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Biomedical subjects

S Ritland

Publications and source records attributed to S Ritland.

At least 91 records · Page 5Linked to original sources
PubMed1977

The electrophoretic mobility of lipoprotein X in postheparin plasma.

After incubation whole plasma and low density lipoproteins (LDL) taken before and 10 min after intravenous administration of heparin, from a patient with primary biliary cirrhosis and a patient with familial lecithin:cholesterol acyltransferase (LCAT) deficiency, have been tested for the presence of lipoprotein X (LP-X) by agar gel electrophoresis. LP-X was present in preheparin whole plasma and LDL. No precipitation lines on the cathodal side of the wells, indicating the absence of LP-X, were seen after electrophoresis of postheparin plasma and LDL. Immunodiffusion revealed the presence of apo-beta-lipoproteins and LP-X in preheparin as well as postheparin LDL. After gel filtration three subfractions and similar patterns were observed in the preheparin and postheparin LDL. Electronmicroscopical examination of the intermediate subfractions showed LP-X-like particles in preheparin and postheparin samples. These observations indicate a changed electrophoretic mobility in agar gel of postheparin LP-X, giving a false negative LP-X test by the conventional agar gel electrophoresis.

Electrophoresis, Agar Gel↗
PubMed1977

Hepatic copper content, urinary copper excretion, and serum ceruloplasmin in liver disease.

Increased liver copper concentration and raised serum ceruloplasmin were demonstrated in primary biliary cirrhosis and disorders of the biliary tract, and occasionally in chronic active hepatitis and cirrhosis of the liver. Eight of 13 patients with primary biliary cirrhosis had liver copper content as high as seen in patients with hepatolenticular degeneration (is greater than 250 mjg/g dry weight). Normal liver content was found in patients with acute hepatitis, steatosis of the liver, hepatic amuloidosis, haemochromatosis, and Gilbert's syndrome. The urinary copper excretion was increased (is greater than 75 mjg/24 h) in half the patients with primary biliary cirrhosis and occasionally in the other patient groups. Serum ceruloplasmin was raised in more than half of all patients, and none had levels below the reference range. Raised heaptic copper content did not always coincide with enhanced urinary copper excretion, but was significantly correlated with this parameter and also with ceruloplasmin, alkaline phosphatases, and vitamin-K-dependent clotting factors, but not with ALAT. Combination of laboratory data, as found in typical cases of hepatolenticular degeneration, was not observed in this study, including 66 patients.

Acute Disease↗
PubMed1976

Changes in the concentration of lipoprotein-X during incubation of postheparin plasma from patients with familial lecithin: cholesterol acyltransferase (LCAT) deficiency.

The concentration of lipoprotein-X (LP-X) has been studied in six patients with familial lecithin:cholesterol acyltransferase (LCAT) deficiency before and after the administration of heparin. In preheparin plasma, LP-X was present in all the patients, the concentrations ranging from 40 to 251 mg/100 ml. When postheparin plasma samples were incubated at 37 degrees C for 4 hours, LP-X could not be detected, whereas it was still present before incubation. LCAT activity was absent in the preheparin as well as in the postheparin samples. Accordingly, the changes in the concentration of LP-X could not be attributed to alterations in plasma LCAT activity. An increase in lysolecithin and a decrease in lecithin was observed during incubation of postheparin plasma samples.

Acyltransferases↗
PubMed1975

Quantitative studies of lipoprotein-X in familial lecithin: cholesterol acyltransferase deficiency and during cholesterol esterification.

In eight patients with familial lecithin: cholesterol acyltransferase (LCAT) deficiency the plasma concentration of the abnormal lipoprotein LP-X ranged from 43 mg/100 ml to 251 mg/100 ml with a mean of 127 mg/100 ml. This is above the mean level of LP-X found in a group of patients with intrahepatic cholestasis (49 mg/100 ml) and below the mean level found in patients with extrahepatic cholestasis (341 mg/100 ml). Following blood transfusions, an increase in LCAT activity and a decrease in the plasma concentration of LP-X were observed. This decrease was not a simple dilution phenomenon. Quantitation of LP-X during long-term incubation of a whole plasma system demonstrated that LP-X was a source of free cholesterol (FC) in the LCAT reaction. More free cholesterol was derived from LP-X during cholesterol esterification than corresponding to the percentage of the plasma free cholesterol found in the LP-X fraction. The present investigation did not answer the question whether LP-X only was an easily accessible source of free cholesterol for cholesterol esterification or whether LP-X acted directly as a substrate for the LCAT reaction.

Acyltransferases↗
PubMed1975

Plasma concentration of lipoprotein-X (LP-X) in experimental bile duct obstruction.

Sequential quantitative determinations of lipoprotein-X (LP-X), measurements of plasma lipids, initial rate of cholesterol esterification, and liver function tests were performed after experimental cholestasis in 6 dogs. In 3 animals ligation and transsection of the common bile duct were combined with cholecystectomy. In 2 other dogs a similar operation, but without removal of the gallbladder, was carried out. In the bile-duct-obstructed and cholecystectomized dogs, LP-X appeared 11-21 hours after operation, and in dogs with preserved gallbladder 32 hours after operation. During the observation periods (6-41 days), the LP-X levels were much higher in the cholecystectomized dogs than in the ones with preserved gallbladders. In most of the bile-duct-obstructed dogs the curves of LP-X concentrations in plasma were bi-phasic. The first peak after 1 to 5 days was followed by a fall, and 10 to 14 days after operation another rise was observed. Concomitant with the changes in the level of LP-X, fluctuations in the levels of phospholipids and free cholesterol occurred. An inverse relationship between LP-X and the activity of lechithin: cholesterol acyltransferase was found.

Acyltransferases↗
PubMed1975

Quantitative determination of the abnormal lipoprotein of cholestasis, LP-X, in liver disease.

Quantitative determination of the abnormal plasma lipoprotein of cholestasis LP-X has been performed in 81 LP-X positive patients with different liver disorders. Great variations in the plasma concentration of LP-X were demonstrated both in the 45 patients with intrahepatic cholestasis (acute hepatitis, toxic hepatitis, primary biliary cirrhosis and cholangitis) and in the 36 patients with extrahepatic cholestasis (extrahepatic biliary obstruction by tumours and choledocholithiasis). The plasma concentratkons of LP-X in the patients with extrahepatic cholestasis (median 158 mg/100 ml) were significantly (psmaller than 0.001) higher than in the patients with intraphepatic cholestasis (median 25 mg/100 ml) was exceeded by 42% of the patients with extrahepatic biliary obstruction, and 33% of the patients with extrahepatic biliary obstruction, had LP-X LEVELS ABOVE 400 MG/100ML. The plasma concentration of LP-X was significantly correlated to the plasma activity of alkaline phosphatases and serum bilirubin, but seemed to be superior to these two parameters in the differentiation between intrahepatic and extrahepatic cholestasis. Plasma levels of LP-X above 400 mg/100 ml are highly indicative of extrahepatic biliary obstruction.

Acute Disease↗
PubMed1975

The esterification of cholesterol in plasma after acute myocardial infarction.

The rate of plasma cholesterol esterification (LCAT activity) and the concentration of eight proteins in the plasma have been studied in the ten male patients during the course of acute myocardial infarction. Samples were drawn 22 hr, 3 days, 8 days, 2 weeks, and 7 weeks after the onset of the acute myocardial infarction. The changes of the plasma proteins were typical for the acute-phase reaction. LCAT activity decreased initially during the illness. The lowest values were found after 8 days. Concomitantly, a reducation in the plasma concentration of total and free cholesterol and cholesteryl esters was demonstrated. The rate of cholesterol esterification correlated significantly with the concentration of prealbumin, alpha-lipoprotein, and albumin. Seven weeks after onset of the infarction, the LCAT values were equal to those in a reference group. The results suggest that the synthesis of LCAT was decreased during the acute-phase reaction.

Acute Disease↗
PubMed1975

Effect of treatment with a bile-sequestering agent (Secholex) on intestinal absorption, duodenal bile acids, and plasma lipids.

Four female and five male patients (mean age 26 years) with hyperlipoproteinaemia type II A were treated with an anion exchange gel (Secholex) 9 g/day for 3 months and 15 g/day for 9 months. After these 12 months clofibrate 1.5 g/day was added to the therapy in 6 patients, whereas 2 patients continued with the resin alone for another 6 months, and one was withdrawn from the trial because of pregnancy. During the first year plasma cholesterol decreased averagely 18% from a mean pretreatment value of 461 mg/100 ml. Dosis of 9 g/day seemed to be as efficient as 15 g/day. When clofibrate was added, a further decrease of plasma cholesterol by 6% was observed, and the levels of triglycerides were reduced. Significantly increased concentrations of bile acids and a rise in the glycine/taurine ratio in duodenal aspirate were caused by the resin. On combined treatment the concentration of bile acids decreased to the pretreatment values, whereas the glycine/taurine ratio remained unchanged. During the trial slight transient changes in serum folic acid, fasting insulin, calcium, alkaline phosphatases, and vitamin B 12-absorption occurred. No changes in serum vitamin A, vitamin-K-dependent clotting factors, serum gastrin, gastric acid output, the absorption of glucose and iron, and faecal excretion of fat were observed. Serum insulin 30 and 60 minutes after an oral glucose loading decreased in the patients on combined treatment, whereas the insulin response remained normal in patients taking Secholex alone. Liver function tests and creatinine were unchanged during the trial. Apart from transient abdominal discomfort in two patients, no side-effects were discovered. The patients found the gel palatable.

Adolescent↗