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T Koivula

Publications and source records attributed to T Koivula.

At least 181 records · Page 10Linked to original sources
PubMed1982

Induction of rat liver cytoplasmic aldehyde dehydrogenase by phenobarbital and polycyclic hydrocarbons. Comparison of different isoenzyme types.

The induction of rat liver cytoplasmic aldehyde dehydrogenase by some xenobiotics and phenobarbital are compared. An acute and a chronic treatment with polycyclic hydrocarbons and with TCDD produce a similar pattern of induced enzymes in isoelectric focusing. The result is clearly different from induction with phenobarbital in the genetically selected rat strain. Another main activity in cytoplasm consists of three different isoenzyme patterns which evidently are normal enzyme types. The induced enzyme of liver cytoplasm after chronic AAF-treatment was purified to homogeneity. The enzyme had a molecular weight of 90000 and a subunit molecular weight of 45000. It had Km-values in the millimolar range for aliphatic aldehydes and in the micromolar range for aromatic aldehydes. Both NAD and NADP were coenzymes of the purified aldehyde dehydrogenase.

Aldehyde Dehydrogenase↗
PubMed1981

Subcellular and perisynaptic distribution of rat brain aldehyde dehydrogenase activity.

The nuclear mitochondrial and synaptosomal fractions of rat brain were each found to contain some 25-30% of the total aldehyde dehydrogenase activity. The cytoplasmic fraction had a very low total aldehyde dehydrogenase activity. There were differences in the distribution of the activity when different aldehydes were used as substrates, suggesting the presence of isoenzymes in the various subcellular compartments. When rats were treated intracisternally with 6-hydroxydopamine there was no change in brain aldehyde dehydrogenase activity, although the noradrenaline content and the activities of tyrosine hydroxylase and dopamine-beta-hydroxylase were markedly decreased. Treatment with 6-hydroxydopamine also had no significant effect on the aldehyde dehydrogenase activity in retinal homogenates. The results suggest that the aldehyde dehydrogenase activity in rat brain is predominantly outside the catecholaminergic nerve terminals.

Aldehyde Dehydrogenase↗
PubMed1981

Immunoassay for transferrin using LKB 8600 Reaction Rate Analyzer.

A rapid immunochemical method for transferrin determination is described. The method is based on measuring turbidity caused by antigen-antibody complexes with an enzyme analyser using diluted antiserum as a starting reagent. This immunoturbidimetric method correlates well with TIBC (r=0.979; n=36). A comparison with the radial immunodiffusion method gave the correlation coefficient 0.984 and the regression line y=1.20x-0.54 (n=36).

Antigen-Antibody Complex↗
PubMed1980

beta-N-acetylglucosaminidase and beta-glucuronidase activities in insulin-dependent diabetic subjects with retinopathy.

The serum activities of two lysosomal enzymes, beta-N-acetylglucosaminidase (EC 3.2.1.30, NAG) and beta-glucuronidase (EC 3.2.1.31, GLU), were determined in 41 insulin-dependent diabetics, 27 age-matched non-diabetic first-degree relatives of the diabetics and 103 age-matched non-diabetic blood-donors. The diabetics were divided into three groups on the basis of ophthalmoscopy: (1) no retinal abnormalities; (2) non-proliferative retinopathy; and (3) proliferative retinopathy. The activities of both serum enzymes were higher in diabetics (NAG 21.39 +/- 5.99; GLU 2.19 +/- 1.01) than in their relatives (NAG 17.22 +/- 3.99; GLU 1.62 +/-0.61). The diabetics with non-proliferative retinopathy had higher serum enzyme levels (NAG 24.05 +/- 6.26; GLU 2.60 +/- 1.06) than diabetics without retinopathy (NAG 17.88 +/- 3.00; GLU 1.69 +/ 0.64), whereas no statistically significant difference was found in patients with the proliferative form of retinopathy (NAG 18.67 +/- 6.28; GLU 1.99 +/- 1.04). In diabetics a positive correlation was found between serum beta-N-acetylglucosaminidase activity and blood glucose (p < 0.01), but not between beta-glucuronidase and blood glucose. Furthermore, the activities of both enzymes in diabetics correlated with the plasma triglyceride level (p < 0.05 for both correlations). No correlation was found between the enzyme levels and signs of other diabetic late complications.

Acetylglucosaminidase↗
PubMed1979

Continuous blood glucose monitoring and characteristics of diabetes in patients on maintenance haemodialysis treatment.

The glucose metabolism of diabetes mellitus during maintenance haemodialysis treatment was studied in four patients with endstage renal failure. There was a large day-to-day variation in the predialysis blood glucose levels, which it was difficult to control by adjusting the insulin dose. In spite of very high blood glucose levels, blood lactate and beta-hydroxybutyrate were not elevated. Triglycerides were markedly and constantly elevated, in no apparent association with the predialysis blood glucose level. The patients were shown to release moderate amounts of glucose, beta-hydroxybutyrate and lactate into the dialysate during the dialysis period. A technique of continuous blood glucose monitoring during the haemodialysis period was applied. With this technique blood sugar levels were accurately determined during the whole dialysis period. A rapid drop in the blood glucose level was found in apparent association with an aggravation of symptoms. A very marked tendency to hypoglycaemia was also revealed. It is concluded that the technique is a valuable aid in the proper management of diabetes in these cases.

Adult↗
PubMed1978

The excretion of urinary N-acetyl-beta-glucosaminidase and beta-glucuronidase as a sign of impending rejection of kidney transplants.

An evaluation was made of the assay of two urinary lysosomal enzymes, N-acetyl-beta-glucosaminidase and beta-glucuronidase, in the diagnosis of impending rejection of renal transplant. The output of enzymes was measured in 34 cadaver transplant recipients, 17 of whom underwent rejection episodes. The enzyme output during the 4 days preceding the definitive diagnosis was compared with the output during a non-rejection period. The mean excretion of both enzymes increased during the period before rejection. The best distinction for diagnostic purposes was obtained by comparing the pre-rejection values with baseline values separately in each case.

Acetylglucosaminidase↗
PubMed1977

Effect of a low-protein diet on acetaldehyde metabolism in rats.

The effect of dietary changes on liver alcohol and aldehyde dehydrogenase activities as related to effects on ethanol and acetaldehyde metabolism was investigated. Feeding rats for 8 weeks on diets rich in carbohydrate or fat, but with normal protein content, induced minor changes relative to giving a balanced diet. A low-protein, high-carbohydrate diet (5 per cent and 80 per cent of calory content, respectively) caused a significant reduction of both alcohol and aldehyde dehydrogenase activities in the liver. The activity of the high-Km aldehyde dehydrogenase in the microsomal and soluble fractions appeared to be more reduced than that of the low-Km enzyme in the mitochondrial fraction. The tail blood acetaldehyde was significantly higher in rats on the protein deficient diet in spite of their reduced ethanol elimination rates. The results suggest that protein deficiency deranges acetaldehyde metabolism and may thus increase the possible contribution of acetaldehyde to the effects caused by ethanol metabolism.

Acetaldehyde↗
PubMed1975

Partial purification and properties of a phenobarbital-induced aldehyde dehydrogenase of rat liver.

Properties of the phenobarbital induced cytoplasmic aldehyde dehydrogenase (EC 1.2.1.3) have been studied in rat liver. 7-12-Fold higher levels were seen in the cytoplasmic activities after phenobarbital treatment in reactor compared to non-reactor animals with high concentrations of acetaldehyde (18 mM) and propionaldehyde (9 mM). No difference was found with 0.12 mM acetaldehyde, 2 mM glycolaldehyde, 6 mM formaldehyde or 0.5 mM betaine aldehyde. The reactor group also had slightly higher activity in the mitochondrial fraction with the high acetaldehyde and propionaldehyde concentrations. In the microsomal fraction, the activities showed no differences at any substrate concentration. An induced aldehyde dehydrogenase was purified 70-fold by chromatographic techniques. It had different molecular and enzymic properties than the main high-Km enzyme normally present in rat liver cytoplasm. The pI of the induced enzyme was about 7.0 as measured by isoelectric focusing. It was active with several aliphatic and aromatic aldehydes but not with formaldehyde, glycolaldehyde or D-glyceraldehyde. The Km-values for propionaldehyde and acetaldehyde were in the millimolar range. Millimolar concentrations of aromatic aldehydes caused a strong substrate inhibition. The enzyme was inhibited by submicromolar concentrations of disulfiram. Estrone, deoxycorticosterone, progesterone and diethylstilbestrol also affected the enzyme activity.

Aldehyde Oxidoreductases↗