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Biomedical subjects

N Lund

Publications and source records attributed to N Lund.

At least 73 records · Page 4Linked to original sources
PubMed1981

Tocopherol in irradiation of temporary hypoxic tumours.

The influence of tocopherol on the effect of local irradiation under induced ischaemia by temporary tourniquet of two rat tumours transplanted intramuscularly into one hindleg was evaluated. An impaired retardation of growth rate occurred in tumours irradiated under ischaemia. This effect was eliminated by pretreatment of animals with tocopherol. In separate experiments the method of inducing ischaemia was investigated by MDO-electrode measurements of tumour tissue oxygen pressure. A significant tumour hypoxia was found under tourniquet of the tumour-bearing leg of the animals. Pretreatment with tocopherol did not influence the tumour pO2.

Animals↗
PubMed1980

Anaphylactoid reaction to infusion of polygelatin (Haemaccel). A study in pregnant women.

A series of allergic reactions to infusion of polygelatin (Haemaccel) in six pregnant women is reported. These women and a control group of five pregnant women were studied with analysis of complement, ELISA and skin tests. No differences were found between the groups in the factors studied. It is concluded that the reactions to polygelatin were caused through direct liberation of histamine, that is, an anaphylactoid reaction.

Anaphylaxis↗
PubMed1980

Skeletal muscle oxygen pressure fields in rats. A study of the normal state and the effects of local anesthetics, local trauma and hemorrhage.

The MDO (Mehrdraht Dortmund Oberfläche) oxygen electrode was used for studies of oxygen pressure fields in rat skeletal muscle. With this multiwire oxygen electrode, the three-dimensional oxygen pressure field was measured and presented as a two-dimensional frequency distribution, i.e., a histogram. Statistical analysis of the histograms was carried out with the two-sample Kolmogorov-Smirnov test. This eliminated the influence of mean values, since these do not always represent the actual biological situation. The oxygen pressure fields in skeletal muscle of anesthetized normal rats breathing air spontaneously were investigated. When the oxygen pressure in the inspired gas was changed (50% and 95%), changes were seen in muscle oxygen pressure curves. The normal oxygen pressure field histograms were compared with those obtained after local anesthesia, after local trauma to the muscle and after hemorrhage. After local anesthesia the histograms were unchanged. Significant changes in the distribution types of the histograms were found after trauma in all rats studied. After hemorrhage significant changes, similar to those seen after trauma, were found in 15 of the 23 rats studied. Local blood flow was also measured with the 133xenon-clearance method in the hemorrhage experiments. No correlation was found between the changes in the mean oxygen tension values and the changes in 133xenon-clearance.

Animals↗
PubMed1980

Data acquisition and information processing in MDO oxygen electrode measurement of tissue oxygen pressure.

In 1956, CLARK presented the principle for the modern, membrane-covered, oxygen electrode, comprising the anode and the cathode within the same unit. A further development was the MDO (Mehrdraht Dortmund Oberfläche) oxygen electrode presented by LUBBERS & KESSLER during the 1960s. This electrode comprises eight separate measuring points for collecting statistical samples to calculate tissue oxygen pressure fields. In order to perform studies on humans and to enable fast presentation of measurement results, a system was developed including a PDP 11/03 D computer, which fulfils patient safety demands. The computer program included corrections for electrode drift and temperature influences, as well as statistical calculations including mean, standard deviation, skewness and kurtosis. Also included was the two-sample Kolmogorov-Smirnov test for comparison of tissue oxygen distributions. Experience from studies on humans has shown that the measurement system enables us to collect and read important patient data directly at the bedside in the intensive care ward.

Computers↗
PubMed1980

A technique for disinfection of the MDO oxygen electrode.

A method for disinfection and aseptic assembly of the MDO (Mehrdraht Dortmund Oberfläche) oxygen electrode has been evaluated. The method is based on treating each electrode component separately and then assembling the different parts under aseptic surgical conditions. The performance of the disinfected electrode was studied and found to be unchanged as compared with a non-disinfected electrode. Bacteriological studies on the effectiveness of the disinfection technique described and on the permeability of the electrode membranes to bacteria and bacterial spores were performed. The electrode membranes were penetrated by bacteria in experiments simulating in-use conditions in about 11% of membranes tested, after contamination of the inner electrode surface with heavy inocula. When studies were performed with the disinfected MDO oxygen electrode on humans, routine cultures from the wound were positive in about 10% of the cases. No clinical wound infection was seen. The majority of the positive cultures were probably caused by the surgical technique rather than the handling of the electrode. The disinfection method for the MDO oxygen electrode described in this paper makes it possible to use the electrode clinically, except in cases of hepatitis.

Bacterial Infections↗
PubMed1980

Skeletal muscle oxygen pressure fields in healthy human volunteers. A study of the normal state and the effects of different arterial oxygen pressures.

The MDO (Mehrdraht Dortmund Oberfläche)oxygen electrode was used for studies of tissue oxygen pressure fields (presented as histograms) in healthy human volunteers breathing room air and gas mixtures with different oxygen concentrations. Forearm blood flow measurements were performed with strain gauge plethysmography, and local blood flow and permeability-surface area product (PS) were studied by the clearances of 133xenon and 51Cr-EDTA. At ordinary arterial oxygen pressure levels the histograms were normal, i.e. their distribution type was approximately Gaussian. Higher arterial oxygen pressures caused changes in tissue oxygenation. However, at arterial oxygen pressure levels above 31 kPa two types of abnormal histogram distribution types were distinguished: scattered multi-population histograms (type a) and a type with predominantly low values (type b). Mean forearm blood flow showed only minor variations, whereas the clearances of 133xenon and 51Cr-EDTA were higher with higher PaO2. A parallel increase was also seen in PS.

Adult↗
PubMed1980

Skeletal muscle oxygen pressure fields in artificially ventilated, critically ill patients.

The MDO (Mehrdraht Dortmund oberfläche) oxygen electrode was used in a study of skeletal muscle oxygen pressure fields, presented as histograms, in critically ill patients artificially ventilated with gas mixtures of different oxygen concentrations. The histograms were compared with forearm blood flow measurements performed with strain gauge plethysmography. Local blood flow and permeability-surface area product (PS) were also studied by the simultaneous clearances of 133xenon and 51Cr-EDTA. The histogram distribution type was normal, i.e. approximately Gaussian, at arterial oxygen pressure levels between 10 and 18 kPa. At arterial oxygen pressures outside this range the histogram distribution types were abnormal, i.e. they showed a non-symmetrical distribution of oxygen pressure values, but their mean was approximately the same as in the normal histogram. However, there were significantly higher tissue oxygen pressure mean values in the patients (3.43 kPa) than in a group of healthy human volunteers (2.25 kPa). Mean forearm blood flow and the clearances of 133xenon and 51Cr-EDTA showed marked variations during the measurements both intraindividually and interindividually. Mean forearm blood flow and mean clearances of 133xenon showed opposite trends compared with arterial oxygen pressures. Mean clearances of 51Cr--EDTA and means PS showed only minor variations at the different arterial oxygen pressure levels.

Adult↗
PubMed1980

Effect of normovolemic hemodilution of skeletal muscle oxygen pressure fields in atherosclerotic mini-pigs. Preliminary report.

Normovolemic hemodilution with dextran-70 was carried out in 4 Göttingen mini-pigs with induced atherosclerosis. Hematocrit was lowered stepwise to 10--15%. Measurements of the skeletal muscle surface oxygen pressure fields were carried out using the MDO oxygen electrode. Results indicated an optimal PO2 histogram at hematocrit between 21 and 25%, with uniformly abnormal histograms at hematocrit 10%. Cardiac output determinations in 1 animal revealed an initial increase in stroke volume (Hct 29%) followed by increasing heart rate at lower hematocrits. The results indicate that normovolemic hemodilution can be tolerated even in the presence of experimental atherosclerosis and that the matter needs further clinical study.

Animals↗
PubMed1978

Influence of tocopherol on tumour cell oxygenation.

Tocopherol, a well known tissue anti-oxidant, given before local X-ray irradiation of 2 transplantable rat tumours was previously found to increase significantly the effect of irradiation. In the present study tocopherol did not influence the development of tumour necroses during growth of a transplantable rat hepatoma. The tumour tissue oxygenation of a transplantable rat sarcoma was neither found to be influenced by tocopherol. This suggests that an enhanced tumour radio-sensitivity by tocopherol is probably not explained by an influence on tumour cell oxygenation.

Animals↗
PubMed1975

Intercostal blocks with etidocaine. Preliminary report.

Although the results are few and should be considered as preliminary, the following conclusions may be drawn: 1. Etidocaine 0.5% and bupivacaine 0.5%, both with adrenaline (5 mug/ml), are comparable with regard to duration of sensory block. 2. Etidocaine 0.5% without adrenaline did not give the same duration of complete sensory block as when adrenaline was present. 3. Etidocaine 0.5% acts as a vasodilator at the site of injection. Adrenaline added to the solution counteracts the dilating effect. 4. Blood level studies of etidocaine do not at present show differences when 0.5% solution with or without adrenaline is used.

Acetanilides↗