Ehrlichia platys (Anaplasma platys) in dogs from Maracaibo, Venezuela: an ultrastructural study of experimental and natural infections.

Since 1982 Ehrlichia platys, now emended as Anaplasma platys, has been diagnosed in dogs from Maracaibo, Venezuela, using buffy coat smears stained with Dip Quick. Three dogs were inoculated with an A. platys strain. When parasitemia reached 60-97%, blood samples obtained from the inoculated dogs and from two naturally infected dogs were centrifuged to obtain platelet-rich plasma, which was mixed with 0.1% glutaraldehyde at 37 C for 10 minutes. Platelet pellets were fixed in 3% glutaraldehyde for 72 hours and processed for conventional transmission electron microscopy. Platelets contained pleomorphic organisms with a distinct double membrane that was not observed when the bodies were in a determinate developmental stage. There were 1-15 individual bodies included in a host cell vacuole. The organisms had an electron-lucent inner area, whereas the internal surface of their inner plasma membranes exhibited an electron-dense rough substance. In naturally infected dogs, organisms with different ultrastructural features were found inside the same platelet. Some organisms contained central dense material surrounded by a pale zone, which was in turn surrounded by a moderately dense peripheral area. Other organisms contained an eccentrically electron-dense material. The intravacuolar space appeared fully electron-lucent. Each organism usually exhibited inner fine strands. Empty structures displaying junctions with the vacuolar membrane were observed. Our results indicate that distinct ultrastructural characteristics are associated with different stages of A. platys development and may differ among A. platys strains.

Continuous, hyperfractionated, accelerated radiotherapy (CHART) versus conventional radiotherapy in non-small cell lung cancer: mature data from the randomised multicentre trial. CHART Steering committee.

BACKGROUND AND METHOD: A randomised controlled trial in locally advanced non-small cell lung cancer (NSCLC), compared CHART which employs 36 fractions of 1.5 Gy 3 times per day to give 54 Gy in 12 consecutive days with conventional radiotherapy-30 fractions of 2 Gy to a total dose of 60 Gy in 6 weeks. A total of 563 patients were entered between April 1990 and April 1995. This report is based upon the data updated to 1 April 1998. RESULTS: The analysis of the mature data shows that the benefits previously reported have been maintained. Overall there was a 22% reduction in the relative risk of death, which is equivalent to an absolute improvement in 2 year survival of 9% from 20 to 29% (P = 0.008) and a 21% reduction in the relative risk of local progression (P = 0.033). In the large subgroup of patients with squamous cell cancer which accounted for 81% of the cases, there was a 30% reduction in the relative risk of death, which is equivalent to an absolute improvement in 2 year survival of 13% from 20 to 33% (P = 0.0007) and a 27% reduction in the relative risk of local progression (P = 0.012). Furthermore, in squamous carcinoma there was a 25% reduction in the relative risk of local and/or distant progression (P = 0.025) and 24% reduction in the relative risk of metastasis (P = 0.043). There was no evidence that CHART gave more or less benefit in any other subgroup. CONCLUSION: This analysis of mature data confirms that CHART is superior to conventional radiotherapy in achieving local tumour control and survival in locally advanced NSCLC. This demonstrates the importance of cellular repopulation as a cause of failure in the radiotherapy of NSCLC. The reduction in the risk of metastasis confirms that improved local tumour control, even in lung cancer, can reduce the incidence of metastasis. This trial shows that control of local tumour can lead to an improvement in long term survival.