Independent validation of the prognostic capacity of the ISUP prostate cancer grade grouping system for radiation treated patients with long-term follow-up.

BACKGROUND: There has been a recent proposal to change the grading system of prostate cancer into a five-tier grade grouping system. The prognostic impact of this has been demonstrated in regards only to biochemical recurrence-free survival (bRFS) with short follow-up (3 years). METHODS: Between 1990 and 2013, 847 consecutive men were treated with definitive external beam radiation therapy at a single academic center. To validate the new grade grouping system, bRFS, distant metastases-free survival (DMFS) and prostate cancer-specific survival (PCSS) were calculated. Adjusted Kaplan-Meier and multivariable Cox regression analyses were performed to assess the independent impact of the new grade grouping system. Discriminatory analyses were performed to compare the commonly used three-tier Gleason score system (6, 7 and 8-10) to the new system. RESULTS: The median follow-up of our cohort was 88 months. The 5-grade groups independently validated differing risks of bRFS (group 1 as reference; adjusted hazard ratio (aHR) 1.35, 2.16, 1.79 and 3.84 for groups 2-5, respectively). Furthermore, a clear stratification was demonstrated for DMFS (aHR 2.03, 3.18, 3.62 and 13.77 for groups 2-5, respectively) and PCSS (aHR 3.00, 5.32, 6.02 and 39.02 for groups 2-5, respectively). The 5-grade group system had improved prognostic discrimination for all end points compared with the commonly used three-tiered system (that is, Gleason score 6, 7 and 8-10). CONCLUSIONS: In a large independent radiotherapy cohort with long-term follow-up, we have validated the bRFS benefit of the proposed five-tier grade grouping system. Furthermore, we have demonstrated that the system is highly prognostic for DMFS and PCSS. Grade group 5 had markedly worse outcomes for all end points, and future work is necessary to improve outcomes in these patients.

Continuous propagation of Ehrlichia sennetsu in murine macrophage cell cultures.

Ehrlichia sennetsu, the etiologic agent of human sennetsu rickettsiosis was successfully propagated in a continuous cell culture using murine cell lines P388D1 and Raw 264. Pleomorphic cytoplasmic inclusion bodies similar to Ehrlichia canis morulae were observed 3-4 days after second post-inoculation split. In the Raw 264 cell line E. sennetsu was not seen until the third passage. Relatively heavier infection was observed in P388D1 than in Raw cell line. The latter reached a maximum of 15% infection whereas P388D1 cell line attained saturation. Structural details of the organism were confirmed by electron microscopy. A unique rippled cell mass surrounding the plasma membrane was observed. Supernatants of cultures were shown to contain infectious organisms. The advantages of propagating E. sennetsu in continuous cell lines are discussed with respect to future physiochemical and immunochemical studies of this organism.

Adaptation of Ehrlichia sennetsu to canine blood monocytes: preliminary structural and serological studies with cell culture-derived Ehrlichia sennetsu.

Ehrlichia sennetsu, the causative agent of human sennetsu rickettsiosis, was successfully propagated in primary canine blood monocyte cultures. The growth cycle of this organism appears to be similar to that of Ehrlichia canis. The antigen derived from our E. sennetsu cultures was used to develop an indirect fluorescent antibody test for detection and titration of serum antibodies to the organism. Using this test system, we found that five human serum samples obtained from patients clinically diagnosed as having sennetsu rickettsiosis were positive for anti-E. sennetsu antibodies. In addition, 29% of the serum samples obtained from 200 patients having a fever of unknown origin and residing in various regions of Malaysia were also serologically positive. All sera from apparently healthy individuals were negative in the test. Dogs inoculated with cell culture-adapted E. sennetsu developed a significant specific antibody titer to E. sennetsu, and the organism was subsequently isolated from their blood. These animals showed no clinical evidence of disease. The possibility of a higher prevalence of human sennetsu rickettsiosis in Southeast Asia and the potential usefulness of the canine model for studies of human sennetsu rickettsiosis are discussed.

Isolation, experimental transmission, and characterization of causative agent of Potomac horse fever.

Potomac horse fever, a disease characterized by fever, anorexia, leukopenia, and occasional diarrhea, is fatal in approximately 30 percent of affected animals. The seasonal occurrence of the disease (June to October) and evidence of antibodies to the rickettsia Ehrlichia sennetsu in the serum of convalescing horses suggested that a related rickettsia might be the causative agent. Such an agent was isolated in cultured blood monocytes from an experimentally infected pony. This intracytoplasmic organism was adapted to growth in primary cultures of canine blood monocytes. A healthy pony inoculated with these infected monocytes also developed the disease. The organism was reisolated from this animal which, at autopsy, had pathological manifestations typical of Potomac horse fever. Cross serologic reactions between the newly isolated agent and antisera to 15 rickettsiae revealed that it is related to certain members of the genus Ehrlichia, particularly to Ehrlichia sennetsu. Since the disease occurs in other parts of the United States as well as in the vicinity of the Potomac River, and since it has also been reported in Europe, the name equine monocytic ehrlichiosis is proposed as being more descriptive.