1.
Bixo, Marie, 1957-
(författare)
Ovarian steroids in rat and human brain : effects of different endocrine states
1987
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Ovarian steroid hormones are known to produce several different effects in the brain. In addition to their role in gonadotropin release, ovulation and sexual behaviour they also seem to affect mood and emotions, as shown in women with the premenstrual tension syndrome. Some steroids have the ability to affect brain excitability. Estradiol decreases the electroshock threshold while progesterone acts as an anti-convulsant and anaesthetic in both animals and humans. Several earlier studies have shown a specific uptake of several steroids in the animal brain but only a few recent studies have established the presence of steroids in the human brain.In the present studies, the dissections of rat and human brains were carried out macroscopically and areas that are considered to be related to steroid effects were chosen. Steroid concentrations were measured by radioimmunoassay after extraction and separation with celite chromatography. The accuracy and specificity of these methods were estimated.In the animal studies, immature female rats were treated with Pregnant Mare's Serum Gonadotropin (PMSG) to induce simultaneous ovulations. Concentrations of estradiol and progesterone were measured in seven brain areas pre- and postovulatory. The highest concentration of estradiol, pre- and postovulatory, was found in the hypothalamus and differences between the two cycle phases were detected in most brain areas. The preovulatory concentrations of progesterone were low and the highest postovulatory concentration was found in the cerebral cortex.In one study, the rats were injected with pharmacological doses of progesterone to induce "anaesthesia". High uptake of progesterone was found and a regional variation in the formation of 5<*-pregnane-3,20-dione in the brain with the highest ratio in the medulla oblongata.Concentrations of progesterone, 5a-pregnane-3*20-dione, estradiol and testosterone were determined in 17 brain areas of fertile compared to postmenopausal women. All steroids displayed regional differences in brain concentrations. Higher concentrations of estradiol and progesterone were found in the fertile compared to the postmenopausal women.In summary, these studies show that the concentrations of ovarian steroids in the brain are different at different endocrine states in both rats and humans and that there are regional differences in brain steroid distribution.
2.
Wanders, A., et al.
(författare)
Abolition of the effect of cyclosporine on rat cardiac allograft rejection by the new immunomodulator LS-2616 (Linomide)
1989
Ingår i: Transplantation. - 0041-1337 .- 1534-6080. ; 47:2, s. 216-7
Tidskriftsartikel (refereegranskat) abstract
The effect of the quinoline-3-carboxamide LS-2616 (Linomide), given alone or together with cyclosporine, was studied in the first set cardiac allograft transplantation model in the rat. PVG rat hearts were transplanted heterotopically to Wistar/Kyoto rat recipients on day 0. The recipients were given LS-2616 orally on day -1 to rejection and/or CsA orally on days 0-9. In untreated animals rejection occurred on days 8-9, as judged by the absence of palpable pulsations. Treatment with CsA (5 or 10 mg/kg) resulted in prolongation of graft survival to days 17-21, i.e., the rejection occurred 8-10 days after cessation of treatment. LS-2616 in a dose of 160 mg/kg did not in itself have any impact on graft survival, but when given in doses of 40 or 160 mg/kg simultaneously with CsA (10 mg/kg), the effect of CsA was totally abolished. Animals treated with LS-2616 together with CsA had slightly lower trough blood levels than those treated with CsA alone. This interaction with CsA pharmacokinetics does not explain the results, as doubling of the CsA dose to 20 mg/kg, which well compensated for the difference in blood levels, was not sufficient to reverse the effect of LS-2616. To our knowledge this is the first compound known to abolish the effect of CsA. The mechanism is unknown, but is is possible that studies on the interaction between these two drugs will shed further light on the molecular basis of their modes of action.
3.
Wanders, A., et al.
(författare)
The enhancing effect of cyclosporine A and sulfasalazine on the prevention of rejection in rat cardiac allografts
1988
Ingår i: Transpl Int. ; 1:2, s. 113-5
Tidskriftsartikel (refereegranskat) abstract
Sulfasalazine (SASP) has been used for many years as a disease-modifying agent in inflammatory bowel disease and in rheumatoid arthritis. However, its mode of action is not entirely clear. Evidence has been accumulated which indicates that its efficacy is due to an immunomodulatory effect. In the present communication, we report that SASP has an immunomodulatory capacity in an experimental rat cardiac allograft model. A combination of 100 mg/kg per day of SASP given orally until rejection and 10 mg/kg per day of cyclosporine A (CyA) given orally for 10 days resulted in a significantly increased graft survival time as compared to that in animals given CyA alone.
4.
Aspenberg, P., et al.
(författare)
Failure of bone induction by bone matrix in adult monkeys
1988
Ingår i: Journal of Bone and Joint Surgery: British Volume. - 0301-620X. ; 70:4, s. 625-627
Tidskriftsartikel (refereegranskat) abstract
Extraskeletal bone formation can be induced in rodents by implantation of demineralised bone matrix and such implantation has been used to treat bone defects in man, but it is uncertain if induction or merely conduction occurs. We studied bone induction in primates by excising segments of the fibulae of adult squirrel monkeys, defatting and demineralising them before reimplanting them into the quadriceps of the same animal. As a control experiment, rat matrix was prepared in exactly the same way and implanted in rats. After six weeks the implants were harvested and either ashed and analysed for calcium content or prepared for histology. In the rats, the calcium content indicated that about 20% of the original matrix had been replaced by new bone. In the monkeys the calcium content was about the same as that in normal body fluid and no bone was seen in histological sections. This result casts doubt on the use of demineralised human bone matrix as a bone inductor, although it may function by other mechanisms.
5.
Aspenberg, Per, et al.
(författare)
Fibroblast growth factor stimulates bone formation bone induction studied in rats
1989
Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 0001-6470. ; 60:4, s. 473-476
Tidskriftsartikel (refereegranskat) abstract
Implantation of demineralized bone matrix in rodents elicits a series of cellular events leading to the formation of new bone inside and adjacent to the implant. This process is believed to be initiated by an inductive protein present in bone matrix. It has been suggested that local growth factors may further regulate the process once it has been initiated. This investigation was designed to study the effect of adding a growth factor to the inductive implant. Pairs of demineralized rat femoral diaphyses were implanted intramuscularly in rats. the marrow canal of one implant in each pair was filled with a carboxymethyl cellulose gel containing 75 ng of recombinant human basic fibroblast growth factor (FGF). the other implant in each pair served as a control. It was either filled with the gel without FGF or left untreated. Bone formation was induced by all the implants after 3 weeks. the amount of mineralized tissue in the FGF-treated implants was 25 percent greater than in untreated controls. the carboxymethyl cellulose gel alone did not affect the bone yield.
6.
Barrett, Alan, et al.
(författare)
The place of human gamma-trace (cystatin C) amongst the cysteine proteinase inhibitors
1984
Ingår i: Biochemical and Biophysical Research Communications. - 1090-2104. ; 120, s. 631-636
Tidskriftsartikel (refereegranskat) abstract
Native γ-trace, a small basic protein present in high concentration in cerebrospinal fluid, semen and neuroendocrine cells, but of unknown biological function, is shown to be a potent inhibitor of the cysteine proteinases papain, ficin, and human cathepsins B, H and L. It proves to be the tightest-binding protein inhibitor of cathepsin B so far discovered. The name cystatin C is proposed for γ-trace to reflect the many similarities in activity and structure to chicken egg-white cystatin and mammalian cystatins A and B. The inhibition constants of cystatin C, taken together with its widespread distribution in human tissues and extracellular fluids, suggest that a physiological function could well be the regulation of cysteine proteinase activity.
7.
8.
Belew, M, et al.
(författare)
Structure-activity studies on synthetic analogs to vasoactive peptides derived from human fibrinogen.
1980
Ingår i: Biochimica et Biophysica Acta. - 0006-3002 .- 1878-2434. ; 632:1, s. 87-94
Tidskriftsartikel (refereegranskat) abstract
Counterparts to two vasoactive peptides previously isolated from fibrin(ogen) degraded by plasmin (EC 3.4.21.7) were synthesized by the solid phase procedure. The synthetic undecapeptide (Ser-Gln-Leu-Gln-Lys-Val-Pro-Pro-Glu-Trp-Lys) was isolated in a homogeneous state by chromatography on Sephadex G-25 and DEAE-Sepharose CL-6B and the pentapeptide (Ala-Arg-Pro-Ala-Lys) by chromatography on BioGel P-6 and column zone electrophoresis. The effect of these two peptides and of fifteen analogs to the pentapeptide on microvascular permeability in rat skin was investigated. The two synthetic counterparts were as potent as the natural peptides. With respect to the analogs, the influence of different functional groups was first studied. This was followed by attempts to minimize the active structure, induce or relieve rigidity of the peptide back-bone or otherwise accomplish modifications by a change in chirality at critical positions. Our results show that the tetrapeptide Arg-Pro-Ala-Lys has the same effect on microvascular permeability as the pentapeptide in the assay system used. Basic amino acids at both ends, as well as a proline residue adjacent to the N-terminal amino acid appear important for full or essentially full activity. On the other hand, substitution of the Ala at position 4 with several other amino acids did not result in a significant loss in biological potency.
9.
Borg, T, et al.
(författare)
Prophylactic and delayed treatment with high-dose methylprednisolone in a porcine model of early ARDS induced by endotoxaemia.
1985
Ingår i: Acta Anaesthesiologica Scandinavica. - 0001-5172 .- 1399-6576. ; 29:8, s. 831-45
Tidskriftsartikel (refereegranskat) abstract
The effects of prophylactic and delayed treatment with high-dose methylprednisolone were evaluated in a porcine model of early adult respiratory distress syndrome induced by endotoxaemia. Spontaneously breathing pigs under ketamine anaesthesia were infused i.v. with E. coli endotoxin (10 micrograms . h-1 . kg-1) over 6h. Twenty animals received endotoxin without treatment. Eight animals were pretreated with methylprednisolone i.v., 60 mg . kg-1, followed by an i.v. infusion at a rate of 10 mg . h-1 . kg-1. Ten animals received the same dosage of methylprednisolone beginning 2 h after the start of endotoxin infusion. Pretreatment with methylprednisolone prevented the endotoxin-induced impairment in pulmonary gas exchange and the development of pulmonary oedema. The pulmonary hypertension was counteracted. Cardiac output (Qt) and O2 delivery were improved. Mean arterial blood pressure (MAP) increased and was higher than in the untreated endotoxin group. The profound fall in PMN count was inhibited, while the accumulation of these cells in the lung was still substantial. Survival was improved. Delayed methylprednisolone treatment prevented further deterioration in pulmonary gas exchange and tended to restore it towards baseline. The pulmonary oedema and pulmonary hypertension were reduced. Qt and O2 delivery did not improve. MAP was higher than in the untreated endotoxin group towards the end of the observation period. The decline in PMN count and the pulmonary accumulation of these cells were not significantly influenced. Survival was improved. These results indicate that high-dose methylprednisolone, when given early in the course of sepsis, might be of clinical value in prevention of the devastating pulmonary and circulatory complications of this disease.
10.
Borg, T, et al.
(författare)
The role of polymorphonuclear leucocytes in the pulmonary dysfunction induced by complement activation.
1985
Ingår i: Acta Anaesthesiologica Scandinavica. - 0001-5172 .- 1399-6576. ; 29:2, s. 231-40
Tidskriftsartikel (refereegranskat) abstract
To determine the role of polymorphonuclear leucocytes (PMNs) in the pulmonary reaction induced by complement activation, pigs were infused with complement-activated plasma (CAP), cell-free supernatant from PMNs activated in vitro, or washed PMN aggregates produced in vitro. Infusion of CAP resulted in transient peripheral leucopenia, a reversible rise in pulmonary vascular resistance (PVR) and decreased arterial oxygen tension (PaO2). Indomethacin did not influence the CAP-induced drop in PMN count or the accumulation of PMNs in the lung, but significantly counteracted the rise in PVR and fall in PaO2. Antihistamines did not prevent the cellular or pulmonary reactions to CAP infusion. Methylprednisolone did not inhibit the decrease in PMN count, but modified the pulmonary reaction to CAP, although it did not prevent the rise in PVR to the same extent as indomethacin; it counteracted the fall in PaO2. Infusion of supernatant from activated PMNs did not influence the PMN count, but caused a reversible increase in PVR and a drop in PaO2. Indomethacin counteracted the pulmonary reaction to this infusion. Infusion of washed PMN aggregates did not result in any cellular or physiological changes. These findings suggest that the pulmonary reaction induced by complement activation is mediated by humoral components generated and/or released during activation of PMNs. Arachidonic acid metabolites play an important role and it is likely that substance(s) released from activated PMNs trigger prostanoid synthesis in other cells. It is conceivable, however, that PMNs exposed to activated complement factors also directly synthesize and release arachidonic acid metabolites.
