The Chinese hamster dihydrofolate reductase replication origin beta is active at multiple ectopic chromosomal locations and requires specific DNA sequence elements for activity.

To identify cis-acting genetic elements essential for mammalian chromosomal DNA replication, a 5.8-kb fragment from the Chinese hamster dihydrofolate reductase (DHFR) locus containing the origin beta (ori-beta) initiation region was stably transfected into random ectopic chromosomal locations in a hamster cell line lacking the endogenous DHFR locus. Initiation at ectopic ori-beta in uncloned pools of transfected cells was measured using a competitive PCR-based nascent strand abundance assay and shown to mimic that at the endogenous ori-beta region in Chinese hamster ovary K1 cells. Initiation activity of three ectopic ori-beta deletion mutants was reduced, while the activity of another deletion mutant was enhanced. The results suggest that a 5.8-kb fragment of the DHFR ori-beta region is sufficient to direct initiation and that specific DNA sequences in the ori-beta region are required for efficient initiation activity.

Selective nonoperative management of blunt grade 5 renal injury.

PURPOSE: We determined the feasibility of a nonoperative approach to blunt grade 5 renal injury. MATERIALS AND METHODS: We retrospectively reviewed the records of all patients with grade 5 renal injury who presented to our level 1 trauma center from 1993 to 1998. Those treated nonoperatively and surgically were assigned to groups 1 and 2, respectively. Each group was compared with respect to the initial emergency department evaluation, computerized tomography findings, associated injuries, duration of hospital stay and intensive care unit stay, transfusion requirements, complications and followup imaging. RESULTS: Of 218 renal injuries evaluated 13 were grade 5. In group 1, 6 patients were treated nonoperatively and in group 2, 7 underwent exploration. Each group had similar average hospitalization (12.0 and 12.8 days, respectively). Patients in group 1 had fewer intensive care unit days (4.3 versus 9.0), significantly lower transfusion requirements (2.7 versus 25.2 units, p = 0.0124) and fewer complications during the hospital course. Followup computerized tomography of nonoperatively managed cases revealed functioning renal parenchyma with resolution of retroperitoneal hematoma. CONCLUSIONS: Conservative management of blunt grade 5 renal injury is feasible in patients who are hemodynamically stable at presentation.

Cocaine associated priapism.

PURPOSE: Cocaine abuse is an ongoing epidemic in the United States. Priapism associated with cocaine use has been reported only twice in the urological literature. To our knowledge we report the first series of priapism associated with cocaine use and the first case associated with the use of this drug in its solid form, known as crack. MATERIALS AND METHODS: We retrospectively reviewed the presentation of 3 patients to our emergency department within the last year. Each patient presented with priapism and no identifiable predisposition other than the use of cocaine within 24 hours, as evident on positive urine toxicology. RESULTS: Each patient delayed seeking treatment, which added to the complexity of therapy. Intracavernosal aspiration and irrigations failed in all 3 cases. Cavernous spongiosal shunting failed in the first 2 cases. Cases 2 and 3 were complicated by the high flow variant of priapism. Case 1 ultimately required partial penectomy for infected, gangrenous, distal penile tissue. CONCLUSIONS: It appears that cocaine can be a cause of refractory priapism and treatment can be challenging. We suggest that urine toxicology screening be considered in such cases. The identification of underlying cocaine abuse is important in preventing priapism recurrence in these patients.