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Biomedical subjects

S Andreasson

Publications and source records attributed to S Andreasson.

At least 37 records · Page 2Linked to original sources
PubMed1990

Effects of exposure to welding fume: an experimental study in sheep.

Welding fume contains various metals and pulmonary effects from their inhalation are largely unknown. We have studied the effects of exposure to welding fume in sheep. The animals were exposed to either a bolus dose of welding fume solution or to five weeks daily exposure. Lung physiology parameters were studied and biopsies taken. Magnetopneumography was used to register the longterm exposure. Acutely exposed animals had elevated pulmonary arterial pressure. Arterial oxygen tension was reduced after fume instillation. These animals had accumulation of iron (Fe), magnesium (Mg) and manganese (Mn) in the lungs. Mn was elevated 40 times. Longterm exposed sheep increased the iron oxide accumulation significantly in lungs as seen with the magnetopneumographic technique. Following long term exposure, Mn was the metal most heavily retained in the lungs. Metals like Mn, Fe and Mg retained in the lungs can possibly give negative health effects. Besides this, the metals could be used for quantitation of welding fume exposure.

Air Pollutants, Occupational↗
PubMed1989

Oleic acid reduces pulmonary microvascular sieving capacity in sheep.

Changes in pulmonary microvascular permeability in sheep, after oleic acid injection, were studied using estimations of the osmotic reflection coefficient (sigma d) for total protein, albumin, immunoglobulins (Ig) G and M and calculation of the equivalent small and large pores of the microvessels. A chronic lung fistula was prepared in eight sheep. After a base-line period, left atrial pressure (Pla) was increased. Oleic acid (0.05 mg/kg body wt) was injected after a filtration-independent state had been obtained, and the spontaneously ventilating animals were then followed for 2 h. The sigma d for the normal lung was 0.65 +/- 0.03, 0.59 +/- 0.02, 0.72 +/- 0.04, and 0.84 +/- 0.02 for total protein, albumin, IgG, and IgM, respectively. The equivalent pore radii were 54 and 225 A. After oleic acid infusion, arterial pressure and arterial O2 tension decreased and leukocytes and platelets were consumed. At the end of the experiment, sigma d's were 0.27 +/- 0.04, 0.24 +/- 0.07, 0.33 +/- 0.06, and 0.55 +/- 0.04 for total protein, albumin, IgG, and IgM, respectively. The equivalent pore radii were 54 and 275 A, and the number of large pores was increased by 195%. The results indicate that oleic acid produces an increased vascular permeability by increasing the size and the numbers of large pores of the pulmonary microvascular walls.

Animals↗
PubMed1989

Proteolytic and lysosomal enzymes in acute trauma-induced lung injury in sheep.

Surgical preparation of a lung lymph fistula in sheep was previously shown to induce temporary permeability disturbance of pulmonary microvessels. Flow and composition of lung lymph were compared in 19 sheep with acute, and 16 with chronic lymph fistula. Lymph and plasma were analyzed regarding activities of prothrombin, antithrombin III, prekallikrein, kallikrein, functional kallikrein inhibitors and 11 acid hydrolases of lysosomal origin. Levels of prothrombin and antithrombin III fell postoperatively in plasma and reached even lower values in lymph, indicating systemic activation of the coagulation system as well as local activation in the lung. The studied components of the plasma-kallikrein system were unchanged. Lysosomal enzymes were released in lung lymph, reflecting cell injury in the lung. Local activation of proteolytic enzyme systems thus occurs in the lung after trauma. Analysis of organ-specific lymph (= interstitial fluid) may contribute to better understanding of the pathophysiology of trauma.

Animals↗
PubMed1988

Alcohol and mortality among young men: longitudinal study of Swedish conscripts.

The association between alcohol consumption and 15 year mortality was studied in a cohort of 49,464 Swedish conscripts, mostly aged 18-19. A strong association was found. The relative risk of death among conscripts with a high consumption of alcohol (greater than 250 g/week) was 3.0 (95% confidence interval (2.3 to 4.1) compared with those with moderate consumption (1-100 g/week). After adjustment for social background variables the relative risk was reduced to 2.1 (95% confidence interval 1.4 to 3.2). Among causes of death a strong predominance was found for violent death, suicide or probable suicide being the leading single cause and accounting for 236 (36%) of all deaths. The reported U shaped curve for total mortality was not confirmed, though when violent deaths were excluded a U shaped curve was suggested for other causes of death. These findings provide important epidemiological data on the drinking habits of young people and the consequences for mortality.

Accidents, Traffic↗
PubMed1988

Local pulmonary activation of proteolytic enzymes after Escherichia-coli-induced lung injury in sheep.

Activation of several cascade systems, e.g. coagulation, fibrinolysis, kallikreinkinin, complement and eicosanoid systems, has been implicated in the etiology of septic-lung microvascular injury. A chronic lung lymph fistula preparation in sheep (n = 9) was used to study coagulation, kallikrein-kinin and eicosanoids during Escherichia coli septicemia. Lung lymph flow and lymph composition indicated an increased lung microvascular permeability approximately 2 h after infusion of bacteria. Stable prothrombin and antithrombin III levels in lymph contradicted local activation of the coagulation cascade in the lung and systemic activation was not evident until 4 h after bacteria infusion. Lymph thromboxane B2 and 6-keto PGF1 alpha peaked early (1 h). Reduced lymph prekallikrein and kallikrein inhibitors indicated local activation of this system in the lung. Systemic activation of kallikrein could not be demonstrated. Thus, (1) changes in systemic blood may not adequately reflect local events and (2) studies of proteolytic enzymes and other inflammatory mediators in lung may contribute to clarifying the etiology of microvascular injury.

Animals↗
PubMed1988

Comparison between surgeons and general practitioners with respect to cardiovascular and psychosocial risk factors among physicians.

The incidence of mortality from ischemic heart disease in Sweden has been reported to be elevated for surgeons in comparisons with most other groups of physicians. The objective of the present investigation was to compare cardiovascular risk factors and psychosocial work characteristics of surgeons and general practitioners, the latter having a substantially lower rate of ischemic heart disease. A random sample of 36 male surgeons and 30 male general practitioners was selected. The results showed no clear-cut differences in physiological risk factors. Overall mental strain was greater among the surgeons, as was the inability to relax after work, perceived work tempo, and total number of workhours. There were significant associations between psychosocial work characteristics and traditional cardiovascular risk factors, and the study gives further support to the validity of using long-term glucose markers, such as fructosamine, as indicators of metabolic stress.

Coronary Disease↗
PubMed1988

Combined monitoring of thoracic duct and lung lymph during E. coli sepsis in awake sheep.

A thoracic duct lymph fistula in combination with a lung lymph fistula in the awake sheep was used to evaluate effects of thoracic lymph diversion during a septic insult and to monitor systemic and local changes in the lung and gastrointestinal tract. Live Escherichia coli 10(9) kg-1 b.w. were infused in 9 sheep. After sepsis, arterial pressure, cardiac output, partial pressure of oxygen, leukocytes and platelets decreased significantly compared to baseline values. Pulmonary arterial pressure increased significantly throughout the experiment with peak values at 44 +/- 4 mmHg after 15 minutes. Lung lymph flow (QL) (n = 6) increased from 23 +/- 0.5 to 11.2 +/- 2.4 ml/30 minutes after 60 minutes. QL then decreased but remained elevated. Lymph to plasma protein concentration ratio (L/P) in lung lymph decreased from 0.62 +/- 0.02 during baseline to 0.47 +/- 0.04 after 60 minutes. L/P then increased and was, after 150 minutes, no longer different from baseline. These lung lymph data favor increased pulmonary microvascular permeability during sepsis. Lymph flow in the thoracic duct (QT) (n = 9) increased from 34.2 +/- 6 to 58.3 +/- 9 ml/30 minutes during the first 30 minutes after bacterial infusion. QT was, after 90 minutes, back to baseline but then progressively increased. L/P in thoracic lymph steadily increased from 0.56 +/- 0.03 to 0.78 +/- 0.04. Thromboxane B2 and 6-keto PGF1 alpha in thoracic duct and lung lymph increased significantly after bacterial infusion and remained elevated thereafter. Combined monitoring of thoracic duct and lung lymph enabled comparison of systemic and pulmonary reactions in septic sheep.

Animals↗
PubMed1987

Lysosomal enzyme pattern in lung lymph and blood during E. coli sepsis in sheep.

Systemic release of lysosomal enzymes and local release in the pulmonary microcirculation from sequestrated and activated leucocytes could be an important factor in the development of the lung microvascular injury seen after septicaemia. The maximal activities of 11 lysosomal acid hydrolases (acid phosphatase, alpha- and beta-glucosidase, alpha- and beta-galactosidase, alpha-mannosidase, beta-acetylglucosaminidase, beta-glucuronidase, arylamidase and cathepsins B and C) were measured in serum and lung lymph from seven sheep before and after infusion of live E. coli bacteria. In the early phase of septicaemia (the first hour) the activities of eight enzymes were increased in serum and/or lung lymph (1.1 to 2X pre-infusion values). In the late phase, 3-4 h after sepsis, there were significantly elevated serum activities of beta-glucosidase (5.4X), alpha- and beta-galactosidases (2.7X, 1.5X), beta-acetylglucosaminidase (2.0X) arylamidase (1.2X) and cathespin B (1.7X). In lymph acid phosphatase (1.7X), alpha- and beta-glucosidases (1.6X, 6.4X), alpha- and beta-galactosidases (2.1X, 1.7X). Beta-acetylglucosaminidase (2.6X), and beta-glucuronidase (4.0X pre-infusion) were elevated. The findings of a heterogenicity of changes in serum and lymph activities, as well as the large molecular sizes of some of the enzymes with changed activities indicated to us that permeability changes were not major causes of increased lymph enzyme activities. The results could indicate a local release of enzymes either from sequestrated leucocytes or lung tissue due to local reactions in the lung or lung microvessels. The heterogenous changes in activities for the various lysosomal enzymes as found in the present study indicated that measurement of only one enzyme could be misleading.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Effects of rectal thiopentone and methohexitone on carbon dioxide tension in infant anaesthesia with spontaneous ventilation.

The influence of rectal administration of barbiturates on PCO2 during mask anaesthesia with spontaneous ventilation was studied in 72 infants. The age of the patients ranged between 6 and 24 months and they were all subjected to minor paediatric surgery. The patients were divided into four equally large groups: a control group receiving no premedication, a group receiving rectal thiopentone 30 mg X kg-1 and two groups receiving methohexitone either 20 or 30 mg X kg-1. In all patients PCO2 was measured in an arterialized capillary blood sample obtained during stable anaesthesia with oxygen, nitrous oxide and halothane before and after surgery. After rectal induction with barbiturates, the mean PCO2 was significantly higher in the different barbiturate groups than in the control group (P less than 0.05). The mean PCO2 value +/- s.d. in kPa for the control group was 5.6 +/- 0.7, for the group receiving thiopentone 30 mg X kg-1 6.5 +/- 1.6, for the groups receiving methohexitone 20 or 30 mg X kg-1 6.1 +/- 1.2 and 6.3 +/- 1.1, respectively. It is concluded that the combination of rectal induction with barbiturates and mask anaesthesia with oxygen, nitrous oxide and halothane carries an increased risk of hypoventilation in infants under 2 years of age.

Administration, Rectal↗
PubMed1987

Sepsis in sheep reduces pulmonary microvascular sieving capacity.

The changes in pulmonary microvascular permeability in sheep, after infusion of live Escherichia coli, were studied using estimations of the osmotic reflection coefficients (sigma) for total protein, albumin, immunoglobins (Ig) G and M and based on these estimations equivalent pore dimensions were calculated. A chronic lung lymph fistula was prepared in seven sheep. After a base-line period, left atrial pressure (Pla) was increased. E. coli (10(9) X kg body wt) were given after attaining filtration independent L/P values. The sigma's for the normal lung were calculated to 0.73 for total protein and to 0.65, 0.76, and 0.91 for albumin, IgG, and IgM, respectively. The equivalent pore radii were determined to 50 and 175 A with 35% of the filtration accounted for by the large pores. After bacterial infusion, the sigma's for total protein, albumin, IgG, and IgM decreased significantly from preseptic values to 0.58, 0.50, 0.64, and 0.83, respectively. After sepsis the small pores were 50 A and the large pores 200 A with 49% of total volume flow at maximum lymph flows occurring through the large pores. Assuming a constant small-pore population the large-pore number increased 32% after bacterial infusion. These results indicate that pulmonary microvascular permeability may have increased due to the sepsis.

Animals↗
PubMed1987

Estimation of equivalent pore radii in pulmonary microvasculature after lung lymph fistula preparation.

The effect of lung lymph fistula preparation on pulmonary microvascular permeability was investigated in sheep. Acutely prepared animals (n = 9) were compared with animals with a chronic lung lymph fistula (n = 5). The osmotic reflection coefficients (sigma) for total protein, albumin, immunoglobins (Ig) G and M, and the equivalent pore dimensions were calculated. Data were achieved at maximal possible lymph flows (QL) following elevation of left atrial pressure. In sheep with a chronic lung lymph fistula sigma's for total protein, albumin, IgG, and IgM at maximal lymph flows were 0.76 +/- 0.01, 0.65 +/- 0.09, 0.79 +/- 0.03, and 0.91 +/- 0.01, respectively. In the acutely prepared group the minimum lymph-to-plasma protein concentration for total protein was 0.39 +/- 0.06, corresponding to a sigma of 0.61 +/- 0.01. The sigma for albumin, IgG, and IgM were 0.48 +/- 0.04, 0.64 +/- 0.02, and 0.87 +/- 0.01, respectively. The equivalent pore radii in the chronic group were determined to be 54 and 190 A with 29% of the filtration accounted for by large pores. In the acute group the small pores were 56 A and the large pores 175 A with 53% of total volume flow at maximum lymph flows occurring through the large pores. Assuming a constant small-pore population the large pore number increased 4.5 times after surgery. For total protein, IgG, and IgM, sigma's in the acutely prepared group were significantly lower than in the control group. These results thus indicate that surgical preparation of a lung lymph fistula in sheep may cause acute increases in pulmonary microvascular permeability.

Animals↗
PubMed1986

Extravascular lung water measurement in septic sheep.

Sheep were prepared with a chronic lung lymph fistula and studied unanesthetized following septicemia by infusion of live Escherichia coli 10(9) ml/kg bw or injection of oleic acid 0.05 ml/kg bw. Extravascular lung water (EVTV) was measured with thermal-dye technique and compared to gravimetrically measured lung water (EVWV). Septic sheep had increased pulmonary artery pressure, reduced mean arterial blood pressure and reduced cardiac output. In control animals there was a correlation between EVTV-EVWV of r = 0.70. In animals given oleic acid lungs were macroscopically edematous and the correlation was r = 0.93. In septic sheep, however, no correlation could be found between EVTV and EVWV (r = -0.25). The thermal-dye technique was found to give erroneously high values. This finding could probably be due to erythrostasis and leukocyte plugging with uneven perfusion and prolonged transit times due to reduced cardiac output.

Animals↗
PubMed1986

The pulmonary microvascular response to infusion of live Escherichia coli in sheep with acutely or chronically prepared lung lymph fistula.

The effects of infusion of live Escherichia coli bacteria in awake sheep with a chronic lung lymph fistula (n = 15) were compared to anesthetized animals (n = 7) receiving the same septic insult after surgical trauma including bilateral thoracotomies for lung lymph cannulation (acute group). During preseptic baseline conditions, pulmonary arterial pressure (Ppa) and central venous pressure (Pcv) were increased and leukocytes decreased in the newly operated animals compared to the sheep with a chronic lung lymph fistula. After i.v. infusion of live E. coli 10(9) X kg-1 b.w. over 20 min, arterial pressure (Psa), cardiac output (Qt), leukocytes, and partial pressure of arterial oxygen (PaO2) decreased in both groups. Ppa peaked after 15 min at 37.2 +/- 2.5 in the chronic and 33.4 +/- 3.3 mm Hg in the acute group. In the chronic group, Ppa remained elevated but not in the acute group during the rest of experiment. Lung lymph flow (QL) increased significantly in both groups during the initial high Ppa, but it increased to a higher level in the chronic group. After 150 min, QL did not differ between the groups but remained elevated over baseline. Lymph-to-plasma concentration ratio (L/P) for total protein decreased in the chronic group during the initial high QL. This decrease was not seen in the acute group that had a significantly higher L/P between 30 and 120 min after sepsis. The high QL with unchanged L/P compared to baseline indicated increased permeability in the pulmonary microvessels in both groups but the changes in permeability, hemodynamics, or respiratory parameters after sepsis were not aggravated by the surgical trauma.

Acute Disease↗
PubMed1986

No protection in sheep by high-dose methylprednisolone against pulmonary microvascular injury following trauma.

The osmotic reflection coefficient (sigma) of the pulmonary microvessels in sheep was estimated after a preparative trauma, and the effect of a single, high (30 mg kg -1 b.w.) dose of methylprednisolone (MP) (n = 7) compared to a dose of normal saline (S) (n = 8) was evaluated. After bilateral thoracotomies for lung lymph cannulation and placement of a balloon catheter in the left atrium, the animals were followed during anesthesia for 1 hour. Left atrial pressure (Pla) was then increased and 2 levels of filtration-independent lymph to plasma protein concentration ratio (L/P) were recorded. After the operation leukocyte and platelet counts in both groups decreased significantly. Lung lymph flow (QL) increased during the first hour without hemodynamic changes, whereas L/P decreased in the MP group but was unaffected in the S group. Partial pressure of oxygen (PaO2) was spontaneously improved postoperatively in the MP group but remained unchanged in the S group. The 2 levels of filtration-independent L/P were reached at Pla 28.7 +/- 2.8 and 34.3 +/- 1.6 mm Hg in the MP group and 25.6 +/- 2.2 and 31.3 +/- 1.3 mm Hg in the S group. QL increased by 500 +/- 80% (n = 7) and 930 +/- 210% (n = 7) at the 2 levels of increased Pla with unchanged L/P at 0.44 +/- 0.03 and 0.46 +/- 0.04, respectively, in the MP group. Corresponding values in the S group were a 590 +/- 160 (n = 5) and 730 +/- 180% (n = 3) increase in QL with L/P 0.41 +/- 0.02 and 0.40 +/- 0.03, respectively. sigma in the MP group was 0.54 +/- 0.04, and sigma in the S group was 0.62 +/- 0.02, which was not significantly different. Thus pretreatment with MP did not prevent the development of a permeability lesion following surgical pulmonary trauma, but an early minor protective effect of MP could not be ruled out.

Animals↗
PubMed1985

The role of high dose corticosteroids (HDC) in pulmonary capillary-alveolar membrane integrity.

Disturbed microvascular integrity is an initial event in the development of respiratory insufficiency following trauma and shock. Increased permeability in the pulmonary microvessels has been demonstrated in both experimental animals and in man. High dose corticosteroids have been used to prevent the development of the permeability lesion and to reduce it once it has occurred. Data from experimental animals are indicative of a positive effect of HDC and in patients with adult respiratory distress syndrome leakage of macromolecules over the capillary alveolar membrane was reduced significantly. Using the lung lymph fistula preparation in sheep we have demonstrated that the pulmonary microvascular sieving capacity was reduced (as indicated by a reduced osmotic reflection coefficient) following the operative trauma and manipulation of lungs necessary for cannulation of the lymphatics. We studied the effects of HDC (methyl-prednisolone 30 mg/kg) given preoperatively in 7 operated sheep and compared to 3 nonoperated controls. Permeability surface area product (PS) and osmotic reflection coefficient (sigma) for total protein were calculated by iterative curve fitting using the non-linear flux equation and data were compared to sigma achieved at maximal lymph flow following increased left atrial pressure. After surgery there were no differences between the two groups in baseline observations. In the experimental group lymph to plasma ratio for total protein (L/P) at maximal lymph flow was 0.46 +/- 0.09 corresponding to a sigma of 0.54. Maximal lymph flow was attained at microvascular pressure (Pmv) 38 +/- 2 mmHg. Calculated sigma was 0.61 +/- 0.03 and PS 0.09 +/- 0.01. Corresponding values in the control group were 0.69 +/- 0.003 and 0.1 +/- 0.0003 respectively. L/P at maximal lymph flow was 0.39 +/- 0.04 at Pmv = 35 +/- 6 mmHg in the control group. In this experiment HDC did not prevent the increase in pulmonary microvascular permeability as demonstrated after operative trauma by a decrease in the osmotic reflection coefficient for total protein. Data from patients indicate however, that HDC may have a beneficial effect on the integrity of the alveolar capillary membrane. Further studies are needed to elucidate these problems.

Animals↗