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Biomedical subjects

M Laitinen

Publications and source records attributed to M Laitinen.

At least 55 records · Page 3Linked to original sources
PubMed1990

Multivitamin supplementation of adult omnivores and lactovegetarians: circulating levels of vitamin A, D and E, lipids, apolipoproteins and selenium.

Serum levels of fat-soluble vitamins, lipids, apolipoproteins, total protein, hemoglobin, iron, and selenium were determined in healthy Finnish adults during a 7-month period beginning in January and ending in August. The subjects were either omnivores or established lactovegetarians, who had consumed their respective diets for at least 6 months prior to the study. Half of the subjects in both groups received daily multivitamin supplementation and the other half served as controls. In the beginning, the lactovegetarians differed from the omnivores in having lower serum levels of protein, apolipoproteins A-I and C-II, and higher levels of standardized alpha-tocopherol. During the study, serum retinol and standardized alpha-tocopherol (in March and May), as well as apolipoproteins A-I and C-II, and selenium decreased in the omnivores and 25-hydroxyvitamin D2, 25-hydroxyvitamin D3, cholesterol, HDL-cholesterol, and the HDL-cholesterol/cholesterol ratio increased. Apolipoprotein B decreased and then increased. In the lactovegetarians, serum selenium and protein decreased during the study, whereas retinol and alpha-tocopherol stayed higher than in the omnivores. Consumption of the lactovegetarian diet was accompanied by lower circulating levels of cholesterol and selenium and higher levels of retinol and standardized alpha-tocopherol than the mixed diet. Multivitamin supplementation may have value especially for omnivores in northern countries, like Finland, in providing better retinol, alpha-tocopherol, vitamin D, and selenium status in late winter and early spring.

Adult↗
PubMed1988

Boreal freshwater fish diet modifies the plasma lipids and prostanoids and membrane fatty acids in man.

The effect of fish diet on 43 healthy male students was studied. They ate a fish-containing meal for 15 weeks on an average of 3.7 times per week. Twenty-one of them voluntarily restricted their lipid intake while the rest ate normally. Controls continued their usual eating habits (19 students). The meals consisted of Finnish freshwater fish (87%) (vendace, pike, perch and rainbow trout) and brackish water fish (13%) (Baltic herring) that provided about 1 g of omega-3 polyunsaturated fatty acids per day (0.25 g eicosapentaenoic acid and 0.55 g docosahexaenoic acid). During the diet, omega-3 fatty acids increased in erythrocyte ghosts and platelets at the expense of omega-6 fatty acids. The concentration of serum cholesterol diminished in those fish consumers who lowered their lipid intake. Apolipoprotein A1 and B were lowered in both fish-consuming groups. Triglyceride levels also showed a tendency to decrease. The formation of thromboxane B2 during incubation of whole blood decreased in both fish-consuming groups. The decrease of plasma 6-keto-PGF1 alpha was not statistically significant, if compared with the controls. The results obtained indicate that a moderate intake of fish-containing meals has some beneficial effects on the plasma lipid and prostanoid metabolism, when coronary heart disease risk factors are considered.

6-Ketoprostaglandin F1 alpha↗
PubMed1988

The effect of selenium on the hepatic drug metabolism and inducibility in rat.

1. Rats were fed either a normal or selenium-deficient diet for 4 weeks. The subgroup on selenium deficient diet had selenium supplementation as 3 ppm Se in the drinking water. Benzo(a)pyrene was given intraperitoneally as an inducer. 2. Se deficiency decreased glutathione peroxidase and cytochrome c-reductase activities while other activities were unchanged as compared to normal diet. 3. Selenium deficiency was a prerequisite for the induction of glutathione peroxidase, S-reductase and S-transferase enzymes. 4. Benzo(a)pyrene increased hepatic microsomal cytochrome P-450 content in rats on normal and selenium supplemented diet but not in the selenium deficient group. 5. The 7-ethoxyresorufin and 7-ethoxycoumarin deethylase, aryl hydrocarbon hydroxylase and cytochrome c-reductase activities were increased by benzo(a)pyrene in all the dietary groups. 6. The UDP-glucuronosyltransferase activity was also increased by benzo(a)pyrene in all the experimental groups and this was true with p-nitrophenol and phenolphthalein as aglycons.

Animals↗
PubMed1987

Lack of effect of hepatic enzyme induction on metabolic control in patients with type 2 (non-insulin-dependent) diabetes.

A placebo-controlled, double-blind crossover study was carried out in 11 non-insulin-dependent (type 2) diabetic patients to find out the effects of a hepatic enzyme inducer (phenobarbital, 100 mg/day for 2 months) on the metabolic control, plasma C-peptide, insulin, serum, and lipoprotein lipid levels. Phenobarbital induced a significant increase in hepatic antipyrine metabolizing activity, but no significant changes were found in fasting or postload blood glucose, plasma C-peptide, or insulin levels during the study. There was a significant increase in serum total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol, as well as in serum total and very low-density lipoprotein triglycerides, during phenobarbital treatment as compared with placebo.

Adult↗
PubMed1985

Lipids and apolipoproteins A-I, B and C-II and different rapid weight loss programs (weight lifters, wrestlers, boxers and judokas).

Apolipoproteins A-I, B, C-II and lipids were studied before and after rapid weight loss schedules. The compared groups were all athletic. Apolipoproteins were determined by electroimmunoassay methods using apoproteins purified by chromatofocusing column method. Dextran T10 was shown to increase rocket height in ApoB assay. Over 1% Dextran concentrations gave poor response. The linearity during calibration was from 0.3 to 3.0 g ApoB/l. Baseline values of ApoA-I in wrestlers, weightlifters, boxers and judokas were slightly higher as compared to "normal" population; ApoB was clearly reduced (mean value of 690 mg/l). Weight-loss was significant in each experimental group; mean value of 4.1% in active exercise, sauna and diuretic groups together. Compared as the whole sportsmen group in passive weight loss (or sauna) and diuretic groups the most pronounced changes were seen to be elevated apoprotein concentrations, whereas weight-loss by active rapid exercise resulted no apoprotein changes, but instead an increment in HDL cholesterol and decrement in triglycerides, respectively. The present study was the first to evaluate baseline values of apoproteins A-I, B and C-II in first class athletes and also the possible changes in these and lipid values in rapid weight-loss practices.

Adolescent↗
PubMed1984

Parenteral soya bean fat emulsions potentiate the hepatotoxicity of E. coli endotoxin in suckling rats.

A dose of soy bean fat emulsion which was injected i.v. in suckling rats accumulated in the cells of liver parenchyma, both in hepatocytes and in reticuloendothelial cells. Subsequent i.p. injection of E. coli endotoxin was followed by extensive liver tissue necrosis and increased activities of serum aspartic and alanine aminotransferase. These signs of liver damage were markedly more pronounced than those observed after the administration of E. coli endotoxin only.

Alanine Transaminase↗
PubMed1984

Glucuronidation in the reindeer: dietary modification in the UDP-glucuronosyltransferase activity with 4-nitrophenol, 1-naphthol and phenolphthalein as acceptors.

The UDP-glucuronosyltransferase activity towards 4-nitrophenol, 1-naphthol and phenolphthalein was measured from the hepatic microsomes of the reindeer (Rangifer tarandus tarandus) after summer, autumn and winter feeding periods. The microsomes were digested with trypsin or digitonin. The UDP-glucuronosyltransferase activity with 4-nitrophenol and 1-naphthol as aglycones was lower in reindeer on winter food than in ones on summer food after trypsin and digitonin digestion. The activity towards phenolphthalein was the same in each feeding period. The different seasonal feeding affects the structure of microsomal membranes and this is reflected as modifications of the UDP-glucuronosyltransferase towards different substrates.

Animals↗
PubMed1983

Determination of human apolipoprotein C-II by electroimmunoassay. Studies on standardization and determination before and after physical training.

1. Human VLDL and HDL were fractionated by sequential ultracentrifugation until free of contaminant plasma proteins. 2. Column chromatofocusing method was used to isolate apolipoprotein C-II from apoVLDL and apo HDL. C-apoprotein peak was rechromatofocused and the second peak was the apo C-II (pI 4.7, homogeneous band on SDS slab gel). 3. New Zealand white rabbits were immunized with apo C-II. Antiserum gave a single precipitate are of identity between whole serum, apoVLDL, apoHDL and apo C-II. 4. Apo C-II concentration was measured by electroimmunoassay method. During standardization 1% Triton X-100 improved the rocket shapes and contours. Total delipidation did not affect the assay system and so the antigenic determinants of apo C-II are all available to antiserum. The lowest concentration of apo C-II possible to determine with this method was 70 ng/sample well. 5. There was no difference between the apo C-II values before (39.8 +/- 7.1 mg/l, n = 19) and after (41.6 +/- 6.4 mg/l, n = 19) moderate physical training among normolipemic subjects. 6. Specific immunoprecipitation technique was also used to determine apo C-II content in standard pool serum.

Adult↗
PubMed1983

Effects of formalin treatment on the blood composition of salmon (Salmo salar) and rainbow trout (Salmo gairdneri).

The effects of treatment with 250 ppm or 1250 ppm formalin on the blood composition were studied in 48 salmon and 56 trout in northern Finland. The blood haemoglobin and packed cell volume of the salmon controls were slightly lower but blood glucose and plasma total protein values significantly (P less than 0.001) lower than those of the rainbow trout. Formalin treatment influenced all blood values studied. Blood Hb and PCV values of the salmon and rainbow trout increased slightly after formalin exposures. The highest Hb values were measured in the fishes exposed twice to 250 ppm formalin or four times to 1250 ppm formalin for 30 min at 24 hr intervals. The blood glucose concentration of the salmon increased when exposed twice to 250 ppm or 1250 ppm formalin for 30 min at 24 hr intervals. The blood glucose value of the rainbow trout was lowest (4.4 mmol/l) when exposed to 250 ppm formalin. High blood glucose values were measured for the groups exposed twice to 250 or 1250 ppm formalin for 30 min at 24 hr intervals. Blood lactate values decreased during exposures. The plasma protein concentration of the salmon and rainbow trout increased during formalin treatments.

Animals↗
PubMed1983

Changes in serum lipids and lecithin: cholesterol acyltransferase enzyme during 1 week weight reduction of women on a low-calorie diet.

In 32 women of normal body weight who volunteered to participate in the study, the effect of rapid weight reduction by a low-calorie liquid diet on serum lipids and lecithin:cholesterol acyltransferase (LCAT) enzyme activity was studied. Women were on this 400 kJ/day diet for 7 days and fasting blood samples were drawn before and immediately after the diet. Serum cholesterol decreased from 5.7 +/- 1.0 to 5.2 +/- 1.1 mmol/l and high density lipoprotein cholesterol from 1.77 +/- 0.43 to 1.50 +/- 0.35 mmol/l. The serum LCAT activity decreased significantly during the weight reduction period. When serum LCAT activity was correlated to lipid parameters, a positive correlation was found with total cholesterol and triglyceride concentrations before weight reduction and also between changes in LCAT activity and total cholesterol concentration. The data suggest that serum LCAT activity might have a prominent role in the regulation of serum lipid levels.

Acyltransferases↗
PubMed1983

Preparation of soluble apolipoproteins A-I, B, and C-II by a chromatofocusing column method, and evaluation of their concentrations in serum in pulmonary disease.

A chromatofocusing column method for isolating ApoB is described. LDL is first isolated by sequential ultracentrifugation and delipidated with n-butanol/diisopropyl ether. Chromatofocusing of ApoLDL yielded a large ApoB peak at pI 5.0-5.3. ApoA-I and ApoC-II were prepared analogously, with HDL and VLDL as the source of apoprotein. Antisera were raised in rabbits, and electroimmunoassay techniques were used for determination. ApoB was water-soluble after chromatofocusing. Intra-assay precision (CV) was 4.7% for ApoA-I, 7.8% for ApoB in the "rocket" electrophoresis. Interassay precision (CV) was 6% for ApoA-I and 8% for ApoB. Apolipoprotein concentrations were measured in subjects who had undergone lung resection and patients with obstructive pulmonary disease. After lung resection, the concentration of ApoA-I in serum was significantly decreased (p less than 0.001) and that of ApoB significantly increased (p less than 0.001) as compared with controls. The ApoA-I/ApoB ratio was significantly lower in the lung-resection group. ApoA-I and ApoB concentrations were unchanged in chronic obstructive pulmonary disease. ApoC-II concentrations in each group were similar to those for control subjects. Of the lipids, values for total cholesterol were above normal after lung resection (p less than 0.002), as were those for triglycerides (p less than 0.02).

Aged↗
PubMed1982

The effects of cholesterol feeding on the membranes of liver cells and on the cholesterol metabolism in the rat.

1. Feeding of rats with a 2% cholesterol diet for 6 weeks increased the serum cholesterol concentration. The activity of lecithin cholesterol acyltransferase was also increased during the feeding time. 2. The activities of aspartate aminotransferase and alanine aminotransferase remained on a constant level during the experiment on rats having cholesterol in their diet. Omitting cholesterol from the diet enhanced the activities of both enzymes and the increase in alanine aminotransferase activity was more pronounced. 3. The activity of alkaline phosphatase was on higher level during the whole experiment in the rats having cholesterol in the diet than in those fed a cholesterol-free diet. 4. Present data suggest that excluding cholesterol from the diet labilizes the membranes of hepatocytes and facilitates the release of aspartate and alanine aminotransferases in the blood.

Alanine Transaminase↗
PubMed1982

Effects of pH on the gill ATPase activity and blood composition of whitefish (Coregonus peled) and trout (Salmo trutta fario).

1. The effects of pH on blood composition and gill (Na+ + Mg2+) ATPase activity were studied in 142 whitefish and trout kept for 3 to 17 hr in tanks at pH 3.0-9.5 in Northern Finland. 2. pH clearly influenced all blood values, except plasma alanine and aspartate aminotransferases. Blood haemoglobin and packed cell volume of whitefish and trout were lower at pH 9.5 but higher at pH 3.0 than those of controls at pH 6.5. 3. Both fishes had lowest plasma sodium and chloride values in groups kept for 9 to 17 hr in tanks with water acidified to pH 3.0 to 3.5. Changes in the plasma chloride concentration were associated with plasma sodium (r = 0.92, n = 102, P less than 0.001). 4. The gill (Na+ + K+ + Mg2+) ATPase of trout showed high activity over wide ranges of pH (6.0-7.5) at 13 degrees C having a distinct optimum at pH 7.0. 5. Blood glucose and lactate concentrations of whitefish and trout increased after exposure to acid and base. High values at pH 3.0 to 3.5 suggested hypoxic stress due to acidaemia.

Adenosine Triphosphatases↗
PubMed1982

Variations in the glucuronidation rate and in the composition of the endoplasmic reticulum of the wild and semi-domestic reindeer (Rangifer tarandus).

1. The activity of UDPglucuronosyltransferase was analyzed in the hepatic and renal microsomes and in the postmitochondrial supernatant fraction of the duodenal mucosa of wild and semi-domestic reindeer. 2. The total activity was about the same in the hepatic microsomes of both animal groups. When the specific activity was analyzed, the semi-domestic reindeer showed twice as high activities as the wild ones. 3. The results in the kidney and duodenum showed similar changes. 4. The protein, cholesterol and phospholipid concentrations of microsomal and postmitochondrial supernatant preparations were higher in the wild reindeer. 5. It is concluded on the basis of present results that the in vitro glucuronidation in the wild reindeer is on a lower level than in the semi-domestic ones. 6. This might be a consequence of changed membrane structure where UDPglucuronosyltransferase is located.

Animals↗
PubMed1982

Effects of anaesthesia with tricaine (MS 222) on the blood composition of the splake (Salvelinus fontinalis X Salvelinus namaycush).

1. The effects of anaesthesia with tricaine (MS 222) and tagging on the blood composition were studied in 123 splakes in Northern Finland. 2. Anaesthetization with tricaine clearly influenced all blood values, except plasma enzyme activities (ASAT, ALAT and SAP). Blood haemoglobin and packed cell volume increased during anaesthesia, and the peak of PCV was reached within 15 min of anaesthesia. 3. the calculated E-MCHC values decreased during anaesthesia and tagging, suggesting swelling of the erythrocytes. The initial haematological values were regained with 3-4 hr of recovery. 4. Anaesthetization elevated the blood lactate concentration and the peak values were measured for splakes anaesthetised and tagged at 1 hr after recovery. 5. The blood glucose was rather stable until the peak was reached within 1 hr of recovery. The initial blood lactate and glucose were regained within 3 and 48 hr, respectively. 6. Repeated anaesthetization had only a slight effect on blood composition, but blood glucose elevated significantly (P less than 0.001) after 4 anaesthetizations.

Aminobenzoates↗
PubMed1982

The effect of pH changes of water on the hepatic metabolism of xenobiotics in fish.

In order to determine the effect of pH changes of water on the metabolism of xenobiotics, fish were exposed for 8 hours to the acidic water (pH3). Two fish species were used, lavaret, (Coregonus lavaretus), and splake (Salvelinus fontinalis X Salvelinus namaycush). The metabolism of xenobiotics was monitored by analyzing aryl hydrocarbon hydroxylase, epoxide hydrase and ethoxycoumarin O-deethylase activities as well as the activity of UDPglucuronosyltransferase using both p-nitrophenol and 4-methylumbelliferone as aglycones. A difference was found between species in measured basal activities. The aryl hydrocarbon hydroxylase activity, epoxide hydrase activity and ethoxycoumarin O-deethylase activity were higher in the splake than in the lavaret. No clearcut differences were detected in UDPglucuronosyltransferase activities. When fish were exposed to water at pH 3, the aryl hydrocarbon hydroxylase activity and epoxide hydrase activity in the splake were lower than in the control fish. The ethoxycoumarin O-deethylase activity was higher in the lavarets at pH 3 than in the controls. The UDPglucuronosyltransferase activity was higher in both splakes and lavarets exposed to pH 3 when analyzed after trypsin digestion of microsomes and with 4-methylumbelliferone as an aglycone.

Animals↗
PubMed1982

Dietary cholesterol-induced changes of xenobiotic metabolism in liver. II. Effects of phenobarbitone and carbon tetrachloride on activities of drug-metabolizing enzymes.

The influence of dietary cholesterol on drug metabolism was studied by feeding rats either a cholesterol-free or a high (2%) cholesterol diet for 4 weeks from weanling onward and giving phenobarbitone (Pb) and/or carbon tetrachloride (CCl4) thereafter. Pb was given in drinking water for 7 days at a dosage of 100 mg/kg and CCl4, at a dosage of 1.5 mg/kg SC 6 days before assays of drug-metabolizing enzymes. The cytochrome P-450 concentration was 2-fold in rats fed the 2% cholesterol diet in comparison with those fed the cholesterol-free diet. Only a weak induction by Pb was found in the cholesterol-free group. Only slight differences due to the cholesterol diets or due to the administration of xenobiotics were found in the NADPH cytochrome c reductase activity. The PPO hydroxylase activity was 2-fold in the livers of rats fed the 2% cholesterol diet in comparison with those fed the cholesterol-free diet. In the ethoxyresorufin deethylase activity, differences between diets were present first after the administration of xenobiotics. No change in the hepatic aryl hydrocarbon hydroxylase activity was found due to changes in the cholesterol content of the diets. The ethoxycoumarin O-deethylase activity was 2-fold in the livers of rats fed 2% cholesterol diet from those fed the cholesterol-free diet. The inducibility of ethoxycoumarin O-deethylase was equal, regardless of which diet was used. The hepatic epoxide hydrolase activity of rats fed 2% cholesterol was 3-fold in comparison with the cholesterol-free group. The inducibility by Pb was higher in the livers of the cholesterol-free (3.3-fold) than 2% cholesterol-fed rats (2.4-fold). The hepatic UDP-glucuronosyl-transferase activity was 1.5-fold in 2% cholesterol-fed rats in comparison with rats fed the cholesterol-free diet. The inducibility by CCL4 was found only in rats fed the cholesterol-free diet. The results suggest that dietary cholesterol modifies the enzyme activities in the liver and modifies their response to enzyme inducers.

7-Alkoxycoumarin O-Dealkylase↗