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Biomedical subjects

T Koivula

Publications and source records attributed to T Koivula.

188 records · Page 11Linked to original sources
PubMed1975

Different forms of rat liver aldehyde dehydrogenase and their subcellular distribution.

1. The properties and distribution of the NAD-linked unspecific aldehyde dehydrogenase activity (aldehyde: NAD+ oxidoreductase EC 1.2.1.3) has been studied in isolated cytoplasmic, mitochondrial and microsomal fractions of rat liver. The various types of aldehyde dehydrogenase were separated by ion exchange chromatography and isoelectric focusing. 2. The cytoplasmic fraction contained 10-15, the mitochondrial fraction 45-50 and the microsomal fraction 35-40% of the total aldehyde dehydrogenase activity, when assayed with 6.0 mM propionaldehyde as substrate. 3. The cytoplasmic fraction contained two separable unspecific aldehyde dehydrogenases, one with high Km for aldehydes (in the millimolar range) and the other with low Km for aldehydes (in the micromolar range). The latter can, however, be due to leakage from mitochondria. The high-Km enzyme fraction contained also all D-glucuronolactone dehydrogenase activity of the cytoplasmic fraction. The specific formaldehyde and betaine aldehyde dehydrogenases present in the cytoplasmic fraction could be separated from the unspecific activities. 4. In the mitochondrial fraction there was one enzyme with a low Km for aldehydes and another with high Km for aldehydes, which was different from the cytoplasmic enzyme. 5. The microsomal aldehyde dehydrogenase had a high Km for aldehydes and had similar properties as the mitochondrial high-Km enzyme. Both enzymes have very little activity with formaldehyde and glycolaldehyde in contrast to the other aldehyde dehydrogenases. They are apparently membranebound.

Aldehyde Oxidoreductases↗
PubMedDate not supplied

Association between M/L55-polymorphism of paraoxonase enzyme and oxidative DNA damage in patients with type 2 diabetes mellitus and in control subjects.

The paraoxonase enzyme (PON) gene polymorphism causes a change of methionine (M-allele) to leucine (L-allele). PON may reduce low density lipoprotein oxidation and prevent atherosclerosis. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) is a sensitive index of oxidative DNA damage. We have studied the association between the PON genotypes and the urinary excretion of 8-OHdG. The study population consisted of 93 Finnish type 2 diabetes patients and 106 non-diabetic control subjects. The 24-h excretion of 8-OHdG was significantly higher in diabetic patients than in control subjects (P < 0.001). In control subjects, the ratio of the 8-OHdG/glomerular filtration rate increased in order of genotype from MM to ML to LL (P < 0.0412). These results suggest that lipid peroxidation may have an effect on DNA oxidation.

8-Hydroxy-2'-Deoxyguanosine↗
PubMedDate not supplied

Amino acids and glucose in human cerebrospinal fluid after acute ischaemic brain damage.

In the search for potential biochemical markers of value for prognosis after acute hypoxic brain damage, amino acids and glucose were assessed in the cerebrospinal fluid (CSF) and glucose in blood. Samples were taken by lumbar puncture 4, 28, 76 and 172 h after resuscitation from 20 patients and once from 10 control patients. Eight of the resuscitated patients recovered neurologically but 12 remained comatose. The concentrations of alanine (P less than 0.001) and phenylalanine (P less than 0.035) differed most in 4-h samples between the groups. The concentration of alanine was higher in all patient groups with hypoxic brain damage as compared to the controls, the concentrations in patients dying within 76 h (disabled-s group) being higher than in the recovered patients. Phenylalanine in the disabled-s group was significantly higher than the control value. Furthermore, there were significant differences between various patient groups in the concentrations of glutamine, isoleucine, leucine, lysine, serine, tyrosine and valine. When taking into account the permeability of the BBB to these amino acids, alanine, valine and isoleucine most clearly represent brain amino acid metabolism. CSF glucose in the control group and in the recovered patients was lower than in patients dying within 76 h.

Acute Disease↗
PubMedDate not supplied

Effect of acetaldehyde on hemoglobin: HbA1ach as a potential marker of heavy drinking.

The appearance of a new acetaldehyde-induced hemoglobin fraction, HbA1ach, and the effect of alcohol consumption on it and on the ratio of HbA1ach and glycated hemoglobin, HbA1c, were studied in vivo by cation exchange liquid chromatography. The mean +/- SEM of blood HbA1ach level was 171 +/- 13.10(-3)% of total hemoglobin as measured in 34 male teetotallers. Blood HbA1ach levels of 127 social drinkers (182 +/- 6.10(-3)%) were compared with those of 72 heavy drinkers (213 +/- 8.10(-3)%, p less than 0.01), 79 alcoholics (209 +/- 6.10(-3)%, p less than 0.01) and 16 diabetics (419 +/- 28.10(-3)%, p less than 0.001). HbA1ach correlated positively with HbA1c (p less than 0.001) and negatively with HbAo (p less than 0.001). The ratio of HbA1ach/HbA1c was effective in detecting the alcohol-induced increase in the HbA1ach fraction because the ratio reduced the disturbing effect of glucose. The sensitivity of the HbA1ach/HbA1c ratio was 33% in the heavy drinker group as compared to 40% of gamma-glutamyltransferase and 24% of mean corpuscular volume. The HbA1ach fraction and the HbA1ach/HbA1c ratio seem to be valuable in detecting excessive alcohol consumption in its early phase.

Acetaldehyde↗
PubMedDate not supplied

Decreased galactose absorption in dumping after colon interposition.

Intestinal absorption was examined using an oral galactose test in colon interposition patients with dumping (no. 4) and without symptoms (no. 5). Normal subjects (no. 5), and patients after total gastrectomy (no. 7) and gastric resection (no. 4) served as controls. Galactose is absorbed in the same way as glucose, but does not stimulate insulin secretion. Colon interposition patients presented abnormally rapid postprandial transit and absorption for 20 minutes after the meal. After this rapid phase, colon interposition patients with dumping demonstrated a strong decrease in absorption rate, whereas the asymptomatic patients presented a normal rate during the whole follow-up period. The elimination of galactose from the blood was studied in eight patients after intravenous infusion of galactose; the disappearance was linear during 10 to 30 min after injection and did not explain the differences in blood galactose levels in the oral galactose test. We suggest a reactive reflux back to the intra-abdominal colon graft loop in the avagotonic intestinal tract as the mechanism for the differences in absorption. The most likely reason for this is the rapid initial phase transit through the coloantral anastomosis and pyloroplasty. To normalize postprandial transit and absorption as much as possible after colon interposition, a short intra-abdominal colon graft loop anastomosed to the posterior proximal stomach is suggested.

Colon↗