PubMed Health⌕ Search

Biomedical subjects

L Mårtensson

Publications and source records attributed to L Mårtensson.

At least 19 recordsLinked to original sources
PubMed1999

Intestinal and hepatic perfusion and metabolism in hypodynamic endotoxic shock. Effects of nitric oxide synthase inhibition.

BACKGROUND: Inhibition of nitric oxide synthase (NOS) has been claimed to be beneficial in septic shock. We investigated the overall and regional effects of a NOS-inhibitor on perfusion and metabolism during severe endotoxic shock. METHODS: Nineteen anaesthetised pigs were catheterised and ultrasonic flow-probes were placed around the portal vein, the hepatic artery, and the superior mesenteric artery. Thirteen animals were given a 3-h infusion of endotoxin; in 6 of these an infusion of NG-nitro-L-arginine-methyl-ester (L-NAME) was started an hour after the start of endotoxin while 7 animals served as controls and received endotoxin only. Six animals were sham operated with no further intervention. RESULTS: Endotoxin produced a hypodynamic shock with pulmonary hypertension. L-NAME did not increase arterial blood pressure, but deepened the fall in cardiac output and enhanced the increase in systemic and pulmonary vascular resistance. The infusion of endotoxin caused a decrease in flows in all regions. The addition of L-NAME induced a further decrease in the mesenteric artery flow only. L-NAME had no additional effect on hepatic artery flow ratio, while a transient decrease was seen in mesenteric flow ratio. Portal flow ratio decreased in the control group only. Global as well as regional oxygen extraction increased in both groups, more so in the L-NAME group. Lactate levels increased with no differences between the groups. CONCLUSION: In hypodynamic endotoxic shock, L-NAME infusion enhanced pulmonary vasoconstriction and increased left ventricular afterload. The resulting hypoperfusion caused an increase in mortality. The effects of L-NAME on global and mesenteric blood flow and metabolism were similar, while L-NAME had no additional effects on hepatic hypoperfusion or oxygen extraction. Thus, nitric oxide does not seem to be a major factor in the preservation of hepatic perfusion during unresuscitated endotoxic shock.

Animals↗
PubMed1999

Labour pain treated with cutaneous injections of sterile water: a randomised controlled trial.

OBJECTIVE: To evaluate the relief of pain in labour with subcutaneous and intracutaneous injections of sterile water, compared with placebo. DESIGN: Randomised controlled trial. SETTING: Labour ward with approximately 3000 deliveries annually in a suburban area near Gothenburg, Sweden. PARTICIPANTS: Ninety-nine pregnant women at term, requiring pain relief for severe lower back pain during the first stage of labour. The women were randomised to receive four injections of 0.1 mL sterile water (without salt) intracutaneously (n = 33), four injections of 0.5 mL sterile water subcutaneously (n = 33) or placebo treatment (n = 33). MAIN OUTCOME MEASURES: Reduction of labour pain measured by visual analogue scale. RESULTS: The median visual analogue scale pain score for labour pain was significantly lower compared with initial values in the two study groups and compared with placebo at 10 and 45 minutes after treatment. The median reductions in visual analogue scores after 10 minutes were 5.0 cm and 4.5 cm in the intracutaneous and subcutaneous injection groups, respectively; women in the placebo group scored a median reduction of 1.7 cm. After 45 minutes the median reductions in the visual analogue scores were 4.9 cm and 4.0 cm in the intracutaneous and subcutaneous injection groups, respectively, compared with 1.0 cm for women in the placebo group. No significant differences in analgesic effect or pain experienced during administration were found between the two study groups. CONCLUSION: The new subcutaneous method of administering sterile water, as well as the earlier described intracutaneous injection method, were effective for the relief of pain in labour.

Adult↗
PubMed1997

A case of foodborne listeriosis in Sweden.

A 70-year-old woman fell seriously ill overnight with meningitis and was admitted to hospital. Cerebrospinal fluid culture yielded Listeria monocytogenes. One of the first problems in solving a human case of listeriosis suspected to be foodborne is to find the foods likely to have been transmitting L. monocytogenes. Two enrichment procedures and a direct plating procedure were used for isolation of the bacteria from different food items collected from the patient's refrigerator, local retail store and producer. Samples of vacuum-packed products of sliced pork brawn, sliced cooked medwurst and berliner wurst of the same brand harboured L. monocytogenes. Serotyping and restriction enzyme analysis (REA) with pulsed-field gel electrophoresis (PFGE) were used to characterize and compare 41 isolates, including the human strain. At least three clones were present in the foods investigated, and one of these was identical to the human clone. This clone was present in samples of medwurst from the patient's refrigerator and the local retail store. This is, to our knowledge, the first proven foodborne case of listeriosis reported in Sweden.

Aged↗
PubMed1997

Differential effects of nitric oxide synthase modulation on porcine systemic and pulmonary circulation in vivo.

OBJECTIVE: To study and compare the effects of inhibiting endothelial nitric oxide synthase on systemic and pulmonary circulation in an in vivo model. DESIGN: Prospective, randomized, controlled study. SETTING: Laboratory for experimental surgery at a university medical center. SUBJECTS: Seventeen anesthetized, mechanically ventilated pigs. INTERVENTIONS: To produce a stable and continuous stimulation of endothelial nitric oxide synthase, an infusion of acetylcholine was given to one group of animals (n = 5) in a dose that decreased mean arterial pressure by 15%. After 45 mins, N(G)-monomethyl-L-arginine (L-NMMA) was given in a dose of 3 mg/kg for 5 mins in order to inhibit the enzyme. A second dose of 10 mg/kg was given 30 mins later. L-arginine was then given in a dose of 100 mg/kg to reverse the inhibition. One group of animals (n = 6) received a single dose of indomethacin (2.5 mg/kg) 15 mins after the start of acetylcholine infusion. L-NMMA and L-arginine were then given. In a control group (n = 5), the effects of L-NMMA and L-arginine were studied without acetylcholine. Circulatory parameters were monitored and resistance indices were calculated via arterial, central venous, and pulmonary artery catheters. MEASUREMENTS AND MAIN RESULTS: In control animals, 3 and 10 mg/kg of L-NMMA induced an increase in mean arterial pressure of 14% and 25%, respectively, with similar increases in systemic vascular resistance. Mean pulmonary arterial pressure increased by 22% and 48%, respectively. Acetylcholine lowered mean arterial pressure by 15% and did not affect the relative changes induced by L-NMMA. Acetylcholine had no effect on pulmonary resting tone but enhanced the pulmonary hypertension and increase in resistance induced by L-NMMA. This enhancement was abolished by indomethacin, which produced systemic hypertension while no effect on pulmonary pressure was seen. CONCLUSIONS: A basal release of nitric oxide contributes to the maintenance of normal vascular tone in the anesthetized pig. Stimulation of endothelial nitric oxide synthase by acetylcholine did not result in any further pulmonary vasodilation as was seen in the systemic circulation. Inhibition of nitric oxide synthase had a greater effect on pulmonary pressure than on systemic pressure. However, this difference was abolished by the administration of indomethacin. Increased nitric oxide release or acetylcholine itself seems to stimulate the production of a vasoconstricting prostanoid in the pulmonary circulation.

Acetylcholine↗
PubMed1997

Generation of nitrate during dialysis as a measure of nitric oxide synthesis.

Nitric oxide (NO) is a recently identified messenger, which influences the local regulation of blood flow and platelets as well as neuronal and inflammatory pathways. Disturbed NO information might be involved in the uremic syndrome and might also cause hypotension during dialysis. To clarify these issues, we analyzed plasma and dialysis fluid concentrations of nitrate, the stable NO metabolite, in 9 patients during hemodialysis. Plasma nitrate was raised at the onset of dialysis as compared with healthy subjects (83 +/- 9 versus 26 +/- 2 mumol/L). The plasma concentration decreased to 20 +/- 2 mumol/L (p < 0.01) during the dialysis. The relative decrease was more pronounced than the relative reduction in creatinine, phosphate, and urea concentrations. A parallel decrease in nitrate was seen in effluent dialysis fluid (32 +/- 4 to 14 +/- 1 mumol/L; p < 0.01). Calculations of the amount of nitrate coming to and from the dialyzer were performed in 7 of the 9 patients, and in 5 of the 7 patients, generation of nitrate within the dialyzer could be postulated. This might explain the paradoxical venodilation noted during hemodialysis.

Aged↗
PubMed1997

Beneficial effect of cold dialysate for the prevention of hemodialysis-induced hypoxia.

Hypoxia occurs frequently during routine hemodialysis (HD). In this study the effect of dialysate temperature on arterial blood gas parameters was investigated. Ten stable HD patients (2 smokers) were dialyzed for 240 min with each of three different dialysate temperatures: 36.5 degrees C (normal temperature HD; NHD), 38.5 degrees C (warm HD; WHD) and 34.5 degrees C (cold HD; CHD). A cuprophane plate dialyzer was used. The ultrafiltration volume was identical in each patient. Arterial blood gas samples were frequently (approximately 10 times/treatment) taken during the dialysis and immediately analyzed. The dialysate temperature significantly affected PaO2 (p < 0.001) but not PaCO2. We also compared the effect of NHD with that of WHD and CHD, respectively, as regards PaO2. NHD and WHD differed significantly p < 0.01), whereas NHD and CHD were not significantly different. However, the relative PaO2 value (% of the baseline value) at the end of CHD (105 +/- 5%) was significantly higher than after both NHD (96 +/- 4%, p < 0.01) and WHD (91 +/- 3%, p < 0.01). In the case of NHD and WHD the fraction of time during which the patients had a PaO2 value below 80 mm Hg was 62 and 64%, respectively. The corresponding figure for CHD was 44%. Arterial oxygen saturation (SaO2) increased during CHD from 95.2 +/- 0.6 to 96.7 +/- 0.6% (p < 0.05), while SaO2 was unchanged during NHD and WHD. The positive effect of CHD was evident in 7 patients. In 1 patient PaO2 was not affected by the dialysate temperature, while in the remaining 2 patients (smokers) a decrease in PaO2 was induced by WHD as well as CHD. A separate statistical analysis with the 2 smokers excluded was performed, which showed that the dialysate temperature significantly affected PaO2 (p < 0.001). A comparison between NHD and CHD showed a significant difference (p < 0.001), whereas NHD and WHD did not differ significantly. When the 2 smokers were excluded from the analysis the fraction of time with a PaO2 value below 80 mm Hg was 60% during NHD and 56% during WHD, but it was reduced to 31% during CHD. In conclusion, despite the existence of interindividual variations most patients seemed to benefit from cold dialysate for the prevention of dialysis-induced hypoxia.

Adult↗
PubMed1996

Nitric oxide inhalation decreases pulmonary platelet and neutrophil sequestration during extracorporeal circulation in the pig.

OBJECTIVE: The inhibiting effect of nitric oxide on the aggregation and adhesion of neutrophils and platelets has been well documented in vitro. In vivo evidence, however, is more scant. In this study, we studied the effects of inhaled nitric oxide on pulmonary cellular sequestration in our sham hemodialysis model. Accumulation of neutrophils and platelets in the lungs has been shown to be an early event in this model. DESIGN: Prospective, randomized, controlled study. SETTING: Animal laboratory at a university medical center. SUBJECTS: Twenty-six anesthetized, mechanically ventilated pigs. INTERVENTIONS: 111Indium-oxine was used to selectively label neutrophils or platelets and the activity over the lungs was followed dynamically with a gamma camera. Sham hemodialysis, using a cuprophan hollow-fiber dialyzer, was instituted via catheters in the femoral vessels. The animals were divided into two main groups: a) the nitric oxide recipient group (n = 12, with platelets labeled in seven animals and neutrophils labeled in five animals); and b) the control group (n = 14, with platelets labeled in seven animals and neutrophils labeled in seven animals). The animals in the former group were given 50 parts per million of nitric oxide in the inspiratory gas from the beginning of dialysis and for 30 mins onward. MEASUREMENTS AND MAIN RESULTS: Inhalation of nitric oxide attenuated the increase in activity over the lungs in both the neutrophil and platelet groups during sham hemodialysis. In addition, an inhibiting effect on the increase in pulmonary pressure was noted. CONCLUSION: Apart from the effects of nitric oxide on central hemodynamics in this model, the scintigraphic findings indicate an in vivo effect of nitric oxide on the accumulation of platelets and neutrophils in the lungs, probably due to inhibition of the adhesion and/or aggregation of these cells.

Adhesiveness↗
PubMed1996

Fetal pulse oximetry. A methodogical study.

BACKGROUND: During recent years fetal pulse oximetry has been under development for use in monitoring fetal oxygenation during labor. In a methodological study we have tested the practical applicability of one type of sensor (FS-10 Oxisensor, Nellcor). Both obstetricians and midwives took active part in sensor placement. The readings of fetal arterial oxygen saturation (SpO2) were not taken into account when managing the patients. METHODS: Oxygenation was monitored during labor in 96 singleton pregnancies. Mean SpO2 levels were calculated when cervical dilatation was 4-7 cm and 8-10 cm, and in the second stage of labor. Student's t-test was used for paired comparisons. A p-value<0.05 was considered significant. RESULTS: Of the 96 oxisensors, 91 (95%) were successfully placed. One mother felt pain which disappeared when the sensor was removed. Two of the newborns manifested an impression mark caused by the sensor, which disappeared completely within a day. No infection or increased bleeding was noted. The mean recording time was 134 minutes. SpO2-values were obtainable during 69% of the recording time. A significant fall of mean SpO2 occurred between the first and second stages of labor. CONCLUSIONS: The method seems to be harmless for mother and child, and allows SpO2-values to be obtained during two thirds of the recording period. Further research is needed to evaluate the possible clinical value of the method.

Adolescent↗
PubMed1994

Iloprost attenuates trauma-related pulmonary sequestration of leucocytes and platelets.

The purpose of this study was to investigate the effects of iloprost, a synthetic prostacyclin analogue, on the pulmonary cellular trapping after a standardized soft tissue trauma. In two groups 1 and 2 iloprost was given in doses of 100 ng/kg/min commencing 30 and 20 min respectively prior to trauma and ceasing 10 min after trauma. 111Indium-oxine was used to label neutrophils in 6 animals from each group. Platelets were labelled in 6 and 7 animals respectively. A third group of 11 pigs served as a control and did not receive iloprost. The pulmonary sequestration of platelets and neutrophils was studied dynamically with a gamma camera and directly after trauma was significantly less in group 1 when compared to the control group. A rise in pulmonary vascular resistance and pulmonary arterial pressure was seen in the control group immediately after trauma but this was not evident in the iloprost groups. PaO2 decreased significantly in group 1 and 2 during the iloprost infusion. The results indicate that iloprost attenuates the pulmonary cellular sequestration and changes in central hemodynamics during trauma in this model.

Animals↗
PubMed1994

Circulatory and ventilatory effects of intermittent nitric oxide inhalation during porcine endotoxemia.

The effects of intermittent inhalation of 57 ppm nitric oxide (NO) were studied in eight anesthetized, ventilated pigs given a continuous infusion of Escherichia coli endotoxin. Seven animals served as controls. By administering NO synchronized with inspiration and close to the orotracheal tube, measurable amounts of the toxic metabolite, NO2, in the inspiratory gas mixture were avoided. No direct systemic effects of NO inhalation were seen, but through counteracting pulmonary vasoconstriction, a fall in cardiac output was delayed. Nitric oxide effectively attenuated the initial peak rise in mean pulmonary artery pressure and resistance, both returning to control levels after cessation of NO. These effects were reproduced during later phases of endotoxemia, giving further proof to the role of gaseous NO as a selective pulmonary vasodilator. Nitric oxide diminished pulmonary shunting, but unimpaired oxygenation was preserved only during the first inhalation period. Leukocyte counts decreased drastically and platelet aggregation was enhanced, but after 1.5 hours of endotoxin infusion, platelet hyperaggregation was maintained in the NO group while it decreased in the control group.

Administration, Inhalation↗
PubMed1994

Delayed decrease in plasma levels of atrial natriuretic peptide during cold hemodialysis.

The high plasma levels of the vasodilating hormone atrial natriuretic peptide (alpha-ANP), observed in patients with chronic renal failure, decrease substantially during hemodialysis (HD), probably owing to volume reduction. Cardiovascular stability is better maintained by the use of cold dialysate although underlying mechanisms are unknown. In order to investigate the effects of different dialysate temperatures on hemodynamic stability and plasma levels of immunoreactive ANP (p-irANP), 10 stable HD patients were dialyzed with bicarbonate dialysis fluid for 240 min with each of 3 different dialysate temperatures: 36.5 degrees C (normal HD; NHD), 38.5 degrees C (warm HD; WHD) and 34.5 degrees C (cold HD; CHD). A Cuprophan plate dialyzer was used. The ultrafiltration volume and ultrafiltration rate were identical in each patient during the treatments. p-irANP was determined by radioimmunoassay, using 2 antisera which different cross-reactivity to ANP-related peptides. During NHD a nonsignificant decrease in mean arterial blood pressure from 111 +/- 5 to 103 +/- 8 mm Hg was observed. A significant (p < 0.05) decrease in mean arterial blood pressure from 109 +/- 4 to 96 +/- 6 mm Hg occurred during WHD, while during CHD it remained stable (111 +/- 4 before, 112 +/- 5 mm Hg after). Irrespective of the dialysate temperature or the antiserum used, p-irANP decreased significantly (p < 0.05) during the treatment. The reduction in p-irANP was delayed during CHD, the decrease being significantly (p < 0.05) less pronounced after 120 min. At the end of the treatment no significant difference was observed between the regimes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Changes in plasma levels of vasoactive substances during routine acetate and bicarbonate hemodialysis.

Hemodynamic stability is better preserved during bicarbonate hemodialysis compared to acetate. We have studied the effects of bicarbonate (HDB) and acetate hemodialysis (HDA) on plasma levels of vasoactive substances. The treatments were performed for 270 min. A cuprophan plate dialyzer was used. The ultrafiltration volume and the ultrafiltration rate were identical in the individual patients during the two treatments. In the case of vasoconstrictors there was an increase in neuropeptide Y (NPY) (20%, p < 0.01) during HDB and arginine vasopressin (AVP) was unchanged. Unlike this was the response during HDA when there was no change in NPY and a decrease in AVP (38%, p < 0.01). An increase in noradrenaline (NA) (41%, p < 0.05) occurred during HDA different from what was the case during HDB. There was a gradual increase in renin (PRA) during both HDB (141%, p < 0.05) and HDA (148%, p < 0.01). With respect to vasodilators there were no differences between the two regimes regarding calcitonin gene-related peptide (CGRP) and motilin (MOT). The change in substance P (SP) during the treatments was also similar but somewhat more pronounced during HDB. Thus, an initial rise occurred (HDB, 81%, p < 0.01; HDA, 36%, p < 0.05) followed by a decrease (HDB, 26%, p < 0.05) or a tendency to decrease (HDA, 12%, p = 0.058) during the remaining part of the treatment. A rise in beta-endorphin (beta-END) occurred during HDB (10%, p < 0.05) but not during HDA. An increase in vasoactive intestinal peptide (VIP) occurred during HDB (27%, p < 0.05) different from the decrease during HDA (11%, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗
PubMed1993

Changes in plasma levels of vasoactive peptides during standard bicarbonate hemodialysis.

During bicarbonate hemodialysis, there is an increase in peripheral vascular resistance of nonadrenergic origin, counteracting the hypotensive effect of fluid removal during the course of the dialysis. In this study, the plasma levels of vasoactive regulatory peptides, noradrenaline and renin, were investigated in 11 patients with chronic renal failure during standard bicarbonate hemodialysis (STHD) for 270 min. As regards vasoconstrictors, an increase in gamma 2-melanocyte-stimulating hormone (gamma 2-MSH), neuropeptide Y (NPY) and plasma renin activity (PRA) occurred. However, arginine vasopressin and noradrenaline were unchanged. With respect to vasodilators, calcitonin gene-related peptide was not changed. An initial increase in beta-endorphin (beta-END) occurred, followed by a decrease during the remaining part of the treatment. Motilin decreased during the first part of the treatment but increased to the baseline level during the latter part. An increase in substance P was observed while vasoactive intestinal peptide decreased. We conclude that an increase in vasoconstricting substances (gamma 2-MSH, NPY, PRA) occurs during STHD, probably owing to the decrease in plasma volume. With the exception of beta-END, the changes in vasodilators were fairly small. The data suggest that vasoactive substances might participate in the hemodynamic response to hemodialysis.

Adult↗
PubMed1993

Changes in plasma levels of vasoactive peptides during sequential bicarbonate hemodialysis.

The hemodynamic response to isolated ultrafiltration (IUF) is characterized by a vasoconstriction, while there is no significant change in peripheral vascular resistance during isovolemic bicarbonate hemodialysis (IVHD). The present investigation was designed to study the plasma levels of vasoactive regulatory peptides together with noradrenaline (NA) and plasma renin activity (PRA) in 11 patients during sequential hemodialysis (SQHD) - IUF for 60 min, followed by IVHD for 210 min. During IUF, the vasoconstrictors arginine vasopressin (AVP), gamma 2-melanocyte-stimulating hormone (gamma 2-MSH), neuropeptide Y (NPY), NA and PRA increased. During IVHD, NPY and PRA remained unchanged on a higher level. A decrease in AVP below the baseline and in gamma 2-MSH and NA to the baseline levels occurred during IVHD. In the case of vasodilators, there were no changes in calcitonin gene-related peptide or motilin during SQHD. An increase in beta-endorphin (beta-END) occurred during IUF, followed by a decrease during IVHD. Substance P and vasoactive intestinal peptide were unchanged during IUF but decreased during IVHD. We conclude that SQHD is characterized by an increase in all the measured vasoconstrictors during IUF in response to loss of fluid, and by a decrease in some vasoconstrictors (AVP, gamma 2-MSH, NA) during IVHD. With the exception of beta-END, there were no changes or only minor ones in vasodilators during SQHD. There are changes in plasma levels of vasoactive substances during SQHD but the importance of these changes for the hemodynamic adaptation to ultrafiltration and dialysis needs to be studied further.

Adult↗
PubMed1993

Increased pulmonary platelet sequestration due to infusion of cold saline during extracorporeal circulation.

We have previously documented that neutrophils (polymorphonuclear leukocytes) aggregate in the lungs 10-15 min after the start of dialysis. The aim of the present study was to investigate the corresponding platelet reaction and evaluate the effect of prewarmed priming solution on this reaction. The animals were divided into two groups, each consisting of 6 pigs. In group 1 the priming solution was prewarmed to 36-38 degrees C whereas it was maintained at room temperature in group 2. Platelets were selectively labelled with 111In-oxine. The activity over the lung was followed dynamically with a gamma camera and already after 2 min a significant difference in platelet sequestration showed between the groups. A significant increase in pulmonary vascular resistance was noted in group 2, but not in group 1. In conclusion, platelet aggregation occurs early on during dialysis in this model. The results also indicate that prewarming the priming solution attenuates the pulmonary platelet sequestration and also seems to decrease the changes in central hemodynamics.

Animals↗