1.
Shimizu, T, et al.
(författare)
Inhibitory effects of theophylline, terbutaline, and hydrocortisone on leukotriene B4 and C4 generation by human leukocytes in vitro.
1994
Ingår i: Pediatric pulmonology. - 8755-6863. ; 18:3, s. 129-34
Tidskriftsartikel (refereegranskat) abstract
Leukotriene B4 (LTB4) and leukotriene C4 (LTC4) are considered to be important mediators in the pathophysiology of asthma. Theophylline, terbutaline, and hydrocortisone are drugs commonly used in the treatment of asthma. In the present study we have investigated the in vitro inhibitory effects of theophylline, terbutaline, and hydrocortisone on LTB4 and LTC4 generation from human leukocytes. After preincubation in the presence of these drugs, the cells were stimulated with the calcium ionophore A 23187 and the supernatants were analyzed for their LTB4 and LTC4 content using reverse-phase high-performance liquid chromatography (HPLC). Total leukotriene (LT) production (the combined amounts of LTB4 and LTC4) was dose-dependently inhibited by pretreatment with theophylline, terbutaline or hydrocortisone. Therapeutic levels of hydrocortisone (5 x 10(-6) M) plus theophylline (5 x 10(-5) M) inhibited LTB4 and LTC4 production in an additive way, as did the combination of hydrocortisone plus terbutaline (5 x 10(-8) M). A statistically significant effect of diminished LTB4 generation was obtained after preincubation with therapeutic levels of theophylline plus terbutaline, but no such effect was seen for LTC4 levels. The in vitro inhibitory effects on LTB4 and LTC4 generation from human leukocytes by theophylline, terbutaline, and hydrocortisone, as well as the additive effect of hydrocortisone plus theophylline or terbutaline, add to our understanding of the therapeutic effects of these drugs in the treatment of bronchopulmonary obstruction.
2.
Wanders, A., et al.
(författare)
Effect of LS-2616 on the graft protection achieved by cyclosporin A, prednisolone, and 15-deoxyspergualin in heart-transplanted rats
1992
Ingår i: Transpl Int. ; 5 Suppl 1, s. S462-3
Tidskriftsartikel (refereegranskat) abstract
The immunostimulator LS-2616 abolishes the effect of cyclosporin A in a rat cardiac transplantation model. The present paper compares the characteristics of rejection obtained under different immunosuppressive regimens with and without additional LS-2616 application in the same model. Cyclosporin A (CyA, 10 mg/kg daily), prednisolone (15 mg/kg daily), or 15-deoxyspergualin (2, 5, or 10 mg/kg daily), all given from the day of transplantation until day 9, protected the grafts during the treatment period. The addition of LS-2616 (160 mg/kg, day -1 until stop) resulted in a total abrogation of the immunosuppressive effect of CyA and prednisolone. However, LS-2616 could only partially or not at all reverse the effect of 15-deoxyspergualine. These results show a certain drug selectivity of LS-2616 in promoting rejection of immunosuppressed allografts. Further studies with LS-2616 may be of benefit in evaluating the mode of action of different immunosuppressive compounds and, thus, contribute to finding more effective antirejection therapies.
3.
Wanders, A., et al.
(författare)
Effects of prostaglandin E2 (PGE2) and drugs affecting PGE2 degradation on acute rejection of rat cardiac allografts
1992
Ingår i: Scand J Thorac Cardiovasc Surg. ; 26:1, s. 33-7
Tidskriftsartikel (refereegranskat) abstract
Systemic administration of prostaglandin E2 (PgE2) has been reported to prolong graft survival of heart transplants. We investigated the influence of systemic injection of two compounds which inhibit the endogenous degradation of PgE2 (CL42A and CL68A) and of local infusion of PgE2 into the transplant on the survival time of rat cardiac allografts. Both CL42A and CL68A gave increased graft survival time in two rat strain combinations, though this was not predictable in individual rats. Locally infused PgE2 gave slight, but not significant prolongation of graft survival in some recipients. Combined PgE2 and cyclosporin A, however, gave significant prolongation of graft survival time compared with cyclosporin A treatment alone. When local PgE2 treatment was begun 5 days after transplantation, graft survival time was prolonged in almost all the rats. Manipulation of the local PgE2 concentration thus seemed to have a positive effect on graft survival, possibly due to down-regulation of certain cells of the immune system by PgE2.
4.
Wanders, A., et al.
(författare)
Enhancement of the effect of low-dose cyclosporin A by sulphasalazine in prevention of cardiac allograft rejection in the rat
1992
Ingår i: Transpl Int. ; 5:3, s. 155-8
Tidskriftsartikel (refereegranskat) abstract
Sulphasalazine (SASP) is an immunomodulatory compound with disease-modifying activity in ulcerative colitis and in other autoimmune disorders. SASP was previously shown to prolong the survival of heart allografts in rats treated with cyclosporin A (CyA) for 9 days after transplantation. We have now evaluated whether SASP also exerts a beneficial effect under continuous treatment with CyA, when CyA is discontinued after 14 days, or alone if given 10 days prior to transplantation. Cardiac grafts were transplanted from PVG donors to Wistar/Kyoto recipients using an accessory cervical heart transplantation technique. Rejection was defined as the absence of palpable contractions and occurred in the control group in a very reproducible manner on day 8 or 9. SASP alone was given orally (100 mg/kg body weight) starting 10 days before transplantation and resulted in a minor prolongation of graft survival. When SASP was given in addition to oral CyA (1 mg/kg or 2 mg/kg from day 0 to rejection) there was a significant prolongation in graft survival [from medians of 8 (range 6-11) and 9 (range 8-11) days, respectively, to medians of 10 (range 8-15) and 12 (range 11-15) days, respectively]. When SASP was given from day 0 to rejection, in addition to a schedule of oral CyA (10 mg/kg) for 15 days, there was no prolongation of graft survival [median of 30 (range 26-42) days vs median of 32 (26-38) days]. The data show that SASP acts as a weak immunosuppressive agent which enhances the effect of CyA given at a low dose.(ABSTRACT TRUNCATED AT 250 WORDS)
5.
Wanders, A., et al.
(författare)
Evidence that LS-2616 (linomide) causes acute rejection of rat allografts protected by cyclosporine but not of long-term surviving allografts
1991
Ingår i: Transplantation. - 0041-1337 .- 1534-6080. ; 52:2, s. 234-8
Tidskriftsartikel (refereegranskat) abstract
The immunomodulator LS-2616 (Linomide) induces rejection of cyclosporine-protected rat cardiac allografts. The aim of this study was to characterize this rejection in the presence of CsA and to test LS-2616 in other models of permanent graft acceptance in the rat. PVG rat hearts were transplanted heterotopically to Wistar/Kyoto (Wi/Ky) rat recipients on day 0. The recipients were treated orally on days 0-9 with CsA (10-40 mg/kg) and/or with LS-2616 (2.5-160 mg/kg) starting at different times (day -7 -+5) until the day of complete rejection. The addition of LS-2616 (day -1--stop) to CsA (10 mg/kg) resulted in a dose-dependent antagonism of the immunosuppressive effect of CsA with daily doses of 2.5-160 mg/kg. Furthermore, the results were similar, irrespective of whether LS-2616 treatment (160 mg/kg) was started on day -7, -1, +1, +3, or +5. LS-2616 (160 mg/kg) pretreatment of the recipient for 7 days before transplantation was considerably less effective. CsA (20 mg/kg) for 14 days after a PVG to DA transplantation resulted in permanent graft survival. This was not abrogated by LS-2616. Neither was rejection induced in long-term surviving grafts of RT1.C incompatible Lewis recipients. Our data suggest that LS-2616 activates already stimulated and sensitized T cells that are otherwise controlled by CsA.
6.
7.
Krettek, Alexandra, 1968-, et al.
(författare)
Quantitation of platelet-derived growth factor receptors in human arterial smooth muscle cells in vitro
1997
Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - : Lippincott Williams & Wilkins. - 1079-5642 .- 1524-4636. ; 17:11, s. 2395-2404
Tidskriftsartikel (refereegranskat) abstract
Platelet-derived growth factor (PDGF) is suggested to play an important role in the development of atherosclerosis as a migratory and mitogenic stimulus to arterial smooth muscle cells (ASMCs). Stimulated and unstimulated ASMCs were studied with respect to PDGF receptor (PDGF-R) mRNA and protein expression. Quantitative RT-PCR was developed for simultaneous evaluation of both PDGF-R alpha and -R beta mRNA expression and a quantitative ELISA for estimation of corresponding PDGF-R subunits. On the mRNA level, the overall PDGF-R beta expression was approximately 100 times lower than that of PDGF-R alpha. Furthermore, although PDGF-R alpha mRNA levels were high irrespective of hASMC phenotype, PDGF-R beta mRNA was influenced by serum stimulation with lower copy numbers in proliferating and confluent cells compared with quiescent cells. On the protein level, quiescent hASMCs expressed 10 times more PDGF-R beta than PDGF-R alpha. Serum stimulation decreased cell surface PDGF-Rs, with most prominent loss of PDGF-R alpha (ELISA and immunohistochemistry). Our results suggest a differential regulatory pattern for PDGF-R alpha and -R beta and are compatible with the usage of alternative promoters for regulation of -R alpha expression. Further, it seems that the number of available receptor subunits is not the only determinant of variations in cell stimulation with different PDGF isoforms.
8.
Lundberg, Fredrik, et al.
(författare)
Presence of vitronectin and activated complement factor C9 on ventriculoperitoneal shunts and temporary ventricular drainage catheters
1999
Ingår i: Journal of Neurosurgery. - : Journal of Neurosurgery Publishing Group (JNSPG). - 0022-3085. ; 90:1, s. 101-108
Tidskriftsartikel (refereegranskat) abstract
Object. The pathogenesis of cerebrospinal fluid (CSF) shunt infection is characterized by staphylococcal adhesion to the polymeric surface of the shunt catheter. Proteins from the CSF-fibronectin, vitronectin, and fibrinogen-are adsorbed to the surface of the catheter immediately after insertion. These proteins can interfere with the biological systems of the host and mediate staphylococcal adhesion to the surface of the catheter. In the present study, the presence of fibronectin, vitronectin, and fibrinogen on CSF shunts and temporary ventricular drainage catheters is shown. The presence of fragments of fibrinogen is also examined. Methods. The authors used the following methods: binding radiolabeled antibodies to the catheter surface, immunoblotting of catheter eluates, and scanning force microscopy of immunogold bound to the catheter surface. The immunoblot showed that vitronectin was adsorbed in its native form and that fibronectin was degraded into small fragments. Furthermore, the study demonstrated that the level of vitronectin in CSF increased in patients with an impaired CSF-blood barrier. To study complement activation, an antibody that recognizes the neoepitope of activated complement factor C9 was used. The presence of activated complement factor C9 was shown on both temporary catheters and shunts. Conclusions. Activation of complement close to the surface of an inserted catheter could contribute to the pathogenesis of CSF shunt infection.
9.
10.
van der Wijngaart, Wouter, et al.
(författare)
Valve-less diffuser fluid micropump
1999
Ingår i: Gordon Research Conference 1999, Analytical Chemistry, New Hampshire, USA.
Konferensbidrag (refereegranskat)
11.
Arroyo-Yanguas, Yolanda, et al.
(författare)
Binding, internalization, and degradation of antiproliferative heparan sulfate by human embryonic lung fibroblasts
1997
Ingår i: Journal of Cellular Biochemistry. - 0730-2312. ; 64:4, s. 595-604
Tidskriftsartikel (refereegranskat) abstract
Binding, internalization, and degradation of 125I-labeled, antiproliferative, or nonantiproliferative heparan sulfate by human embryonic lung fibroblasts was investigated. Both L-iduronate-rich, antiproliferative heparan sulfate species as well as L-iduronate-poor, inactive ones were bound to trypsin-releasable, cell-surface sites. Both heparan sulfate types were bound with approximately the same affinity to one high-affinity site (Kd approximately 10(-8) M) and to one low-affinity site (Kd approximately 10(-6) M), respectively. Results of Hill-plot analysis suggested that the two sites are independent. Competition experiments with unlabeled glycosaminoglycans indicated that the binding sites had a selective specificity for sulfated, L-iduronate-rich heparan sulfate. Dermatan sulfate, which is also antiproliferative, was weakly bound to the cells. The antiproliferative effects of heparan and dermatan sulfate appeared to be additive. Hence, the two glycosaminoglycans probably exert their effect through different mechanisms. At concentrations above 5 micrograms/ml (approximately 10(-7) M), heparan sulfate was taken up by human embryonic lung fibroblasts, suggesting that the low-affinity site represents an endocytosis receptor. The antiproliferative effect of L-iduronate-rich heparan sulfate species was also exerted at the same concentrations. The antiproliferative species was taken up to a greater degree than the inactive one, suggesting a requirement for internalization. However, competition experiments with dextran sulfate suggested that both the high-affinity and the low-affinity sites are involved in mediating the antiproliferative effect. Structural analysis of the inactive and active heparan sulphate preparations indicated that although sulphated L-iduronate appears essential for antiproliferative activity, it is not absolutely required for binding to the cells. Degradation of internalized heparan sulfate was analyzed by polyacrylamide gel electrophoresis using a sensitive detection technique. The inactive species was partially degraded, whereas the antiproliferative one was only marginally affected.
12.
Ahrenstedt, O, et al.
(författare)
Increased luminal release of hyaluronan in uninvolved jejunum in active Crohn's disease but not in inactive disease or in relatives.
1992
Ingår i: Digestion. - 0012-2823 .- 1421-9867. ; 52:1, s. 6-12
Tidskriftsartikel (refereegranskat) abstract
Recently obtained data suggest that there is a subclinic inflammatory activity in the apparently uninvolved intestinal mucosa in Crohn's disease (CD). As CD is characterized by an activation of connective tissue and fibrosis, we investigated the extent to which hyaluronan (HA), an essential component of the connective tissue, was released into the lumen of an isolated jejunal segment in CD patients and in relatives. Patients with active CD of the terminal ileum (CD activity index, CDAI, > 150; n = 14), patients with CD in remission (CDAI < 150 n = 10), first-degree relatives of the CD patients (n = 21) and healthy controls (n = 43) were orally intubated with a catheter allowing occlusion and perfusion of a segment of the proximal jejunum. The jejunal fluid concentration of HA was 65 +/- 45 micrograms/l in patients with active CD in the terminal ileum, significantly higher than the value for 43 healthy controls (42 +/- 23 micrograms/l; p < 0.05), and the corresponding values for patients in remission (42 +/- 23 micrograms/l) and for first-degree relatives of the CD patients (53 +/- 52 micrograms/l), were not increased compared to the control group. To localize HA in the tissue, small bowel biopsies were taken during surgery from patients with CD and from controls and affinity stained for HA. There was an intense staining for HA in the lamina propria of the villi, both in biopsies from patients with CD and from controls, but no staining in the epithelium.(ABSTRACT TRUNCATED AT 250 WORDS)
13.
Chen, Q, et al.
(författare)
Desaturation and chain elongation of n - 3 and n - 6 polyunsaturated fatty acids in the human CaCo-2 cell line
1993
Ingår i: Biochimica et Biophysica Acta. - : Elsevier BV. - 0006-3002. ; 1166:2-3, s. 193-201
Tidskriftsartikel (refereegranskat) abstract
Human CaCo-2 cells were incubated with [14C]linoleic (18:2(n - 6)), [14C]linolenic (18:3(n - 3)) and [3H]eicosapentaenoic acid (20:5(n - 3)), and the interconversion of the radioactive fatty acids to higher homologues and their acylation into triacylglycerols (TG) and phospholipids were examined. An active conversion of [14C]18:3 to [14C]20:5 and [14C]docosapentaenoic acid (22:5(n - 3)) and of [3H]20:5 to [3H]22:5, but not to [3H]docosahexaenoic acid (22:6(n - 3)) was observed. In relation to the amounts that had been incorporated into cellular phospholipids and TG, the interconversion of [14C]18:3 clearly exceeded that of [14C]18:2. Addition of 10-100 microM 18:2 or 10-50 microM arachidonic acid (20:4(n - 6)) increased the percent interconversion of [14C]18:2 to [14C]20:4. E.g., addition of 50 microM 20:4 increased the formation of [14C]20:4 from 4.4 +/- 0.1% to 5.9 +/- 0.8%, decreased the incorporation into phospholipids from 64.8 +/- 6.3% to 31.4 +/- 1.2% and increased the incorporation into TG from 8.8 +/- 0.4% to 28.8 +/- 1.1%. In contrast, addition of 10-100 microM 18:3 or 20:5 significantly decreased the interconversion of both [14C]18:2 and [14C]18:3. E.g., addition of 50 microM 20:5 decreased the formation of [14C]20:4 from [14C]18:2 from 4.4 +/- 0.1% to 0.9 +/- 0.1%, whereas the effects on the acylation reactions were very similar to those of 20:4. 20:5 also decreased the formation of interconversion products from [14C]18:3. 18:2 and 20:4 caused a smaller decrease in the formation of [14C]20:5 and actually increased percent conversion to [14C]22:5. The percent conversion of [3H]20:5 to [3H]22:5 was also increased by the addition of 50-100 microM unlabeled 20:5. [14C]18:2 and [14C]18:3 were predominantly incorporated into phosphatidylcholine (PC) whereas more of the radioactive 20:4, 20:5 and 22:5 was incorporated into phosphatidylethanolamine (PE). An active fatty acid interconversion catalyzed by delta 6 and delta 5 desaturases thus occurs in the human CaCo-2 cell line, whereas conversion of 20:5(n - 3) to 22:6(n - 3) could not be demonstrated. The desaturation-elongation pathway has a preference for 18:3(n - 3) and is subjected to an efficient feedback regulation by 20:5(n - 3). Formation of 22:5 increases with available 20:5 mass and by the presence of other polyunsaturated fatty acids competing with 20:5 for acylation into phospholipids.
14.
Eriksson, Johan, et al.
(författare)
Decabromodiphenyl ether
1999
Ingår i: Acta crystallographica Section C. - : Wiley. - 0108-2701. ; 55:12, s. 2169-2171
Tidskriftsartikel (refereegranskat) abstract
Bis(pentabromophenyl) ether, C12Br100, shows strangedifferences in the endocyclic angles between the twodifferent rings, although they are both substituted inthe same manner. Several short van der Waals contact distances give clues to the anomalous endocyclic anglesand some hints to the formation of decompositionproducts. We suggest that the intermolecular Br...Brcontacts contribute to the distortions of the ring systems.Usually distortions of this kind would be explained fromhighly anisotropic TLS behaviour, but the data from thetitle compound do not show any conclusive TLS effects.
15.
Falkenberg, Maria, 1968, et al.
(författare)
The herpes simplex virus type 1 helicase-primase. Analysis of helicase activity.
1998
Ingår i: The Journal of biological chemistry. - 0021-9258. ; 273:48, s. 32154-7
Tidskriftsartikel (refereegranskat) abstract
The rate of unwinding of duplex DNA by the herpes simplex virus type 1 (HSV-1)-encoded helicase-primase (primosome) was determined by measuring the rate of appearance of single strands from a circular duplex DNA containing a 40-nucleotide 5' single-stranded tail, i.e. a preformed replication fork, in the presence of the HSV-1 single strand DNA-binding protein, infected cell protein 8 (ICP8). With this substrate, the rate at low ionic strength was highly sensitive to Mg2+ concentration. The Mg2+ dependence was a reflection of both the requirement for ICP8 for helicase activity and the ability of ICP8 to reverse the helicase reaction as a consequence of its capacity to anneal homologous single strands at Mg2+ concentrations in excess of 3 mM. The rate of unwinding of duplex DNA by the HSV-1 primosome was also determined indirectly by measuring the rate of leading strand synthesis with a preformed replication fork as template in the presence of the T7 DNA polymerase. The value of 60-65 base pairs unwound/s by both methods is consistent with the rate of 50 base pairs/s estimated for the rate of fork movement in vivo during replication of pseudorabies virus, another herpesvirus. Interaction with the helicase-primase did not increase its helicase activity.
16.
Falkenberg, Maria, 1968, et al.
(författare)
The UL8 subunit of the heterotrimeric herpes simplex virus type 1 helicase-primase is required for the unwinding of single strand DNA-binding protein (ICP8)-coated DNA substrates.
1997
Ingår i: The Journal of biological chemistry. - 0021-9258. ; 272:36, s. 22766-70
Tidskriftsartikel (refereegranskat) abstract
The Herpes simplex virus type 1 primosome consists of three subunits that are the products of the UL5, UL8, and UL52 genes. The heterotrimeric enzyme has DNA-dependent ATPase, helicase, and primase activities. Earlier studies show that a subassembly consisting of the UL5 and UL52 gene products was indistinguishable from the heterotrimeric enzyme in its helicase and primase activities. We demonstrate here that the UL8 protein is required for the helicase activity of the UL5/52 subassembly on long duplex DNA substrates (>30 nucleotides) with a single-stranded DNA loading site fully coated with the virus-encoded single strand DNA binding protein, ICP8. The Escherichia coli single strand DNA binding protein cannot substitute for ICP8, suggesting a specific physical interaction between ICP8 and the UL8 protein. Surface plasmon resonance measurements demonstrated an interaction between ICP8 and the UL5/52/8 heterotrimer but not with the UL5/52 subassembly or the UL8 protein alone. At a subsaturating level of ICP8, the UL5/52 subassembly does show helicase activity, suggesting that the subassembly can bind to single-stranded DNA but not to ICP8-coated DNA.
17.
Farzad, A, et al.
(författare)
Luminal release of hyaluronan (hyaluronic acid) in intestinal ischemia in the rat.
1993
Ingår i: Digestion. - 0012-2823 .- 1421-9867. ; 54:3, s. 168-72
Tidskriftsartikel (refereegranskat) abstract
Hyaluronan (HA) is a glycosaminoglycan, the water-binding properties of which are suggested to be pivotal for an optimal hydration of tissues. The lamina propria of the intestinal villi is characterized by a high concentration of HA. Increased amounts of HA are observed in the intestinal lumen in patients with Crohn's disease. We have evaluated whether epithelial denudation as such is sufficient to increase the concentration of HA in the lumen of the small intestine. Epithelial damage was accomplished by reversible ischemia-reperfusion injury to the rat ileum and the concentration of HA was determined in luminal perfusate. The perfusate concentration of HA was increased from 26 +/- 8 micrograms/l before ischemia, to 68 +/- 13 and 41 +/- 12 micrograms/l 0-30 and 30-60 min after a 60-min period of subtotal ischemia without venous stasis (p < 0.05). In sham-operated animals, in contrast, the perfusate concentration of HA was virtually unchanged (31 +/- 18, 13 +/- 3 and 10 +/- 1 microgram/l, respectively). Specific staining for HA on sections revealed loss of HA from the villus tips after ischemia. The results show that epithelial denudation results in loss of HA from the villus interstitium to the intestinal lumen.
18.
19.
20.
21.
22.
23.
24.
25.
Gerdin, Bengt, 1947-, et al.
(författare)
Dynamic role of hyaluronan (HYA) in connective tissue activation and inflammation.
1997
Ingår i: Journal of Internal Medicine. - 0954-6820 .- 1365-2796. ; 242:1, s. 49-55
Tidskriftsartikel (refereegranskat) abstract
An increased tissue accumulation of HYA occurs in several human and experimental inflammatory conditions. Such is the case in sarcoidosis, idiopathic pulmonary fibrosis and farmer's lung in man, and experimental bleomycin-induced lung damage in rats. Graft rejection in man and rats, experimental myocarditis in mice and myocardial infarction in rats follow the same pattern. Increased amounts of HYA also appear in gut luminal perfusion fluid in human inflammatory bowel disease. A transient accumulation of HYA is seen in wound healing, which is more sustained in fetuses. An increased accumulation of water and presentation of ligands for receptors on inflammatory cells are two consequences of the HYA accumulation.
26.
Hagberg, L, et al.
(författare)
Determination of biomechanical characteristics of restrictive adhesions and of functional impairment after flexor tendon surgery : a methodological study of rabbits.
1991
Ingår i: Journal of Biomechanics. - 0021-9290 .- 1873-2380. ; 24:10, s. 935-42
Tidskriftsartikel (refereegranskat) abstract
Formation of restrictive adhesions is one of the main obstacles in rehabilitation following hand surgery. Most experimental work, however, involves only a macroscopic and/or histologic evaluation of the amount of adhesions, and their functional characteristics are poorly described. The aim of this study was to develop an experimental technique for characterization of the biomechanical properties of the finger-tendon unit. An instrument was developed for continuous and simultaneous recording of tensile load, tendon excursion and angular rotation in the distal interphalangeal joint of rabbit digits. Utilizing this instrument, it was revealed that the first 50 degrees of flexion required virtually no tensile load either in unoperated digits or immediately after tenorrhaphy. Thereafter, the load required to obtain further flexion was progressively increased. The strength of adhesions, determined 2 weeks after tenorrhaphy, was best expressed as the maximum tensile load recorded before 50 degrees of flexion was reached. This measurement could also be used to register the strength of the tendon repair and to detect partial tendon rupture during the measurement. The technique allows both adequate measurements of the strength of the adhesions and of the tendon gliding ability after flexor tendon surgery.
27.
Hagberg, L, et al.
(författare)
Elimination of exogenously injected sodium-hyaluronate from rabbit flexor tendon sheaths.
1991
Ingår i: Journal of Orthopaedic Research. - : Wiley. - 0736-0266 .- 1554-527X. ; 9:6, s. 792-7
Tidskriftsartikel (refereegranskat) abstract
To obtain information about the elimination of Na hyaluronate (NaHe) deposited in flexor tendon sheaths in rabbits, two flexor tendon sheaths from each hind limb were operatively exposed in 15 animals and each filled with one of four different NaHe preparations, namely: 10 mg/ml, MW 2.6 x 10(6); 10 mg/ml, MW 6.3 x 10(6); 19 mg/ml, MW 3.0 x 10(6); and 19 mg/ml, MW 6.5 x 10(6). One, 3, and 7 days after surgery, the NaHe concentration was measured in frozen specimens from the tendon sheaths. One day after surgery, NaHe concentration in the tendon sheath fluid was close to 10 mg/ml in all groups. Three and 7 days after surgery it was higher in tendon sheaths in which NaHe preparations with a high (19 mg/ml) rather than with a low concentration (10 mg/ml) had been deposited. At 3 days, NaHe concentration was also higher in sheaths that had received a preparation with a high MW (6.5 x 10(6)) than those with a lower MW (2.6 or 3.0 x 10(6)). The findings suggest that within the first 24 h, a dilution of concentrated NaHe preparations takes place, probably as a result of their hyperoncotic properties. After 24 h, there was a slower decline in NaHe concentration when more concentrated solutions (19 mg/ml) and solutions with high MWs (6.5 x 10(6)) were administered. Development of pharmaceutical NaHe preparations with slow elimination from tendon sheaths should reasonably be focused on a solution with a high MW and high concentration.
28.
Hagberg, L, et al.
(författare)
Hyaluronic acid in flexor tendon sheath fluid after sheath reconstructions in rabbits. A comparison between tendon sheath transplantation and conventional two stage procedures.
1991
Ingår i: Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. - 0284-4311 .- 1651-2073. ; 25:2, s. 103-7
Tidskriftsartikel (refereegranskat) abstract
Because the synovial environment has been suggested to be important in limiting the number of postoperative adhesions after flexor tendon surgery, and a high concentration of hyaluronic acid is a characteristic feature of synovial fluid, we have examined the hyaluronic acid concentrations in fluid collected from different kinds of reconstructed flexor tendon sheaths in rabbits. The hyaluronic acid concentration in normal rabbit flexor tendon sheaths was similar to that in normal human sheath and joint fluid. Rabbit tendon sheaths restored by autologous sheath grafts and partial pseudosheaths contained similar or somewhat lower hyaluronic acid concentrations, whereas in complete pseudosheaths the concentrations were considerably lower. The data suggest that tendon sheath reconstructions should consist at least partly of synovial membrane so that they are as similar as possible to normal synovial membrane.
29.
Hagberg, L, et al.
(författare)
Sodium hyaluronate as an adjunct in adhesion prevention after flexor tendon surgery in rabbits.
1992
Ingår i: Journal of Hand Surgery-American Volume. - 0363-5023 .- 1531-6564. ; 17:5, s. 935-41
Tidskriftsartikel (refereegranskat) abstract
Topical application of sodium-hyaluronate (NaHe) has been proposed to decrease the formation of adhesions after tendon surgery, but reports published thus far have been contradictory. A new test instrument capable of simultaneous registration of tensile load, tendon excursion, and joint motion was therefore developed and used to evaluate the effect of locally administered NaHe of different concentrations and molecular weights on the outcome after tenorrhaphy of rabbit hindlimb flexor tendons. Immediately after tenorrhaphy, NaHe or saline solution was deposited into the tendon sheath. The functional characteristics of the digits were evaluated 15 days after surgery. NaHe with a concentration of 19 mg/ml and a molecular weight of 6 x 10(6) significantly limited the strength of the adhesions formed without impairment of tensile strength. These results suggest that the efficacy of NaHe is affected by both the concentration and the molecular weight of the NaHe preparation used.
30.
Haglund, U, et al.
(författare)
Oxygen-free radicals (OFR) and circulatory shock.
1991
Ingår i: Circulatory shock. - 0092-6213. ; 34:4, s. 405-11
Tidskriftsartikel (refereegranskat) abstract
During the past decade a large body of information has been collected showing that formation of short-lived highly reactive metabolites (i.e., radicals) constitutes an important principle of tissue injury. There are several sources of information which suggest that radicals are formed in connection with tissue ischemia and shock, and they may then cause damage to cells and contribute to the pathophysiology of ischemia and shock. In the present review we attempt to discuss how radicals damage tissue as well as the data which suggest that radicals are causing tissue injury in shock.
31.
Hallengren, B, et al.
(författare)
80-year-old men have elevated plasma concentrations of catecholamines but decreased plasma renin activity and aldosterone as compared to young men
1992
Ingår i: Aging (Milan, Italy). - 0394-9532. ; 4:4, s. 5-341
Tidskriftsartikel (refereegranskat) abstract
Plasma concentrations of adrenaline, noradrenaline, aldosterone and plasma renin activity were determined in a selected group of 80-year-old men (N = 41) in good health without clinical signs of cardiovascular disease, and were compared to levels in young healthy males (N = 20, 24-28 years). Plasma adrenaline and noradrenaline concentrations were higher (0.24 median; 25th-75th percentiles 0.16-0.34 nmol/L vs 0.15; 0.11-0.18 nmol/L, p < 0.01 and 2.22; 1.58-3.27 nmol/L vs 1.15; 1.00-1.74 nmol/L, p < 0.001), and plasma renin activity and plasma aldosterone concentration were lower in the old than in the young men (0.65; 0.35-1.04 micrograms/L/1h vs 2.09; 1.23-2.41 micrograms/L/1h, p < 0.001 and 0.12; 0.09-0.19 nmol/L vs 0.38; 0.28-0.54 nmol/L, p < 0.001). In conclusion, increased plasma concentrations of catecholamines and decreased plasma concentration of aldosterone and plasma renin activity in old men, as compared to young men, must be considered when interpreting data of these hormones in elderly men.
32.
Holtz, A, et al.
(författare)
Effect of methylprednisolone on motor function and spinal cord blood flow after spinal cord compression in rats.
1990
Ingår i: Acta Neurologica Scandinavica. - 0001-6314 .- 1600-0404. ; 82:1, s. 68-73
Tidskriftsartikel (refereegranskat) abstract
The effect of methylprednisolone (MP) on neurologic recovery and spinal cord blood flow (SCBF) was investigated up to 4 days after a spinal cord compression injury in rats. The injury was produced at midthoracic level by applying a load of 35 g on a 2.2 x 5.0 mm compression plate for 5 min, which resulted in transient paraparesis. MP was given as a bolus dose of 30 mg/kg i.v. 60 min after injury (n = 20) and controls were given saline (n = 10). The motor performance was assessed daily as the capacity angle on the inclined plane and SCBF was measured by 14C-iodoantipyrine autoradiography on Days 1 or 4. On Day 1 the capacity angle was reduced from about 63 degrees preoperatively to 33 +/- 2 degrees (mean +/- SEM) in the control group and to 50 +/- 1 degrees in the group treated with MP (p less than 0.05). Thereafter there was a slight improvement in both groups, but the difference persisted throughout the observation period. On Day 4 both gray and white matter SCBF was better preserved in MP-treated animals than in the control group (59 +/- 4 versus 49 +/- 3 ml/min/100 g tissue for gray matter and 13.6 +/- 0.6 versus 10.7 +/- 0.8 ml/min/100 g tissue for white matter). Posttraumatic treatment with MP, thus, improved both the neurologic recovery during the first 4 days and SCBF as measured on Day 4. It is speculated that the effect of MP is at least partly exerted on the vascular bed.
33.
Holtz, A, et al.
(författare)
Efficacy of the 21-aminosteroid U74006F in improving neurological recovery after spinal cord injury in rats.
1992
Ingår i: Neurological Research. - 0161-6412 .- 1743-1328. ; 14:1, s. 49-52
Tidskriftsartikel (refereegranskat) abstract
The efficacy of three different regimens of the 21-aminosteroid U74006F in counteracting the neurological damage after spinal cord compression causing paraparesis in rats was investigated. Three groups of ten animals each were given totally 6 mg/kg of U74006F in different regimens beginning one hour after injury (A: bolus doses of 1.5 mg/kg at 1, 4, 7 and 10 hours; B: bolus of 1.5 mg/kg at 1 hour and 4.5 mg/kg as an infusion over the next 9 hours; and C: infusion alone, 6 mg/kg, given between 1 and 10 hours after trauma). Two groups of ten animals each received vehicle alone in administration modes comparable to those of the U74006F treated animals. The motor function was assessed daily on the inclined plane. On day one, the capacity angle had decreased from about 62 degrees preoperatively to 28-30 degrees in the two vehicle-treated groups and in group C. In these groups there was a similar improvement in neurological function and on day 9 the capacity angles were 49-55 degrees. In groups A and B, both of which received a bolus dose of U74006F at 1 hour, the neurological outcome improved on day one with capacity angles of 38-40 degrees. The difference in neurological function between the animals given U74006F as bolus doses and those given vehicle alone persisted over the entire observation span until day 9. The data suggest that early treatment with a bolus dose seems to be required in order to obtain an effect of U74006F on neurological recovery.
34.
Holtz, A, et al.
(författare)
MK 801, an OBS N-methyl-D-aspartate channel blocker, does not improve the functional recovery nor spinal cord blood flow after spinal cord compression in rats.
1991
Ingår i: Acta Neurologica Scandinavica. - 0001-6314 .- 1600-0404. ; 84:4, s. 334-8
Tidskriftsartikel (refereegranskat) abstract
Damage to the central nervous system is followed by local release of excitatory amino acids, e.g. glutamate. These have been claimed to increase the metabolic need of already hypoxic neurons, and thereby to promote cell death. To investigate whether N-methyl-D-aspartate (NMDA) receptor-mediated mechanisms are involved in the damage consequent to spinal cord injury, 20 rats were exposed to 5-min compression of the thoracic spinal cord produced with a load of 35 g on a 2.2 x 5 mm sized plate. One group of animals was given a noncompetitive NMDA channel blocker, MK-801, in a dose of 10 mg/kg b.w and one group saline alone. The neurologic function was evaluated on the inclined plane for 4 days when spinal cord blood flow (SCBF) was measured with the 14C-iodoantipyrine autoradiographic technique. One day after trauma the animals in both groups were paraparetic and exhibited a significantly decreased capacity angle at the inclined plane test (about 35 degrees compared with about 63 degrees before compression). Thereafter, the motor function improved slightly, but to a similar extent in the two groups. On Day 4, gray and white matter SCBF was similar in the two groups. The results indicate that MK 801 in the dose used does not prevent the development of neurologic dysfunction or the reduction in SCBF after spinal cord compression.
35.
Holtz, A, et al.
(författare)
Neuropathological changes and neurological function after spinal cord compression in the rat.
1990
Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 7:3, s. 155-67
Tidskriftsartikel (refereegranskat) abstract
As part of a series of experimental investigations of the effects of various pharmacological agents on the outcome of compressive spinal cord trauma in the rat, the time course of the cell changes in the cord at the site of and distal to the compression was studied at the light microscopic level. The degree of compression used with the present model results in a transient paraparesis that recovers almost completely over a period of 3 weeks as judged by the inclined plane technique. The most significant morphological findings were as follows. Initially (1 and 24 h after the impact) there was pronounced swelling and hemorrhage at the compression site, chiefly in the gray matter of the cord. On day 4 there was severe necrosis in the same region, with numerous macrophages and leukocytes. Rats killed after 21 days showed either minor residual signs of necrosis or essentially normal tissue architecture. Surprisingly, necrosis with delayed onset also developed in the dorsal columns, involving the pyramidal tracts. This necrosis was detected in animals killed after 9 and 21 days but not in those observed after 4 days or earlier. The longitudinal tracts of the white matter showed reduced staining in paraffin sections of the compression site. Epon sections revealed splits in the myelin sheaths and enlarged periaxonal spaces as early as 1 h after the impact. The alterations in the longitudinal tracts persisted throughout the 21-day observation period and extended down to L2-L4. There was gradual functional recovery, documented by the inclined plane test. Preinjury values were almost reached on day 21, although the cord still showed some morphological damage. In individual animals, no relation was found between degree of function as tested by inclined plane and extent of morphologic injury. Additional functional and morphological methods obviously are needed in future investigations of the effects of treatments on the outcome of compressive spinal cord injury.
36.
Holtz, A, et al.
(författare)
Relation between spinal cord blood flow and functional recovery after blocking weight-induced spinal cord injury in rats.
1990
Ingår i: Neurosurgery. - 0148-396X .- 1524-4040. ; 26:6, s. 952-7
Tidskriftsartikel (refereegranskat) abstract
Spinal cord blood flow (SCBF) and motor performance on the inclined plane were measured up to 9 days after a reversible spinal cord compression injury in 49 Sprague-Dawley rats. A load of 35 g on 11 mm2 of the thoracic spinal cord for 5 minutes caused transient paraparesis with a decrease in the capacity angle on the inclined plane from 62 +/- 1 degree (mean +/- SEM) before injury to 33 +/- 1 degree on Day 1, 45 +/- 2 degrees on Day 4, d and 54 +/- 3 degrees on Day 9. SCBF was measured by the [14C]iodoantipyrine method, and in gray matter there was a decrease from 78.4 +/- 2.3 ml/min/100 g of tissue in uninjured animals to 33.7 +/- 1.5 ml/min/100 g of tissue on Day 1 after injury, increasing to 50.1 +/- 2.0 on Day 4 and to 70.5 +/- 2.7 ml/min/100 g of tissue on Day 9. At the corresponding times, the SCBF values in white matter were 14.5 +/- 0.5, 6.7 +/- 0.5, 10.2 +/- 0.6, and 13.4 +/- 0.6 ml/min/100 g of tissue, respectively. The animals in another group were loaded with 25 g for 5 minutes and on Day 1 exhibited a capacity angle of 43 +/- 2 degrees while the SCBF values for gray and white matter were 55.1 +/- 2.0 and 11.1 +/- 0.4 ml/min/100 g of tissue, respectively; thus, the results in this group were similar to the values on Day 4 in the animals loaded with 35 g.(ABSTRACT TRUNCATED AT 250 WORDS)
37.
Hugosson, S, et al.
(författare)
Glycosphingolipid binding specificities of Neisseria meningitidis and Haemophilus influenzae: detection, isolation, and characterization of a binding-active glycosphingolipid from human oropharyngeal epithelium.
1998
Ingår i: Journal of biochemistry. - 0021-924X. ; 124:6, s. 1138-52
Tidskriftsartikel (refereegranskat) abstract
The glycosphingolipid binding specificities of Haemophilus influenzae and Neisseria meningitidis were investigated as to the binding of radiolabeled bacteria to glycosphingolipids on thin-layer chromatograms. Thereby, similar binding profiles, for the binding of the two bacteria to lactosylceramide, isoglobotriaosylceramide, gangliotriaosylceramide, gangliotetraosylceramide, lactotetraosylceramide, neolactotetraosylceramide, and sialylneolactohexaosylceramide, were obtained. On a closer view the binding preferences of the bacteria could be differentiated into three groups. The first specificity is recognition of lactosylceramide. The second specificity is binding to gangliotriaosylceramide and gangliotetraosylceramide, since conversion of the acetamido group of the N-acetylgalactosamine of gangliotriaosylceramide and gangliotetraosylceramide to an amine prevented the binding of the bacteria, and thus the binding to these two glycosphingolipids represents a separate specificity from lactosylceramide recognition. Preincubation of H. influenzae with neolactotetraose inhibited the binding to neolactotetraosylceramide, while the binding to lactosylceramide, gangliotetraosylceramide, or lactotetraosylceramide was unaffected. Thus, the third binding specificity is represented by neolactotetraosylceramide, and involves recognition of other neolacto series glycosphingolipids with linear N-acetyllactosamine chains, such as sialyl-neolactohexaosylceramide. The relevance of the detected binding specificities for adhesion to target cells was addressed as to the binding of the bacteria to glycosphingolipids from human granulocytes, epithelial cells of human nasopharyngeal tonsils and human plexus choroideus. Binding-active neolactotetraosylceramide was thereby detected in human granulocytes and the oropharyngeal epithelium.
38.
Hällgren, R, et al.
(författare)
Accumulation of hyaluronan (hyaluronic acid) in myocardial interstitial tissue parallels development of transplantation edema in heart allografts in rats.
1990
Ingår i: Journal of Clinical Investigation. - 0021-9738 .- 1558-8238. ; 85:3, s. 668-73
Tidskriftsartikel (refereegranskat) abstract
By using biotin-labeled proteoglycan core protein, hyaluronan (hyaluronic acid; HA) was visualized in rat heart grafts at different times (2, 4, and 6 d) after transplantation. In normal, nontransplanted hearts HA was present in the adventitia of arteries and veins and in the myocardial interstitial tissue. An increased accumulation of HA was evident in the edematous interstitial tissue, infiltrated with lymphocytes, on day 4 after allogeneic transplantation, and was even more pronounced by day 6. No apparent increase in HA was seen in syngeneic grafts. Biochemical assay of HA in heart tissue demonstrated that the myocardial content of HA had increased 60% by day 2 after transplantation in allogeneic as well as syngeneic grafts, indicating that surgical trauma may induce some HA accumulation in heart grafts. The extractable amount of HA declined during the following days in the syngeneic grafts, but increased progressively during the development of rejection in the allogeneic grafts, and increased on average three times by day 6. The relative water content also increased progressively during rejection of allogeneic grafts and correlated with the HA accumulation. The interstitial accumulation of HA, a glycosaminoglycan with unique water-binding qualities, is presumably implicated in the development of interstitial edema during rejection of heart grafts.
39.
Hällgren, R, et al.
(författare)
Hyaluronic acid accumulation and redistribution in rejecting rat kidney graft. Relationship to the transplantation edema.
1990
Ingår i: Journal of Experimental Medicine. - 0022-1007 .- 1540-9538. ; 171:6, s. 2063-76
Tidskriftsartikel (refereegranskat) abstract
By using biotin-labeled proteoglycan core protein and an avidin-enzyme system, hyaluronic acid (HA) was visualized in rat kidney. In the normal kidney, HA was localized in the extracellular space of the inner medulla and increased markedly towards the papillary tip. No staining for HA was seen in the interstitial tissue of the cortex or the outer medulla. During the development of rejection of allogeneic renal grafts, a progressive increase in accumulated HA was seen in the interstitial tissue of the cortex and outer medulla. The extractable amounts of HA increased, on average, 40 times in the cortex and outer medulla; no increase was measured in the inner medulla and papilla. The relative water content of the cortex and outer medulla also increased progressively and correlated with the HA accumulation. The extractable amounts of HA in syngeneic grafts increased by day 2 and then leveled off, indicating that surgical trauma may induce some transient HA accumulation after transplantation. Interstitial accumulation of HA, a glycosaminoglycan with unique water-binding qualities, would presumably influence water transport and osmotic activity and should thereby be implicated in the normal papillary function, but also in the development of the interstitial edema of the cortex and outer medulla during rejection of renal grafts.
40.
Jahnson, S, et al.
(författare)
Anastomotic blood-flow reduction in rat small intestine with chronic radiation damage.
1998
Ingår i: Digestion. - 0012-2823 .- 1421-9867. ; 59:2, s. 134-41
Tidskriftsartikel (refereegranskat) abstract
BACKGROUND/AIMS: Anastomoses in previously irradiated intestine are prone to leakage, possibly due to an impeded blood supply. Whether or not chronic radiation damage actually predisposes to a disturbed blood flow in the vicinity of anastomoses was investigated in the rat small bowel.METHOD: A 2-cm segment of rat ileum was irradiated with a single dose (21 Gy). After 20 weeks an anastomosis was created in the irradiated segment and in the corresponding segment of controls. Another 4 days later local blood flow was studied with the 14C-iodoantipyrine autoradiography technique in 16 sectors around the circumference both in the anastomotic segment and in a segment 4 mm apart.RESULTS: In the anastomotic segment, the average blood flow was reduced in irradiated compared with non-irradiated animals in the mucosal layer (p = 0.034), but not in the muscular layer (p = 0.08). In the mesenteric quadrant blood flow was reduced in irradiated compared with non-irradiated animals, both in the mucosal layer (p = 0.012) and in the muscular layer (p = 0.05). More irradiated than non-irradiated animals showed a blood-flow reduction to 15% or more in 13-16 sectors both in the mucosal (p = 0.015) and the muscular layer (p = 0.04).CONCLUSIONS: The results favor the hypothesis that anastomoses in previously irradiated intestine are vascularly compromized and thereby have an increased risk of leakage.
41.
Jahnson, S, et al.
(författare)
Anastomotic breaking strength and healing of anastomoses in rat intestine with and without chronic radiation damage.
1995
Ingår i: European Journal of Surgery. - 1102-4151 .- 1741-9271. ; 161:6, s. 425-30
Tidskriftsartikel (refereegranskat) abstract
OBJECTIVE: To assess the influence of chronic radiation damage on anastomotic healing in the small bowel in rats.DESIGN: Controlled laboratory study.SETTING: University hospital, Sweden.MATERIAL: 90 male Sprague-Dawley rats.INTERVENTIONS: A short segment of the distal ileum was exteriorised and irradiated with a single dose (experimental group, n = 45) or exposed only (control group, n = 45). Twenty weeks later resection and anastomosis were done within this segment using 7/0 polypropylene.MAIN OUTCOME MEASURES: The anastomotic breaking strength, the amount of perianastomotic hydroxyproline, and the number of anastomotic complications.RESULTS: The breaking strength and the amount of perianastomotic hydroxyproline were higher in the irradiated than in the non-irradiated group. In contrast, anastomotic complications were significantly more common in irradiated animals.CONCLUSION: Anastomotic complications in irradiated intestine are not related to the amount of perianastomotic collagen or to breaking strength.
42.
Jahnson, S, et al.
(författare)
Prognosis of surgically treated radiation-induced damage to the intestine.
1992
Ingår i: European Journal of Surgical Oncology. - 0748-7983 .- 1532-2157. ; 18:5, s. 487-93
Tidskriftsartikel (refereegranskat) abstract
A series of 88 patients operated on during 24 years for radiation-induced damage (RID) to the intestinal tract were retrospectively reviewed and clinical and surgical factors were related to the ultimate prognosis by multivariate analysis. The first operation was performed on the small intestine in 47 patients, the large intestine in 32 patients or both in nine patients. Postoperative complications occurred in 35 patients (40%), with fatal outcome in 12 (13%). Thirty-one patients (35%) required further surgery and altogether 19 patients (22%) ultimately died from RID. Negative prognostic factors after the first operation were postoperative intestinal leak (P < 0.05) and operation for fistula or perforation (P < 0.01). The outcome after the last operation was negatively influenced by intestinal leak (P < 0.001) by the choice of bypass as operative procedure (P < 0.01) and by operation for fistula or perforation (P < 0.01). In addition, 43% of the patients in whom the disease had progressed between two explorations died from RID. Thus, the severity of the RID as diagnosed at laparotomy, and progression of the disease between two subsequent explorations were related to the prognosis. Care should be taken to avoid intestinal leak. Resections should be preferred to bypass of injured intestine whenever possible.
43.
Jahnson, S, et al.
(författare)
Reduced mucosal perianastomotic capillary density in rat small intestine with chronic radiation damage.
1998
Ingår i: Radiation Research. - 0033-7587 .- 1938-5404. ; 150:5, s. 542-8
Tidskriftsartikel (refereegranskat) abstract
Anastomoses in an intestine with chronic radiation damage are prone to leakage, possibly due to a reduced blood supply induced by a reduced capillary bed. In an animal model, the numerical capillary density in the perianastomotic area was investigated in intestine with or without chronic radiation damage. A 2-cm segment of rat ileum received a single dose of 21 Gy. Twenty weeks later, when the chronic radiation-induced changes were established, an anastomosis was constructed in this segment and in a corresponding segment in control rats. In situ perfusion fixation of the intestine was done 4 or 7 days after construction of the anastomosis, sections of the intestine were removed surgically, the specimens were embedded in methacrylate plastic and sectioned at 2.5 microm, and capillaries were counted under a light microscope. The circumferential mucosal capillary density was lower in irradiated than in nonirradiated animals at both 4 and 7 days (P < 0.001 and P = 0.04, respectively). This reduction was greater in the mesenteric quadrant than in the other quadrants around the circumference. These results are indicative of a reduced capillary bed in the vicinity of anastomoses in intestine with chronic radiation damage, which might lead to an impeded blood supply and subsequent leakage.
44.
Johansson, C B, et al.
(författare)
A removal torque and histomorphometric study of bone tissue reactions to commercially pure titanium and Vitallium implants.
1991
Ingår i: The International journal of oral & maxillofacial implants. - 0882-2786. ; 6:4, s. 437-41
Tidskriftsartikel (refereegranskat) abstract
Screw-shaped commercially pure (CP) titanium and Vitallium implants were inserted in the rabbit tibial metaphysis. After a healing period of 3 months, it was demonstrated that a higher torque was needed to remove the CP titanium implants (average 24.9 Ncm) compared to Vitallium implants (average 11.7 Ncm). The histomorphometric part of the study revealed more bone-to-metal contact for the CP titanium implants (average 34.7%) compared to the Vitallium implants (average 21.7%). The results obtained in this study could be explained by differences in the topography or in biocompatibility of the metals, or a combination of these two factors.
45.
Karlsson, B R, et al.
(författare)
Effect of cerebral ischemia on hypotension-induced increase in plasma vasopressin and hepatic glycogen concentration in the rat.
1991
Ingår i: Circulatory shock. - 0092-6213. ; 34:4, s. 371-8
Tidskriftsartikel (refereegranskat) abstract
The effect of cerebral ischemia on the vasopressin response to hemorrhagic hypotension and on the hepatic and muscular glycogen mobilization was studied in rats. The addition of cerebral ischemia to the hemorrhage required withdrawal of significantly more blood to lower mean arterial pressure (MAP) to 50 mmHg but not if combined with ganglionic blockade. The increase in plasma vasopressin concentration during hypotension was not significantly different in rats with and without concurrent cerebral ischemia. Ganglionic blockade blunted the vasopressin response. Thus cerebral ischemia in fact attenuated the vasopressin response to hemorrhage. One hour after the insult, the hormone concentration in rats exposed to combined cerebral ischemia and hemorrhagic hypotension without ganglionic blockade was still above control levels and higher than in all other groups. Concomitantly the hepatic but not the muscular glycogen concentration in these rats was significantly lower than in the other groups.
46.
Karlsson, Karl-Anders, 1935, et al.
(författare)
Microbial interaction with animal cell surface carbohydrates.
1992
Ingår i: APMIS. Supplementum. - 0903-465X. ; 27, s. 71-83
Tidskriftsartikel (refereegranskat) abstract
Microbes have selected primarily carbohydrates for attachment to host animal cells. Recent studies have revealed essential characteristics in the recognition of receptor carbohydrates. Of importance is the property of recognizing also sequences placed inside an oligosaccharide chain, which differs from most animal antibodies. This is the basis for series of isoreceptors with the minimum receptor sequence in common but with separate neighbouring groups. There are families of microbial ligands that show different preferences for members within one series of isoreceptors, indicating only slight differences in the complementary binding sites of the proteins. Such differences may explain shifts in the selectivity of separate host tissues for infection. A second characteristic is the low affinity interaction often found where simple receptor-containing saccharides are unable to inhibit attachment. Technical possibilities are rapidly developing for the design of synthetic receptor analogues to be used in the therapy of clinical infections. This is urgently needed in cases where no rational therapy exists today.
47.
Karlsson, Karl-Anders, 1935, et al.
(författare)
Unexpected carbohydrate cross-binding by Escherichia coli heat-labile enterotoxin. Recognition of human and rabbit target cell glycoconjugates in comparison with cholera toxin.
1996
Ingår i: Bioorganic & medicinal chemistry. - 0968-0896. ; 4:11, s. 1919-28
Tidskriftsartikel (refereegranskat) abstract
The bacterial protein enterotoxins, cholera toxin (CT) of Vibrio cholerae and heat-labile toxin (LT) of Escherichia coli, induce diarrhea by enhancing the secretory activity of the small intestine of man and rabbit (animal model). This physiological effect is mediated by toxin binding to a glycolipid receptor, the ganglioside GM1, Gal beta 3GalNAc beta 4(NeuAc alpha 3)GAl beta 4Glc beta 1Cer. However, LT, but not CT, was recently shown by us to bind also to paragloboside, Gal beta 4GlcNAc beta 3Gal beta 4Glc beta 1Cer, identified in the target cells. By molecular modeling of this tetrasaccharide in the known binding site of LT, the saccharide-peptide interaction was shown to be limited to the terminal disaccharide (N-acetyllactosamine). This sequence is expressed in many glycoconjugates, and we have therefore assayed glycolipids and glycoproteins prepared from the target tissues. In addition to paragloboside, receptor activity for LT was detected in glycoproteins of human origin and in polyglycosylceramides of rabbit. However, CT bound only to GM1. Two variants of LT with slightly different sequences, human (hLT) and porcine (pLT), were identical in their binding to target glycoproteins and polyglycosylceramides, but different regarding paragloboside, which was positive for pLT but negative for hLT. This difference is discussed on basis of modeling, taking in view the difference at position 13, with Arg in pLT and His in hLT. Although N-acetyllactosamine is differently recognized in form of paragloboside by the two toxin variants, we speculate that this sequence in human glycoproteins and rabbit polyglycosylceramides is the basis for the common binding. Much work remains, however, to clear up up this unexpected sophistication in target recognition.
48.
Karlsson, Niclas G., 1966, et al.
(författare)
Analysis of monosaccharide composition of mucin oligosaccharide alditols by high-performance anion-exchange chromatography.
1995
Ingår i: Analytical biochemistry. - : Elsevier BV. - 0003-2697. ; 224:2, s. 538-41
Tidskriftsartikel (refereegranskat) abstract
A simple one-step method for the analysis of monosaccharides including galactosaminitol after acidic hydrolysis is described. The hydrolyzate was re-N-acetylated and analyzed by high-performance anion-exchange chromatography and the sugars were detected by a pulsed amperometric detector. The method was applied on a mixture of neutral oligosaccharides released from mucin glycopeptides of rat small intestine by alkaline borohydride. Sugars were detected down to the nanomole range and the results were compared with monosaccharide compositional analysis performed by gas chromatography of acetylated alditols.
49.
Krettek, Alexandra, 1968-, et al.
(författare)
Effect of phenotype on the transcription of the genes for platelet-derived growth factor (PDGF) isoforms in human smooth muscle cells, monocyte-derived macrophages, and endothelial cells in vitro
1997
Ingår i: Arteriosclerosis, Thrombosis and Vascular Biology. - : Lippincott Williams & Wilkins. - 1079-5642 .- 1524-4636. ; 17:11, s. 2897-2903
Tidskriftsartikel (refereegranskat) abstract
Proliferation of arterial smooth muscle cells (ASMCs) contributes considerably to enlargement of the arterial wall during atherosclerosis. The platelet-derived growth factor (PDGF) is a well-known mitogen and chemoattractant for ASMCs. Quantitative reverse transcription-polymerase chain reaction showed that cells appearing in atherosclerotic lesions, such as ASMCs, endothelial cells, and monocytes/macrophages, expressed mRNAs for both PDGF A and B chains in vitro, with the highest expression in endothelial cells. On proliferation, ASMCs and endothelial cells upregulated PDGF A mRNA. Differentiation of macrophages increased the amount of both mRNAs. Thus, the regulation of PDGF A- and B-chain expression depends on cell types and phenotypic states of the cells, which have also been found in vivo in human atherosclerotic lesions. PDGF A can be produced as short and long isoforms. The latter binds with high affinity to glycosaminoglycans. Irrespective of phenotype, only the minor part of total PDGF A mRNA consisted of the long variant in ASMCs, while endothelial cells produced 40% of total PDGF A as the long form. The differentiation of macrophages increased the production of the long PDGF A mRNA from 10% to 40%. Thus, increasing numbers of stimulated cells in the atherosclerotic lesion may increase the transcription of PDGF isoforms, and particularly of the long PDGF A isoform. Together with increasing amounts of ASMC-derived proteoglycans in developing lesions, this may contribute to accumulation of PDGF in the arterial wall matrix, resulting in prolonged stimulation of ASMCs.
50.
Lanne, B, et al.
(författare)
Binding of the galactose-specific Pseudomonas aeruginosa lectin, PA-I, to glycosphingolipids and other glycoconjugates.
1994
Ingår i: Glycoconjugate journal. - 0282-0080. ; 11:4, s. 292-8
Tidskriftsartikel (refereegranskat) abstract
The carbohydrate-binding specificity of Pseudomonas aeruginosa lectin I (PA-I) in iodinated or biotinylated form was studied. A large number of glycosphingolipids, as well as some glycoproteins and neoglycoproteins were used as ligands. Also, inhibition by free saccharides of PA-I binding to glycosphingolipids was tested. It was found that the lectin binds most strongly to terminal and nonsubstituted Gal alpha 3Gal- or Gal alpha 4Gal-structures.
