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Biomedical subjects

A Isaksson

Publications and source records attributed to A Isaksson.

At least 109 records · Page 6Linked to original sources
PubMed1987

beta-Hexosaminidase in plasma and liver after partial hepatectomy in normal and cirrhotic rats.

The liver and plasma level of the lysosomal enzyme beta-hexosaminidase was analyzed in partially (about 70%) hepatectomized rats with normal liver or carbon tetrachloride (CCl4)-induced cirrhosis. The enzyme level of the liver did not show marked changes after partial hepatectomy in either normal or cirrhotic rats. In contrast, the plasma basal level was significantly higher in cirrhotic rats and increased to a peak at 6 h, followed by a decrease to a minimum level 24 h after operation. The enzyme returned to its high plasma basal level at 36 h after partial hepatectomy, when the liver had recovered to 70% of its initial weight. In rats with normal liver the plasma beta-hexosaminidase showed another pattern, with a rapid increase at 6 h and thereafter gradually reaching a peak at 36 h after hepatectomy. We conclude that the cells responsible for increased plasma beta-hexosaminidase in cirrhotic rats are situated in the liver.

Alanine Transaminase↗
PubMed1986

Metabolism of the human serum beta-hexosaminidase isoenzymes in the rat: an in vivo and in vitro study.

Plasma clearance of purified human serum beta-hexosaminidase isoenzymes was studied in the rat. The serum beta-hexosaminidase isoenzymes (A, B and P) showed a slow clearance from circulation compared to their tissue counterparts. After desialylation, the clearance rate of all serum isoenzymes was markedly enhanced. The uptake of native as well as desialylated serum beta-hexosaminidase isoenzymes was studied in rat liver nonparenchymal cells and hepatocytes. No detectable uptake of any native serum isoenzyme was noticed in either cell type. However, when these isoenzymes were desialylated by neuraminidase treatment, isoenzymes A and B were taken up by the nonparenchymal cells. No uptake was observed for the P form. None of the desialylated serum forms was taken up by hepatocytes.

Animals↗
PubMed1986

Tissue content and localization of lysosomal enzymes in cholestatic rats.

Levels of the lysosomal enzymes beta-glucuronidase and beta-hexosaminidase were determined in tissues from rats at 1-7 weeks after permanent bile duct occlusion (28 animals) and sham operation (16 animals). With increasing duration of bile duct occlusion, increasing levels were found in the liver and spleen, whereas levels were unaffected in the pancreas, kidneys, brain, muscle, and skin. Histochemical investigation showed that the lysosomal enzymes accumulated in the hepatocytes and in the increasing numbers of reticuloendothelial cells of the liver and spleen during cholestasis. No significant accumulation of lysosomal enzymes was seen in the pancreas. In preparations of isolated hepatocytes and non-parenchymal cells increased specific activity of lysosomal enzymes in cholestasis appeared in both cellular fractions. It is assumed that the serum increase of lysosomal enzymes in late cholestasis is partly due to a release from activated macrophages in the liver and spleen.

Animals↗
PubMed1985

Activity of lysosomal hydrolases in human placenta, amnion, decidua and myometrium in the 2nd and 3rd trimester.

Six lysosomal hydrolases were studied in tissues of human placenta, amnion, decidua, and myometrium obtained in the 2nd and 3rd trimester. No significant increase in the activity of any lysosomal hydrolase was found in the 3rd-trimester values compared with those obtained in the 2nd trimester. Thus, the increased activity of lysosomal hydrolases in maternal serum at term, previously described in several studies, seems not to be paralleled by a corresponding increase in the activity of these enzymes in the tissues of the pregnant uterus. We speculate that the increase in maternal serum towards term may reflect a macrophage activation initiated by elevated estrogen concentrations in the 3rd trimester.

Amnion↗
PubMed1985

Lysosomal enzymes in plasma, liver and spleen from rats with carbon tetrachloride-induced liver cirrhosis.

Plasma levels of the lysosomal enzymes, beta-hexosaminidase and beta-glucuronidase, were analyzed in rats with carbon tetrachloride induced liver cirrhosis. Out of 22 animals, 15 showed cirrhotic and 4 pre-cirrhotic livers. 4 cirrhotic animals exhibited cholestatic features with increased bilirubin, alkaline phosphatase (ALP) and aspartate aminotransferase (ASAT) in plasma. The remaining 15 pre-cirrhotic and cirrhotic rats showed clear significant changes only in ASAT levels. These 15 rats showed no consistent increase in plasma, spleen or liver lysosomal enzyme activities, whereas the 4 rats with cholestatic features exhibited considerable increases of lysosomal enzymes. The increased activities might be attributed to decreased biliary excretion and/or increased production of lysosomal enzymes by activated macrophages.

Alkaline Phosphatase↗
PubMed1985

Influence of ethanol on the human serum level of beta-hexosaminidase.

Serum activities of the lysosomal enzymes beta-hexosaminidase, alpha-fucosidase and alpha-mannosidase in teetotalers, healthy persons with 'ordinary' alcohol consumption, chronic alcoholics and patients with alcoholic liver cirrhosis were compared. There was no difference between controls and teetotalers, whereas serum from chronic alcoholics and patients with alcoholic liver cirrhosis showed a significant increase of lysosomal enzymes compared to controls and teetotalers. The effect of daily alcohol ingestion on the serum activity of lysosomal enzymes was studied in 9 healthy volunteers. A minor but significant increase was found for beta-hexosaminidase. It is concluded that the increase of lysosomal enzyme activity in serum from alcoholics is due to the liver dysfunction.

Adolescent↗
PubMed1985

The effects of glucose and insulin on beta-hexosaminidase in cultured fibroblasts from diabetic and non-diabetic subjects.

The effects of glucose and insulin in culture medium on the release and cellular content of beta-hexosaminidase were studied in fibroblast cultures obtained from patients with type II diabetes and from control subjects. The release of beta-hexosaminidase was (positively) correlated to extracellular glucose concentration. The cellular activity was not influenced by glucose. Insulin had no effect on the cellular activity or the release of beta-hexosaminidase. The results were similar for both cell types. It is proposed that increased plasma levels of lysosomal hydrolases (e.g. beta-hexosaminidase) from human diabetics might be due to increased release from cells exposed to elevated glucose concentrations.

Cells, Cultured↗
PubMed1985

Lysosomal enzymes, alkaline phosphatase, and bilirubin in plasma after bile duct transection in the rat.

Plasma levels of the lysosomal enzymes beta-glucuronidase and beta-hexosaminidase were studied for 6 weeks after permanent bile duct occlusion (19 animals) or sham operation (5 animals). The bile duct-occluded animals had a stable bilirubinemia throughout the observation period. The median level of beta-glucuronidase in controls was 0.45 U/l. In jaundiced animals the median level was 1.09 at 0.5 weeks, 1.28 at 2 weeks, and 1.58 at 6 weeks after bile duct occlusion. The median level of beta-hexosaminidase in controls was 18.5 U/l. In jaundiced animals the median level was 18.0 at 0.5 weeks, 20.8 at 2 weeks, and 53.3 at 6 weeks after operation. Compared with beta-glucuronidase, prominent elevation of the beta-hexosaminidase level appeared much later after bile duct obstruction, which might suggest a closer association with reticuloendothelial system function for the latter enzyme.

Alkaline Phosphatase↗
PubMed1984

Total fasting serum bile acids and beta-hexosaminidase in alcoholic liver disease.

Total serum bile acid levels and beta-hexosaminidase activity were studied in 22 normal subjects, 35 non-cirrhotic patients with acute alcohol intoxication, 45 patients with alcoholic liver cirrhosis and 11 patients with alcoholic liver cirrhosis and surgical portal-systemic shunts. Comparison was made with traditional liver function tests. beta-Hexosaminidase was most frequently elevated in acute alcohol intoxication (94%) while total serum bile acids were elevated in all patients with alcoholic liver cirrhosis. Total serum bile acid levels were found to discriminate most efficiently between acute alcohol intoxication and liver cirrhosis. The combined determination of serum beta-hexosaminidase and total serum bile acids is proposed for evaluating alcoholic liver disease.

Alcoholic Intoxication↗
PubMed1984

Activity of lysosomal hydrolases in plasma at term and post partum.

The activity and isoenzyme pattern in plasma of beta-hexosaminidase (abbreviated Hex) and four other lysosomal hydrolases (alpha-fucosidase, beta-glucuronidase, alpha-hexosaminidase, alpha-mannosidase) were studied in 50 women at term and in 10 women at various intervals during the first 6 days after parturition. All hydrolases had elevated activity at term, compared with controls. After parturition the activity of alpha-mannosidase returned to the normal level within 2 days and that of Hex, beta-glucuronidase, and alpha-hexosaminidase within 6 days; alpha-fucosidase having a slightly elevated activity even at the end of this period. Isoenzyme analysis by isoelectric focusing was informative only in the case of Hex. Thus, the increased activity of Hex at term was mainly due to an increase in the isoenzyme form(s), with pI(s) between 5.6 and 6.8. The enzyme pattern of Hex during pregnancy and post partum observed in this study seems to have certain similarities to the previously noted enzyme pattern of Hex in acute ethanol intoxication and following withdrawal of ethanol. As lysosomal membranes are labilized by elevated levels of steroids, it is of interest to note that high levels of these hormones are found in plasma both at term and in chronic liver disease.

Female↗
PubMed1984

Influence on plasma beta-N-acetyl-D-glucosaminidase of reticuloendothelial stimulation and depression: an experimental study in rats.

Plasma levels of the lysosomal enzyme, beta-N-acetyl-D-glucosaminidase (EC 3.2.1.30; 2-acetamido-2-deoxy-beta-D-glucoside acetamidodeoxyglucohydrolase ) were estimated 120 minutes after intravenous injection of zymosan in rats. Different groups of animals were investigated according to pretreatment with agents influencing reticuloendothelial activity. Pretreatment for two days with the reticuloendothelial stimulating agent, zymosan, or the reticuloendothelial suppressing agent, methyl palmitate, did not influence the basal plasma levels of beta-N-acetyl-D-glucosaminidase. In all groups after zymosan injection, plasma beta-N-acetyl-D-glucosaminidase activity was increased in comparison with basal levels. The increase of enzyme activity was most pronounced after pretreatment with zymosan and differed significantly from enzyme activity after pretreatment with methyl palmitate. Alcohol administration in combination with zymosan did not cause a further rise of beta-N-acetyl-D-glucosaminidase activity in normal rats nor in rats pretreated with zymosan. The observations suggest that plasma levels of beta-N-acetyl-D-glucosaminidase in rats after a standardized zymosan injection are related to the functional status of the reticuloendothelial system (RES).

Acetylglucosaminidase↗
PubMed1983

Plasma and urinary beta-hexosaminidase in juvenile diabetes mellitus.

The activity of beta-hexosaminidase (E C 3.2.1.30) in plasma and urine was determined in 99 patients with juvenile diabetes mellitus and in 40 age-matched controls. Plasma enzyme activities were above normal in plasma from diabetics and showed significant correlations with blood glucose and glycosylated HbA1 (GHbA1) but not with the presence of retinopathy. The urinary excretion of beta-hexosaminidase, which is a sensitive indicator of renal injury, was also excessive in the diabetics and showed a significant correlation with blood GHbA1. The results show that plasma and urinary beta-hexosaminidase correlate with parameters of diabetic control and that urinary beta-hexosaminidase may be more sensitive than urinary albumin as an indicator of early renal damage.

Adolescent↗
PubMed1983

Isoenzyme pattern of serum beta-hexosaminidase in liver disease, alcohol intoxication, and pregnancy.

The isoenzyme distribution of serum beta-hexosaminidase was studied in 11 pregnant women, 18 patients with cirrhosis of the liver, 14 patients with cholestasis, and 9 chronic alcoholics with acute ethanol intoxication. Serum beta-hexosaminidase activity was elevated in sera from all groups. The results of isoenzyme separation by isoelectric focusing demonstrated that the isoenzyme pattern in the different patient groups was similar to pregnancy with a preferential increase of isoenzyme forms with pI's between 5.6 and 6.8.

Alcoholic Intoxication↗
PubMed1983

Uptake of beta-hexosaminidase by nonparenchymal liver cells and peritoneal macrophages.

The uptake of beta-hexosaminidase (EC 3.2.1.30) in nonparenchymal liver cells (i.e. endothelial and Kupffer's cells) and peritoneal macrophages has been determined by an enzymatic assay. A considerable uptake was noted in nonparenchymal liver cells, whereas no measurable uptake was seen in peritoneal macrophages. The endothelial cells were more active in the uptake of beta-hexosaminidase than were the Kupffer's cells. The uptake of beta-hexosaminidase by nonparenchymal liver cells showed saturation kinetics and was competitively inhibited by mannan. These findings support the concept that a cell surface receptor on nonparenchymal liver cells mediates uptake of beta-hexosaminidase and suggests a difference in the receptor mechanisms on liver and peritoneal macrophages.

Animals↗
PubMed1983

Pattern of serum beta-hexosaminidase in liver cirrhosis.

The activity of the primarily lysosomal hydrolase, beta-hexosaminidase (EC 3.2.1.30), was studied in serum from 53 patients with bleeding esophageal varices, portal hypertension, and liver cirrhosis (31 alcoholic, 13 cryptogenic, and 9 primary biliary). The serum enzyme activity was determined on 89 occasions and was increased in 93%. There was no difference in the distribution between the three patient groups, but in patients who underwent portal-systemic shunt surgery there was a significant increase after 9-12 months. Serum beta-hexosaminidase activity correlated significantly with other biochemical tests known to be influenced by portal-systemic shunting. It is concluded that determination of this enzyme might become a useful liver test, since it sensitively detects liver disease and also might be specific, since besides liver disease only pregnancy and lysosomal disorders are known to show considerable elevations in serum activity.

Esophageal and Gastric Varices↗