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Biomedical subjects

L Eriksson

Publications and source records attributed to L Eriksson.

At least 199 records · Page 11Linked to original sources
PubMed1989

[Autopsies--necessary for medical services?].

The number of clinical autopsies has continuously declined in the last 20 years. The introduction of the new Swedish Autopsies Act is frequently mentioned as the principal reason for this development. This article presents an alternative explanatory model in which changes of attitudes within the medical services and the society appear as the major cause of the reduction in the number of autopsies. Some suggestions are offered with a view to breaking this trend.

Attitude to Death↗
PubMed1988

Stereoselective binding of 11C-raclopride in living human brain--a search for extrastriatal central D2-dopamine receptors by PET.

The selective D2-dopamine receptor antagonist raclopride and its pharmacologically inactive (R)-enantiomer FLB472 were labelled with 11C and used in a study with positron emission tomography to examine the stereoselectivity of 11C-raclopride binding to central D2-dopamine receptors in three healthy men. After the injection of 11C-raclopride, there was a high accumulation of radioactivity in the dopamine-rich basal ganglia, whereas after the injection of 11C-FLB472 there was no such accumulation of radioactivity. Thus, the binding of 11C-raclopride is stereoselective. Distribution ratios [radioactivity in a brain region/"free" (not protein-bound) radioactivity in plasma] were calculated for the two enantiomers to study regional differences in the accumulation of radioactivity. The distribution ratios in white matter were similar for the two enantiomers. In the putamen, a three to four-fold higher distribution ratio was found for 11C-raclopride than for 11C-FLB472, reflecting the presence of specific binding of 11C-raclopride binding to D2-dopamine receptors in the basal ganglia. In the temporal and frontal cortices the distribution ratios were, however, only a few per cent higher for 11C-raclopride than for 11C-FLB472, indicating that if D2-dopamine receptors are present in the human neocortex, then their density is indeed very low.

Adult↗
PubMed1988

Nocturnal hypoxaemia in severe scoliosis.

The relationship between spirometry and daytime blood gases on the one hand and hypoxaemia during sleep on the other was studied in 13 patients with severe thoracic scoliosis. Eight patients had hypoxaemia (mean Sao2 less than 90%) during sleep. They were characterized by a lower vital capacity (30 versus 50% of predicted, P less than 0.01) and by a greater fall in vital capacity from sitting to supine (26 versus 7% of sitting VC, P less than 0.05). All patients with hypoxaemia during sleep were hypercapnic during the daytime. The fall in Sao2 with sleep was related to the increase in transcutaneous PCO2, indicating hypoventilation as the main mechanism behind hypoxaemia during sleep in scoliosis patients.

Adult↗
PubMed1988

Benzo[a]pyrene metabolism and induction of enzyme-altered foci in regenerating rat liver.

The metabolism of benzo[a]pyrene (BP) in regenerating rat liver and the induction of enzyme-altered foci (EAF) in the liver of partially hepatectomized rats, treated with BP and promoted with 2-acetylaminofluorene (2-AAF)/CCl4 was investigated. The aim was to examine factors that might be of importance for the tumorigenicity of BP in the regenerating rat liver, such as cytochrome P-450 activity and glutathione levels. In regenerating rat liver, obtained 18 h after partial hepatectomy (PH), the amount of microsomal cytochrome P-450 was reduced by 20% whereas the level of glutathione was elevated by 15% and the cytosolic glutathione transferase activity towards chlorodinitrobenzene and (+/-)-7 beta,8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydro-BP (BPDE) was unaffected. Microsomes from these animals had a reduced capacity to activate (-)-trans-7,8-dihydroxy-7,8-dihydro-BP (BPD) to DNA-binding products but the pattern of BP metabolites was similar to that observed with control rat liver microsomes. Treatment of rats with 3-methylcholanthrene (MC, 50 mg/kg body wt.) increased cytochrome P-450 levels and glutathione transferase activity towards both substrates. Regenerating livers from these animals retained their cytochrome P-450 level and enzymatic activity towards BP and BPD. Regenerating rat liver microsomes from MC-treated animals were about 35 times more efficient in activating BPD than microsomes from uninduced, partially hepatectomized animals. Intraperitoneal administration of BP (50 mg/kg body wt.) 18 h after PH induced EAF in rats subsequently promoted with 2-AAF/CCl4. Pretreatment of rats with MC 66 h before PH and 84 h before BP administration, increased the number of EAF. In accordance with results by Tsuda et al. (Cancer Res., 40 (1980) 1157-1164), these studies demonstrate that BP is tumorigenic in regenerating rat liver, despite a reduced ability of the liver to activate this compound. Furthermore, MC, an inducer of certain cytochrome P-450 species ("aryl hydrocarbon hydroxylase"), potentiates the effect of BP.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1988

Taurine in the osmoregulation of the Brattleboro rat.

The function of taurine in mammalian osmoregulation was studied in the Brattleboro rat with hereditary hypothalamic diabetes insipidus (DI). DI rats are chronically dehydrated because of their inability to synthesize vasopressin. One day of water deprivation did not affect the water balance in rats with normal vasopressin synthesis, whereas DI rats were markedly dehydrated and lost considerably body weight. Taurine content and 3H-taurine accumulation by platelets were significantly higher in DI rats, with a further increase after one day of water deprivation. In DI rats, water deprivation also evoked a clear taurine increase in skeletal muscle and in the brain. These findings indicate that taurine has an osmoregulatory function in mammals.

Animals↗
PubMed1988

Disk-repositioning onlays in the treatment of temporomandibular joint disk displacement: comparison with a flat occlusal splint and with no treatment.

Sixty-three patients with an arthrographic diagnosis of disk displacement with reduction were randomly assigned to three treatment groups: (I) onlays to maintain disk repositioning, (II) flat occlusal splint, or (III) untreated controls. Guidance for construction of the disk-repositioning onlays was established during arthrography to obtain a recaptured disk position relative to the condyle. The onlays were cemented to the teeth and maintained the new intercuspal position anteriorly and inferiorly. The flat occlusal splint was used at night only and was adjusted to maintain a maximal occlusal contact in centric relation and centric occlusion. Clinical examinations were performed before and after 6 months of treatment. The disk-repositioning onlays improved joint function and reduced joint and muscle pain when compared with the flat occlusal splint and with nontreatment. The signs and symptoms in the flat occlusal splint group were no different from those in the control group. It is concluded that disk-repositioning onlays are effective in reducing pain and dysfunction associated with disk displacement with reduction in patients in whom the disk can be maintained in a normal relationship to the condyle with the aid of such onlays. The symptoms, however, returned when the onlays were removed after 6 months; this raises the question of whether a permanent change in the intercuspal position is necessary for long-term success.

Adolescent↗
PubMed1988

Direct comparison of single-scan autoradiographic with multiple-scan least-squares fitting approaches to PET CMRO2 estimation.

The time course of local cerebral radioactivity concentration after bolus inhalation of oxygen gas labeled with O-15 was measured in a rapid dynamic sequence of positron tomographic images. Four normal subjects were studied at rest. In each study, 15 multiple-slice image sets were acquired over a 3-min period in a Scanditronix model 384 tomograph. The radioactivity concentration in arterial blood was measured at 1-s intervals by means of a pump-fed flow-through detector. Pump effluent was directed to discrete samples that were separated into plasma and cell fractions to estimate the accumulation of labeled, recirculating water arising from systemic metabolism. Stereotactically matched scans of local cerebral blood flow and volume were acquired in the same imaging session, and the derived values were used as fixed parameters in the model fits of the time courses of pixel radioactivity in the oxygen study. Rapid nonlinear least-squares parameter optimization was used to estimate simultaneously the local CMRO2 and the brain/blood relative distribution volume for water in each image pixel. The same scan data were combined into effective single frames of various starting times and durations for analysis using the single-scan ("autoradiographic") approach to CMRO2 estimation, which requires a presumed value for relative distribution volume. Oxygen use values derived using this approach were observed to be strongly dependent on the relative distribution volume value chosen, particularly for long study durations. However, for each gray matter region of interest studied, a uniform value for the relative distribution volume existed such that the estimated CMRO2 values were independent of the starting time and duration of the single scan used, and were furthermore the same as that yielded by the multiple-scan least-squares fitting of the total time course in the same region. We conclude that the properties of the single-scan and multiple-scan approaches are very similar at the same total study duration, provided that the value selected for the water relative distribution volume brings the measured and computed tissue time courses into correspondence.

Autoradiography↗
PubMed1988

The bottom and top system: a new technique for blood component preparation and storage.

A new, automated technique for the preparation of blood components is described. A system of 3 or 4 integrally connected plastic containers (Optipac) is handled by a new type of extractor (Optipress). The container in which the blood is collected has an outlet at the top and another at the bottom. After normal centrifugation to obtain separation of the blood components, these are squeezed out from the top and bottom simultaneously under control of a photocell. The primary separation step results in three components: a leukocyte-poor red-cell suspension in SAGM medium, CPD plasma, and a buffy-coat preparation. The system has been tested in two laboratories (lab A and lab B). A 'heavy-spin' centrifugation to obtain a maximum yield of cell-poor plasma gave the best removal of leukocytes from the red cells; the remaining leukocyte content was 0.46 +/- 0.25 (lab A) and 0.5 +/- 0.4 (lab B) x 10(9)/red-cell unit. Platelet concentrates can be prepared either the normal way via platelet-rich plasma or from buffy coat. Red-cell 24-hour autologous posttransfusion survival using labeling with 51Cr was 87.5 +/- 4.1% (lab A) after 35 days, and 84.2 +/- 4.2% (lab A) and 77.5 +/- 1.5% (lab B) after 42 days. Red-cell morphology and fluidity compared favorably to previous studies using the same additive solution in traditional plastic-bag systems. The total adenine nucleotide concentration was maintained normal for 42 days.(ABSTRACT TRUNCATED AT 250 WORDS)

2,3-Diphosphoglycerate↗
PubMed1988

Distribution of blood gases, glucose and lactate within stored blood units.

The distribution of respiratory gases, hydrogen ions, glucose and lactate were studied in red cells suspended in SAGM solution and stored undisturbed at +4 degrees C in plastic (PVC) bags. After 42 days' storage there were considerable concentration differences between the supernatant and the red cell layer, as well as concentration gradients within the latter. Thus, pO2, sO2, pH and the glucose concentration were higher in the supernatant and pCO2 and the lactate concentration were higher in the red cell layer. These findings show that sampling from the mixed content of blood which has been stored sedimented in plastic containers will not be representative for the erythrocyte environment at the end of shelf life. This is of importance in attempts to understand storage effects on red cells.

Blood Banks↗
PubMed1988

Secretory pattern of growth hormone regulates plasma concentration of pregnancy-associated murine protein-1 in the non-pregnant rat.

Serum concentrations of pregnancy-associated murine protein-1 (PAMP-1) were followed in hypophysectomized adult female rats during treatment with oestradiol and continuous or intermittent human growth hormone (hGH). After hypophysectomy a rapid decrease in PAMP-1 values was recorded while concentrations of albumin and the acute phase alpha 2-macroglobulin were unaffected. PAMP-1 values were completely restored by continuous infusion of hGH (1.4 i.u./kg/day). Neither the same dose of hGH given as two daily injections nor oestrogen replacement treatment had any effect. It is concluded that the serum concentration of PAMP-1 in the non-pregnant rat is regulated by the sexually dimorphic secretory pattern of GH.

Animals↗
PubMed1988

Continuous 24-hour secretion of growth hormone during late pregnancy. A regulator of maternal metabolic adjustment?

A dramatic change in growth hormone secretion was demonstrated during the 3rd trimester of human pregnancy, when compared with the non-pregnant state. The pulsatile pattern, with intermittent high peaks, and low or undetectable levels between peaks, characteristic of normal men and non-pregnant women, was completely abolished. All the 10 pregnant women investigated had the same stable basal circulating growth hormone concentration. Values were in the range 6-10 mU/l and there was no evidence of pulsatile activity. Previously, in animal experiments, a continuous secretion of growth hormone has been shown to 'feminize' hepatic steroid metabolism, hepatic prolactin receptors, hepatic sulphatase activity and to stimulate pregnancy protein synthesis. The same biological principle could be valid also during human pregnancy and be related to maternal metabolic adjustment.

Circadian Rhythm↗
PubMed1988

Growth hormone secretion during termination of pregnancy. Further evidence of a placental variant.

Serum profiles of growth hormone (GH), hPL and hCG were recorded in 5 pregnant women during termination of pregnancy at cesarean section and legal abortion. Two monoclonal antibodies directed against different epitopes on the GH molecule were used to distinguish the pituitary 22K-GH from the placental GH variant. After placental removal at cesarean section, a rapid fall in GH as well as in hPL and hCG concentrations was recorded. On the other hand GH levels were unaffected when early pregnancy was terminated by legal abortion. The importance of an intact placental function for the maintenance of high GH levels lends further support to the concept that a placental GH variant is produced during late pregnancy.

Abortion, Induced↗
PubMed1988

Nocturnal asthma: effects of slow-release terbutaline on spirometry and arterial blood-gases.

The effect of terbutaline, in a slow-release preparation, on spirometry and arterial blood-gases, was studied in fourteen patients with nocturnal asthma. The patients were treated with either 15 mg of slow-release terbutaline or placebo given as a single dose at 10 pm for eight days in a double-blind crossover trial. The patients were studied in the hospital for one night at the end of each treatment period. During active treatment the patients had a significantly higher FEV1 and PaO2 compared with placebo. Tolerance to the high single dose was good and none of the patients discontinued treatment because of side-effects. In patients with nocturnal asthma treatment with a high dose of slow-release terbutaline given as a single dose in the evening appears to be effective.

Asthma↗
PubMed1987

Tracers for aerosol ventilation scintigraphy: Tc-99m versus In-113m.

113mIn has been proposed as a suitable tracer for aerosol ventilation scintigraphy in combination with 99mTc pulmonary perfusion scintigraphy. The high energy (393 keV) of 113mIn allows it to be detected in the presence of 99mTc, but degrades the spatial resolution which can be achieved. We have compared the resolution obtained with 99mTc and 113mIn in phantom experiments and in aerosol ventilation scans in 14 patients with airways disease. The resolution at the distances from the collimator encountered in lung scintigraphy was 10-20 mm for 99mTc and 15-40 mm for 113mIn. Aerosol ventilation images were abnormal in all patients. The 99mTc images showed peripheral defects and frequently central hot spots reflecting increased local aerosol deposition. In the 113mIn images, the lower resolution had a smoothing effect, the central hot spots were less striking, and the distribution of activity appeared more uniform, some detail was lost in the periphery. It is suggested that 113mIn is useful for ventilation scintigraphy in the diagnosis of pulmonary embolism, but that 99mTc is the tracer of choice if aerosol ventilation scintigraphy is used to study airways disease.

Female↗
PubMed1987

The normal pituitary examined with positron emission tomography and (methyl-11C)-L-methionine and (methyl-11C)-D-methionine.

Four patients with radiologically normal pituitary gland were examined with positron emission tomography after the administration of (methyl-11C)-L-methionine. On a following day the examination was repeated with (methyl-11C)-D-methionine. The accumulation rate of L-methionine in the pituitary was measured, giving a value that was about twice that of normal brain tissue. The accumulation rate of D-methionine in the pituitary was almost a factor of 10 lower than that of L-methionine. In the normal brain tissue that ratio was 2.3. The study clearly indicates that the methionine uptake in the pituitary is stereospecific. 11C-D-methionine is freely distributed in the tissue without entrapment, whereas 11C-L-methionine is irreversibly bound. It is concluded that PET with 11C-L-methionine can be used to study amino acid utilization in the pituitary.

Adult↗