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Biomedical subjects

S E Strand

Publications and source records attributed to S E Strand.

At least 91 records · Page 5Linked to original sources
PubMed1988

Thyroid uptake of iodine-131 and iodine-133 from Chernobyl in the population of southern Sweden.

The accident at the nuclear power plant of Chernobyl on April 26, 1986 led to radioactive contamination of many countries including Sweden. The population was exposed to released radionuclides, both by inhalation and from contaminated food. We have studied the content of gamma-emitting radioisotopes in the thyroid glands of a normal population from southern Sweden using measurements of samples taken at autopsy. The first samples are from a person who died on April 27, 1986. This report contains results for 131I and 133I. The time-activity curve for 131I shows an immediate uptake with a maximum 18-26 days after the accident. No measurable levels were observed after 93 days. We have found that the increase in dose equivalent to the thyroid for the population of southern Sweden due to the released 131I and 133I will be less than 0.1 mSv. This may lead to an increase in the incidence of thyroid cancer of 0.1% during a period of 25 yr.

Accidents↗
PubMed1987

Scintigraphic method to quantify the passage from brain parenchyma to the deep cervical lymph nodes in rats.

In order to investigate the kinetics of the passage from the brain parenchyma to the lymphatic system in vivo a high resolution scintillation camera technique was developed. Albumin, albumin colloids and dextran labelled with 99mTc were injected into the right side of the thalamus of anesthetized rats. Continuous measurement of the activity distribution in head and neck were performed for 70 min. Rate constants were calculated by means of a computer program for compartment analysis. The animals were killed 10 h postinjection, to measure the activity in tissue samples. For some animals, images were registered up to 24 h after injection. This work presents an in vivo technique to clarify the particle flow paths in the brain and make quantification possible. The method is simple and does not require continuous blood or lymph sampling. Our work shows that there is a substantial flow of injected material from the brain via lamina cribriformis to the lymphatic system. This route is of great interest for the drainage of the interstitial fluid of the brain. We have also shown a difference in flow for dextran particles with different charge.

Albumins↗
PubMed1987

Early post-traumatic changes in hemodynamics and pulmonary ventilation in alcohol-pretreated pigs.

Time relations among trauma, pulmonary and systemic circulation, and lung function were studied in pigs. Eleven animals (b.w. 25-30 kg) were investigated under balanced anesthesia. Ventilation was mechanically controlled. Hemodynamics, pulmonary ventilation, and gas exchange were serially recorded. Seven animals were pretreated with 40% ethanol in saline and four with saline only. Ninety minutes after the ingestion of alcohol or saline, the animals were subjected to a standardized soft-tissue trauma. Cardiac output decreased significantly 2 minutes after trauma and remained low in both groups throughout the observation period of 30 minutes. Pulmonary vascular resistance was significantly increased in the alcohol-pretreated group but was virtually unchanged in the control animals. Systemic vascular resistance was similarly reduced in the two groups. Total compliance was somewhat lower in alcohol-pretreated animals and 10 minutes after the trauma arterial oxygen tension was significantly lower in the alcohol group than in control animals. Carbon dioxide elimination was reduced after trauma in both groups. It is concluded that pulmonary vascular response increased and that total pulmonary compliance is somewhat decreased shortly after trauma in the alcohol group while gas exchange is almost unchanged. The results indicate a negative interaction between alcohol and trauma.

Alcoholic Intoxication↗
PubMed1987

The "critical colloid dose" in studies of reticuloendothelial function.

The [99mTc]sulfur colloid distribution in rat organs was investigated after the administration of different amounts of colloid particles. Saturation of the liver and spleen was not observed. Blood clearance was significantly reduced 15 min after injection above approximately 3 X 10(9) particles per kg body weight. With an increasing number of injected particles, lung uptake increased and bone marrow uptake decreased. Microfiltration studies showed that the colloid is unaffected by dilution with saline but may be affected after incubation in normal rat plasma. We conclude that the distribution of [99Tc]sulfur colloid in organs varies with the number of injected particles and therefore, is not dependent upon the blood flow to the reticuloendothelial organs alone. The "critical colloid dose" may differ among the reticuloendothelial organs and cannot, therefore, be evaluated by blood clearance measurements alone. The considerable influence of the number of injected colloid particles on bone marrow uptake should also be recognized when carrying out dosimetric calculations.

Animals↗
PubMed1986

Early posttraumatic pulmonary platelet trapping and its potentiation by oral pretreatment with alcohol.

Soft tissue trauma is associated with platelet aggregation and sequestration in the lungs. This is believed to be an early step in the later development of adult respiratory distress syndrome. In the present experiment using a new method for in vivo dynamic studies of platelet sequestration, we wanted to evaluate the effect of soft tissue trauma on pulmonary platelet trapping in pigs and the influence of acute alcohol intoxication. The results show that significant pulmonary platelet trapping is registered within minutes of trauma and that alcohol significantly increases platelet sequestration in the lungs. This indicates an increased risk for posttraumatic pulmonary problems in alcohol-intoxicated trauma victims.

Administration, Oral↗
PubMed1986

Healing of esophagojejunal anastomoses after experimental total gastrectomy. A comparative study using manually sutured or stapled anastomoses.

In construction of the eosphagojejunostomy after total gastrectomy, the EEA stapled (US Surgical Corporation, Norwalk, CT) and the two-layer interrupted 3-0 Dexon anastomoses are compared concerning the radiological appearance, breaking strength, circulation, and collagen concentration. Thirty female pigs were used. After total gastrectomy and Roux-en-Y preparation, the pigs were randomized to achieve sutured or stapled anastomoses. 141Ce-labeled microspheres were used for measurements of anastomotic blood flow. After the pigs were killed, the breaking strength of the anastomosis was recorded, the collagen content determined, and an anastomotic index calculated comparing two perpendicular diameters in the anastomosis and 5 cm above. Breaking strength, leakage frequency, and anastomotic index were the same in the two groups. One week after surgery, there was a significant increase in anastomotic circulation (p less than 0.05) in both the sutured and the stapled anastomoses compared to controls. Collagen increased equally with time in the two groups (p less than 0.01). The stapled esophagojejunostomy was faster to perform (20 min) than the sutured (28 min) (p less than 0.05).

Animals↗
PubMed1986

Oxidation of chloroform in an aerobic soil exposed to natural gas.

Acclimation of a sandy soil to an air-natural gas mixture stimulated the biological oxidation of chloroform to carbon dioxide. Acetylene and methane inhibited chloroform oxidation. Chloroform oxidation continued up to 31 days in the absence of methane. Chloroform oxidation rates increased at chloroform concentrations up to 5 mug g of soil.

Journal Article↗
PubMed1986

Effect of ticlopidine and prostaglandin E on endotoxin-induced pulmonary platelet sequestration in vivo.

Prostaglandin E1 has earlier been shown to decrease pulmonary platelet trapping (PPT) following shock. This experiment was performed to evaluate a new method to study PPT in vivo, and to study the effect of prostaglandin E1 and a new antiplatelet drug (ticlopidine) on PPT in rabbits after i.v. administration of endotoxin. Following platelet labeling with In-111, the rabbits were placed under a scintillation camera for continuous measuring of the activity distribution for 40 minutes. The first five minutes represented reference values, whereafter endotoxin E. coli was injected i.v. The following 2-4 minutes showed a sudden increase of radioactivity over the lungs and a simultaneous decrease over the heart, indicating PPT in the nontreated animals, followed by a slow decrease to almost preshock values during the following 30 minutes. Animals receiving prostaglandin E1 showed a significantly lower activity peak in the lungs after the administration of endotoxin, while the corresponding peak in ticlopidine-treated animals did not differ from that seen in the nontreated animals. In all groups, endotoxin caused a decrease in platelet count, but it was significantly lower in the PGE1-treated animals. The results have shown that this diagnostic model for PPT is reliable and may be used for evaluation of the effect on platelet aggregation in vivo of different drugs.

Alprostadil↗
PubMed1985

The early platelet uptake and distribution of platelets in small-diameter polytetrafluoroethylene (PTFE) vascular grafts in vivo.

Platelet deposition onto the surface of biomaterial is an important component of the interaction between blood and a prosthetic arterial graft. To understand the thrombotic process in small-diameter by-pass grafts, we used pigs to study the early in vivo uptake of 111In-oxine-labelled platelets in polytetrafluoroethylene (PTFE; GoreTex) grafts. In each experimental animal, 12 PTFE grafts (internal diameter, 3 mm; length, 5 cm) were placed in the femoral artery as interposition grafts. 111In-Labelled autologous platelets were injected. Sequential-scintillation camera images of the graft area were taken over a period of 3.5 h. Platelet deposition in vivo was calculated as an activity ratio for the entire grafts as well as for different segments of the graft. The grafts were harvested, cut into 0.6-cm pieces and weighed, and the 111In activity was measured. The distribution along the graft surface was calculated. Blood flow was measured continuously. The activity ratios rapidly increased, and a maximum was reached 60 min after the re-establishment of blood flow; thereafter the activity ratios slowly decreased. The distribution of platelets along the graft surface was found to be non-uniform where more platelets were deposited towards the distal anastomoses.

Animals↗
PubMed1985

A method for studies of tracheobronchial microvascular permeability to macromolecules.

Probably because of methodological problems, little is known about permeability to macromolecules and edema formation in the tracheobronchial microcirculation. A novel atraumatic technique of exposing the guinea pig airway mucosa to mediators has been developed. The intralumenal surface of the trachea and main bronchus is superfused (0.02 ml/min) via a thin plastic tubing introduced into the trachea through the mouth in anesthetized, tilted, and spontaneously breathing guinea pigs. Erythrocytes were labelled in vivo with Technetium 99m and individual hematocrit values and plasma concentrations of Fitc-dextran were determined. By quantification of content of a macromolecular tracer (Fitc-dextran MW 70,000) and blood pool in excised airway tissue the amount of extravasated macromolecules was calculated. In control animals where airways were superfused with saline (0.02 ml/min) during 30 min the extravasated amount of tracer was 0 +/- 14 micrograms/g trachea (n = 15), which was similar to what was found in animals without any superfusion (n = 6). Capsaicin 10(-6) M (total dose 0.1 nmol), probably by activating nerves, produced an extravasation of Fitc-dextran of 223 +/- 32 micrograms/g, n = 8, (p less than 0.005). In guinea pigs intubated for artificial respiration and prepared for vagal stimulation the base-line microvascular values were deranged, and large amounts of macromolecules leaked from the vascular compartment. Still, vagal stimulation in these animals produced further extravasation of macromolecules. It is suggested that atraumatic techniques such as the present superfusion method should be employed in studies of physiological and pharmacological control of permeability to macromolecules in the tracheobronchial microvasculature.

Animals↗
PubMed1984

Influence of a reticuloendothelial-suppressing agent on liver tumor growth in the rat.

Reticuloendothelial (RE) function was evaluated by measuring the biokinetics of a standardized 99Tcm-sulphur colloid. Methyl palmitate was administered intravenously on two consecutive days. A statistically significant reduction in the colloid uptake rate of the liver was registered after methyl palmitate administration. Histological examination revealed no signs of destruction of RE cells or microembolization. Inoculation of an experimental nitrosoguanidine-induced transplantable adenocarcinoma to the liver was performed in 16 rats one day after methyl palmitate administration and in 16 controls. Tumor size was significantly larger in methyl-palmitate-treated animals at 7 and 14 days after inoculation. Survival was significantly decreased in methyl-palmitate-treated rats. These rats showed signs of fatty vacuolization and necrosis of liver parenchyma earlier than controls. Analyses of beta-hexosaminidase and lactate dehydrogenase revealed no deviation of enzyme levels either before or after tumor inoculation. The results indicate that a temporary suppression of RE function at the time of tumor inoculation may influence subsequent tumor growth.

Adenocarcinoma↗
PubMed1984

Lymphoscintigraphy in patients with malignant melanoma: a quantitative and qualitative evaluation of its usefulness.

Lymphoscintigraphy using 99mTcSb2S3 colloid was performed in 32 patients with malignant melanoma. Subcutaneous injections were made peritumorally in 20 patients and dorsopedally in 12 patients. Regional lymph node dissections were carried out on the following day in 16 patients and the resected lymph nodes were weighted, measured for radioactivity, and examined by light microscopy. Lymph flow to regional lymph nodes was shown in all but 2 patients. Twenty-nine of 239 lymph nodes contained metastases. Radioactivity was demonstrated in 17 of these nodes. In 5 of 11 patients with metastatic disease, the highest uptake was found in cancerous lymph nodes. The specific activity-uptake distribution in isolated ilio-inguinal lymph nodes after a dorsopedal injection was log-normal with a mean of 0.05%/g indicating a good saturation of colloid particles. This investigation concludes that the observed lymph flow directions in patients injected peritumorally are of value for the follow-up. Quantitative lymphoscintigraphy in patients with melanoma of the lower extremities is, however, of no value for excluding ilio-inguinal lymph node metastases.

Animals↗
PubMed1984

An experimental method for in vivo studies of pulmonary platelet sequestration.

It has been reported in earlier in vitro studies that soft tissue trauma and endotoxin-induced shock causes pulmonary platelet trapping (PPT). This paper describes a noninvasive in vivo technique for dynamic studies of PPT in rabbits. Autologous platelets were labeled with 111In and reinfused into the animals. The following day, the rabbits were anesthetized and placed in a supine position under a scintillation camera. Continuous measurement of the activity distribution in the animal was performed for 35 min. The first 5 min represented a preshock measurement, whereafter endotoxin E. coli was injected IV. The following 2-3 min showed a sudden increase of radioactivity in the lungs indicating PPT, and thereafter a slow decrease to almost the preshock level. A simultaneous decrease in the number of platelets and the radioactivity in peripheral blood also indicated the induction of PPT. This study clearly shows that PPT can be detected in vivo with an easy, noninvasive scintillation camera method.

Animals↗
PubMed1984

Quantitative in vivo and in vitro comparison between radiolabelled colloids, biomolecules and blood cells in their ability to diagnose deep venous thrombosis.

Three radiopharmaceutical groups (colloids, specific biomolecules and blood cells) and a control group were investigated with regard to their ability to rapidly diagnose deep venous thrombosis in an experimental rabbit model. An artificial thrombus was induced in the jugular vein and the radiopharmaceuticals were injected either homolaterally or contralaterally relative to the thrombus. The accumulation of the radioactivity in the thrombus 30 min after the induction was determined in vivo from scintillation camera images. After dissection of the jugular vein, the radioactivity of the thrombus was measured in vitro. None of the investigated radiopharmaceutical groups showed any marked high thrombus uptake after contralateral injections, not even the groups that consisted of substances known to be actively involved in coagulation and fibrinolysis. The results exclude a high degree of specific interaction between the radiopharmaceuticals and the thrombus in our model. After homolateral injection only colloids and reduced 99Tcm-pertechnetate showed a high thrombus uptake, thus also excluding a specific binding to thrombus. This investigation shows that none of the specific radiopharmaceuticals had a greater ability to accumulate in the thrombus than the colloids, and it is therefore suggested that the clinical usefulness is due to other mechanisms, like circulatory changes secondary to the DVT.

Animals↗
PubMed1984

Aerobic microbial degradation of glucoisosaccharinic Acid.

alpha-Glucoisosaccharinic acid (GISA), a major by-product of kraft paper manufacture, was synthesized from lactose and used as the carbon source for microbial media. Ten strains of aerobic bacteria capable of growth on GISA were isolated from kraft pulp mill environments. The highest growth yields were obtained with Ancylobacter spp. at pH 7.2 to 9.5. GISA was completely degraded by cultures of an Ancylobacter isolate. Ancylobacter cell suspensions consumed oxygen and produced carbon dioxide in response to GISA addition. A total of 22 laboratory strains of bacteria were tested, and none was capable of growth on GISA. GISA-degrading isolates were not found in forest soils.

Journal Article↗
PubMed1983

Platelet adhesion in polytetrafluoroethylene (PTFE) vascular grafts in vivo and the influence of increased intramuscular pressure--an experimental model.

Thrombogenicity of graft material is involved in early graft failure in small diameter grafts. The frequently seen postoperative swelling of the leg after distal revascularization may cause an increased intramuscular pressure and early graft failure. Pairs of 4 mm polytetrafluoroethylene (PTFE) grafts were implanted. Autologous platelets were labeled with 111In-oxine. Platelet adhesiveness onto the grafts were analyzed from gamma camera images. Intramuscular pressures were measured with wick technique. Blood flow was measured. One graft served as control the other as test graft. Ninety minutes after declamping the i.m. pressure was increased in the test-leg to 30 mmHg, and later to 60 mmHg. In the control-graft platelet uptake increased to a maximum 60 min after declamping. Blood flow and i.m. pressure remained uneffected. The test-grafts were initially similar but when i.m. pressure was increased to 30 mmHg activity in the grafts increased significantly. Blood flow decreased with 12% of initial flow. When i.m. pressure was raised to 60 mmHg platelet uptake continued to increase. An increased intramuscular pressure of 30 mmHg or more significantly increase the amount of platelets adhering onto PTFE grafts, emphasizing the need for measuring intramuscular pressures after lower limb vascular revascularizations.

Animals↗