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T Nilsson

Publications and source records attributed to T Nilsson.

At least 271 records · Page 15Linked to original sources
PubMed1983

A new simple method for determination of C1-esterase inhibitor activity in plasma.

A convenient method for the determination of C1-esterase inhibitor activity in plasma samples is described. The method is based on addition of purified C1s to plasma and measuring excess C1s with a new chromogenic tripeptide-p-nitroanilide substrate with a recording spectrophotometer. Addition of C1s to C1-esterase inhibitor-depleted plasma did not result in any appreciable inactivation of the enzyme for three hours. The concentration of C1-esterase inhibitor in 19 healthy individuals was estimated as 1.63 +/- 0.27 (SD) mumol/l. The correlation with C1-esterase inhibitor antigen in these individuals and 19 patients with varying concentrations of C1-esterase inhibitor was excellent. The correlation with an antikallikrein assay was found to be poor.

Complement Activating Enzymes↗
PubMed1983

Venous and nerve invasion as prognostic factors in postoperative survival of patients with resectable cancer of the rectum.

The histopathologic and clinical findings in 682 patients with carcinoma of the rectum have been analyzed. Invasion of veins and nerves by primary growth was found in 38.9 and 34.9 per cent, respectively. The five-year survival rate for patients with resectable tumors was 49 per cent. The age, Dukes' staging, and presence and/or absence of liver metastases, of venous invasion, and of nerve invasion were found to be of statistically significant importance for the prognosis. Sex was found to be on the borderline of significance and Broders' grading was even less significant. Invasion of veins was found statistically significant more frequently than nerve invasion, but the present investigation revealed the importance of the invasion of veins as well as of nerves. When venous invasion was observed, liver metastases developed over three times as frequently in these patients as when metastases were not demonstrated. In contrast to Dukes' staging. Broders' grading can be applied to tumor biopsies preoperatively. The importance of venous and nerve invasion for the selection of patients for adjuvant therapy after termination of surgical treatment is discussed.

Adolescent↗
PubMed1983

Effects of intensive plasmapheresis on the haemostatic system.

Intensive plasmapheresis was performed on 7 alloimmunized pregnant women. About 60% of the plasma volume was removed each day, Monday to Friday, with pauses over the weekends. This treatment resulted in drops in immunoglobulin levels to about 1/3 of the pre-treatment concentrations, whereas the haemostatic parameters studied remained within normal limits. Thus, generally the treatment (as performed in this study) does not seem to induce changes that predispose for thrombotic or haemorrhagic complications. However, in one of the patients, antithrombin III became progressively depleted over the weeks of treatment. Therefore it is suggested that the patients be screened for their haemostatic profile prior to and after a few weeks of plasmapheresis treatment.

Antithrombin III↗
PubMed1982

Studies on a form of alpha 2-antiplasmin in plasma which does not interact with the lysine-binding sites in plasminogen.

A method for the specific determination of a form of alpha 2-antiplasmin which does not interact with the lysine-binding sites in plasminogen (NPB-AP) has been elaborated. Basically, the method is an electroimmnoassay utilizing an intermediate gel, which adsorbs the plasminogen-binding form of alpha 2-antiplasmin (PB-AP). The plasma concentration of NPB-AP in healthy individuals was determined as 0.40 mumol/1 +/- 0.14 (SD), constituting 35% +/- 11 (SD) of the total plasma alpha 2-antiplasmin concentration. During extensive plasmapheresis of two pregnant severely D-immunized women the NPB-AP form decreased significantly, while the PB-AP form increased, thus maintaining the total alpha 2-antiplasmin at an almost constant level. The increased biosynthesis rate of alpha 2-antiplasmin during the extensive plasmapheresis is thus accounted for by PB-AP indicating this form to be the one primarily synthesized and that the non-binding form is formed in plasma from PB-AP secondarily.

Binding Sites↗
PubMed1982

Circular dichroism studies on alpha 2-antiplasmin and its interactions with plasmin and plasminogen.

Spectropolarimetric studies of alpha 2-antiplasmin in the far ultraviolet region indicates a content of 16% alpha-helix, 18% beta-structure and 66% random coil. Two of its three disulphide bridges are reduced under non-denaturing conditions without major changes in conformation of functionality. Cleavage of the third disulphide bridge requires denaturing agents and is accompanied by complete loss of activity. The interaction of alpha 2-antiplasmin with plasminogen or fragments derived from plasminogen by elastase digestion has been studied by circular dichroism analysis in the near ultravoilet region. The results indicate that the fragment of plasminogen constituting the three NH2-terminal triple-loop structures contains at least two lysine-binding sites: one with high affinity and one with low affinity. One of these sites, probably the high-affinity site, is involved in the interaction with alpha 2-antiplasmin. This site seems also to be exposed in the intact plasminogen molecule. The formation of the stable complex between plasmin (EC 3.4.21.7) and alpha 2-antiplasmin is also accompanied by conformational changes.

Binding Sites↗
PubMed1982

Purification and characterization of human C1-esterase inhibitor.

A new purification method for C1-esterase inhibitor is described, which is essentially a three-step procedure: precipitation with poly(ethylene glycol), chromatography on DEAE-cellulose and hydrophobic interaction chromatography on hexyl-Sepharose. The final product is a single-chain glycoprotein with a molecular weight of about 100 000 and NH2-terminal asparagine. The molecule is fully active as judged by complex formation with C1s. Two of its three disulphide bridges can be easily reduced and S-carboxymethylated under non-denaturing conditions without loss of activity. However, at high dithioerythritol concentration the third disulphide bridge is also cleaved and accompanied by loss of the activity, indicating that this disulphide bridge is involved in maintaining the conformation around the reactive site in the inhibitor.

Amino Acids↗
PubMed1982

Biomechanical studies of rabbit abdominal wall. Part I.--The mechanical properties of specimens from different anatomical positions.

Using biomechanical investigations of the intact abdominal wall of the rabbit, the influence of the position (location) of specimens on the mechanical characteristics (the measured variables) was analysed. The intact abdominal wall was investigated in the transverse plane as well as in the longitudinal plane. The mechanical testing was performed using a materials testing machine (Alvetron). The testing revealed that the results for the different measured parameters depended on the position from which specimens originated. The influence of the original position of specimens on the mechanical characteristics was not only due to different quantities and qualities of tissue from different positions, but also might be due to differences in fibre direction in the different specimens. The results obtained are related to biomechanical investigations of wound healing in general.

Abdominal Muscles↗
PubMed1982

Biomechanical studies of rabbit abdominal wall. Part II.--The mechanical properties of specimens in relation to length, width, and fibre orientation.

In a biomechanical investigation of tractus iliotibialis and abdominal wall tissue from rabbits, an analysis was made of the influence that the fibre orientation in specimens as well as the length and width of specimens has on the measured parameters. The mechanical testing was performed with a materials testing machine (Alvetron). The investigation showed that the mechanical characteristics of specimens, when the width was kept constant, depended upon the fibre orientation in the specimens and the length of the specimens. The investigation further demonstrated that in intact abdominal wall no proportionality exists between, on the one side, the width of specimens (2, 4, 6 and 8 mm) and, on the other, the breaking strength, the energy absorption, and the elastic stiffness, respectively. For the 6 day old abdominal wall wounds a proportionality, however, could be demonstrated between the 4 and 8 mm broad specimens on the one side and the breaking strength, the energy absorption, and the elastic stiffness on the other. A possible explanation of the difference between the mechanical characteristics of short and long specimens can be given by the theoretical possibility that the short specimens contain relatively more fibres running all the way through the specimen from clamp to clamp than do the long specimens. The consequences on biomechanical investigations rendered by the result of the analyses are discussed.

Abdominal Muscles↗
PubMed1982

Mechanical properties of Prolene and Ethilon sutures after three weeks in vivo.

The influence of mechanical loading and degradation on the mechanical characteristics of two different materials for suturing, Prolene and Ethilon, is presented. Sutures and loops were dissected out from rabbit abdominal wounds and muscle pockets, respectively, 21 days after implantation. Testing of the sutures and the loops was carried out in a materials testing machine, and the load-deformation curves were recorded, from which a number of parameters were calculated. The investigation showed that sutures undergo in vivo changes in their mechanical characteristics partly due to mechanical loading, and partly to the degradation. The changes were dissimilar in the two materials and moreover, they depended on the size of the suture.

Animals↗
PubMed1982

Effect of strain rate on tensile strength and strain of surgical suture materials.

The present work demonstrates the influence of the strain rate on the mechanical characteristics of Prolene and Ethilon loops. The testing of the loops was performed on a materials testing machine and complete load deformation curves were recorded. Various mechanical parameters were calculated and analysed by computer. The present study demonstrates that calculating energy absorption (areas L/S and S/S) is necessary, and that isolated measurements of breaking strength (Fmax) and tensile strength (delta max) values are misleading as measures of functional suture strength. The investigation showed that the mechanical characteristics of the thread and the knot, and thus the loop, depend on the strain rate and examples are given on the practical importance of this. It is emphasized that the in vivo situation with its varying strain rate necessitates an international standard with more detailed and clinically applicable test procedures for surgical suture material.

Stress, Mechanical↗
PubMed1982

Effect of increased and reduced tension on the mechanical properties of healing wound in the abdominal wall.

Using rabbits as experimental animals, the changes of the mechanical characteristics in different areas of healing abdominal wall wounds were investigated. Wounds closed under 'hyper-tension' and under 'reduced tension' were investigated, as well as wounds closed with Prolene and steel sutures (elastically yielding or immobilizing, respectively). The mechanical testing was performed after healing periods of varying length up to 4 weeks, and the following four parameters were measured: the breaking strength, the energy absorption, the maximum strain, and the elastic stiffness. The investigation showed that strong tension as well as immobilization of the edges of the wound cause a functionally weaker abdominal wall wound. The possible clinical importance of the results is discussed.

Abdominal Muscles↗
PubMed1982

The relative rate of wound healing in longitudinal and transverse laparotomy incisions. Animal experiments.

The wound healing of longitudinal and transverse laparotomy incisions was investigated in rabbits. The longitudinal incision was made in the linea alba cranially and caudally to the umbilicus, and the transverse at the level of the umbilicus. The mechanical testing was performed with a materials testing machine (Alvetron). In order to eliminate the influence on the different incisions of different forces acting upon them the mechanical characteristics of the wounds were expressed in per cent of those from the intact tissues. The measurements of the relative energy absorption displayed no significant difference between healing transverse (comprising rectus muscle) and longitudinal incision wounds. When the rectus wound is excluded, the transverse incision was more resistant to rupture than the longitudinal during the 28 days of wound healing studied. A comparison between the present results and those from investigations of holding power of tissues against suture shows, that the transverse incision should be preferred to the linea alba incision.

Animals↗