Identification of patients at high risk for Clostridium difficile infection: development and validation of a risk prediction model in hospitalized patients treated with antibiotics.

To develop and validate a prediction model for Clostridium difficile infection (CDI) in hospitalized patients treated with systemic antibiotics, we performed a case-cohort study in a tertiary (derivation) and secondary care hospital (validation). Cases had a positive Clostridium test and were treated with systemic antibiotics before suspicion of CDI. Controls were randomly selected from hospitalized patients treated with systemic antibiotics. Potential predictors were selected from the literature. Logistic regression was used to derive the model. Discrimination and calibration of the model were tested in internal and external validation. A total of 180 cases and 330 controls were included for derivation. Age >65 years, recent hospitalization, CDI history, malignancy, chronic renal failure, use of immunosuppressants, receipt of antibiotics before admission, nonsurgical admission, admission to the intensive care unit, gastric tube feeding, treatment with cephalosporins and presence of an underlying infection were independent predictors of CDI. The area under the receiver operating characteristic curve of the model in the derivation cohort was 0.84 (95% confidence interval 0.80-0.87), and was reduced to 0.81 after internal validation. In external validation, consisting of 97 cases and 417 controls, the model area under the curve was 0.81 (95% confidence interval 0.77-0.85) and model calibration was adequate (Brier score 0.004). A simplified risk score was derived. Using a cutoff of 7 points, the positive predictive value, sensitivity and specificity were 1.0%, 72% and 73%, respectively. In conclusion, a risk prediction model was developed and validated, with good discrimination and calibration, that can be used to target preventive interventions in patients with increased risk of CDI.

Quantum-memory effects in the emission of quantum-dot microcavities.

The experimentally measured input-output characteristics of optically pumped semiconductor microcavities exhibits unexpected oscillations modifying the fundamentally linear slope in the excitation power regime below lasing. A systematic microscopic analysis reproduces these oscillations, identifying them as a genuine quantum-memory effect, i.e., a photon-density correlation accumulated during the excitation. With the use of projected quantum measurements, it is shown that the input-output oscillations can be controlled and enhanced by an order of magnitude when the quantum fluctuations of the pump are adjusted.

[Dangerous thrombocytopenia in thrombolytic therapy of venous thrombosis of the leg]. / Gefährliche Thrombozytopenie unter thrombolytischer Therapie einer Beinvenenthrombose.

Two days after 5 days heparin treatment of a superficial thrombophlebitis a 45 year old woman was admitted to hospital with an extended phlebothrombosis of a leg. Before starting thrombolytic treatment a bolus of 5000 U heparin followed by 1000 U/h was administered. During thrombolytic treatment with ultrahigh streptokinase the platelet count dropped from 172,000/microliter to 73,000 and 29,000/microliter. Thrombocytopenia was considered not to be a complication of thrombolytic therapy but by demonstrating heparin induced platelet antibodies to be due to a heparin-associated thrombocytopenia type II (HAT Type II).

[A protocol for the treatment of periodontal disease]. / Een protocol bij parodontale aandoeningen.

The importance of a number of clinical indicators for the diagnosis, the treatment and the evaluation of periodontal disease is discussed.