Biostability and blood-contacting properties of sulfonate grafted polyurethane and Biomer.

Sulfonate-containing polyurethanes were evaluated for in vivo biodegradation using subcutaneously implanted tensile bars. In addition, these anionically charged polyurethanes were evaluated for in vivo activation of human complement C3a and ex vivo platelet deposition in arteriovenously-shunted canines. The sulfonate derivatized polymers included laboratory synthesized polyurethane and Biomer. Other polymers used for references included Intramedic polyethylene, Silastic and a poly(ethylene oxide) based polyurethane. The biodegradation results indicated that Biomer and the laboratory sulfonated Biomer (both manufactured with stabilizers), remained mechanically stable, retaining both tensile strength and elasticity after 4 weeks of subcutaneous implantation. The unstabilized polyurethanes (with or without sulfonation), however, showed marked cracking and a loss of mechanical properties after the same period of subcutaneous implantation. Sulfonated polyurethanes depressed human complement C3a activation in plasma, as indicated by decreased levels of anaphylatoxin production. The results of canine ex vivo blood contacting experiments were conducted in both an acute and chronic model and demonstrated decreased platelet deposition and activation for the sulfonated polyurethanes.     

Early complications of stenting in patients with congenital heart disease: a multicentre study.

AIMS: Stenting has become an established interventional cardiology procedure for congenital heart disease. Although most stent procedures are completed successfully, complications may occur. This multicentre study evaluated early complications after stenting in patients with congenital heart disease, including potential risk factors. METHODS AND RESULTS: In this combined Dutch-Belgian retrospective study, 309 consecutive patients had undergone 366 catheterizations and received 464 stents in 13 different anatomical positions (418 sites). Seventy-two stenting-related complications (19%) occurred, of which 24 (5.7%) were major. Seven procedure-related deaths were documented (2.3%). Stent malpositioning and embolization were most common (7.7%). The use of non-premounted stents tended to be associated with higher complication rates. Centre inexperience with stenting and stenting of native vs. post-surgical stenosis tended to be associated with increased major complication rates. CONCLUSION: After stenting, complications are common for congenital heart disease. The vast diversity of stenotic sites combined with relatively small patient populations makes these procedures sensitive to complications. Combining operator experience may reduce the risks of stenting in congenital heart disease. The availability of premounted stents for greater vessel diameters will likely reduce incidences of stent migration and embolization.     

Evaluation of stem cell reserve using serial bone marrow transplantation and competitive repopulation in a murine model of chronic hemolytic anemia

Serial transplantation and competitive repopulation were used to evaluate any loss of self-replicative capacity of bone marrow stem cells in a mouse model with increased and persistent hemopoietic demands. Congenic marrows from old control and from young and old mice with hereditary spherocytic anemia (sphha/sphha) were serially transplanted at 35-day intervals into normal irradiated recipients. Old anemic marrow failed or reverted to recipient karyotype at a mean of 3.5 transplants, and young anemic marrow reverted at a mean of 4.0 transplants, whereas controls did so at a mean of 5.0 transplants. In a competitive assay in which a mixture of anemic and control marrow was transplanted, the anemic marrow persisted to 10 months following transplantation; anemic marrow repopulation was greater if anemic marrow sex matched with the host. It is possible that lifelong stress of severe anemia decreases stem cell reserve in the anemic sphha/sphha mouse marrow. However, marginal differences in serial transplantation number and the maintenance of anemic marrow in a competition assay would suggest that marrow stem cells, under prolonged stress, are capable of exhibiting good repopulating and self-replicating abilities.     

The traumatic dural sinus injury — a clinical study

Summary In a period of 13 years 978 cases of severe head injuries were operated on in our clinic. An analysis of the medical reports includes injuries of the superficial dural sinus (39 cases=4%): among these injuries of the anterior and central part of the superior sagittal sinus (66 per cent), injuries of the transverse sinus (18 per cent), injuries of the posterior part of the superior sagittal sinus (8 per cent), and combined injuries of different dural sinuses (8 per cent).Clinical data, i.e. the causes of accident, radiological examination results, intracranial lesions, operation technqiues and outcome are analysed and discussed. The analysis of cases with dural sinus injuries shows a high mortality rate (total mortality rate: 16 patients=41%; intra-operative mortality rate: 8 patients=20%).     

Relationship between monitoring parameters and perinatal outcome in severe, early intrauterine growth restriction.

OBJECTIVE: To investigate whether pathological changes in the umbilical artery (UA), ductus venosus (DV) and short-term fetal heart variation are related to perinatal outcome in severe, early intrauterine growth restriction (IUGR). METHODS: This multicenter, prospective, longitudinal, observational study was carried out in the Departments of Fetal Medicine and Obstetrics in Hamburg, Amsterdam, Utrecht and London. In 70 singleton pregnancies with IUGR fetuses, delivered at 26-33 weeks of gestation because of antepartum fetal distress, short-term variation (STV) of fetal heart rate, pulsatility index of the fetal UA (UA PI) and DV pulsatility index for veins (DV PIV) were assessed at least weekly. The final measurement was performed within 24 h of delivery. Standard cut-off levels (2 SD or 3 SD, absent flow or reversed flow) were used and new cut-off levels were calculated by means of receiver-operating characteristics analysis. Adverse outcome was defined as perinatal death, cerebral hemorrhage (> or = Grade II) or bronchopulmonary dysplasia before discharge. The predictive value for adverse outcome was calculated for different cut-off levels of the monitoring parameters, adjusted for gestational age (GA), by multivariate logistic regression analysis. Data were analyzed separately for three different time blocks, namely 8-14, 2-7 and 0-1 days before delivery. RESULTS: Adverse perinatal outcome occurred in 18/70 (26%) infants. During the last 24 h before delivery DV PIV and UA PI were significantly higher and STV lower in the adverse outcome group, while 2-7 days before delivery only DV PIV was significantly higher. Adverse perinatal outcome could be predicted at 0-1 days before delivery by DV PIV at a cut-off of three multiples of the SD (odds ratio (OR) 11.3; 95% CI 2.3-57) and GA (OR 0.4; 95% CI 0.3-0.8), at 2-7 days by DV PIV at 2 SD (OR 3.0; 95% CI 0.8-12) and GA (OR 0.5; 95% CI 0.3-0.8) and at 8-14 days by DV PIV at 2 SD (OR 3.9; 95% CI 0.8-20) and GA (OR 0.5; 95% CI 0.3-0.8). Other parameters did not contribute to the multivariate model. CONCLUSIONS: DV PIV measurement is the best predictor of perinatal outcome. This measurement may be useful in timing the delivery of early IUGR fetuses and in improving perinatal outcome, even when delivery may be indicated at an earlier GA. However, as GA was also an important factor influencing outcome, with poorer outcome at earlier gestation at delivery, this hypothesis needs to be tested in a multicenter, prospective, randomized trial.     

Use of digital photography in the Case orthodontic clinic.

In 2002, the orthodontic clinic at Case Western Reserve University totally converted to digital photography. We want to share the learning curve during this transition with clinicians planning the same change. A system and a protocol were developed for this transition; they have been in use for over a year. This system allows the handling of digital cameras when there are more clinicians than cameras; it can be applied to various specialties or fields.