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Biomedical subjects

B Larsson

Publications and source records attributed to B Larsson.

At least 415 records · Page 23Linked to original sources
PubMed1978

Caesarean section. A clinical study with special reference to the increasing section rate.

At Huddinge University Hospital 539 Caesarean Sections (C.S.) were made among 8415 deliveries from October 1972 to June 1976, corresponding to an over all C.S. rate of 6.4%. Over these years the rate has increased from 3.5% in 1972 to 9.7% in 1976. The main increase was due to a higher incidence of abdominal deliveries in cases of imminent fetal asphyxia. The maternal complication rate and the neonatal morbidity rate were both 6.5 times higher and the neonatal mortality rate was 4.1 times higher in emergency than in elective surgery. There was neither any mortality nor any morbidity in infants delivered by elective C.S. from healthy mothers at term.

Adolescent↗
PubMed1978

Lack of enterohepatic circulation of intact biliary phosphatidylcholine in the rat.

The bile phosphatidylcholine was radioactively labelled by intraperitoneal or intravenous injection of [3H]- or [14C]-palmitic acid into bile fistula rats. The radioactive bile was infused intraduodenally into other bile fistula rats. On an average, only 1.0% of the infused radioactive phosphatidylcholine fatty acid reappeared in bile phosphatidylcholine, whereas about 68% of simultaneously infused [3H]-taurocholate was recovered over the same period of time (6 hours). There is thus no significant enterohepatic circulation of intact biliary phosphatidylcholine.

Animals↗
PubMed1978

Radiation response modified by degradable starch microspheres. Experiments on the rat's foot.

Skin reaction in the rat's foot was used as an experimental method to evaluate the protective potential of profound temporary hypoxia against roentgen radiation produced by a linear accelerator. Hypoxia was induced by intraarterial injection of degradable starch microspheres. The irradiation dose needed to evoke a certain reaction in the hypoxic feet was 2.0 times the dose giving the same reaction in a control group. The results point towards a new technique of inducing local hypoxia in healthy tissues which need to be protected in an irradiation field.

Animals↗
PubMed1978

Mucosal protection during irradiation of exteriorized rat ileum. Effect of hypoxia induced by starch microspheres.

Transient hypoxia induced by intra-arterial injection of degradable starch microspheres was used for protection of exteriorized segments of the rat ileum. Microscopic evaluation of the injury to the mucosa gave a dose modification factor of 0.44 +/- 0.04, which corresponds to an oxygen enhancement ratio of 2.30. A similar factor was also found from measurements of the mucosal weight. No significant development of mucosal oedema could be demonstrated, neither in protected nor in non-protected segments.

Animals↗
PubMed1978

Serum lipids, lipoproteins and musculoskeletal disorders among 50- and 60-year-old men. An epidemiologic study.

Several recent reports have indicated a relationship between hyperlipoproteinaemias and migratory polyarthritis and musculoskeletal disorders of unknown etiology. These studies were uncontrolled and the study populations were small. In the study presented here, 787 60-year-old men and 226 50-year-old men--all randomly selected from the general population--were examined by questionnaire regarding the presence of joint symptoms, backache, pain in the legs and consumption of analgetics. Serum lipoprotein phenotype, serum cholesterol and triglyceride levels were determined. No consistent relationship between symptoms or analgetics consumption and serum lipid levels or serum lipoprotein patterns was found. An association between musculoskeletal disorders and and hyperlipoproteinaemias or high serum lipid levels within the range of this study seems unlikely.

Age Factors↗
PubMed1978

Surgicel--an absorbable hemostatic material--in prevention of peritoneal adhesions in rats.

Forty rats were laparotomized and subjected to a standardized cecal trauma. In half the number of the rats, the injured cecum was embedded in oxidized regenerated cellulose (Surgicel). In the remaining 20 rats, which served as controls, the cecum was left uncovered. The rats were sacrificed at 14 days after the operation and examined for intraperitoneal adhesions. Adhesions were significantly (p less than 0.001) less common in the group treated with oxidized regenerated cellulose. In a separate series eight rats were used for histological examination of the traumatized cecal wall. No macroscopic residuum of the implant was seen after one or two weeks. However, the histological examination demonstrated small remnants surrounded by ingrowing fibroblasts and inflammatory cells.

Absorption↗
PubMed1977

The concentration of copper in human uterine secretion during four years after insertion of a copper-containing intrauterine device.

The contraceptive action of a copper-containing intrauterine device (Cu IUD) is mainly associated with the copper ions released, thus its efficiency varies with the surface area of the copper wire. It is of considerable clinical interest to know the usful life-span of a Cu IUD. Therefore, the concentration of copper in the uterine secretion of women wearing a Cu-7 IUD (Gravigard) with a surface area of the copper wire of 200 sq mm was determined by atomic absorption spectroscopy. No decrease in the concentrations of copper was found in a series of women followed for 4 years after the insertion of a Cu IUD.

Adult↗
PubMed1977

Oxyphenbutazone--an adjuvant to be used in prevention of adhesions in operations for fertility.

A laparotomy was performed in 40 rats and the cecum was subjected to a standardized trauma. Half the rats were treated with oxyphenbutazone in a dose of 40 mg/kg body weight daily for 14 days. The remaining 20 rats served as controls. All of the rats were killed 2 weeks after the laparotomy, and the number of intraperitoneal adhesions was recorded. There were significantly (P less than 0.001) fewer rats with adhesions in the group treated with oxyphenbutazone than in the control group.

Administration, Oral↗
PubMed1976

The influence of copper on the in vitro motility of the human Fallopian tube.

Experiments were designed to examine whether one contraceptive action of the copper intrauterine contraceptive devices (Cu-IUD's) could be associated with an influence on the smooth muscle activity of the Fallopian tube. Sections of the isthmic portion of human oviducts were removed during operation. Preparations from the circular muscle layer were mounted for isometric recording of contractile activity. Subsequently, spontaneous rhythmic contractions appeared within one to five minutes after the preparation procedure was completed. Transmural nerve stimulation or addition of norepinephrine or prostaglandin F2alpha to the Tris buffer medium caused an increase in tone and frequency. Addition of CuCl2 caused a concentration-dependent increase in frequency and a concomitant decrease in amplitude. High concentrations of CuCl2 produced a marked initial increase in frequency, but the rhythmic activity was soon abolished. Metallic copper in the incubation medium caused the same qualitative effects on the smooth muscle preparation as CuCl2. Influences of copper on contractions of rat portal vein preparations were studied in the same way, and similar effects were found. The copper concentration of the secretion in the Fallopian tube was measured by atomic absorption in seven patients wearing CU-IUD's until operation. The levels found were of the same order of magnitude as the concentration of free copper ions which in vitro caused effects on the smooth muscle. It is concluded that copper can affect smooth muscle activity. An influence of copper on the motility of the human oviduct has to be considered as a possible factor contributing to the contraceptive action of the Cu-IUD.

Adult↗
PubMed1976

Active site of ribonucleoside diphosphate reductase from Escherichia coli. Inactivation of the enzyme by 2'-substituted ribonucleoside diphosphates.

Ribonucleoside diphosphate reductase is an allosteric enzyme consisting of two nonidentical subunits, proteins B1 and B2. B1 contains dithiols which participate in the oxidation-reduction reactions of electron transport, while B2 contains a free radical essential for activity. Ribonucleoside diphosphates are bound to B1 but not to B2. Addition of 2'-deoxy-2'-chloro ribonucleoside diphosphates to ribonucleotide reductase irreversibly inactivates B1 without affecting B2. The reaction is specific since (a) it requires the presence of active B2, (b) it is controlled by allosteric effectors, (c) B1 is protected against inactivation by the normal substrates, and (d) the chloro-substituted nucleoside monophosphates have no effect. The inactivation of B1 is caused by a modification of the oxidation-reduction dithiols. The chloro derivatives decompose into free base, chloride ion, and 2-deoxyribose 5-diphosphate as a consequence of reaction with the enzyme. 2'-Deoxy-2"-azido ribonucleoside diphosphates cause an irreversible inactivation of B2 without affecting B1. The reaction is specific by the above criteria, indicating that the azido derivatives also bind to the active site of the enzyme. On reduction by ribonucleotide reductase, the azido derivatives function as radical scavengers and selectively destroy the free radical of B2, indicating that this radical participates in ribonucleotide reduction directly. On the basis of these results, a model of the active site of ribonucleotide reductase is proposed in which the site is formed from both B1 and B2. In the site the electron-donating oxidation-reduction active dithiols of B1 are in close contact with the free radical of B2. The azido derivative also inactivates the adenosylcobalamin-dependent ribonucleoside triphosphate reductase from Lactobacillus leichmannii and a ribonucleotide reductase preparation from calf thymus, indicating a general involvement of free radical intermediates in enzyme-catalyzed ribonucleotide reduction.

Escherichia coli↗
PubMed1976

Body composition and glucose metabolism in hypertensive middle-aged males.

Body fat, body cell mass, fasting blood sugar, glucose tolerance and fasting insulin have been determined in 106 hypertensive males aged 47-54years and in 41 normotensive 50-year-old males. Both groups were derived from screening examinations in random population samples. The hypertensive subjects were more often obese and had more often an impaired glucose tolerance and a higher fasting insulin compared with the normotensive subjects. The metabolic differences were not explained simply by the higher degree of obesity in the hypertensive subjects, as the differences remained when the hypertensive subjects were matched for body fat with normotensive controls. The impaired glucose metabolism demonstrated quantitatively in an unselected group of hypertensive subjects, might be one of the factors explaining the variable prognosis in hypertensive subjects.

Blood Glucose↗
PubMed1976

Intracerebroventricular glycerol: a potent inhibitor of ADH-release and thirst.

Infusions of isotonic or hypertonic (0.3 or 0.5 M) glycerol into the lateral cerebral ventricle (60 min, 0.02 ml/min) of non-hydrated goats invariably induced a conspicuous and sustained water diuresis. Corresponding infusions of 0.3 M glycerol/0.16 M NaCl were almost equally efficient in this respect. A more short-lasting and less pronounced water diuresis was obtained in response to equivalent infusions of pure d-glucose, and the response to 0.3 M glucose/0.16 M NaCl was variable. Intravenous injections of vasopressin blocked the glucose-induced diuresis, but only postponed the glycerol-induced diuresis. Intracerebroventricular (IVT) infusions of 0.5 M glycerol caused a sustained, complete inhibition of the urge to drink in the 48 h dehydrated goat, whereas IVT glucose only attenuated dehydrative drinking. Twenty min after the infusions of glycerol the CSF [Na+] in the lateral ventricle was about 15% below normal. About 10% reduction of CSF [Na+] was obtained 20 min after the IVT infusion of glycerol/NaCl. The corresponding infusion of pure d-glucose reduced the CSF [Na+] by less than 5%. The glycerol and glycerol/NaCl infusions caused a moderate reduction of renal Na+ + K+ excretion. The possibility is discussed that the observed effects of IVT glycerol is a manifestation of its efficiency to inhibit choroidal and/or juxtaventricular (Na+-K+)-ATPase activity.

Animals↗