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Biomedical subjects

L Eriksson

Publications and source records attributed to L Eriksson.

At least 217 records · Page 12Linked to original sources
PubMed1987

Characterization of the proteolytic compartment in rat hepatocyte nodules.

Persistent liver nodules (hepatocyte nodules, neoplastic nodules) were produced in rat liver by intermittent feeding with 2-acetylaminofluorene. Dense bodies (secondary lysosomes) were purified and characterized from the nodules. The purity of the dense body fraction was 90%. The levels of various lysosomal enzyme activities were lower in these dense bodies in comparison with dense bodies from control liver. Similarly, protein degradation was 50% lower in dense bodies from liver nodules than in control liver. The number of autophagic vacuoles (AVs) in the nodular tissue increased considerably after 3 h vinblastine treatment. We have taken advantage of this expansion in an effort to isolate these organelles from liver nodules. Autophagic vacuoles have been isolated recently from liver and kidney but not from putatively premalignant liver nodules. Fraction purity of AVs from liver nodules was 95%. As with dense bodies, AVs from nodular tissue displayed lower activities of proteinases and lower rates of protein degradation when compared with their counterparts from normal liver tissue. Accordingly, the lower rate of overall protein degradation in liver nodules can be ascribed to a decrease in lysosomal activity. A diminished autophagic sequestration capacity is the most plausible explanation for the decreased rate of proteolysis in cells. This could conceivably give these nodular cells a growth advantage and assist in their selective outgrowth as well as in their transformation from neoplastic into true cancer cells.

2-Acetylaminofluorene↗
PubMed1987

Destructive lesions of the mandibular condyle following diskectomy with temporary silicone implant.

Dacron-reinforced silicone is widely used as disk-replacement implant material in the temporomandibular joint. A retrospective radiographic analysis was undertaken in a series of thirty-two patients on whom diskectomy had been performed. Twenty patients had received temporary silicone implants, whereas twelve patients had surgery without disk-replacement implants. Six of the patients with implants had destructive lesions of the mandibular condyles at follow-up examinations, but no such lesions were seen in any of the patients who had surgery without implants. Histologic analysis of material removed from one patient who had a second operation showed multiple particles of foreign material surrounded by focally marked inflammatory reaction with foreign body granulomas. The underlying cartilage and bone showed focal resorption and bone destruction. Electron microscopy combined with energy-dispersive x-ray microanalysis showed that the foreign material contained silicone. It was concluded that the radiographically observed destructive lesions of the mandibular condyle may be a sign of a reactive synovitis induced by silicone particles abraded from the silicone implant.

Adult↗
PubMed1987

Effect of adenosine on human cerebral blood flow as determined by positron emission tomography.

The effect of intravenous infusion of adenosine on CBF was studied in seven patients with cerebral arteriovenous malformation. The patients were examined with positron emission tomography with controlled ventilation using [15O] water and [11C] fluoromethane as tracers. Total and regional CBF were determined before and during infusion of adenosine at rates producing a reduction of the MABP by approximately 10-40%. Six patients were normoventilated, and one was hyperventilated. Mean CBF in areas with normal brain tissue was 54 ml/100 g/min before adenosine infusion under normoventilation. Adenosine infusion increased mean CBF with 23-85%. Mean CVR was decreased with 43-65% and exceeded the percentage reduction of MABP in all normoventilated subjects. In the hyperventilated patient, the reduction of CVR was similar to the reduction of MABP, and CBF was unaffected, except for the 30% increase in the thalamus. It is concluded that intravenous administration of adenosine produces marked cerebral vasodilation in normoventilated subjects and that this response can be counteracted by hyperventilation.

Adenosine↗
PubMed1987

Cardiovascular and allied actions of xylazine and atropine in the unanaesthetized goat.

The cardiovascular effects of xylazine and atropine, separately and in combination, were studied in goats. Methylatropine was used to distinguish between the central and peripheral effects of atropine. Mean arterial blood pressure and heart rate were recorded, and the sedative effect and changes in respiration and salivation noted. Intravenous infusion of xylazine (2.4-80.0 micrograms/kg) decreased mean arterial blood pressure and heart rate in a dose-dependent manner. Single intravenous injections of both atropine sulphate (0.1 mg/kg) and methylatropine bromide (0.05 mg/kg) increased blood pressure and heart rate. After methylatropine, tachycardia lasted twice as long as after atropine. Following atropinization, a potentiated rise in mean arterial blood pressure was present during the infusion of xylazine (80 micrograms/kg). Xylazine-induced bradycardia was reversed by both atropine and methylatropine. The action of atropine is presumed to be primarily peripheral because of the similar effects with methylatropine. Xylazine-induced sedation was dose dependent. At the highest dose the goats were unable to stand for 30-60 min, respiration became irregular with periods of apnoea, and saliva started to drip a few minutes after infusion without increased salivation. Atropine had no visible effect on the sedation, pattern of respiration or saliva dripping effect of xylazine.

Animals↗
PubMed1987

Studies on the mechanism of human red cell loss of viability during storage at +4 degrees C in vitro. III. Effects of mixing during storage.

Red cells supended in saline-adenine-glucose-mannitol solution were stored for 42 days at +4 degrees C. One portion was packed by centrifugation and stored unmixed; the other portion was mixed once a week. Red cell fluidity and adenine nucleotide concentration were significantly lower in unmixed than in mixed units and also differed within the packed layer, showing a decrease towards the bottom. Hemolysis was 2.5-fold and microvesiculation 5-fold higher in cells stored unmixed. It is suggested that, during liquid storage, an early accumulation of acid metabolites in the bottom part of packed red cells may play an important role both for adenylate loss and microvesiculation, but lack of membrane-stabilizing action of diethylhexylphthalate may in part explain the latter. Both of these two changes are factors associated with impaired red cell viability. Mixing appears essential to optimize storage conditions for red cells.

Adenine Nucleotides↗
PubMed1987

Renal and hormonal responses to atrial natriuretic peptide infusions in goats on high and low sodium intake.

Synthetic atrial natriuretic peptide (ANP) was infused intravenously (1 microgram min-1; 60 min) in five goats during two series of experiments. For at least 4 weeks before the ANP infusions the goats received either no salt supplementation (= low sodium diet), or were given 16 g NaCl mixed with the food each day (Na = 274 mmol day-1; high sodium intake). The goats were changed between the treatments at random. ANP infusions caused diuresis, natriuresis and haemoconcentration during both diets. The urinary Na excretion increased about four-fold during the high sodium intake, and about 10 times during the low sodium intake. The urinary K excretion increased significantly during the low sodium diet, but decreased slightly during the high sodium intake. During both diets the K excretion became significantly lowered after the infusions. The mean glomerular filtration rate (GFR) was generally lower during the low sodium diet, but increased significantly during ANP infusions on both diets. The GFR returned to baseline immediately after the infusions, in contrast to urine flow and urinary Na excretion. Renal free water clearance increased slightly at the end of the infusion during the low sodium diet, but did not change during the high salt diet. Plasma renin activity (PRA) and plasma aldosterone concentration fell during ANP infusions in goats on the low sodium intake, but did not change significantly during the high sodium diet. These results indicate that the diuresis and natriuresis observed during intravenous ANP infusions in goats are mainly due to increased GFR.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗
PubMed1987

Relation between lung function, exercise capacity, and exposure to asbestos cement.

A group of 137 male workers with known exposure (mean 20 fibre years per millilitre) to asbestos cement who had symptoms or signs of pulmonary disease was studied together with a reference group of 49 healthy industrial workers with no exposure to asbestos. Lung function measurements were made at rest and during exercise. Evidence of lung fibrosis was found as well as of obstructive airways disease in the exposed group compared with the reference group. Asbestos cement exposure was related to variables reflecting lung fibrosis but not to variables reflecting airflow obstruction. Smoking was related to variables reflecting obstructive lung disease. Exercise capacity was reduced in the exposed workers and was related to smoking and to lung function variables, reflecting obstructive airways disease. There was no significant correlation between exercise capacity and exposure to asbestos cement.

Asbestos↗
PubMed1987

Oxygen desaturation during sleep and exercise in patients with interstitial lung disease.

The relations between mean and maximum fall in arterial oxygen saturation (SaO2) during sleep, hypoxaemia during moderate and maximum exercise, and lung mechanics were studied in 16 patients with interstitial lung disease. Mean and minimum SaO2 during sleep were significantly related to each other and to daytime oxygenation but not to lung mechanics. Although the maximum fall in SaO2 during sleep was similar to the fall during maximum exercise (a level seldom achieved during normal daily activities), profound hypoxaemic episodes during sleep were rare and brief and therefore contributed little to the mean SaO2. The fall in mean SaO2 during sleep was not significant and was considerably less than during moderate exercise (average 0.5 v an estimated 4.5%, p less than 0.05). It is therefore concluded that in patients with interstitial lung disease oxygen desaturation during sleep is mild and less severe than hypoxaemia during exercise.

Humans↗
PubMed1987

Measurement of lung density by x-ray computed tomography. Relation to lung mechanics in workers exposed to asbestos cement.

We measured lung density by means of x-ray computed tomography and lung mechanics in 33 workers exposed to asbestos cement and in 39 normal subjects. The exposed group showed evidence of lung fibrosis with reduced static lung volumes and lung compliance, although only three subjects had signs of interstitial fibrosis at standard chest radiography. Lung density was significantly increased in the exposed workers compared to control subjects, with greater differences between nonsmokers than between smokers. Lung density correlated inversely with static lung volumes. There was no appreciable difference in the regional distribution of lung density between exposed workers and control subjects. We conclude that lung density is often increased in workers with mild asbestosis, even in the presence of a normal chest radiograph. Measurement of lung density may be of value in the evaluation of asbestos-exposed workers for assessment of the extent of parenchymal disease.

Asbestosis↗
PubMed1987

Effects of oxygen and mixing on red cells stored in plastic bags at +4 degrees C.

When red cells are stored in plastic (PVC) containers the penetration of blood gases--O2 entering into and CO2 escaping out of the blood units--influences the red cell metabolism; ATP and energy charge are better maintained at anaerobic storage. When sedimented cells are stored unmixed, the blood gas diffusion is markedly restricted and the concentration of metabolites is rapidly increasing. This leads to disturbed metabolism, increased microvesiculation and decreased erythrocyte fluidity. In a blood transfusion service producing blood components, this is likely to have an important impact on the quality of the red cells. It seems advisable to store red cells in a sufficiently large volume of a suspension medium (such as the SAGM solution) and apply mixing during storage.

Blood Preservation↗
PubMed1987

Hemorrhagic cystitis--a manifestation of graft versus host disease?

In 125 allogeneic bone marrow transplant recipients conditioned with cyclophosphamide (CY) with or without total body irradiation (TBI), three different protocols for prevention of CY urotoxicity have been used. The three protocols consisted of forced alkaline diuresis alone and then in combination with mesna (sodium 2-mercaptoethane sulfonate) at a low or high dose (60-90% and 150% of the CY dose, respectively). Hemorrhagic cystitis (HC) occurred in 21 patients: there were four immediate episodes without subjective symptoms which healed within a week after starting CY and 20 late episodes, starting between 17 and 51 (median 27) days. There was no correlation between the occurrence of HC and the different protocols used for prevention of urothelial toxicity. Late HC, however, except in one patient, always appeared together with acute graft-versus-host disease (GVHD) and the severity of the HC correlated with the severity of the GVHD (p less than 0.001). When acute GVHD commenced the HC started within 24 hours in three patients and in 11 patients when the dose of prednisolone given for an ongoing GVHD was reduced. In four other patients CY was not used for conditioning, but mustargen or melphalan in combination with TBI. In this group no urothelial protection was used. One of these patients developed a severe HC together with a grade II GVHD. Adenovirus and cytomegalovirus infections were not associated with HC.

Acute Disease↗
PubMed1987

Results of temporomandibular joint diskectomies in Sweden 1965-85.

There have been divergent opinions about the prognosis of temporomandibular joint diskectomy. Therefore we have retrospectively evaluated all diskectomies performed in Sweden during the period from 1965 to 1985. Eighty-seven patients had been operated upon with this technique and 69, with a follow-up time of 6 months or longer (median 20 months), were analyzed. The median of maximal opening increased and 74% of the patients had less frequent and less intensive pain at the follow-up examination than before surgery. The overall results of the operations were good in 51% of the patients (none or mild pain and opening greater than or equal to 35 mm and horizontal movements greater than or equal to 5 mm), acceptable in 22% of the patients (none or mild pain and opening greater than or equal to 30 mm) and bad in 28% of the patients (severe pain or opening less than 30 mm). The preoperative pain was found to be more diffuse in the patients with bad postoperative results than in the patients with good and acceptable results. This emphasizes the importance of avoiding operating on patients with sources of pain and functional limitation other than the temporomandibular joint proper. The operation should be used restrictively and only on accurately diagnosed patients with severe pain and functional limitation that originate in the joint and have not been alleviated by adequate nonsurgical treatment. The risk of residual pain or limitation of opening should be included in the preoperative evaluation.

Adolescent↗
PubMed1987

Jaw fractures in Malmö 1952-62 and 1975-85.

The aim of this study was to compare frequency, etiology and location of jaw fractures in Malmö during the periods 1952-62 and 1975-85. The following statistically differences were found. The number of patients with jaw fractures increased from 1 to 2 per 10,000 inhabitants and year. The proportion of women increased from 18% to 26%. The proportion of fractures caused by violence increased from 26% to 44% while fractures caused by traffic accidents decreased from 41% to 22%. The proportion of maxillary fractures increased from 16% to 25%. The most striking findings in this study were that jaw fractures were twice as common in Malmö during the last decade as during the fifties and that violence replaced traffic accidents as the most common cause.

Accidents, Traffic↗
PubMed1987

Does mental activity change the oxidative metabolism of the brain?

Previous studies have shown that sensory stimulation and voluntary motor activity increase regional cerebral glucose consumption and regional cerebral blood flow (rCBF). The present study had 3 purposes: (1) to examine whether pure mental activity changed the oxidative metabolism of the brain and, if so, (2) to examine which anatomical structures were participating in the mental activity; and to examine whether there was any coupling of the rCBF to the physiological changes in the regional cerebral oxidative metabolism (rCMRO2). With a positron-emission tomograph (PET), we measured the rCMRO2, rCBF, and regional cerebral blood volume (rCBV) in independent sessions lasting 100 sec each. A dynamic method was used for the measurement of rCMRO2. The rCMRO2, rCBF, and rCBV were measured in 2 different states in 10 young, healthy volunteers: at rest and when visually imagining a specific route in familiar surroundings. The rCBF at rest was linearly correlated to the rCMRO2: rCBF (in ml/100 gm/min) = 11.4 rCMRO2 + 11.9. The specific mental visual imagery increased the rCMRO2 in 25 cortical fields, ranging in size from 2 to 10 cm3, located in homotypical cortex. Active fields were located in the superior and lateral prefrontal cortex and the frontal eye fields. The strongest increase of rCMRO2 appeared in the posterior superior lateral parietal cortex and the posterior superior medial parietal cortex in precuneus. Subcortically, the rCMRO2 increased in neostriatum and posterior thalamus. These focal metabolic increases were so strong that the CMRO2 of the whole brain increased by 10%. The rCBF increased proportionally in these active fields and structures, such that d(rCBF) in ml/100 gm/min = 11.1 d(rCMRO2). Thus, a dynamic coupling of the rCBF to the rCMRO2 was observed during the physiological increase in neural metabolism. On the basis of previous functional activation studies and our knowledge of anatomical connections in man and other primates, the posterior medial and lateral parietal cortices were classified as remote visual-association areas participating in the generation of visual images of spatial scenes from memory, and the posterior thalamus was assumed to participate in the retrieval of such memories.

Adult↗