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Biomedical subjects

B Larsson

Publications and source records attributed to B Larsson.

At least 433 records · Page 24Linked to original sources
PubMed1975

Proton and heavy ion therapy.

Penetrating ion beams are considered interesting supplements to the types of radiation, mostly electrons and gamma rays, that have dominated in radiation research and radiotherapy during the last decades. Biomedical experimentations and clinical studies ar larger ion accelerators (100-1000 MeV/amu) are therefore undertaken in order to exploit their possible clinical use in cancer therapy. It is concluded that an accelerator that permits effective use of protons (ca. 200 MeV) and deutrons (ca. 50 MeV, for neutron therapy) located in a central hospital would represent a convenient tool for clinical investigations at a larger scale.

Humans↗
PubMed1975

Adipocyte metabolism in endogenous hypertriglyceridemia.

In order to define specific metabolic abnormalities of adipose tissue metabolism in endogenous hypertriglyceridemia (EH) patients with this condition were compared with normolipidemic controls matched for body fat and fat cell size. In vitro the enlarged fat cells of EH were found to have an increased basal and noradrenaline-stimulated lipolysis in comparison with cells of the same size from normolipidemic controls. The insulin inhibition of noradrenaline-stimulated lipolysis was blunted. Lipoprotein lipase activity in these cells was clearly depressed. Basal triglyceride synthesis from labeled glucose was low in relation to plasma insulin. The reduction of insulin tolerance in vivo suggested that the depression of plasma glycerol and free fatty acid concentration was small in EH, suggesting that the more detailed findings in vitro were of relevance for in vivo conditions. It was suggested that the hyperinsulinemia and decreased glucose tolerance of EH may well be responsible for some of the aberrations of adipocyte metabolism in EH. The decreased responsiveness of lipolysis to insulin and the low lipoprotein lipase activity are, however, findings not typical for enlarged fat cells exposed chronically to insulin and might be characteristic for the fat cells of EH. It seems of importance to further define the factor(s) responsible for these metabolic aberrations, because the abnormalities of the acipocyte metabolism in EH may well offer a possible explanation to the pathogenesis of that condition.

Adipose Tissue↗
PubMed1975

Effect of an energy-reduced dietary regimen in relation to adipose tissue cellularity in obese women.

Twenty-eight obese women were divided after arbitrary statistical guidelines obtained from control studies into hyperplastic (increase in fat cell number) (n equal to 10), hypertrophic obesity (increase in average fat cell size) (n equal to 11), and a remaining group (n equal to 7). All these subjects were treated on an outpatient basis with an energy-reduced diet (1,100 kcal/day) until weight decrease failure occurred. The fat cells of the femoral and gluteal regions were larger than in the abdominal region in hypertrophic obese subjects. This regional fat cell size profile was found also in middle-aged and young controls. The hyperplastic obese subjects on the other hand had larger fat cells in the abdominal site. At failure of therapy enlarged fat cells in either of the two obesity groups had decreased to the size of fat cells of controls. Fat cell number remained unchanged. Thus the hypertrophic obese patients ended up with a normal body fat while hyperplastic obese subjects had a pronounced remaining obesity. The results suggest that when the fat cell size in different regions of an individual are known, as well as the total fat cell number, the success of an energy-reduced dietary regimen might be approximately predicted both in terms of remaining total body fat and in regional fat depot decrease.

Adipose Tissue↗
PubMed1975

Influence of copper intrauterine contraceptive devices (Cu-7-IUD) on the menstrual blood-loss.

In a series of 43 healthy women menstrual blood loss was determined before and after insertion of copper IUD (Gravigard). The menstrual blood loss before insertion was compared with the blood loss 1, 2, 3, 4, 5, 6, 7 and 12 months after insertion. An increase amounting to approximately 20 ml per period without significant variations during the study was recorded. No significant influence upon serum iron and TIBC was found in 15 of the subjects selected by random. Compared with plastic IUD's the tested copper IUD causes a less pronounced increase of the menstrual blood loss. The menstrual blood loss in a small group of women with menorrhagia was determined before and up to 5 months after insertion of copper IUD. No aggravation of the menorrhagia was however recorded in this group.

Blood↗
PubMed1975

Influence of absorbed dose and field size on the geometry of the radiation-surgical brain lesion.

Specimens from a number of patients locally irradiated in the thalamus for intractable pain with a multiple gamma beam technique have been examined. The geometry of well circumscribed necrotic lesions was ascertained. No correlation was seen between the dimensions of the lesions and the size of the field, 3 mm X 5 mm or 3 mm X 7 mm, within the clinically useful dose range, 16 to 25 krad.

Adult↗
PubMed1975

Increased fibrinolytic activity in the endometrium of patients using copper-iud (gravigard).

The use of an IUD often causes an increase in the menstrual blood loss, and this is the most common reason for removing the device. The fibrinolytic activity of the endometrium was studied histochemically in 15 women before and after the use of copper-IUD for 2-5 as well as for 8-12 months. The fibrinolytic activity in the endometrium was found to be increased at both examinations. This increase is probably a contributory cause of the menorrhagia in patients with IUD. No significant difference in fibrinolytic activity was found between the two examinations after insertion of the IUD, which thus suggests that the increase in endometrial fibrinolytic activity was steady.

Adult↗
PubMed1975

Effect of copper and plastic intra-uterine devices on the fibrinolytic activity of the endometrium in the rat.

The effect of copper and plastic intrauterine devices (IUD) on the fibrinolytic activity of the endometrium was studied in the rat. A copper or a plastic device was placed in one of the uterine horns, while the other horn served as a control. Biopsy specimens were obtained from both horns and examined histochemically. The copper concentration was determined by atomic absorption spectroscopy. The fibrinolytic activity of the control horn was found to be localized to small vessels in the outer layer of the uterine wall, while that of the endometrium was low. Plastic as well as copper IUDs increased the fibrinolytic activity which, in contrast with what was seen in the controls, was localized to the endometrium. Compared with the effect of the plastic device, the increase in the fibrinolytic activity induced by the copper device was more widespread in the endometrial area and was accompanied by an increase in the concentration of copper. These findings might help to explain why the contraceptive effect of IUDs is more reliable when they are partly coated with copper.

Animals↗
PubMed1974

Irradiation of small structures through the intact skull.

The physical conditions for producing minute disc-shaped lesions for functional radiation surgery by means of narrow beam irradiation are discussed. The intention was a treatment procedure for routine clinical use and with high physical and mechanical reproducibility. The possibilities of using high energy electrons, supervoltage roentgen radiation, gamma emitting nuclides or fast neutrons in a technique for routine clinical use were investigated. The radiation of choice taking physical properties, radiation biologic factors and practical circumstances into account was considered to be 60-Co gamma radiation. A treatment apparatus containing 179 60-Co sources within a spherical sector of 70 degrees latitude and 160 degrees longitude was constructed.

Brain Diseases↗