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Biomedical subjects

I Johansson

Publications and source records attributed to I Johansson.

At least 199 records · Page 11Linked to original sources
PubMed1980

Carotid angiography of arteriovenous malformations during operation.

The value of carotid angiography during operation in the surgical treatment of arteriovenous malformation is illustrated by 4 patients. After obliteration of the main supply to the malformation the blood may be redistributed to possible smaller feeding vessels now dilated and more clearly demonstrable than preoperatively. In some cases, angiography both preoperatively and during operation may be needed for a demonstration of the whole malformation with all its feeding vessels. Angiography during operation reduces the need for postoperative angiography.

Adult↗
PubMed1979

Chromatographic properties of Sephacryl S-300 Superfine.

Sephacryl S-300 Superfine is a new gel filtration medium that consists of allyldextran crosslinked with N,N'-methylenebisacrylamide. It was shown to have a separation range for proteins that extends to 1--2 x 10(6) dalton. The gel filtration properties were characterized by fractionation of human serum and of bovine colostrum. Thyroglobulin from pig could be isolated in one step in a very pure form. The flow properties were characterized by the relationship between flow rate and pressure drop. It was shown that Sephacryl has very good flow properties in comparison with Sephadex G-200 and that it can be used in large-scale columns.

Acrylic Resins↗
PubMed1979

Catalytic properties of the liver microsomal hydroxylase system in reconstituted phospholipid vesicles.

Two types of cytochrome P-450, P-450LM2 and P-450LM3, have been purified from rabbit liver microsomes and incorporated into phospholipid vesicles by a cholate gel filtration technique together with purified preparations of NADPH-cytochrome P-450 reductase. The catalytic properties of the vesicles have been compared with a system reconstituted with small amounts of dilauroylphosphatidylcholine (DLPC). 6 beta-Hydroxylation of androstenedione proceeded at a rate 10 times higher in the vesicles compared to the DLPC-system. The kinetics for the reaction were the same in the vesicles as in intact microsomes i.e. sigmoidal substrate curves were obtained and Hill-coefficients of about 1.4 were calculated in these systems. In contrast, Michaelis-Menten kinetics were obtained for 6 beta-hydroxylation in the DLPC-system. The results could indicate cooperativity between different P-450 molecules in the intact membrane but not in the DLPC-system. P-450LM2-catalyzed 16-hydroxylation of androstenedione was in contrast to the situation with P-450LM3 inhibited in the vesicles as compared to the DLPC system. It is suggested that for evaluation of substrate specificity and other properties of different types of liver microsomal P-450, phospholipid vesicles may be a more relevant integration level than the DLPC-system.

Androstenedione↗
PubMed1978

Copper intrauterine contraceptive devices in adolescent nulliparae.

Copper intrauterine contraceptive devices (IUCDs) were used in 243 young nulligravidae attending a gynaecological clinic for schoolgirls in Uppsala between March 1973 and June 1975; 226 of these girls (93%) were seen again during December 1975 making a total of 3138 months of observation. At the time of follow up, 126 patients (55.8%) still had the IUCD in situ; 20% had expelled the IUCD and in another 24.2% the IUCD had been removed because of bleeding and/or pain or because of suspected pelvic inflammatory disease (7 patients). Twelve of the girls conceived during the period of observation making the Pearl index 4.6; nine of the conceptions occurred within nine months of the insertion of the IUCD. Unlike others we do not advocate the use of the IUCD for young nulligravidae.

Adolescent↗
PubMed1972

Inhibitory and stimulatory effects of secretin on gastric secretion in conscious rats.

1. The effect of pure secretin on gastrin-induced secretion has been studied in conscious rats with Pavlov or Heidenhain pouches.2. Rapid intravenous injection of secretin did not inhibit a plateau secretion of acid in the Heidenhain pouch, but infusion of the same amount of secretin over two hours inhibited secretion in both Heidenhain and Pavlov pouches.3. A rapid intravenous injection of secretin before the onset of gastrin infusion enhanced the acid secretory response to gastrin in both types of pouches.4. Secretin stimulated pepsin secretion.

Animals↗
PubMed1972

Gastric secretion and its facilitation as related to gastric mucosal histamine.

1. In conscious rats provided with Pavlov or Heidenhain pouches the acid and pepsin responses to vagal stimulation, or infusions of gastrin, histamine, methacholine, and to various combinations of these stimulants have been established. The concomitant mobilization and increased formation of gastric mucosal histamine have also been examined.2. Histamine evoked graded acid responses in the Pavlov and Heidenhain pouches. The innervated pouch was more sensitive to histamine than the denervated. Stimulation of pepsin secretion was apparent only in the Heidenhain pouch.3. The acid response to vagal stimulation evoked by 2-deoxy-D-glucose was facilitated by infusion of histamine, but not that of pepsin, the secretion of which was depressed.4. Acid secretion in response to graded infusion of methacholine was enhanced by background infusions of histamine in subthreshold, sub-maximal and maximal dosages.5. The acid response to vagal stimulation was enhanced by a background infusion of gastrin, but not that of pepsin, the secretion of which was depressed.6. A background infusion of a large dose of histamine depressed the maximal acid response to gastrin in both types of pouches.7. Administration of histamine restrained the accelerating effect of gastrin on histidine decarboxylase activity, probably by a feed-back coupling.8. The increase in gastric mucosal histamine, as reflected in its urinary excretion, in response to gastrin infusion was enhanced by vagal stimulation.9. The amounts of histamine that can be mobilized and newly formed in the gastric mucosa have been evaluated and found to be fully adequate for efficient stimulation of the parietal cell.

Animals↗
PubMed1971

Inhibition of gastric secretion by atropine in conscious rats.

1. The effect of atropine on acid and pepsin secretion, stimulated by feeding, vagus excitation or infusions of gastrin, histamine and methacholine, was studied in conscious rats provided with a Pavlov or a Heidenhain pouch.2. The acid and pepsin secretion in response to food was substantially suppressed by atropine in the Pavlov pouch.3. The strong stimulatory effect of 2-deoxy-D-glucose on acid and pepsin secretion in the Pavlov pouch was almost abolished by atropine.4. A plateau secretion of acid obtained by infusion of submaximal doses of hog gastrin II, was significantly inhibited by atropine in the Pavlov and the Heidenhain pouch.5. Methacholine-induced acid and pepsin secretion in the denervated Heidenhain pouch was nearly completely inhibited by atropine.6. A plateau secretion of acid evoked by infusing histamine in a near maximal dosage was inhibited by atropine to the same extent as the gastrin-induced secretion in the Pavlov pouch.7. The mode of action of atropine as a gastric secretory inhibitor is discussed.

Animals↗