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Biomedical subjects

O Jonsson

Publications and source records attributed to O Jonsson.

At least 91 records · Page 5Linked to original sources
PubMed1984

Evaluation of kidney viability during hypothermic perfusion or cold storage.

The effect of up to 6 days of hypothermic perfusion and up to 72 h of cold storage on tissue viability were studied from measurements of sodium potassium pump activity and adenosine nucleotide content. For the hypothermic perfusion two different albumin-based perfusates were used, one with, the other without addition of caprylic acid and amino acids. No difference could be found in the parameters studied between perfusion with these two perfusates. For both perfusates total adenine nucleotide content (TAN) decreased by approximately 60% during perfusion while energy charge potential (ECP) and the ATP/ADP ratio remained constant. During cold storage a decrease of both TAN and ECP and the ratio ATP/ADP was seen, the main decrease occurring within the 1st h. The transmembrane potassium influx as deduced from potassium content in incubated cortical slices during steady state conditions decreased during 6 days of hypothermic storage to 24.5 +/- 2.4 mumol/kg which was a significantly higher level than after 24 h of cold storage. Thus, addition of extra substrate to the perfusate does not seem to improve kidney cortex viability during hypothermic perfusion. Parenchymal viability is better preserved with continuous hypothermic perfusion, compared to simple cold storage in a solution of the same ionic composition as that used for perfusion.

Adenine Nucleotides↗
PubMed1983

Hypothermic perfusion of human kidney carcinoma: effects on viability and perfusate distribution.

A more deteriorating effect on tumour tissue than on normal renal parenchyma by hypothermic perfusion has previously been observed. The purpose of this study was to further evaluate changes in the perfusate distribution and the viability of normal cortical tissue and of kidney carcinoma during hypothermic perfusion. Tumour-involved kidneys obtained by nephrectomy from 12 patients were studied either with regard to viability, as measured with the Na+-K+ pump function in incubated tissue slices, or with regard to perfusate flow, as analysed with an isotope labelled microsphere technique. Six days of hypothermic perfusion decreased the potassium content in the tumour tissue, while it was mainly unchanged in the cortical tissue. The steady-state level of potassium in incubated slices reflected that the transmembrane K+ influx was unchanged after 6 days of perfusion in normal cortical tissue, whereas a significant reduction was observed in the tumour tissue. The relative perfusate flow in the tumour, when compared to the normal kidney cortex flow, was reduced from 60% after 1 hr of perfusion to 30% after 6 days of perfusion.

Adult↗
PubMed1983

Effects of free radical scavengers on renal circulation after ischaemia in the rabbit.

The intrarenal erythrocyte distribution, total renal blood flow and renal vascular resistance were studied before and during recirculation after 60 min of warm ischaemia in three groups of rabbits. One group was pretreated with superoxide dismutase, another with catalase and the third group was not pretreated at all. In non-pretreated ischaemic kidneys there was a significant trapping of labelled erythrocytes in the outer stripe of the medulla. This trapping was not seen in non-ischaemic control kidneys and was completely prevented by pretreatment with either superoxide dismutase or catalase. In non-pretreated ischaemic kidneys there was a transient increase in total renal blood flow during the first 5 min of recirculation, after which it returned to preischaemic values. After pretreatment with catalase the postischaemic increase in blood flow was more pronounced but again the blood flow returned to preischaemic values within 30 min. Pretreatment with superoxide dismutase resulted in a rapid postischaemic increase in blood flow which remained high throughout the 30 min period studied. The renal vascular resistance decreased initially during recirculation after ischaemia in both pretreated and non-pretreated kidneys. In the latter it returned to pre-ischaemic values within 10 min whereas a slower increase was observed after catalase pretreatment. After pretreatment with superoxide dismutase the resistance remained low during the 30 min recorded.

Animals↗
PubMed1983

Changes in intraerythrocyte content and transmembrane fluxes of sodium during salt loading in subjects with and without family history of hypertension.

We studied 17 young normotensive men with family history of hypertension (H) in two generations (father and grandfather) and 17 age matched control subjects (C) with respect to intraerythrocyte sodium (IeNa), sodium influx, and rate of sodium efflux. The investigation was done during ordinary salt intake and after four week's salt load. H had a significantly higher IeNa (9.5 +/- 0.4 mmol/l) compared to C (8.2 +/- 0.3 mmol/l), p less than 0.01. After salt loading H decreased significantly to 8.1 +/- 0.3 mmol/l while C did not change significantly (7.6 +/- 0.3 mmol/l). There was no significant difference between H and C in Na influx either on normal or on high salt intake. The rate constant for Na efflux was significantly lower on normal salt intake in H (0.0038 +/- 0.0003 vs 0.0050 +/- 0.0004 min-1, p less than 0.05). High salt intake increased the efflux rate constant significantly in H (0.0048 +/- 0.0003 min-1, p less than 0.05), while control subjects showed no difference (0.0053 +/- 0.0004 min-1) compared to pre-salt conditions. Our results suggest that young men with heredity for hypertension have a higher intraerythrocyte Na-content secondary to a lower rate of Na efflux. The Na influx did not differ between the two groups probably indicating an unchanged permeability for sodium in subjects with a family history of hypertension.

Cell Membrane Permeability↗
PubMed1983

Influence of age on the response to increased salt intake: effects on blood pressure and sodium in erythrocytes.

Blood pressure (BP), sodium in erythrocytes (IeNa) and transmembrane sodium fluxes were determined in normotensive 30 and 50-year-old men with a family history of hypertension (group H; n = 17 and 11 respectively) and without such history (group C; n = 15 and 26 respectively) during normal salt intake and after four weeks on ordinary diet plus 12 g NaCl daily. The 50-year-old men showed a significant increase in BP and weight during high salt intake while the younger men did not. On normal salt, group H had a significantly higher IeNa than group C in both age groups. In the younger group this was accompanied by a decreased Na efflux rate constant. IeNa decreased significantly in group H in both age groups. The decrease in IeNa and increase in pump activity in group H during high salt intake does not support the existence of a sodium transport inhibitor. The increase in BP in the older group during high salt indicates that age is an important factor in BP response.

Adult↗
PubMed1982

Electrically induced short-lasting tetanus of the calf muscles for prevention of deep vein thrombosis.

Electrical calf muscle stimulation during surgery has been used for the prevention of deep vein thrombosis (DVT) with varied results in several studies. This effect is mainly achieved by the reduction of venous stasis in the legs. Another possible beneficial effect might be an increased fibrinolytic activity of the blood secondary to the muscle contractions. Previously, single electrical impulses have been used for stimulation, giving rise to 'single twitches' in the muscles. In the present study the effect on calf volume of muscle stimulation with groups of impulses giving a short-lasting tetanus was investigated. Changes in calf volume were recorded by strain gauge plethysmography. Optimal values for duration, number and frequency of the impulses within the groups were determined. Stimulation with groups of impulses reduced calf venous volume approximately three times more efficiently than stimulation with single impulses. Calf muscle stimulation did not enhance the increase in fibrinolytic activity of venous blood observed after oesophago- or laryngoscopies under general anaesthesia.

Adult↗
PubMed1982

Prediction and prophylaxis of postoperative thromboembolism--a comparison between peroperative calf muscle stimulation with groups of impulses and dextran 40.

The effects of peroperative electrical calf muscle stimulation with groups of impulses giving a short lasting tetanus of the calf muscles on postoperative deep venous thrombosis (DVT) and pulmonary embolism (PE) were compared with that of dextran 40 given per and postoperatively. The incidence of DVT and PE during the first 4-6 postoperative days was recorded. The diagnosis of DVT was based on the 125I-fibrinogen uptake test and phlebography and of PE on pre- and postoperative perfusion pulmonary scintigram and chest X-ray examination. Both methods reduced the incidence of PE. Calf muscle stimulation reduced the DVT incidence in patients with malignant disease while the reduction in DVT incidence for the whole group only was significant in the stimulation as well as the dextran 40 group. Mean values for preoperatively determined levels of antithrombin III, beta-thromboglobulin, fibrinopeptide A, plasminogen and ability to release fibrinolytic activity during venous stasis did not differ between those patients who developed or those who did not develop postoperative DVT or PE. However, antithrombin III levels below 80 per cent appeared to predispose to postoperative thromboembolism. The two prophylactic methods have similar effects on the incidence of postoperative thromboembolism. The stimulation method has certain advantages due to its safety and simplicity.

Adult↗
PubMed1982

Metabolism in the hypothermically perfused kidney: utilization of mevalonate in the human and in the dog kidney.

The metabolism of mevalonate was studied in 6 dog kidneys and in 5 human tumour-involved kidneys during 6 days of hypothermic perfusion. 14C-mevalonate in the perfusate decreased and was incorporated into the total lipid fraction of the cortex in both human and dog kidneys. 80% of the incorporated radioactivity was found in the non-saponifiable lipids and after separation of that lipid fraction the radioactivity was recovered in cholesterol as well as in the cholesterol precursors lanosterol and squalene. Only very low levels of radioactivity were recovered in the tumour lipids. It is concluded that the kidney utilizes mevalonate for cholesterol synthesis during hypothermic perfusion and that addition of mevalonate may be of importance for preserving the membrane stability. Furthermore, it is suggested that hypothermic perfusion has a more deteriorating effect on the viability of the tumour tissue when compared to normal renal parenchyma.

Animals↗
PubMed1981

[Metabolic and circulatory aspects of hypothermic perfusion of human kidney cancers].

In this study a report is made on the hypothermal perfusion of 15 renal tumours. Protein synthesis by incorporation of 14C leucine, lipide synthesis by conversion of 14C mevalonic acid and the activity of the sodium-potassium pump by incubation of sections of tissue were used as parameters of the vitality of the tissue. Circulation was studied before and after perfusion by means of angiography and the microsphere technique. After 6 days of perfusion the tumour tissue is found to be less vital in comparison with the renal cortex.

Cold Temperature↗
PubMed1979

Metabolism in hypothermically perfused human kidney carcinoma: utilization and production of amino acids and glucose.

The metabolism of human kidney carcinoma was studied during hypothermic perfusion. Ten kidneys with carcinomas of different size were perfused in a Gambro perfusion machine for 6 days at +8 degrees C to +10 degrees C. The tumourous kidneys were allocated to one of two groups depending on the relative size of the tumour. Tumours occupying more than 40% of the total kidney volume were designated as "large tumours" and tumours occupying less than 40% as "small tumours". The net glucose uptake was greater during perfusion of kidneys with large tumours than during perfusion of kidneys with small tumours. A lower gluconeogenesis was found in kidneys with large tumours compared to perfusion of kidneys with small tumours and this could explain a large part of the difference in net glucse uptake. The uptake of fatty acids per unit kidney weight was lower during perfusion of kidneys with large tumours. A considerable uptake and release of amino acids were found in both groups. The uptake of proline, aspartate, glycine, and arginine as well as the release of alanine and serine was lower during perfusion of kidneys with large tumours. The nitrogen balance was negative in both groups, with a net release of amino acids to the perfusate. The results suggest a higher glucose uptake, a lower gluconeogenesis, a lower fatty acid uptake and a decreased metabolization of amino acids in the tumour compared to the renal tissue. The model appears promising for studies of human kidney carcinomas at various experimental conditions.

Aged↗
PubMed1979

Metabolism in hypothermically perfused human kidney carcinoma: incorporation rate of leucine into proteins.

Protein synthesis in tumour-involved human kidneys was studied before, during and after hypothermic perfusion. Before and after perfusion the incorporation rate of leucine into tumour and kidney cortex proteins was determined by incubation of tissue slices at 37 degrees C. During perfusion the incorporation of leucine from the perfusate into tumour and kidney cortex proteins was determined. Before hypothermic perfusion the incorporation rate of leucine into proteins at 37 degrees C was almost the same in kidney cortex and tumour. Leucine was incorporated linearly with time into kidney cortex and tumour proteins during hypothermic perfusion but the incorporation rate was 3-4 times higher into kidney cortex proteins than into tumour proteins. After 6 days of hypothermic perfusion the leucine incorporation rate into proteins at 37 degrees C was depressed by 50% in kidney cortex and by 90% in tumour tissue. The specific activity of leucine in the perfusate decreased during the perfusion period indicating a release of leucine from degradation of proteins. It is concluded that the effect of hypothermic perfusion on protein synthesis was more pronounced in the tumour than in the normal renal parenchyma.

Aged↗
PubMed1978

Effect of glucagon and blood transfusion on liver metabolism in hemorrhagic shock.

Treatment with glucagon in addition to blood transfusion was compared with blood transfusion alone after one hour of hemorrhagic shock in the rat. In liver tissue Na+ increased and K+ decreased during haemorrhagic shock. After treatment the initial values were restored equally in both groups within ten minutes. Incubation of liver slices in cold Krebs' solution resulted in a pronounced increase in Na+ and decrease in K+, the values being partially restored to initial levels after subsequent incubation at 37 degrees. Thirty minutes after treatment the liver slices obtained from rats given glucagon showed a more normal ion composition after leaching and rewarming than slices from rats not given glucagon. ATP decreased and glucose and lactate increased in liver tissue during hemorrhagic shock. These variables were partially restored 30 minutes after treatment. No difference between the treatment groups was noted. Animals trreated with glucagon were, however, more efficient in reducing the elevated blood lactate level. The results suggest that the use of glucagon in the treatment of hemorrhagic shock might be of benefit for cellular function in the liver.

Adenosine Triphosphate↗
PubMed1977

Metabolism in the hypothermically perfused dog kidney. Utilization and production of amino acids.

The uptake and utilization of amino acids in dog kidneys during hypothermic perfusion were studied. 21 kidneys were perfused in a Gambro perfusion machine for 6 days with perfusates based on human albumin with and without addition of 17 L-amino acids. Net glucose uptake by the kidney was lower during perfusion with amino acids in the perfusate than during perfusion without amino acids. A decrease in specific activity of labelled glucose was found during perfusion with amino acids in the perfusate indicating a considerable gluconeogenesis which could explain the difference in net glucose uptake. A higher uptake of fatty acids by the kidney was found during perfusion with amino acids in the perfusate than during perfusion without amino acids. In perfusion without amino acids the concentration in the perfusate of almost all amino acids and ammonia increased and thus a net release of nitrogen was found indicating degradation of protein. In perfusion with amino acids in the perfusate a considerable uptake and release of amino acids by the kidney were found. The most pronounced uptake was registered for glutamine, proline and glycine. The most pronounced release was registered for glutamate, alanine and ammonia. During perfusion with amino acids in the medium, the uptake and release of nitrogen were balanced as distinguished from perfusion without amino acids in the perfusate.

Alanine↗