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Biomedical subjects

A Nilsson

Publications and source records attributed to A Nilsson.

At least 433 records · Page 24Linked to original sources
PubMed1988

Lipoprotein-deficient serum stimulates the uptake of chylomicron remnants in cultured rat hepatocytes.

Rat hepatocyte monolayers were cultured in the presence of 1-10% lipoprotein-deficient foetal calf serum. This increased the uptake and degradation of chylomicron remnant cholesteryl ester significantly. The increase occurred at all cell densities, i.e. also with less dense cultures where the basal rate of uptake per mg protein was highest. This indicates that tissue culture medium content of lipoprotein cholesterol can regulate the uptake of chylomicron remnants in hepatocytes, analogous to the regulation of the LDL receptor in extrahepatic cell.

Animals↗
PubMed1988

Evaluation of magnesium status in Crohn's disease as assessed by intracellular analysis and intravenous magnesium infusion.

The magnesium status was evaluated in 30 subjects with Crohn's disease and in 30 controls. Subjects with Crohn's disease had lower concentrations of magnesium in muscle biopsy specimens (p less than 0.001), mononuclear cells (p less than 0.05), and in urine collected during 24 h (p less than 0.001) as compared with controls. After intravenous infusion of 60 mmol magnesium and 80 mmol potassium to 17 subjects with Crohn's disease a significant increase in concentrations of magnesium in muscle specimens (p less than 0.05), mononuclear cells (p less than 0.01), and plasma (p less than 0.01) was noted. The retention of intravenously infused magnesium was significantly higher in subjects with Crohn's disease than in 11 healthy controls (p less than 0.001) and was inversely correlated with the content of magnesium in muscle specimens (r = -0.52; p less than 0.05). The implication of these findings is that analysis of magnesium in muscle specimens and estimation of magnesium retention during an intravenous magnesium infusion are useful to confirm a suspected magnesium deficiency.

Adolescent↗
PubMed1988

Bile salts in the esophagus of patients with esophagitis.

It is controversial whether bile salts are important in the pathogenesis of esophagitis. By sampling esophageal contents during ambulatory 24-h pH-monitoring we found that in a group of 18 patients with esophagitis all but 1 had detectable concentrations of bile salts in their esophagus. The concentrations of bile salts were low, however, and similar to those found in the gastric juice of 10 normal controls. It is concluded that bile salts are present in the esophagus of patients with esophagitis and that their presence results from duodenogastric reflux. The role of these refluxed bile salts in the pathogenesis of esophagitis is, however, unclear.

Adult↗
PubMed1988

Intestinal absorption of phosphatidylcholine and triglyceride after ileal resection.

The intestinal absorption of (14C)oleoyl moieties in triglyceride and phospholipid was investigated by means of (14C)phosphatidylcholine and (14C)triolein breath tests. In patients who had undergone ileal resection the absorption of both phosphatidylcholine and triglyceride was subnormal, as reflected by a lower production of 14CO2. In healthy subjects the production of expiratory 14CO2 after oral administration of (14C)phosphatidylcholine was slightly higher than after administration of (14C)triolein. This was also observed in the patient group, indicating that the absorption of both triglyceride and phospholipid was decreased to similar extents, although triglyceride absorption tended to be more affected after major ileal resection. In patients with lipid malabsorption the proportion of linoleic acid in serum phosphatidylcholine was subnormal, and the decrease was correlated to the decrease in lipid absorption. The concentration in serum of selenium, alpha-tocopherol, and carotene but not of ascorbic acid and retinol was subnormal after ileal resection.

Adolescent↗
PubMed1988

Potentiating and inhibiting effects of steroid hormones on the incidence of 90Sr induced osteosarcoma.

Eight hundred and twenty male CBA-mice, 75 +/- 3 days of age were divided into four main series. Three of these; A, B and C were further divided into three subgroups. To these 90Sr was given at three different dose levels alone (A) or in combination with either oestrogen (B) or prednisolone (C). In one series (D) all animals were given only oestrogen. The development of intramedullary oestrogen induced bone formation and the early events of bone tumour induction are reported. The 90Sr activities were selected in such a way that the lowest one would be below, the intermediate beyond and the highest well above the limit of bone tumour induction. Comparing the 90Sr injected animals with those given also oestrogen revealed that oestrogen had no promoting effect at the lowest and intermediate dose levels but increased the tumour incidence with a factor 4 at the highest dose level whereas prednisolone had an inhibitory effect. From the results obtained it was proposed that oestrogen may act only as a preparatory promoter and not assist in the initiating events. As has been reported elsewhere, the frequency of osteoblastic and osteoclastic osteosarcomas was higher in animals given oestrogen and 90Sr than 90Sr only. Mice given only oestrogen did not develop bone tumours.

Animals↗
PubMed1988

Effects of flumazenil on post-operative recovery after total intravenous anesthesia with midazolam and alfentanil.

Midazolam and alfentanil were infused in a totally i.v. anesthetic technique (TIVA) to patients undergoing hysterectomy. Correlations of midazolam plasma concentrations and effects were made during recovery. Due to the high doses of midazolam administered during TIVA, metabolism and not redistribution mainly governed the duration of effects post-infusion. The concomitant administration of alfentanil contributed to the sedative effect, as illustrated by a shift of the concentration-response curve to the left. As a result of these effects, recovery was prolonged and extended over 2-6 h. The effect of the benzodiazepine antagonist flumazenil on post-operative performance after total i.v. anaesthesia with midazolam and alfentanil was studied. A bolus dose of flumazenil, 1.0 mg i.v., significantly improved recovery during the first post-operative hour but was followed later by resedation. The reduction in sedation followed by improvement in ventilation, without reduction of analgesia, demonstrated that antagonism of hypnosis is the primary factor in enhancing recovery from total i.v. anaesthesia.

Alfentanil↗
PubMed1988

Oral administration of magnesium hydroxide to subjects with insulin-dependent diabetes mellitus: effects on magnesium and potassium levels and on insulin requirements.

Intra- and extracellular levels of magnesium and potassium were determined in 16 subjects with insulin-dependent type I diabetes mellitus (IDDM) and 30 healthy controls. Subjects with IDDM had lower levels of magnesium in muscle biopsies (p less than 0.001), plasma (p less than 0.001), and mononuclear cells (p less than 0.05), and higher urinary excretions of magnesium (p less than 0.01), and lower levels of potassium in muscle biopsies (p less than 0.001), and erythrocytes (p less than 0.05), as compared with those in controls. Magnesium hydroxide (500 mg/day) was administered orally to the diabetics. The levels of magnesium and potassium in muscle biopsies increased (p less than 0.001; p less than 0.001), while the plasma levels of magnesium and the urinary excretions of magnesium increased only temporarily, during 21 weeks of treatment. The requirements of insulin were reduced (p less than 0.001) during the course of the study, whereas the levels of glycosylated hemoglobin (HbA1c) and glucose were not changed. The findings indicate that administration of magnesium hydroxide is useful to treat muscular magnesium and potassium deficiency in diabetics.

Adult↗
PubMed1987

Studies on the interrelated stimulation of microsomal omega-oxidation and peroxisomal beta-oxidation in rat liver with a partially hydrogenated fish oil diet.

To investigate the mechanism for initiation of peroxisomal beta-oxidation by high-fat diets the time-courses of peroxisomal beta-oxidation and microsomal omega-oxidation stimulated by 20% (w/w) partially hydrogenated fish oil were studied. The relative stimulation of these two activities developed in a very similar way. We also observed an elevated level of long-chain acyl-CoA with partially hydrogenated fish oil, but not of free fatty acids. There was, however, a significant shift in the composition of free fatty acids to a higher amount of monoenes and lower amounts of 18:2 and 20:4 fatty acids. In peroxisomes purified by Nycodenz gradient centrifugation there was no lauric acid hydroxylation. This study indicates that with partially hydrogenated fish oil we obtain a parallel stimulation of reactions in two different cellular compartments. Dicarboxylic fatty acids, which are products of the omega-oxidation, had only a slight stimulatory effect on peroxisomal beta-oxidation. Therefore, the primary stimulatory agent of peroxisomal beta-oxidation and microsomal omega-oxidation is still unknown. It was speculated that this agent may activate a gene-locus responsible for both reactions.

Acyl Coenzyme A↗
PubMed1987

Regulation of apolipoprotein A-I synthesis in lymph-drained rats.

The effect of lymph diversion on plasma apolipoprotein A-I levels was studied. In lymph fistula rats apolipoprotein A-I levels in plasma stayed constant in spite of a loss of an equivalent of one-half plasma pool of apolipoprotein A-I per day through the lymph fistula. This indicates that synthesis of apolipoprotein A-I increases or that catabolism of apolipoprotein A-I decreases in a compensatory manner as intestinal apolipoprotein A-I is diverted. By using incorporation of [3H]leucine into newly synthesized apolipoprotein A-I it was shown that 2.6-times as much [3H]leucine was incorporated into apolipoprotein A-I in thoracic duct drained animals compared to controls. In experiments in which 125I-labeled HDL was injected intravenously into rats, it was shown that catabolism of HDL and apolipoprotein A-I was not decreased in lymph-drained rats. These data thus suggest that an increased synthesis of apolipoprotein A-I occurs when the intestinal contribution of apolipoprotein A-I diminishes. This is probably due to an increase in liver protein synthesis.

Animals↗
PubMed1987

Cell-density-dependent uptake of chylomicron remnants in rat hepatocyte monolayers. Effects of compactin and mevalonic acid.

In rat hepatocytes cultured in lipoprotein-deficient serum, the uptake and degradation of chylomicron remnant cholesteryl ester per mg cell protein varies inversely with cell density. Compactin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme-A reductase, stimulates the uptake at all cell densities. Mevalonic acid, on the other hand, can suppress a significant part of the remnant uptake. Chylomicron remnant uptake in hepatocyte cultures can thus be influenced by factors known to regulate the apolipoprotein-BE receptor activity.

Animals↗
PubMed1987

Effects of unilateral arterial infusion of GH and IGF-I on tibial longitudinal bone growth in hypophysectomized rats.

We have studied the effect of local arterial infusion of bacterially produced human growth hormone (hGH), insulinlike growth factor I (IGF-I), or pituitary-derived ovine prolactin (oPRL) on longitudinal bone growth of hypophysectomized rats. The substances were infused during a 14-day period by osmotic mini-pumps through a catheter which was implanted into the femoral artery of one hindlimb. Longitudinal bone growth was measured by the intravital marker tetracycline. Infusion of 1 microgram hGH per day stimulated bone growth only of the treated limb and not of the uninfused contralateral limb. Infusion of 10 micrograms hGH per day also stimulated unilateral longitudinal bone growth, but the uninfused contralateral limb also showed a significant growth response, probably because local administration of GH at this dose caused a significant elevation of GH in the systemic circulation. As a result, the differential growth response between the GH-treated and untreated limbs decreased compared to rats that were infused with 1 microgram hGH per day. Unilateral arterial infusion of 5 micrograms human IGF-I or 10 micrograms oPRL per day did not produce a significant growth response. The results of the present study confirm the observation by Schlechter and co-workers, who demonstrated that unilateral arterial infusion of GH maintained tibial cartilage width following hypophysectomy in the rat. The results of Schlechter and coworkers and the results of the present study show that GH in vivo stimulates epiphyseal cartilage growth directly. However, an increased local production of insulinlike growth factors is probably of importance for the expression of the direct effect of GH on longitudinal bone growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Acidic deposition and human exposure to toxic metals.

Acid precipitation affects the solubility of several metals in aquatic systems and in soil. Cadmium levels in tap water samples from geological areas having low resistance to acidic pollution were significantly higher than those in samples from a neighbouring reference area where there was a different geological structure. The median cadmium levels and pH values were 0.14 microgram l-1 and 5.6 respectively, for the acidic areas compared with 0.07 microgram l-1 and 6.4 respectively for the reference area. Further, there was a significant inverse relationship between both cadmium and lead contents and the pH values of the samples. The mobility of the metals was thus dependent on the acidity. The blood lead levels in 195 subjects from the acidic areas were lower than those in 91 subjects from the reference area (medians 60 vs. 70 micrograms l-1); no significant differences were found in blood cadmium or blood mercury levels. Subjects in the acidic areas had lower plasma selenium levels than those from the reference area (medians 85 vs. 90 micrograms l-1); the difference was mainly attributed to subjects with private wells. The data may indicate a negative effect of the acidic pollution on selenium intake via water and/or foods. There was also a positive relationship between intake of fish on the one hand and blood mercury and plasma selenium on the other, which is in accordance with the role of fish as a source of these metals.

Cadmium↗
PubMed1987

Pharmacokinetics of midazolam in total i.v. anaesthesia.

The pharmacokinetics of midazolam during total i.v. anaesthesia were determined in 15 female patients undergoing major surgery. Midazolam was administered together with an analgesic drug and a neuromuscular blocking drug. The dose regimen of midazolam, based on simulations, included two consecutive infusions following a bolus injection at the induction of anaesthesia. Multiple blood samples were drawn and a two-compartment open model was fitted to the measured plasma concentrations. Plasma clearance (483 ml min-1), apparent volume of distribution (1.94 litre kg-1) and terminal half-life (3.1 h) were in agreement with other reports. Thus, there was no obvious evidence that the surgical procedure or the concomitant use of other drugs, or both, influenced the pharmacokinetics of midazolam. The relatively rapid elimination makes midazolam suitable for use by infusion in a total i.v. technique.

Adult↗
PubMed1987

Photoaffinity labeling of felodipine-binding proteins in vascular smooth muscle.

[3H]-Felodipine and high-intensity ultraviolet irradiation were used in the photoaffinity labeling of soluble proteins prepared from porcine mesenteric vascular smooth muscle. Irradiation of the soluble proteins in the presence of [3H]-felodipine resulted in the labeling of a protein with an apparent molecular weight of 62 kDa when analyzed by SDS-polyacrylamide gel electrophoresis. Labeling of the protein did not occur without ultraviolet irradiation. An [3H]-azido analog of felodipine was found to show less specificity than felodipine in its protein labeling when irradiated, since proteins with apparent molecular weights of 44, 29, and 14, as well as 62 kDa, were labeled. The photoaffinity labeling of the proteins were inhibited by excess of unlabeled felodipine.

Affinity Labels↗
PubMed1987

Atracurium infusion in total intravenous anesthesia.

The neuromuscular blocking effect of atracurium given as a bolus dose (0.5 mg X kg-1) followed by a maintenance infusion was studied during two different anesthetic techniques. It has been reported that benzodiazepines interact with non-depolarising neuromuscular blockers. In this study no difference was found in the effect of atracurium given with conventional fentanyl/nitrous oxide anesthesia when compared to total intravenous anesthesia using midazolam/alfentanil. More than 90% twitch depression was achieved after 123 and 137 s, respectively. Recovery time to 10% twitch height following the bolus dose was around 32 min. The dosage range for atracurium given by infusion (0.29-0.44 mg X kg-1 X h-1) was confirmed.

Adult↗