Incompatibility of contrast agents with intravascular medications. Work in progress

In vitro and in vivo precipitation of iodinated contrast agents when ioxaglate and papaverine are given together has been reported. To verify these reports and to investigate other medications not previously tested, the authors analyzed mixtures of contrast agents and medications in vitro with a light spectrophotometer and observed them for visible precipitates for up to 120 minutes. Previously reported incompatibilities between ionic or low-osmolality contrast media and medications were verified, and several new incompatibilities were discovered. No incompatibilities were found when the drugs tested were mixed with the new nonionic contrast media.     

Chlamydial etiology of acute lower respiratory tract infections in children in the Sudan

The role of Chlamydia pneumoniae in 110 Sudanese children with signs of acute lower respiratory tract infections (ALRI) was investigated. Four (3.6%) had evidence of C. pneumoniae infection, of whom 3 were culture-positive, while 1 had an antibody response suggesting a recent infection. IgG antibodies at a titer of ≥1:32 to C. pneumoniae, Chlamydia psittaci and Chlamydia trachomatis were detected in 27 (24.5%), 27 (24.5%) and 7 (6.4%) of the 110 ALRI cases, respectively. C. pneumoniae, C. trachomatis or C. psittaci were not detected in nasopharyngeal secretions from any of 110 patients when fluorescence-labeled specific monoclonal antibodies were used. In a seroepidemiological survey, 318 healthy Sudanese persons aged between 1 month and 67 years were studied for C. pneumoniae antibodies.     

Sweet's syndrome—therapy with cyclosporin

We report the case of a 39-year-old female patient suffering from Sweet's syndrome after an upper respiratory tract infection. Cyclosporin A at a dose of 10 mg/kg per day was given as initial treatment. Skin lesions and general malaise resolved within 9 days. The cyclosporin dose was decreased within 21 days, without recurrence of the eruption. Cyclosporin is a potent inhibitor of T lymphocytes, but affects granulocyte and monocyte functions as well. Success of treatment in our case shows that cyclosporin represents an alternative to steroid treatment in patients with Sweet's syndrome.     

Time-resolved particle image velocimetry and laser doppler anemometry study of the turbulent flow field of bileaflet mechanical mitral prostheses

Dynamic particle image velocimetry (PIV) was applied to the study of the flow field associated with prosthetic heart valves. The results were compared with those of laser Doppler anemometry (LDA). Anatomically and antianatomically oriented Jyros (JR) and St. Jude Medical (SJM) valves were compared in the mitral position to study the effects of valve design on the downstream flow field. The experimental program used a dynamic PIV system utilizing high-speed, high-resolution video to map the true time-resolved velocity field inside the simulated ventricle. This system was complemented by a study using the more traditional LDA system for comparison. Based on the experimental data, the following general conclusions can be made. High-resolution dynamic PIV can capture true chronological changes in the velocity and turbulence fields. It also produces very detailed velocity and turbulence information comparable to the LDA results. In the vertical measuring plane that passes both the center of the aortic and mitral valves (A-A section), the two valves (the SJM and the JR) show distinct circulatory flow patterns when the valve is installed in the antianatomical orientation. Small differences in valve design can generate noticeable differences, particularly during the accelerating flow phase. The SJM valve maintains a relatively high velocity through the central orifice; the curved leaflets of the JR valve generate higher velocities with a divergent flow during the accelerating and peak flow phases. In the velocity field directly below the mitral valve and normal to the previous measuring plane (B-B section), where characteristic differences in valve design will be visible, symmetrical twin circulations were observed because of the divergent nature of the flow generated by the two inclined half-disks installed in the antianatomical orientation. The SJM valve, with a central downward flow near the valve, is contrasted with the JR valve, which has a peripheral downward circulation with higher, turbulent stresses.     

Cost-effective use of autologous bone marrow transplantation: few answers, many questions, and suggestions for future assessments

High dose chemotherapy with the support of autologous bone marrow transplantation (ABMT) or peripheral blood progenitor cells (PBPC) has been increasingly used in a variety of haematological and epithelial cancers over the last decade. The rationale of this approach is to overcome the chemotherapy resistance of tumour cells by increasing the dose of cytotoxic drugs. However, the clinical benefit of dose-intensification has been difficult to prove. Almost all studies of ABMT have been done without randomised comparisons with the standard form of therapy for a specific condition. From an economic perspective, the cost of ABMT has been steadily decreasing with improvements in supportive care primarily. Still, current ABMT cost estimates range from $US70 000 to $US150 000 for each uncomplicated procedure. Despite the lack of compelling evidence in support of dose-intensification, ABMT has become a default standard of care after relapse for many patients with lymphoma or leukaemia. We used a decision analysis model to estimate the cost effectiveness of the timing of ABMT in relapsed Hodgkin's disease. The model illustrates the difficulty of using available clinical trial data when follow-up of promising early reports is not available. The model showed that in most situations the optimal strategy is ABMT in second relapse despite growing consensus that immediate ABMT is the treatment of choice. ABMT for women with high-risk or early metastatic breast cancer is one of the most controversial areas in clinical oncology. In the US, several ongoing major randomised trials are addressing the role of ABMT in breast cancer. Using a Markov process we found that ABMT is the preferred strategy under almost all assumptions. The size of the benefit and cost effectiveness of ABMT varied markedly depending on the assumptions made. The model does not supplant the need for randomised trials that concurrently measure efficacy, quality of life, and resource utilisation. However, such analyses point out the critical areas where costs could be cut substantially without effecting efficacy. Drawing conclusions about the cost effectiveness of ABMT for all conditions is hampered by the lack of randomised comparisons of efficacy. Concurrent economic appraisals of selected phase III comparative trials should be considered since the supportive care costs associated with ABMT appear to be stabilising. However, the most important point is that randomised trials are the only mechanism for estimating the therapeutic effect of high dose chemotherapy.