In vitro and in vivo activity of iclaprim, a diaminopyrimidine compound and potential therapeutic alternative against Pneumocystis pneumonia.

Pneumocystis pneumonia is a serious complication that may affect immunosuppressed patients. The absence of reliable and safe therapeutic alternatives to trimethoprim-sulfamethoxazole (TMP/SMX) justifies the search for more effective and less toxic agents. In this study, the in vitro and in vivo anti-Pneumocystis jirovecii activity of iclaprim, a diaminopyrimidine compound that exerts its antimicrobial activity through the inhibition of dihydrofolate reductase (DHFR), as does TMP, was evaluated alone or in combination with SMX. The antimicrobial activity of iclaprim was tested in vitro using an efficient axenic culture system, and in vivo using P. carinii endotracheally inoculated corticosteroid-treated rats. Animals were orally administered iclaprim (5, 25, 50 mg/kg/day), iclaprim/SMX (5/25, 25/125, 50/250 mg/kg/day), TMP (50 mg/kg/day), or TMP/SMX (50/250 mg/kg/day) once a day for ten consecutive days. The in vitro maximum effect (Emax) and the drug concentrations needed to reach 50% of Emax (EC50) were determined, and the slope of the dose-response curve was estimated by the Hill equation (Emax sigmoid model). The iclaprim EC50 value was 20.3 µg/mL. This effect was enhanced when iclaprim was combined with SMX (EC50: 13.2/66 µg/mL) (p = 0.002). The TMP/SMX EC50 value was 51.4/257 µg/mL. In vivo, the iclaprim/SMX combination resulted in 98.1% of inhibition compared to TMP/SMX, which resulted in 86.6% of inhibition (p = 0.048). Thus, overall, the iclaprim/SMX combination was more effective than TMP/SMX both in vitro and in vivo, suggesting that it could be an alternative therapy to the TMP/SMX combination for the treatment of Pneumocystis pneumonia.

In vivo electric conductivity of cervical cancer patients based on B1⁺ maps at 3T MRI.

The in vivo electric conductivity (σ) values of tissue are essential for accurate electromagnetic simulations and specific absorption rate (SAR) assessment for applications such as thermal dose computations in hyperthermia. Currently used σ-values are mostly based on ex vivo measurements. In this study the conductivity of human muscle, bladder content and cervical tumors is acquired non-invasively in vivo using MRI. The conductivity of 20 cervical cancer patients was measured with the MR-based electric properties tomography method on a standard 3T MRI system. The average in vivo σ-value of muscle is 14% higher than currently used in human simulation models. The σ-value of bladder content is an order of magnitude higher than the value for bladder wall tissue that is used for the complete bladder in many models. Our findings are confirmed by various in vivo animal studies from the literature. In cervical tumors, the observed average conductivity was 13% higher than the literature value reported for cervical tissue. Considerable deviations were found for the electrical conductivity observed in this study and the commonly used values for SAR assessment, emphasizing the importance of acquiring in vivo conductivity for more accurate SAR assessment in various applications.

Præventis, the immunisation register of the Netherlands: a tool to evaluate the National Immunisation Programme.

Vaccination coverage is an important performance indicator of any national immunisation programme (NIP). To monitor the vaccination coverage in the Netherlands, an electronic national immunisation register called 'Præventis' was implemented in 2005. Præventis has a link with the population register and can produce letters of invitation for the NIP, register and validate administered vaccinations. The database is used to monitor the vaccination process, produce reminder letters, control the stock of vaccines and provides information used for paying the fees to the different executive organisations involved. Præventis provides a crucial tool for the evaluation of the NIP by producing (sub)national vaccination coverage estimates with high accuracy and allowing additional research: identifying populations at high risk for low coverage based on existing data, conducting specific studies where individuals included in the immunisation register are approached for further research, using vaccination coverage data for the interpretation of (sero)surveillance data, and linking the immunisation register with disease registers to address vaccine safety or vaccine effectiveness. The ability to combine Præventis data with data from other databases or disease registers and the ability to approach individuals with additional research questions offers opportunities to identify areas of priority for improving the Dutch NIP.

Acute effects of different nutritional supplements on symptoms and functional capacity in patients with chronic obstructive pulmonary disease.

BACKGROUND: Use of nutritional supplements in depleted patients with chronic obstructive pulmonary disease (COPD) requires optimization between positive effects on outcome and potential acute adverse effects on metabolism and exercise performance. OBJECTIVE: The aim of this study was to investigate the acute effects of nutritional supplements on metabolism and exercise capacity in stable COPD patients. DESIGN: In part 1, the effects of 3 different energy loads (placebo, 1046 kJ, and 2092 kJ) with a normal distribution of macronutrients were investigated in 14 COPD patients. In part 2, the effects of a fat-rich compared with a carbohydrate-rich supplement (both 1046 kJ) were studied in 11 COPD patients. The study was performed in a randomized, double-blind, crossover fashion. Metabolic and ventilatory variables were measured postprandially and during a submaximal cycle endurance exercise test. RESULTS: Overall, no immediate negative effects of the supplements were found in part 1. A slight but significant postprandial increase in respiratory quotient was found after the 1046-kJ and 2092-kJ supplements compared with placebo. There was no significant difference in metabolism or exercise capacity after a fat-rich or carbohydrate-rich supplement. Surprisingly, the change in shortness of breath (postprandial compared with preprandial) was significantly greater after the fat-rich supplement. CONCLUSIONS: An energy load up to 2092 kJ had no adverse immediate effect in COPD patients compared with placebo. The subjects who consumed the fat-rich supplement experienced more shortness of breath than did the subjects who consumed the carbohydrate-rich supplement.