Biomedical subjects

M Laato

Publications and source records attributed to M Laato.

78 records · Page 5Linked to original sources

PubMed1985

Granulation tissue formation in experimental wounds inoculated with Staphylococcus aureus.

The effects of inoculated Staphylococcus aureus microorganisms on developing granulation tissue were studied in rats. Hollow cylindrical viscose cellulose sponges were implanted subcutaneously as an inductive matrix for the growth of granulation tissue. The control implants were injected immediately after implantation with 1 ml of physiological saline while the experimental implants were injected with a corresponding volume of saline solution containing live staphylococci in the following concentrations: 10(2), 10(3), 10(4) or 10(5) microorganisms per milliliter. Analyses of wound fluid and granulation tissue were carried out two weeks after implantation. Implants inoculated with 10(3) or more organisms reproducibly developed infection which delayed healing while implants inoculated with 10(2) bacteria showed no infection and were usually able to clear themselves from the organisms. In the latter implants the number of wound fluid monocytes and macrophages was markedly elevated and the mean amount of collagen hydroxyproline exceeded the control level by 55%. This demonstrates that wound healing can be accelerated to a certain extent by inoculation of live staphylococci. The acceleration concerns only such bacterial concentrations which are able to promote a local inflammatory response but which can be governed by wound defence mechanisms.

Animals↗

PubMed1984

Use of activated clotting time to monitor anticoagulation during cardiac surgery.

The use of a fixed dosage schedule was compared with the use of activated clotting time (ACT) for monitoring heparin anticoagulation and its neutralization during and after extracorporeal circulation in patients undergoing coronary artery bypass grafting. Use of ACT resulted in a statistically significant decrease in heparin and protamine dosages and statistically significant reductions in postoperative blood loss and blood transfusion needs. Postoperative levels of blood hemoglobin concentration were significantly higher and the activated partial thromboplastin time was significantly shorter with ACT monitoring than with use of a fixed dosage schedule. The results confirmed the superiority of the ACT method for monitoring anticoagulation during cardiac surgery.

Blood Coagulation Tests↗

PubMed1983

Effects of extreme haemodilution on the immediate post-operative course of coronary artery bypass patients.

The immediate post-operative course was investigated in 70 patients who had undergone coronary artery bypass grafting under normovolaemic moderate and subsequent extreme haemodilution, and in 70 control patients who underwent a similar operation with a haemic prime in the heart-lung machine. Altogether 8 patients (5.7%), 4 from the haemodilution group and 4 from the controls required re-exploration for excessive post-operative bleeding and were examined as their own group. There were no marked differences in bleeding through chest tubes or in blood haemoglobin concentration between patients who had undergone intra-operative haemodilution and controls. Post-operatively both patient groups required approximately analogous amounts of infused blood, colloids and crystalloids. Central venous pressure was consistently lower in haemodiluted patients. Opening of peripheral circulation as indicated by a rise in skin temperature occurred significantly faster in haemodiluted patients than in controls. Before and after weaning from the respirator, arterial blood oxygen tension was slightly lower in patients who had undergone intra-operative haemodilution. Serum creatinine levels were lower and blood platelet counts significantly higher in haemodiluted patients than in controls. Rates of peri-operative myocardial infarctions showed no essential difference between the groups.

Adult↗

PubMedDate not supplied

Stimulation of wound healing by the immunomodulator LS-2616 (Linomide).

LS-2616 (Linomide), a quinoline-3-carboxamide, is an immunomodulator that has been suggested to act on macrophage-like cells. Based on a hypothesis that LS-2616 would stimulate macrophages in the wound and affect the healing process, the effects of LS-2616 on developing granulation tissue were evaluated using a wound model in rats. Subcutaneously implanted cylindrical cellulose sponges were used as an inductive matrix for the ingrowth of granulation tissue. LS-2616 was continuously present at a concentration of 1.2 mg/ml in the drinking water either for 7 days before implantation or starting at the implantation of sponges. Seven days after implantation LS-2616 treatment increased the mean amounts of nitrogen and collagen hydroxyproline over the control level [+20% (p < 0.05) and +59% (p < 0.05), respectively]. The effect was less pronounced in the rats receiving LS-2616 in advance [+7% (NS) and +38% (p < 0.05), respectively]. The mean amounts of nucleic acids and proteoglycans tended to decrease in the rats receiving LS-2616 in advance compared to the control rats [-12% to 13% (NS) and -25% (p < 0.05), respectively]. It was concluded that continuous oral administration of LS-2616 enhanced wound repair in the rat. This immunoenhancement of wound healing results in increased accumulation of collagen.

Adjuvants, Immunologic↗

PubMedDate not supplied

Different metabolism of hexose sugars and sucrose in wound fluid and in fibroblast cultures derived from granulation tissue, hypertrophic scar and keloid.

Viscose cellulose sponge implants in the rat and fibroblast cultures established from granulation tissue, hypertrophic scar, or keloid were treated with different concentrations of glucose, fructose, galactose, mannose, and sucrose. The concentrations of the above-mentioned sugars in wound fluid and cell culture medium were examined at the termination of experiments by liquid chromatography. Results showed that glucose was present in wound fluid in relatively low levels. In addition to glucose, only mannose was found in wound fluid. On the other hand, cell culture studies showed that virtually all the added sugars were found in cell culture medium. The most prominent exception was the decreased concentration of mannose in keloid fibroblast cultures. In addition, glucose concentration in culture medium of keloid fibroblasts was constantly very low except in mannose-treated cultures where the consumption of glucose was dose-dependently decreased compared to increased mannose concentration. Similarly, increased concentrations of galactose and mannose resulted in dose-dependent lowered consumption of glucose in granulation tissue and hypertrophic scar fibroblasts. These findings suggest that the sugar metabolism may differ in various fibroblast cultures. Further, at least in our wound model, only glucose and mannose are present in wound fluid, and excess sugar is rapidly cleared from wound fluid.

Animals↗

PubMedDate not supplied

Effect of epidermal growth factor (EGF) on blood flow and albumin extravasation in experimental granulation tissue.

This work was prompted by an earlier observation according to which daily local administration of epidermal growth factor (EGF) enhances granulation tissue formation. Effects of EGF on blood flow and albumin extravasation in developing granulation tissue and various skin regions were studied in the rat. Cylindrical hollow cellulose sponge implants were used as an inductive matrix for the growth of granulation tissue. In the test group the implants were injected daily with a solution containing 5 micrograms of EGF in 0.1% albumin while the implants of the control group were treated correspondingly with the carrier solution only. Analyses of local blood flow and albumin extravasation were made 7 days after implantation. In EGF-treated rats granulation tissue blood flow was significantly higher than that in control rats. In both groups blood flow values of the incision scar region were significantly higher than those of the lumbar skin, but no inter-group differences were detected. In implants injected with EGF the albumin extravasation clearly exceeded that of control implants. Albumin extravasation in the incision scar region was higher than that in the lumbar skin in both groups. Elevated local blood flow and increased albumin extravasation as a possible sign of enhanced neovascularization and augmented inflammatory response may partly explain the accelerated repair observed in EGF-treated wounds.

Albumins↗