Frequency and fitness consequences of bacteriophage φ6 host range mutations.

Viruses readily mutate and gain the ability to infect novel hosts, but few data are available regarding the number of possible host range-expanding mutations allowing infection of any given novel host, and the fitness consequences of these mutations on original and novel hosts. To gain insight into the process of host range expansion, we isolated and sequenced 69 independent mutants of the dsRNA bacteriophage Φ6 able to infect the novel host, Pseudomonas pseudoalcaligenes. In total, we found at least 17 unique suites of mutations among these 69 mutants.

Migration enhances adaptation in bacteriophage populations evolving in ecological sinks.

Migration between populations can be a major evolutionary force. However, some disagreement exists as to precisely how migration affects population adaptation. Some theories emphasize the inhibitory effects of gene flow between locally adapted populations, whereas others propose that migration can enhance adaptation.

A prospective evaluation of rectal bleeding after dose-escalated three-dimensional conformal radiation therapy using an intrarectal balloon for prostate gland localization and immobilization.

Objectives: To estimate the rates of rectal bleeding after dose-escalated three-dimensional conformal radiation therapy (3D-CRT) on a prospective, Phase II study in which a modified intrarectal balloon was used for prostate gland localization and immobilization.

Methods: The study cohort comprised 100 men with biopsy-proven adenocarcinoma of the prostate and at least one high-risk feature (prostate-specific antigen level greater than 10 ng/mL, Gleason score 7 or higher, or clinical or radiographic T3 disease). Treatment consisted of androgen suppression therapy and four-field 3D-CRT with an intrarectal balloon for the initial 15 treatments.

Acute gastrointestinal, genitourinary, and dermatological toxicity during dose-escalated 3D-conformal radiation therapy (3DCRT) using an intrarectal balloon for prostate gland localization and immobilization.

Purpose: We determined the acute gastrointestinal (GI), genitourinary (GU), and dermatologic (D) toxicity during dose-escalated three-dimensional conformal radiation therapy (3DCRT). A modified intrarectal balloon (Medrad) was used for prostate gland localization and immobilization.

Methods: Forty-six men with clinical category T1c to T3a, and at least one high-risk feature (PSA >10, Gleason > or =7, or MRI evidence of extracapsular extension or seminal vesical invasion) comprised the study cohort.

Impact on rectal dose from the use of a prostate immobilization and rectal localization device for patients receiving dose escalated 3D conformal radiation therapy.

Purpose: When >25% of the rectum is irradiated to > or = 70 Gy, the risk of developing Grade 2 or higher rectal complications is significantly increased. This study evaluates the impact on dose to the rectum from the use of an intrarectal (IR) balloon device, previously shown to immobilize the prostate gland and localize the rectum, in patients receiving dose escalated 3-dimentional (3D) conformal radiation therapy.

Materials And Methods: From July 2001 through February 2003, 28 consecutive patients with prostate cancer underwent computerized tomography-based simulation with and without the IR balloon in place.