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Biomedical subjects

A Nilsson

Publications and source records attributed to A Nilsson.

At least 523 records · Page 29Linked to original sources
PubMed1978

Uptake and degradation of iodine-labelled chylomicron remnant particles by monolayers of rat hepatocytes.

1. Rat chylomicrons were labelled with 125I with 69--72% of the iodine in the protein moiety. Less than 1 nmol of iodine was incorporated per nmol of protein. Of the peptide radioactivity 44--56% was in apolipoprotein A-1, 30--40% in the C peptides and 11--15% in apolipoprotine B. The arginine-rich peptide, which accounted for about 14% of the chylomicron protein mass as determined by scanning of sodium dodecyl sulphate-polyacrylamide gels, contained very little radioactivity. 2. Chylomicron remnants generated with postheparin plasma from iodine-labelled chylomicrons showed a relative increase in the percentage of the arginine-rich peptide (76--90% of the apolipoprotein mass according to gel scanning). The major portion of the peptide iodine label was present in apolipoprotein A-1 (43--57%), B (22--32%) and C peptides (17--35%). 3. When iodine-labelled chylomicron remnants were added to rat hepatocytes in primary culture, labelled peptides were taken up and degraded by the hepatocytes by a saturable process. The Vmax. for the uptake was calculated to the 300ng of protein/h per mg of cell protein and the apparent Km as 7.7 microgram of protein/mg of cell protein. A larger proportion of the 125I-labelled lipids of the remnants (mainly polar lipids) was taken up. This suggest that these may also enter the cells by a mechanism that does not involve particulate uptake, such as phospholipid exchange. 4. The degradation of labelled peptides was inhibited by colchicine, concanavalin A, chloroquine and NH4Cl, which also inhibit degradation of the cholesteryl ester portion. All these drugs exerted their inhibition mainly after the uptake of labelled peptide. No degradation occurred at 4 degrees C, and also the uptake was markedly decreased. 5. The uptake of labelled chylomicron remnant peptide was 77 times as effective as that of labelled sucrose, which is likely to be taken up randomly by pinocytosis.

Ammonium Chloride↗
PubMed1978

Effect of metoprolol on blood glycerol, free fatty acids, triglycerides and glucose in relation to plasma catecholamines in hypertensive patients at rest and following submaximal work.

Studies were performed in nine male patients with moderate hypertension. Treatment with metoprolol, 50--150 mg three times daily for 4--17 weeks, had no effect on the plasma level of glycerol, free fatty acids, triglycerides or glucose under basal conditions, neither in the supine nor in the upright position. Submaximal work, performed postprandially, increased plasma glycerol before medication but not during metoprolol, in spite of a marked increase in plasma noradrenaline. The work load employed caused no change in free fatty acids, triglycerides or glucose, neither before medication nor during metoprolol.

Blood Glucose↗
PubMed1978

Lack of enterohepatic circulation of intact biliary phosphatidylcholine in the rat.

The bile phosphatidylcholine was radioactively labelled by intraperitoneal or intravenous injection of [3H]- or [14C]-palmitic acid into bile fistula rats. The radioactive bile was infused intraduodenally into other bile fistula rats. On an average, only 1.0% of the infused radioactive phosphatidylcholine fatty acid reappeared in bile phosphatidylcholine, whereas about 68% of simultaneously infused [3H]-taurocholate was recovered over the same period of time (6 hours). There is thus no significant enterohepatic circulation of intact biliary phosphatidylcholine.

Animals↗
PubMed1978

Irradiation of mice pre-treated with radiation protective substances. A pathologic and haematologic investigation.

CBA male mice were irradiated with single doses of 7.1, 8.6, 10.0, 11.4 or 12.8 Gy, respectively. A protective substance, 2,2-Dithiobis(N-[(1-adamantyl)methyl]acetamidine)-dihydrochloride, here called S-75, was administered orally, 45 min before start of irradiation. Cysteamine-HCl was used as a reference protective substance. Pathologic and haematologic examination of irradiated animals was performed. Cysteamine had somewhat better protective abilities than did S-75, but the latter had some other properties which indicate its possible usefulness in practice.

Acetamides↗
PubMed1978

Stereotactic gamma irradiation of basilar artery in cat. Preliminary experiences.

Irradiation of the basilar artery of cats by stereotactic technique was performed with doses varying from 100 to 300 Gy in a gamma unit. Histologically, vascular lesions such as vacuolization, degeneration and desquamation of the endothelium and hyalinization and necrosis of the muscular coat predominated, whereas reparatory reactions were relatively sparse. Thrombosis was completely absent.

Animals↗
PubMed1978

Experiences with bromocriptine treatment in acromegaly--a preliminary report.

Seven acromegalic patients were treated with 20 mg bromocriptine daily for 3--8 weeks. Four responded with reduction but not normalization of plasma growth hormone (GH) whereas three showed no response. In all patients with subjective symptoms of joint stiffness, sweating and headache improvement occurred, but this was independent of GH response. Hyperacidity and/or obstipation occurred in five patients. These side effects were slight and transitory in four but severe in one. Prolactin levels were normal in all patients before treatment and became unmeasurable during bromocriptine.

Acromegaly↗
PubMed1978

Effect of the dopamine agonist bromocriptine on blood pressure, catecholamines and renin activity in acromegalics at rest, following exercise and during insulin induced hypoglycemia.

Seven acromegalic patients were given bromocriptine, starting with 1.25 mg/day, then gradually increased to 20 mg daily, which dosage was continued for 3--9 weeks. Treatment with bromocriptine resulted in a significant fall of systolic and diastolic blood pressure in supine and upright position accompanied by a marked reduction in plasma and urinary noradrenaline but without effect on adrenaline. Plasma renin activity fell during institution of bromocriptine and remained significantly lower during prolonged treatment. Urinary aldosterone showed no significant changes during medication. The plasma noradrenaline response to physical exercise was reduced by bromocriptine treatment, whereas the adrenaline response was unaltered. The plasma catecholamine response to hypoglycemia was not statistically different during bromocriptine as compared to before medication.

Acromegaly↗
PubMed1977

Binding, interiorization and degradation of cholesteryl ester-labelled chylomicron-remmant particles by rat hepatocyte monolayers.

1. The cholesteryl ester of isolated chylomicron-remnant particles was efficiently degraded by hepatocyte monolayers. The degradation was sensitive to metabolic inhibitors. 2. With increasing amounts of remnant cholesteryl ester the rate of uptake approached saturation and conformed to a linear double-reciprocal plot. The V(max.) was determined as 80ng of cholesteryl ester/h per mg of protein and the apparent K(m) as 1.4mug of cholesteryl ester per mg of protein. The time course for the uptake and hydrolysis suggested that binding of particles to the cell surface preceded the degradation. 3. Cholesteryl esters of native chylomicrons were degraded to a much smaller extent and their presence had only a small inhibitory effect on the degradation of chylomicron remnants. Intestinal very-low-density lipoproteins were degraded somewhat faster than chylomicrons, and caused more inhibition of remnant degradation. Rat high-density lipoproteins inhibited the hydrolysis of remnant cholesteryl ester by up to 50%, but had less influence on the amount of cholesteryl ester that was bound to the cells. Serum decreased both the uptake and hydrolysis, whereas d=1.21 infranatant had no effect. 4. The cholesteryl ester hydrolysis after the uptake by the cells was inhibited by chloroquine and by colchicine. Only 28-36% of the unhydrolysed cholesteryl ester could be released from these cells by trypsin treatment, indicating that the major portion was truly intracellular. The particles that could be released from the cell surface by trypsin and those remaining in the medium had the same triacylglycerol/cholesteryl ester ratio as the added remnant particles. Significant amounts of denser particles were thus not formed during contact with the cell surface. 5. The presence of heparin, as well as preincubation of the cells with heparin, increased the uptake of chylomicron remnants. This effect was most marked in the presence of serum. A much smaller proportion of the other serum lipoproteins was taken up, and this proportion was not increased by heparin.

Animals↗
PubMed1977

Effects of anti-microtubular agents and cycloheximide on the metabolism of chylomicron cholesteryl esters by hepatocyte suspensions.

1. Post-heparin plasma that promoted rapid hydrolysis of about 90% of the triacylglycerol markedly stimulated the uptake or binding of chylomicron cholesteryl ester by suspended hepatocytes. The net hydrolysis of chyle cholesteryl ester after the uptake by the cells was, however, slower than in vivo. 2. The cholesteryl ester uptake in the presence of post-heparin plasma was larger if the cells had been preincubated for 2h. It was inhibited by the presence of colchicine, vinblastine or cycloheximide during the preincubation, and by mild trypsin treatment of the preincubated cells. 3. The results suggested that the anti-microtubular agents, but not cycloheximide, also inhibited the hydrolysis of chyle cholesteryl ester after uptake or binding to the cells. 4. The uptake of isolated chylomicron remnant particles was more efficient than that of native chyle lipoproteins. It was, however, still stimulated by heparin alone and by post-heparin plasma. The heparin-stimulated uptake was markedly decreased if cycloheximide was present during the preincubation period.

Animals↗
PubMed1977

Psychogenic vertigo within an anxiety frame of reference: an experimental study.

The theoretical point of departure here was the assumption that a psychogenic vertigo patient displaces affect, or experience of anxiety to one of dizziness, the dizziness serving as an anxiety equivalent. This is seen to imply a change in the locus of experience from the me to the not-me sphere. "Percept-genetic" techniques and a spiral after-effect measurement were used to compare 23 patients with presumed psychogenic vertigo with a control group matched in sex, age, education and occupation. Results of the percept-genetic techniques showed the patients to display stronger signs of affect anxiety than subjects in the control group. Also two main subgroups of patients were differentiated with the help of the descriptive instruments, one group with signs of a primitive-hysteroid mode of functioning, the other with signs of an obsessive-compulsive mode. For both subgroups the suggested displacement mechanism seemed to be functioning. Its apparent effect differed, however, for the two subgroups: in the "primitive-hysteroid" group the displacement mechanism was more effective. The "obsessive-compulsive" group showed stronger signs of affect anxiety, dizziness here being better characterized as a concomitant than as an equivalent of anxiety. Results of a follow-up two years after the investigation also showed a poorer development of symptoms within the "obsessive-compulsive" group.

Adult↗
PubMed1976

Hydrolysis of chyle cholesterol esters with cell-free preparations of rat liver.

1. The effect of pH on the hydrolysis of chylomicron and chylomicron remnant cholesterol ester with rat liver homogenate was examined. The hydrolysis had three pH optima, at pH 4.5, at pH 6.0-6.5 and at pH 8.5. At the two upper pH optima extensive cholesterol ester hydrolysis occurred without simultaneous degradation of the triacylglycerol portion. 2. Similarly, microsomes (at pH 6.5-8.0) and 100 000 X g supernatant (at pH 7.5-8.5) efficiently hydrolyzed the cholesterol ester but not the triacylglycerol of chylomicron remnants. 3. With the same substrate no enrichment of neutral cholesterol esterase activity was seen in isolated plasma membranes. 4. At pH 4.5 lysosomes efficiently hydrolyzed both the cholesterol ester and the triacylglycerol portion of chylomicron remnants. 5. Three conclusions are drawn: (a) the study provides evidence against the existence of a plasma membrane-bound enzyme-hydrolyzing chylomicron cholesterol ester before or during its penetration into the cell; (b) enzymes of the cell sap and possibly of the endoplasmic reticulum can degrade cholesterol ester of chylomicron remnants without preceeding hydrolysis of the triacylglycerol core; and (c) lysosomal enzymes can degrade both the cholesterol ester and the triacylglycerol portion of chylomicron remnants if these are taken up as whole particles by endocytosis.

Animals↗