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Biomedical subjects

I Jansson

Publications and source records attributed to I Jansson.

At least 73 records · Page 4Linked to original sources
PubMed1985

Pulmonary trapping of platelets and fibrin after musculoskeletal trauma: an experimental model.

A new experimental model is described in which pulmonary changes identical with the adult respiratory distress syndrome (ARDS) can be induced by reproducible musculoskeletal trauma in anesthetized pigs. The pigs were studied in maintained anesthesia for 3 days after the trauma under standardized conditions. The intrapulmonary aggregation of platelets and fibrin was monitored by external detection of radioactivity arising from pretrauma intravenous injection of 51Cr-labeled platelets and 125I-labeled fibrinogen. Pulmonary trapping of platelets and fibrin was significantly greater in the traumatized pigs than in nontraumatized but otherwise identically handled controls. Radiologic and morphologic changes corresponding to ARDS developed in the traumatized animals, but not in the controls. The experimental model offers new possibilities for study of factors influencing the occurrence and development of ARDS. After further experimental evaluation, the procedure for registering pulmonary microembolism by external detection may be useful in the clinical management of ARDS.

Animals↗
PubMed1985

Isolation and comparison of four cytochrome P-450 enzymes from phenobarbital-induced rat liver: three forms possessing identical NH2-terminal sequences.

Phenobarbital pretreatment of male rats induced four microsomal cytochrome P-450 enzymes, at least one of which has previously not been reported. Three of the induced forms of the cytochrome possess identical NH2-terminal amino acid sequence for the first 32 residues (PBRLM5, 6 and 7). This sequence is identical to that shown earlier for PB-4 and PB-5. Apparent values for minimum molecular weight on SDS-PAGE were 52,000 (PBRLM4), 53,000 (PBRLM5), 53,500 (PBRLM6) and 54,000 (PBRLM7). Isomeric metabolite patterns from testosterone and progesterone differed for each enzyme further indicating their unique natures. Studies reveal similarity of PBRLM4 to PB-1, of PBRLM5 to P-450b and PB-4, and PBRLM6 to P-450e and PB-5. PBRLM7, which does not correspond to any reported forms, metabolizes steroids poorly. It preferentially hydroxylates testosterone at the 16 beta-position. It is the largest and least active of the enzymes shown for all of the substrates tested. This study further provided a cautionary note against assuming that chromatographic pools, like a P-450 PB-B fraction, are homogeneous.

Amino Acid Sequence↗
PubMed1985

Ovarian steroid production in a woman with polycystic ovary syndrome associated with endometrial cancer.

A young woman with typical polycystic ovary syndrome (PCO) underwent laparotomy for moderately differentiated endometrial cancer. Specimens from the hyperplastic thecal and stromal tissue of the ovaries were incubated for 2 hours in the presence or absence of hCG, 100 IU/ml. Following incubation the tissue content of cyclic AMP and the amounts of progesterone (P), androstenedione (A), testosterone (T) and estradiol-17 beta (E2) in the incubation medium were analysed. For comparison, thecal cells from normal ovaries of regularly menstruating women were incubated under identical conditions. In vivo, the PCO ovaries secreted several-fold greater amounts of T than normal ovaries. In vitro, the thecal cells were much more active, steroidogenically, than the stromal cells of the PCO ovary. Furthermore, the hyperplastic thecal cells of the PCO ovary produced several-fold greater amounts of androgens, and appeared more sensitive to stimulation with hCG, as compared with thecal cells from normal ovaries. The results indicate that in women with PCO associated with endometrial cancer the hyperplastic thecal cells are a significant site of abnormal androgen production and abnormal sensitivity to gonadotropin.

Adenocarcinoma↗
PubMed1985

Posttraumatic respiratory distress syndrome and high-dose corticosteroids.

Many authors have advocated glucocorticoids for prophylaxis against or treatment of Adult Respiratory Distress Syndrome (ARDS) or post-traumatic pulmonary microembolism. One of the theories underlying this advocacy is that the activation of the complement system possibly is preventable by pharmacologic doses of corticosteroids. Studies on traumatized patients are difficult to standardize, and clinical observations are correspondingly difficult to evaluate. Animal models for study of the microembolism syndrome have often comprised too short a time and most have greatly differed from the clinical situation. We have earlier evolved an experimental model by means of which changes identical to the microembolism syndrome can be induced from a reproducible musculo-skeletal trauma in pigs observed under long-term anesthesia under standardized conditions. In this study, early and long-term effects of corticosteroids on the course of post-traumatic microembolism was evaluated by following the pulmonary function and X-ray appearance, pulmonary trapping of platelets and fibrin and histologic changes in pigs, using this standardized trauma model. Methylprednisolone sodium succinate (30 mg/kg bw) was given to 9 pigs one hour after trauma and thereafter every 8th hour during a 72 hour observation period. Two other groups of animals were used for comparison, 13 traumatized, non-treated and 15 non-traumatized, non-treated pigs. Intrapulmonary microembolism was measured quantitatively by repeated external detection of labelled platelets (51Cr) and fibrinogen (125I), sequential chest X-rays and morphologic examination of the lungs post mortem.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Posttraumatic hypophosphataemia and urinary phosphate excretion with and without phosphate supplementation. An experimental study in pigs.

Hypophosphataemia commonly follows trauma of various types. Several aetiologic factors have been proposed and the clinical significance of posttraumatic hypophosphataemia has been discussed. For study of the mechanisms underlying hypophosphataemia associated with surgical trauma, an experimental model has been developed which permits induction of hypophosphataemia under standardized conditions in anaesthetized and traumatized pigs. In the present study this model was used to investigate the relationship between posttraumatic hypophosphataemia and urinary excretion of with or without phosphate supplementation. The results suggest that the adrenaline release associated with stress and trauma induced an immediate and rapid fall in the serum phosphate (S-P) level. The abrupt fall was followed after 24 hours by a slower decrease. This second phase of S-P decrease was not induced by catecholamine release or by glucose infusion and was not prevented by phosphate supplementation. It appeared to be related to an inadequate renal response to the hypophosphataemia, i.e. a relative phosphaturia. The cause of this phosphaturia is not fully understood, but both extracellular volume expansion and the humoral response to trauma are possible explanations.

Animals↗
PubMed1983

High-performance size-exclusion chromatography of 63Ni-constituents in renal cytosol and microsomes from 63NiCl2-treated rats.

Fractionations of 63Ni-constituents were performed by high-performance size-exclusion chromatography upon samples of renal cytosol and washed renal microsomes from rats that were killed 1 h after an im injection of 63NiCl2 (50 or 125 mumol/kg body wt). The kidney homogenates contained 2.0 +/- 0.4% of the total dose of 63Ni. Renal cytosol contained 55 +/- 5% and washed microsomes contained 5.4 +/- 1.2% of 63Ni that was present in the kidney homogenates. Chromatography of renal cytosol on TSK-GEL SW-2000 and SW-3000 separated 63Ni into six fractions. The largest component (Fraction F) contained approximately 80% of cytosolic 63Ni. Since Fraction F was eluted near the total permeation volume of SW-2000 columns and beyond the total permeation volume of SW-3000 columns, its molecular weight could not be reliably estimated. The other components, which comprised collectively the remaining 20% of cytosolic 63Ni, had apparent molecular weights of 168,000 (Fraction A), 84,000 (Fraction B), 51,000 (Fraction C), 24,000 (Fraction D), and approximately 10,000 (Fraction E). Solubilized washed microsomes from kidneys of 63NiCl2-treated rats contained 63Ni in five components with elution profiles and 63Ni-contents that resembled Fractions A, B, D, E, and F of renal cytosol, based upon chromatography on SW-3000 columns. The solubilized microsomes also contained a 63Ni-component with high molecular weight (Fraction M, greater than 700,000 daltons), which accounted for 3% of microsomal 63Ni. This study provides a rapid, convenient, and reproducible technique to fractionate 63Ni-components in tissue extracts, and it demonstrates in vivo binding of 63Ni to several constituents of renal cytosol and microsomes from 63NiCl2-treated rats.

Animals↗
PubMed1982

Primary fracture immobilization as a method to prevent post-traumatic pulmonary changes- an experimental model.

Post-traumatic pulmonary insufficiency or "respiratory distress syndrome" (RDS) is one of the most feared complications of severe trauma. The aetiology is probably multifactorial, and is obscure. Although modern treatment has reduced the mortality, there is no certain way of preventing the syndrome. The aim of the investigation was to develop an experimental model on anaesthetized pigs subjected to trauma and folllowed up for 3-4 days, still under anaesthesia, the repeated lung X-rays and post-mortem naked-eye and histological examination of lung tissue. 26 pigs were used. 12 (Group I) were subjected to missile trauma of a limb, with a fracture that was left without immobilization. 10 were treated similarly but with immobilization of the fracture (Group II). Four control animals were prepared and observed under anaesthesia but no trauma was inflicted (Group III). In Group I, all but two developed, 10-70 h after the injury, roentgen and morphological changes identical to those seen in patients with clinically documented RDS. No such changes were seen in the controls or in Group II. With our experimental model it seems possible to induce in experimental animals roentgen and morphological changes corresponding to RDS in man. The method provides new means of studying the mechanisms behind and the effects of different forms of treatment in RDS. The results also support the hypothesis that early immobilization of fractures is an important step in preventing RDS.

Animals↗
PubMed1980

Skin blood flow in normal pregnancy measured by venous occlusion plethysmography of the hand.

Total hand blood flow was measured by venous occlusion plethysmography in 14 healthy primigravid women. Consecutive measurements were made from the 15th week of pregnancy until term and after delivery. During pregnancy the mean hand blood flow, measured under standard resting conditions with the subjects supine, increased progressively from 7.7 in early pregnancy to 28.9 ml/100 ml/min at term. Simultaneously the peripheral vascular resistance decreased from 19.3 to 3.3 PRU100. When examined at 6--16 weeks after delivery hand blood flow and peripheral resistance were not yet returned to normal.

Adult↗