assessed the microtitre plate method for sensitivity and precision and compared the results with those measured by an ES-300 automatic analyser. Both methods have the same measurement range for troponin T of 0.1 to 15 micrograms/l. For daily routine use of the microtitre plate method we recommend duplicate determinations.

Autoanalysis↗
PubMed1993

Correlation between the ratio of serum low-density lipoprotein cholesterol and high-density lipoprotein cholesterol with that of serum apolipoproteins B and A-I.

Phosphowolframate/magnesium chloride, a commonly used precipitation method for the determination of high-density lipoprotein cholesterol in human serum, yields a supernatant containing almost all of the lipoproteins apo A-I and apo A-II but no lipoprotein apo B. The correlation between high-density lipoprotein cholesterol and apo A-I was very high (r = 0.94), as well as that between the precipitation method and ultracentrifugal analysis (r > 0.95, P < 0.001). In contrast, detergent precipitation (for the determination of low-density lipoprotein cholesterol in human serum) produced sediments which contained the major proportion of apo B and only minor amounts of apo A-I and apo A-II. The precipitation method for low-density lipoprotein cholesterol showed very good agreement with ultracentrifugal analysis (r = 0.99). Yields of 80.2% were obtained for apo B with both methods. Results obtained using the precipitation methods showed excellent agreement with those obtained using the Friedewald formula (r > 0.99). Results were also very similar when hypertriglyceridemic serum samples were briefly centrifuged before analysis of cholesterol, high-density lipoprotein cholesterol and triglyceride values. The present study shows highly significant correlations between cholesterol/high-density lipoprotein cholesterol or low-density lipoprotein cholesterol/high-density lipoprotein cholesterol and apo B/apo A-I ratios (P < 0.001). Apo B and apo A-I levels could be used in addition to low- and high-density lipoprotein cholesterol values when assessing the risk of cardiovascular disease, if the methods for determining serum apolipoproteins have been properly standardized.

Apolipoprotein A-I↗
PubMed1993

Quality specifications for glycated hemoglobin A1c.

Berne has suggested that a change in the measured value (in per cent) of GHbA1c that is smaller than 1.0% does not lead to any therapeutic action from the clinician. Since the meeting of the "Friibergh Herrgård Seminar", April 23-24, 1990 on the "Medical Need for Quality Specifications in Laboratory Medicine" we have discussed this with our specialists at the Kuopio University Hospital and they share Berne's opinion. Keeping this in mind we have standardized our method so that the total analytical variation of the GHbA1c is small as compared to the measured biological variation of GHbA1c in nondiabetic and diabetic subjects. In this report we describe how we have succeeded in keeping the coefficient of variation of our routine method for GHbA1c analyses small enough for clinical purposes.

Chromatography, High Pressure Liquid↗
PubMed1992

Characterization of a distinct group of slowly growing mycobacteria by biochemical tests and lipid analyses.

A group of slowly growing mycobacterial strains (n = 14) isolated from respiratory tract specimens was collected from 1971 to 1990 on the basis of growth characteristics and uncommon biochemical and glycolipid profiles. Growth at 25 to 45 degrees C, a negative Tween 80 hydrolysis test, a strong positive reaction in a 14-day arylsulfatase test, and susceptibility to ethambutol in combination with resistance to cycloserine were important for the initial separation. The strains had a distinctive glycolipid pattern which was unlike those of other mycobacterial species. Analyses of cellular fatty acids by gas-liquid chromatography and mycolic acids by thin-layer chromatography further characterized this homogeneous group of mycobacteria. The presence of 2-eicosanol (2-OH-20:0alc) and hexacosanoic acid (26:0) combined with the lack of 2-docosanol (2-OH-22:0alc) differentiated this group from other slowly growing mycobacteria.

Bacteriological Techniques↗
PubMed1992

Contents of apolipoprotein A-I, A-II and B of the human serum fractions for high-density and low-density lipoproteins prepared by common precipitation methods.

Two common precipitation methods for the determination of HDL-cholesterol in human serum were used, dextran sulphate/MgCl2 and phosphowolframate/MgCl2. They yield supernatants which contained almost all of the apoA-I and apoA-II lipoproteins but no lipoprotein apoB. The correlations between chol-HDL and apoA-I were about the same with these methods (r = 0.79 and 0.80). The correlation between the precipitation methods and ultracentrifugal analysis for chol-HDL was highly significant (r = > 0.95). Correspondingly, two common precipitation methods for the determination of LDL-cholesterol in human serum, buffered heparin, and polyvinyl sulphate procedures, produced sediments, which contained the major proportion of the apoB and only small amounts of apoA-I and apoA-II. However, yields of only 69.0-80.2% were obtained for apoB from the sediments and of 85.8-89.4% from supernatants calculated as the difference from chylomicron free serum. This difference might be due to alterations of the molecular structure of apoB by the precipitation reagents. Comparison of the results with the precipitation methods to those using the Friedewald formula showed excellent agreements (r = > 0.91). Very comparable results were also obtained in the case of marked hypertriglyceridaemia provided that the serum samples were briefly centrifuged before analysis of chol, chol-HDL, and triglyceride values for the formula of chol-LDL. The precipitation methods for chol-LDL showed very good agreement with the values obtained by ultracentrifugal analysis (r = > 0.93). There were no remarkable differences in the correlation of apoB and chol-LDL values measured by different methods (r = 0.85). According to the present results it was found that highly significant correlations existed between chol/chol-HDL or chol-LDL/chol-HDL and apoB/apoA-I ratios (p < 0.001). It is quite evident that apoB and apoA-I values could be used to replace chol-LDL and chol-HDL values when the risk for the cardiovascular diseases is to be assessed.

Apolipoprotein A-I↗
PubMed1992

Rapid separation of serum lipids for fatty acid analysis by a single aminopropyl column.

A rapid and simple method for separation of serum lipid classes for fatty acid analysis with a single aminopropyl solid phase glass column is described. The recoveries of cholesteryl esters, triglycerides, free fatty acids, and phospholipids were all at least 98%. Coefficients of variation less than 10% were obtained for absolute and relative amounts of most individual fatty acids analyzed after separation of serum lipid classes. This method provides an efficient and convenient tool to follow fatty acid patterns in serum lipid fractions.

Cholesterol Esters↗
PubMed1987

Carcinogen metabolizing enzymes in nude mice.

Hepatic and cutaneous microsomal hydroxylating and conjugating enzymes from female and male NMRI nu/nu mice were analyzed, and the response of these enzymes to repeated exposures with 3-methylcholanthrene were studied. Sex differences were observed in basal activities of hydroxylating enzymes. These differences were not the same in the liver as in the skin and were reversed in female and male. Activity ratios of hepatic and cutaneous hydroxylating enzymes were between 40-200. The ratios between hydroxylating and conjugating enzymes were much lower in the skin than in liver. Furthermore the ratios were depending on hydroxylating enzymes. 3-Methylcholanthrene treatment increased both hydroxylating and conjugating enzymes in the liver and in the skin. Again, there were sex differences in the induction pattern, and also the induction in the liver was unrelated to that in the skin. There was no correlation in induction between hydroxylating and conjugating enzymes.

Animals↗
PubMed1987

Effect of phenobarbital on the distribution of drug metabolizing enzymes between periportal and perivenous rat hepatocytes prepared by digitonin-collagenase liver perfusion.

Intact periportal (pp) or perivenous (pv) hepatocytes were prepared by digitonin-collagenase liver perfusion. The degree of separation was indicated by significant differences between the pp and pv cells in their activity of the pp markers, alanine aminotransferase (pp/pv = 2.1), gamma-glutamyltranspeptidase (3.4) and lactate dehydrogenase (1.3), and of the pv markers, glutamate dehydrogenase (0.73) and pyruvate kinase (0.81). This pattern was not altered by a 3-day pretreatment with phenobarbital (PB). The hepatocytes isolated from the pv area contained higher activities of microsomal NADPH-cytochrome c reductase, 7-ethoxycoumarin O-deethylase, 7-ethoxyresorufin O-deethylase and benzo(a)pyrene hydroxylase, and of cytosolic glutathione transferase. Cytochrome P-450 and UDP-glucuronosyltransferase were slightly higher in pv cells. Treatment with PB induced NADPH-cytochrome c reductase, glutathione transferase, cytochrome P-450 and UDP-glucuronosyltransferase but the degree of induction was found to be at least as strong in pp cells as in pv cells. The induction of 7-ethoxyresorufin O-deethylase and 7-ethoxycoumarin O-deethylase was clearly more prominent in pp cells. On the other hand, PB reduced the activities of benzo(a)pyrene hydroxylase and alcohol dehydrogenase in both cell types. These results demonstrate by direct enzyme assay of separated cells the dominance of the pv-region for metabolizing drugs in the normal liver. Contrary to several other studies, however, our data indicate that induction by PB occurs panacinarily, i.e., relatively more in the pp region, thus diminishing rather than exaggerating the original pv dominance.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1986

Monooxygenase activity of fish liver in biomonitoring aquatic environment.

The hepatic biotransformation activity of four cultivated freshwater fish, Amur carp (Ctenopharyngodon idella), carp (Cyprinus carpio), rainbow trout (Salmo gairdneri) and tench (Tinca tinca) were studied one day after catching the fish from ponds and a river in the south of GDR and in fish kept for two weeks in clean filtrated and deacidified water. Aryl hydrocarbon hydroxylase, 7-ethoxycoumarin O-deethylase and 7-ethoxyresorufin O-deethylase activities fell to about 20% during the stay in clean water in rainbow trout liver microsomes. The reductions were smaller in the other species studied.

7-Alkoxycoumarin O-Dealkylase↗