Trovafloxacin versus high-dose amoxicillin (1 g three times daily) in the treatment of community-acquired bacterial pneumonia.

Once-daily trovafloxacin 200 mg was compared with high-dose amoxicillin, 1 g three times daily, given for 7 to 10 days. At end of treatment (day 10), the response was clinically successful (cure + improvement) in 93% of 152 clinically evaluable trovafloxacin patients and in 89% of 160 amoxicillin patients. At study end (day 35), respective rates were 91% and 81% (95% confidence interval: 1.6, 17.6; P=0.01). In evaluable patients with positive baseline radiographs, 93% of trovafloxacin and 88% of amoxicillin patients demonstrated radiological resolution at end of treatment. Streptococcus pneumoniae and Haemophilus influenzae eradication rates were comparable at end of treatment in both treatment groups, but at study end Streptococcus pneumoniae eradication rates were higher in trovafloxacin patients (100% vs 81%). At study end, all four trovafloxacin patients with baseline penicillin-resistant Streptococcus pneumoniae were clinically cured with pathogen eradication, whereas two of five amoxicillin patients with baseline penicillin-resistant Streptococcus pneumoniae were clinical failures with pathogen persistence. For patients in whom no pathogen was identified, trovafloxacin was significantly more effective at end of treatment (P=0.096) and study end (P=0.013). Treatment-related adverse events were comparable; the most common were headache, vomiting and dizziness in trovafloxacin patients, and diarrhoea. headache and abdominal pain in amoxicillin patients.

Kinetics and sites of destruction of 111Indium-oxine-labeled platelets in idiopathic thrombocytopenic purpura: a quantitative study.

Kinetics and quantification of the sites of destruction of 111-Indium-oxine-labeled autologous platelets were investigated in eight patients with idiopathic thrombocytopenic purpura. The mean platelet count was 17 +/- 9 X 10(9)/liter; platelets were separated by differential centrifugation and labeled with 5.6 +/- 2.5 MBq 111In. Whole body and organ 111In-platelet distribution was quantitated with a scintillation camera and a computer-assisted imaging system acquisition matrix. Areas of interest were selected with the computer and organ 111In-radioactivity expressed as a percentage of whole body activity. Mean platelet survival was 49.5 +/- 29.6 hr and the survival curves were exponential. Equilibrium percentage organ 111In-radioactivity was (normal values in parentheses): spleen 33.7 +/- 8.8 (31.1 +/- 10.2); liver 16.1 +/- 9.5 (13.1 +/- 1.3); thorax 22.8 +/- 3.7 (28.2 +/- 5.6). Percentage organ 111In-activity at the time when labeled platelets had disappeared from the circulation was: spleen 44.5 +/- 16.4 (40 +/- 16); liver 16.0 +/- 11.5 (32.4 +/- 7.2); thorax 19.7 +/- 6.0 (17.7 +/- 10.3). Thorax activity corresponds to bone marrow radioactivity. Three patterns of platelet sequestration were evident. Three patients had mainly splenic sequestration, two mainly hepatic sequestration, and three diffuse reticuloendothelial system sequestration with a major component of platelets destroyed in the bone marrow. Splenectomy was performed in two patients. The pattern of 111In-platelet sequestration was not predictive of response of glucocorticoid therapy or indicative of the necessity for splenectomy. Quantitative 111In-labeled autologous platelet kinetic studies provide a new tool for the investigation of platelet disorders.U

Quantification of the distribution of 111In-labelled platelets in organs.

A single and practical approach to the in vivo quantification of 111indium-oxine labelled blood platelets with a scintillation camera and computer assisted imaging system was evaluated. Radioactivity of the 172 and 247 keV energies was measured in a phantom at various source distances from the collimator and the accuracy of anterior and posterior mode measurements compared with that of the geometrical mean (GM) method, with and without correction for Compton scatter (CS). Organ radioactivity, expressed as a percentage of whole body radioactivity, was determined in vivo in five baboons and the accuracy of the methods verified by post mortem quantification in the animals. Measurements in the anterior mode significantly overestimates hepatic and underestimates splenic radioactivity; posterior mode quantification reverses these results. Correction with the GM method made the accuracy and reproducibility very acceptable. Further correction for anterior-posterior attenuation and/or CS did not improve results materially. The GM method could readily be applied in five human subjects. This study showed that the GM method is an accurate and practical method for the in vivo quantification of organ and regional distribution of 111In-labelled platelets.

Kinetics and sites of sequestration of indium 111-labeled human platelets during cardiopulmonary bypass.

A new approach for the study of the kinetics and quantification of the in vivo and ex vivo sites of sequestration of platelets during cardiopulmonary bypass (CPB) is described. Autologous platelets of four patients were labeled with 111In-oxine and reinfused on the day prior to CPB for coronary artery bypass grafting. Changes in blood 111In-labeled platelet radioactivity and blood platelet counts were monitored during the operation. In vivo 111In-labeled platelet redistribution was quantified with a scintillation camera and a computer-assisted imaging system before and after CPB. Sequestration of 111In-labeled platelets in the bubble oxygenator was measured. 111In-labeled platelet activity in the blood decreased by 46% +/- 5% within 5 minutes of CPB, but this decrease was mostly due to hemodilution; the true loss of platelets from the circulation was 13% +/- 4%. Intraoperatively, whole body 111In activity decreased by oxygenator 10.8% +/- 1.3% of administered platelets were sequestered, especially in the innermost active layers of the defoaming mesh of the bubble oxygenator. Mean survival time of circulating platelets was 58 +/- 8 hours and fitted an exponential function best. The bleeding time increased to 40 minutes during operation and returned to normal within 24 hours. During operation 111In-labeled platelets accumulated somewhat in the liver (10.7%) but not in the spleen, thorax, or head. In the 48 hours after operation, platelets were sequestered mainly in the liver. The scintillation camera with computer-assisted imaging allows in vivo quantitative studies of platelet kinetics of a type which has not been possible with previous techniques.