In vitro leucocyte adhesion to modified polyurethane surfaces. I. Effect of ionizable functional groups.

To study the effect of ionizable functional groups on the adhesion of leucocytes to surfaces, both poly(ethyleneimine) and poly(acrylic acid) were immobilized on polyurethane films, resulting in the introduction of amine and carboxylic acid groups, respectively. This was confirmed by contact angle measurements and XPS analysis. In vitro adhesion of granulocytes and lymphocytes on untreated and modified surfaces was compared. The number of adherent cells on modified surfaces as a function of time was significantly higher than on untreated surfaces. This effect was most pronounced for the adhesion of lymphocytes to surfaces modified with amine groups. In this case, the number of adherent cells after 1 h of exposure was three times higher than on untreated surfaces. A moderate enhancement of leucocyte adhesion was observed in the case of surfaces modified with carboxylic acid groups. There is evidence that these groups were not ionized under the experimental conditions used. The modification procedures described may be used to improve polyurethane filters for the removal of leucocytes from blood.     

Prevention, diagnosis and treatment of blood group immunization during pregnancy

In the Netherlands last year two important policy changes were introduced to prevent haemolytic disease of the newborn: antenatal administration of anti RhD immunoglobulin and screening for antibodies against irregular erythrocyte antigens in all pregnant women. As the predictive value of such antibodies for the detection of hemolytic disease of the newborn is limited, it is uncertain if this measure is really cost-effective. Because blood transfusion is the most important probable cause of the immunization, and because of the clinical severity of anti-K antibodies, it is advised to give exclusively K negative blood to girls and women under the age of 45 years. In addition there is a need for a uniform protocol to deal with women who have been exposed to immunization.     

The hemodynamic effects of cell-free hemoglobin during general and epidural anesthesia

Local anesthetics inhibit edema and improve circulation in experimental burns. We evaluated the effect of topical local anesthetics on human skin burns in volunteers using computerized color analysis that allowed repeated noninvasive quantitative measurements. A standardized partial-thickness burn (1 cm2) was induced in one forearm of 10 healthy volunteers and in the opposite forearm a week later. The burned areas were treated with lidocaine/prilocaine cream (EMLA; Astra, Sweden) or a placebo cream for 1 h. The experimental skin area was photographed before and 1, 2, 4, and 12 h postburn. Digitized images were evaluated using normalized red-green-blue and Hue-Saturation-Intensity. Differences in erythema between skin treated with EMLA and placebo were not significant during the first 4 h postburn. However, 12 h postburn, a pronounced decrease in the degree of erythema was observed in EMLA-treated skin compared with placebo-treated skin. We conclude that topical local anesthetics administered for 1 h postburn significantly reduces the duration of erythema after a mild thermal injury, which suggests a potential use in clinical practice in the treatment of minor skin burns. IMPLICATIONS: Burn injury constitutes a serious type of tissue damage that activates inflammatory mechanisms, often causing pain, disfiguration, or malfunction. We treated burns using an anesthetic cream and demonstrated a reduction in burn-induced inflammation by using computer-based color image analysis.     

Relational support and person characteristics in adolescence

In this paper, an heuristic model of the personality characteristics of adolescents and the supportive dimensions of interactions, relationships and groups is presented. The model takes the concept of developmental tasks as its starting point and it is assumed that developmental tasks can be characterized in terms of four modalities: intentions, behaviour, cognitions and affect. The same four modalities can also be used to characterize dimensions of personality and aspects of interactional and relational support. The results of several empirical studies are presented to illustrate the model. Together, these studies present a transactional picture of the personality of adolescents and their relationships in which personality and relationships influence each other and jointly determine psychosocial functioning.     

Dose distribution in tissues

Biological effects of ionising radiation are dependent on the distribution of doses in tissue. In this article parameters influencing the distribution of dose in tissue are discussed with emphasis on intraoral and rotational panoramic radiography. For both examinations the probability to develop stochastic effects is estimated. For intraoral radiography the probability ranges from 0.1 to 0.3 per million exposures and for rotational panoramic radiography from 0.4 to 0.8 per million. For the whole Dutch population the probability to develop stochastic effects is 0-2 persons per year and 0-1 person per year respectively. Dental radiography is therefore justified if further diagnostic information is to be expected and exposure circumstances are optimal.     

Intra-articular clonidine analgesia after knee arthroscopy

Recently, it was suggested that peripherally-mediated analgesia can be accomplished by the intra-articular delivery of the mu-opioid morphine or of the a2-agonist clonidine. This clinical study assesses the potential peripheral analgesic effect of the combination of morphine and clonidine after intra-articular administration. Sixty patients (American Society of Anesthesiologists status I or II) undergoing arthroscopic repair of the knee during general anaesthesia were randomized to receive after operation, in a double-blind manner, either 1 mg morphine intra-articularly (group 1); 150 microg clonidine intra-articularly (group 2); or 1 mg morphine + 150 microg clonidine intra-articularly (group 3); or normal saline intra-articularly (group 4) in a volume of 30 mL, respectively. Visual analogue pain scores (VAS), duration of analgesia as defined by first demand for supplemental analgesics, subsequent 24 h consumption of postoperative supplementary analgesics, and patient satisfaction were evaluated. Co-administration of morphine + clonidine (group 3) resulted in a significant VAS reduction at 2 h after injection compared with the other groups. There was a tendency towards a lower need for supplementary rescue analgesia and towards a more prolonged analgesia in group 3 (211 min +/- 224 min SD) compared with group 1 (173 min +/- 197 min SD) and group 4 (91 min +/- 21 min SD). More patients were very satisfied with the postoperative analgesic regimen receiving the combination of morphine and clonidine (group 3) at 24 h postoperatively. Thus we conclude, that the peripheral co-delivery of an opioid and an a2-agonist will result in improved postoperative pain relief, when compared with each single agent given alone.     

Interleukin 8 and venous thrombosis: evidence for a role of inflammation in thrombosis

Elevated plasma levels of interleukin 8 (IL-8) were previously shown to be associated with recurrent venous thrombosis. To assess the risk of venous thrombosis, IL-8 plasma concentrations were measured in patients and control subjects of the Leiden Thrombophilia Study (LETS). This population based case-control study included 474 patients with a first deep-vein thrombosis and 474 age- and sex-matched controls. The risk of venous thrombosis for subjects with elevated IL-8 levels (above 90th percentile of controls) compared with subjects with IL-8 levels below the 90th percentile was increased 1.8-fold (95%CI 1.2-2.8). Adjusted for age and sex, the odds ratio was 1.9 (95%CI 1.3-2.8). IL-8 concentrations were weakly correlated with age, male sex, and concentrations of C-reactive protein, factor VIII coagulation activity and homocysteine, but adjustment for these factors did not substantially affect the association between IL-8 and venous thrombosis. Our results suggest that IL-8 is a risk factor for venous thrombosis.