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Biomedical subjects

A Rautio

Publications and source records attributed to A Rautio.

At least 37 records · Page 2Linked to original sources
PubMed1995

Ginseng therapy in non-insulin-dependent diabetic patients.

OBJECTIVE: To investigate the effect of ginseng on newly diagnosed non-insulin-dependent diabetes mellitus (NIDDM) patients. RESEARCH DESIGN AND METHODS: In this double-blind placebo-controlled study, 36 NIDDM patients were treated for 8 weeks with ginseng (100 or 200 mg) or placebo. Efficacy was evaluated with psychophysical tests and measurements of glucose balance, serum lipids, aminoterminalpropeptide (PIIINP) concentration, and body weight. RESULTS: Ginseng therapy elevated mood, improved psychophysical performance, and reduced fasting blood glucose (FBG) and body weight. The 200-mg dose of ginseng improved glycated hemoglobin, serum PIIINP, and physical activity. Placebo reduced body weight and altered the serum lipid profile but did not alter FBG. CONCLUSIONS: Ginseng may be a useful therapeutic adjunct in the management of NIDDM.

Affect↗
PubMed1995

A genetic polymorphism in coumarin 7-hydroxylation: sequence of the human CYP2A genes and identification of variant CYP2A6 alleles.

A group of human cytochrome P450 genes encompassing the CYP2A, CYP2B, and CYP2F subfamilies were cloned and assembled into a 350-kb contig localized on the long arm of chromosome 19. Three complete CYP2A genes--CYP2A6, CYP2A7, and CYP2A13--plus two pseudogenes truncated after exon 5, were identified and sequenced. A variant CYP2A6 allele that differed from the corresponding CYP2A6 and CYP2A7 cDNAs previously sequenced was found and was designated CYP2A6v2. Sequence differences in the CYP2A6v2 gene are restricted to regions encompassing exons 3, 6, and 8, which bear sequence relatedness with the corresponding exons of the CYP2A7 gene, located downstream and centromeric of CYP2A6v2, suggesting recent gene-conversion events. The sequencing of all the CYP2A genes allowed the design of a PCR diagnostic test for the normal CYP2A6 allele, the CYP2A6v2 allele, and a variant--designated CYP2A6v1--that encodes an enzyme with a single inactivating amino acid change. These variant alleles were found in individuals who were deficient in their ability to metabolize the CYP2A6 probe drug coumarin. The allelic frequencies of CYP2A6v1 and CYP2A6v2 differed significantly between Caucasian, Asian, and African-American populations. These studies establish the existence of a new cytochrome P450 genetic polymorphism.

Alleles↗
PubMed1994

Metabolic interactions of methoxsalen and coumarin in humans and mice.

Methoxsalen (8-methoxypsoralen) is a very potent inhibitor of human cytochrome P450 2A6 (CYP2A6) and mouse Cyp2a-5-mediated coumarin 7-hydroxylation in vitro. To determine the effect of methoxsalen on coumarin 7-hydroxylation in humans in vivo, five subjects were given 45 mg of methoxsalen and 5 mg of coumarin. Methoxsalen inhibited in vivo coumarin metabolism by 47 +/- 9.2% (mean +/- SEM). Methoxsalen was metabolized in human liver microsomes at the rate of 50-100 pmol/mg protein/min (approx. 30% of the activity in mouse liver microsomes). Metabolism was not inhibited by the anti-Cyp2a-5 antibody in human liver microsomes. NIH 3T3 cells stably expressing catalytically active CYP2A6 enzyme did not metabolize methoxsalen, indicating that CYP2A6 does not accept methoxsalen as a substrate. In pyrazole-induced mouse liver microsomes, methoxsalen metabolism was inhibited by the anti-Cyp2a-5 antibody. Cyp2a-5 protein expressed in the yeast Saccharomyces cerevisiae was capable of metabolizing methoxsalen, indicating that methoxsalen is a substrate of Cyp2a-5. Although kinetic studies indicated that the inhibition of coumarin 7-hydroxylation by methoxsalen is competitive in human liver microsomes, methoxsalen does not appear to be a substrate for CYP2A6. Methoxsalen and coumarin have the potential of strong metabolic interactions in man.

Animals↗
PubMed1994

Interindividual variability of coumarin 7-hydroxylation in a Turkish population.

One hundred healthy Turkish volunteers (70 male, 30 female) aged from 19 to 56 years were given 5 mg coumarin p.o. after an overnight fast. Urine samples were collected before and 2, 4 and 8 h after drug administration. The extent and rate of formation of 7-OH-coumarin (7OHC) was determined by the urinary excretion of the metabolite as measured with the fluorometric method. On average, 80% of 7OHC formed was excreted in 2 h. The total amount of 7OHC formed was 59.8% (21.5%) (mean and SD, n = 100, range 17-100%) of the given dose. The percentage of 7OHC excreted during the first 2 h compared with the 7OHC excretion at 8 h was a constant and stable individual characteristic for the rate of the formation of 7OHC ('2 h coumarin test'). Although four individuals had relatively slow coumarin test values (34-40%), no clear-cut polymorphism in the rate of 7OHC formation was found. However, 7OHC formation was lower in males and in cigarette smokers.

Adult↗
PubMed1994

Effects of heme arginate on cytochrome P450-mediated metabolism of drugs in patients with variegate porphyria and in healthy men.

We investigated the effects of heme on metabolism of coumarin, debrisoquin, caffeine, and lidocaine in seven female patients with variegate porphyria and in 10 healthy men. During baseline conditions metabolism of the drugs was identical in the two groups. Compared with the results without heme, a single infusion of heme arginate (3 mg/kg heme) significantly decreased the debrisoquin/4-hydroxy-debrisoquin metabolic ratio in subjects with porphyria (p = 0.016) and in the control subjects (p = 0.016) and increased formation of monoethylglycinexylidide from lidocaine (p = 0.016 and p = 0.004, respectively). Metabolism of coumarin and caffeine was not affected by heme. Our results show that, in patients with porphyria and in healthy subjects, exogenous heme is able to accelerate the reactions mediated by the cytochrome isozymes CYP2D6 (debrisoquin) and CYP3A4 (lidocaine) but not reactions mediated by CYP1A2 (caffeine) and CYP2A6 (coumarin). This suggests that influence of heme on drug metabolism is P450 isozyme-specific.

Adult↗
PubMed1993

Response of mouse liver coumarin 7-hydroxylase activity to hepatotoxins: dependence on strain and agent and comparison to other monooxygenases.

Acute effects of a single intraperitoneal dose of allyl alcohol (AA, 64 mg/kg), dimethylnitrosamine (DMNA, 30 mg/kg), hexachlorobutadiene (HCBD, 50 mg/kg), carbon tetrachloride (CCl4, 24 mg/kg), cocaine (60 mg/kg) and pyrazole (300 mg/kg) on the hepatic histology and monooxygenases in DBA/2 and C57Bl/6 strains of mice were investigated. All substances caused histologically verified injury to the liver, which varied in appearance and severity depending on the compound and the mouse strain. Responses of P450-catalyzed reactions were highly dependent on the toxin and varied between different monooxygenase (MO) reactions and two mouse strains. In DBA/2 strain, coumarin 7-hydroxylase (COH) activity was increased from 3- to 5-fold by pyrazole, cocaine, HCBD and CCl4. With respect to P450 content and other MO activities, no changes or even decreases were generally observed. Some exceptions to this rule were found: HCBD significantly increased T15 alpha OH, PROD and EROD activities in C57Bl/6 mice, whereas cocaine caused a significant stimulation of T15 alpha OH and PROD in DBA/2 mice, It is concluded that i) different hepatoxins cause different types of liver injury and responses of the monooxygenase complex ("hepatotoxinspecific finger prints"), ii) although DBA/2 and C57Bl/6 mice responded rather similarly to hepatotoxins, also with respect to P450 content and most MO activities, they displayed a profound difference in the behaviour of COH activity, and iii) within the P450 superfamily, the regulation of COH activity seems to be rather unique, also when compared to its structurally close enzyme, testosterone 15 alpha-hydroxylase.

Animals↗
PubMed1992

Effect of insulin on serum amino-terminal propeptide of type III procollagen in non-insulin-dependent diabetes mellitus.

The effect of insulin on the serum levels of the amino-terminal propeptide of type III procollagen (PIIINP) was investigated in patients with non-insulin-dependent diabetes mellitus, whose disease was unsatisfactorily controlled by oral drugs. Before insulin therapy the PIIINP values of the patients (3.2 +/- 1.3 micrograms/l, n = 38) varied within the range of healthy subjects (3.1 +/- 0.6 micrograms/l, n = 50, NS). Insulin therapy (6-20 IU at bedtime plus the oral drugs) improved the glycemic control and increased the serum PIIINP during a 4 week (3.1 +/- 0.9 to 3.8 +/- 1.1 micrograms/l, P less than 0.01, n = 8) and an 8 week period (3.2 +/- 1.3 to 3.8 +/- 1.6 micrograms/l, P less than 0.001, n = 22). The values were still elevated after 6 months on insulin (3.5 +/- 1.5 to 4.0 +/- 1.7 micrograms/l, P less than 0.01, n = 12). Placebo-insulin did not alter the concentration of PIIINP (3.1 +/- 0.6 to 2.8 +/- 0.6 micrograms/l, NS, n = 8) whereas the glycemic control improved and body weight decreased. The PIIINP values correlated with fasting insulin before (r = 0.403, P less than 0.05, n = 30) and after the therapy (r = 0.452, P less than 0.001, n = 60). Insulin therapy, while correcting the hormone deficiency and restoring glucose and protein metabolism, seems to activate the synthesis of type III procollagen in patients with NIDDM. This may promote the atherosclerotic process.

Adult↗
PubMed1992

Interindividual variability of coumarin 7-hydroxylation in healthy volunteers.

A test designed to estimate the extent and rate of formation of 7-hydroxycoumarin by measuring the urinary excretion of the metabolite in humans after administering 5 mg coumarin was developed. Coumarin was rapidly metabolized after oral administration and more than 95% of the 7OHC formed was excreted in 4 h. The total amount of 7OHC formed was 64 +/- 15% (mean +/- SD, variation 20-100%) of the dose given. The percentage of 7OHC excreted in 2 h, as compared with the 7OHC excretion in 4 h, was found to be a constant and stable individual characteristic for the rate of the formation of 7OHC ('2 h coumarin test'). In 110 volunteers, there was a great interindividual variability in the extent and rate of 7OHC formation. Four individuals had relatively 'slow' coumarin test values (50-60%), but much larger populations would be needed for the demonstration of polymorphism.

Adult↗
PubMed1991

Time dependent effects of medroxyprogesterone acetate on hepatic ultrastructure in rats.

The present study demonstrates that MPA treatment may alter liver ultrastructure in rats. This was seen as a slight cytoplasmic vacuolization in light microscopy. In electron microscopy the most striking findings were the increase in the size of hepatocytes, the volume of smooth endoplasmic reticulum (SER) and the number of mitochondria. Minor changes in mitochondrial size and structure, and SER outline were also obtained. The amount of rough endoplasmic reticulum was decreased and bleb formation was common. The effect of MPA on liver ultrastructure was time-dependent. The main changes were found in rats receiving MPA daily for seven days. Most of the observed changes disappeared within 17 days after the cessation of the regimen. MPA induced alterations in liver morphology may partly be due to induction phenomenon although the hormonal property of MPA also may play some etiological role.

Animals↗
PubMed1990

Immunochemical detection of human liver cytochrome P450 forms related to phenobarbital-inducible forms in the mouse.

Polyclonal antibodies generated to four distinct mouse liver phenobarbital-inducible cytochrome P450 isoforms were used to analyse related forms in human liver. N-terminal sequence analysis and biochemical properties of the P450s used as antigens suggest that they belong to P450 subfamilies IIB (P450PBI), IA (P450PBII), IIC (P450PBIII) and IIA (P450Coh). In immunoblot analysis, anti-P450PBII detected a single protein presumed to be P450IA2 in all the human livers tested. No proteins corresponding with P450IA1 could be detected. Anti-PBIII and anti-P450Coh antibodies each detected one band (54 and 48 kDa, respectively) in the liver samples. No bands were revealed by anti-P450PBI antibody. Protein dot-immunobinding analysis showed that P450s immunodetectable by anti-P450PBII, anti-P450PBIII and anti-P450Coh antibodies are expressed in human liver (range 9 to 69 pmol P450/mg protein). In immunoinhibition experiments the activity of 7-ethoxyresorutin O-deethylase (EROD) was blocked up to 90% by the anti-P450PBII antibody. Aryl hydrocarbon hydroxylase (AHH) was inhibited only by anti-P450PBIII, and coumarin 7-hydroxylase (COH) only by anti-P450Coh antibody. Testosterone hydroxylations in positions 6 beta, 7 alpha, 15 alpha and 16 alpha were not affected significantly by any of the antibodies. These data suggest that the human liver P450IA2 is responsible for most of the elevated EROD activity, P450s in the IIC subfamily for constitutive AHH and P450s in the IIA subfamily for all of COH activity.

Adult↗
PubMed1990

High-density lipoprotein subfractions, apolipoproteins and antipyrine clearance in normal subjects.

Serum high density lipoprotein (HDL) subfractions HDL2 and HDL3, apolipoproteins, and plasma antipyrine clearance (AP-CL) rate, an index of liver microsomal enzyme activity, were determined in 21 healthy subjects. High HDL cholesterol and HDL2 cholesterol concentrations and HDL cholesterol/cholesterol and HDL2/HDL3 cholesterol ratios were associated with high AP-CL. Phenobarbital enhanced antipyrine elimination and increased the apolipoprotein A-I/A-II ratio. Subjects who had high AP-CL had a more antiatherogenic HDL subfraction and apolipoprotein profile than those with low AP-CL.

Adult↗
PubMed1990

Lipid peroxides, glutathione peroxidase, high density lipoprotein subfractions and apolipoproteins in young adults.

Lipid peroxides have been implicated in the initiation of atherogenesis. In this study of 23 young healthy subjects, high levels of serum lipid peroxides were associated with low serum HDL2 cholesterol concentrations and low HDL2/HDL3 cholesterol and apolipoprotein A-I/A-II ratios. Low levels of LDL cholesterol and apolipoprotein B, and low apolipoprotein B/A-I ratios were typical of subjects with high serum glutathione peroxidase activities. Serum lipid peroxide levels varied widely in subjects without abnormal cholesterol, HDL cholesterol or LDL cholesterol concentrations. This variation may play a role in the frequent occurrence of coronary artery disease in normolipidaemic individuals.

Adult↗
PubMed1989

Reversibility of rat liver cirrhosis by medroxyprogesterone acetate.

The possible effects of a synthetic progesterone, medroxyprogesterone acetate (MPA), on carbon tetrachloride/phenobarbital (CCl4/PB)-induced rat liver injury were studied by morphological methods. CCl4/PB-treated rats showed extensive liver fibrosis consisting of procollagen type III aminoterminal propeptide-positive strands and fibres with concomitant extensive basement membrane deposits and fibronectin synthesis. MPA treatment after CCl4/PB-induced liver damage reduced alterations in cytoplasmic organelles, inflammation and hemorrhages and reversed the fibrosis, mostly around individual liver cells, possibly due to the normalization of cellular structure and function with a decrease in fibronectin deposits.

Animals↗
PubMed1987

Growth of human aortic smooth muscle cells cultured with human serum is retarded when serum lipids are lowered by medroxyprogesterone.

Human aortic smooth muscle cells were cultured in the presence of sera from 7 normolipidemic women before and after treatment with high-dose medroxyprogesterone acetate, which caused 16% and 25% decreases in serum cholesterol and HDL-cholesterol concentrations, respectively. As assessed by cell counting and by DNA determination the growth of the cells was retarded significantly in the presence of sera taken after the treatment. At the same time, there were no marked changes in the incorporation rate of [3H]proline into collagen or [3H]glucosamine into hyaluronic acid by the cells. The results indicate that: (1) the mitogenicity of human serum can be altered by drug treatment of serum donors, (2) simultaneously with a lowering of serum lipids in man in vivo, a decreased mitogenicity of sera occurs in vitro.

Aged↗
PubMed1986

Polyamine biosynthesis and monooxygenase enzyme activity in rat liver cirrhosis and regeneration.

Chemically induced liver cirrhosis in the rat was associated with an increased biosynthesis of the hepatic polyamines putrescine and spermidine and a reduction in the activities of the cytochrome P-450-associated monooxygenase enzymes aryl hydrocarbon hydroxylase, ethoxycoumarin O-deethylase and ethoxyresorufin O-deethylase. These parameters were normalized after a 4-week spontaneous regeneration period. The results suggest an independent regulatory mechanism of polyamine biosynthesis and monooxygenase expression.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1985

Treatment of liver cirrhosis with microsomal enzyme-inducing compound in the rat.

The effect of therapy with a microsomal enzyme-inducing drug on the cirrhotic liver in male Wistar rats was investigated by morphological and biochemical means. The cirrhotic animals were treated with medroxyprogesterone acetate (MPA) 100 mg/kg body wt, i.p. daily for a week. In the cirrhotic rats liver weight was enhanced, liver protein content was increased while total liver DNA content remained unchanged upon MPA treatment. The hepatic regenerative nodule size increased, as determined by morphological means. Hepatic microsomal metabolic activity was improved, as seen by increases in NADPH-cytochrome P-450 reductase and aminopyrine N-demethylase activities and cytochrome P-450 content. Since the increases in liver protein content and metabolic activity were relatively greater in the cirrhotic than intact animals upon MPA treatment, it was suggested that the spontaneous regeneration associated with liver cirrhosis may affect the induction phenomenon. The results demonstrate that an enzyme inducer may have beneficial effects on the cirrhotic liver by elevating metabolic activity and parenchymal mass.

Aminopyrine N-Demethylase↗