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Biomedical subjects

M Carlsson

Publications and source records attributed to M Carlsson.

At least 181 records · Page 10Linked to original sources
PubMed1985

Purification of in vitro produced mouse monoclonal antibodies. A two-step procedure utilizing cation exchange chromatography and gel filtration.

A method for production of purified and concentrated mouse monoclonal antibodies was developed. The rationale for the procedure is, firstly, to expand hybridoma cell number in culture medium-containing serum; secondly, to transfer the cells to serum-free medium for production of antibodies; and finally, to harvest antibodies from the conditioned medium by means of cation exchange chromatography on SP-Sephadex C-50, followed by gel filtration on Superose 6B. When compared with chromatography of monoclonal antibodies on protein A-Sepharose our results suggest that the method is particularly useful for purification of antibodies of the IgG1 subclass. Experience from production and purification of 15 various monoclonal antibodies is reported.

Animals↗
PubMed1985

Rat brain serotonin: biochemical and functional evidence for a sex difference.

Male and female rats were compared with respect to brain serotonin (5-HT) levels, synthetic capacity, receptor sensitivity, and CNS functions. Levels of whole brain 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) were higher in females. The accumulation of 5-HT after treatment with the monoamine oxidase inhibitor pargyline alone and in combination with the 5-HT precursor L-tryptophan was greater in females than in males. 5-HT increased and 5-HIAA decreased to the same extent in both sexes after administration of the 5-HT agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT). The temperature fall after all drug treatments was greater in females, but the "5-HT behavioural syndrome" was more pronounced in females merely after pargyline plus tryptophan; the behavioural response after 8-OH-DPAT did not differ between the sexes. These results are indicative of sex differences in the brain 5-HT neuronal systems. They are discussed in relation to differences between males and females in sexual behaviour, aggression and affective disorders.

Animals↗
PubMed1985

Evaluation of an apparatus for continuous monitoring of gas exchange in mechanically ventilated patients.

Indirect calorimetry has been integrated with a commercially available ventilator, permitting continuous monitoring of energy expenditure and respiratory quotient. This equipment, the ventilator Erica, the Engström metabolic computer EMC and the carbon dioxide analyzer Eliza (Gambro Engström AB, Sweden) was evaluated in laboratory tests and in critically ill patients. In the laboratory evaluation, the variability in FIO2 was less than 0.05% at FIO2 less than 0.47. The linearity error of the oxygen sensor and the CO2 analyzer was less than 0.06%. The variability of the oxygen sensor was 0.01% O2 and of the CO2 analyzer 0.04% CO2. The CO2 analyzer was sensitive to oxygen concentration and underestimated CO2 concentration by 3.3% at FIO2 = 0.5 if calibrated on room air. The pneumotachometer was oxygen dependent and overestimated inspired volume by 5.5% at 100% O2, if calibrated on room air, and was negligibly affected by changes in minute volume or PEEP within the physiological range for adults. In the patient evaluation, 15 measurements of gas exchange were performed in 9 critically ill patients and the results were compared with data obtained simultaneously by the Scholander technique or mass spectrometry. The standard deviation of the mean difference in comparison with the reference methods was 9.4% for O2 uptake, 6.6% for CO2 elimination, 12.5% for respiratory quotient and 3.9% for minute volume. Paired t-test analysis showed no systematic difference between the various methods. It is concluded that the EMC has an accuracy sufficient for clinical use and represents a commercially available technique of potential clinical value.

Adult↗
PubMed1985

Overestimation of caloric demand in a long-term critically ill patient.

This case report deals with a clinical situation in which an alteration in the nutritional regimen based on indirect calorimetric monitoring may have promoted recovery. A 43-year-old man with a history of acute haemorrhagic pancreatitis, intra-abdominal sepsis, and requirements of mechanical ventilation and total parenteral nutrition over 9 weeks was studied metabolically by means of indirect calorimetry in an attempt to interpret his clinical condition, which was characterised by difficulties in weaning off the ventilator, jaundice and muscular wasting. The caloric load was found to be 56% above measured energy expenditure. The respiratory quotient (RQ) was > 1, indicating the presence of lipogenesis. An alteration in the nutritional regimen based on these findings was followed by a decrease in RQ and a rapid improvement in spontaneous breathing and clinical condition. These results suggest that monitoring of gas exchange in the long-term critically ill patient may be of great importance as a means of avoiding detrimental effects of inadequate nutritional therapy.

Journal Article↗
PubMed1984

Clinical implications of continuous measurement of energy expenditure in mechanically ventilated patients.

Energy expenditure was monitored in 20 critically-ill mechanically ventilated patients using the Siemens-Elema Oxygen Consumption Calculator (OCC 980). Energy expenditure was measured continuously over the 24-h period in all patients (altogether, over 2500 patient hours; range 48-288 h). A predicted energy expenditure was calculated for each patient from standard tables for basal metabolic rates modified according to previously published reports on the influence of trauma, infection and elevated body temperature. For all patients combined, the agreement between the predicted and the measured energy expenditure was good. However, in individual patients the measured energy expenditure varied between 48 and 148% of the predicted value. The measured energy expenditure in surviving traumatized and/or septic patients correlated well (95-100%) with the predicted value at the time when weaning off the ventilator could be initiated. On the first day of measurements, the energy expenditure (in % of the predicted value) in the six patients who later died was significantly lower than in surviving patients (84 +/- 6 vs 107 +/- 2%; p < 0.01). Over a 24-h period, energy expenditure, defined as the value noted during a stable 30-40-min period of measurement, varied between 12 and 50% in the individual patients. This study shows that energy expenditure cannot be accurately predicted in the individual patient, that an energy expenditure below predicted values appears to be indicative of a poor prognosis and that short periods of energy expenditure monitoring may fail to reflect 24-h conditions.

Journal Article↗
PubMed1984

Does iron deficiency in treated polycythemia vera affect whole blood viscosity?

The relation between whole blood viscosity and iron status was studied in 11 patients with polycythemia vera (PV) who were treated with venesection without iron supplementation. Six were already iron deficient at the start of the study, five were followed from normal iron status to deficiency. Iron status was investigated with serum ferritin, erythrocyte protoporphyrin, mean cell volume and mean cell hemoglobin. There was no correlation between whole blood viscosity at a fixed erythrocyte volume fraction of 44% and any of these variables. The mean whole blood viscosity during iron deficiency and during normal iron state did not differ. Even after several months of iron deficiency there was no increase in whole blood viscosity. It is concluded that iron deficiency in treated PV does not give increased whole blood viscosity.

Anemia, Hypochromic↗
PubMed1981

Influence of exogenous substrates on adenosinetriphosphate (ATP) concentration in normal and diabetic rat aorta in vitro.

In diabetic rat aorta glucose metabolism is impaired and changes in the activities of several enzymes are found. The aim of this study was to investigate whether the metabolic alterations in diabetic vascular tissue influence energy production. Aortas of normal and diabetic male Sprague-Dawley rats were incubated in vitro for up to 120 min with various substrates added to the incubation medium. Diabetes was induced by streptozotocin and the rats were used after a diabetes duration of two weeks. When normal and diabetic aorta were incubated in the presence of 5.6 mmol/l glucose no significant difference in ATP-concentration was found after 60 min while after 120 min the ATP-concentration was lowered in diabetic aorta. Addition to the incubation medium of a substrate mixture containing amino acids in the same concentrations as in rat plasma, 3 mmol/l DL-beta-hydroxybutyrate and 1.5 mmol/l palmitate increased the ATP-concentration, measured after 120 min, in diabetic aorta but not in normal aorta. No significant difference in ATP-concentration was found between normal and diabetic aorta incubated in a medium containing all substrates. When diabetic aorta was incubated with each substrate separately beta-hydroxybutyrate but not glucose, palmitate or amino acids, increased the ATP-concentration to about the same level as the complete substrate mixture. The results suggest that the ability to utilize glucose for ATP production is impaired in diabetic vascular tissue and that other substrates such as ketone bodies are of importance for energy production in diabetic vessels.

Adenosine Triphosphate↗