Dependency of detrusor contractions on calcium sensitization and calcium entry through LOE-908-sensitive channels.

1. The subcellular mechanisms regulating stimulus-contraction coupling in detrusor remain to be determined. We used Ca(2+)-free solutions, Ca(2+) channel blockers, cyclopiazonic acid (CPA), and RhoA kinase (ROK) inhibitors to test the hypothesis that Ca(2+) influx and Ca(2+) sensitization play primary roles. 2. In rabbit detrusor, peak bethanechol (BE)-induced force was inhibited 90% by incubation for 3 min in a Ca(2+)-free solution. By comparison, a 20 min incubation of rabbit femoral artery in a Ca(2+)-free solution reduced receptor-induced force by only 5%. 3. In detrusor, inhibition of sarcoplasmic reticular (SR) Ca(2+) release by 2APB, or depletion of SR Ca(2+) by CPA, inhibited BE-induced force by only 27%. The CPA-insensitive force was abolished by LaCl3. By comparison, 2APB inhibited receptor-induced force in rabbit femoral artery by 71%. 4. In the presence of the non-selective cation channel (NSCC) inhibitor, LOE-908, BE did not produce an increase in [Ca(2+)]i but did produce weak increases in myosin phosphorylation and force. 5. Inhibitors of ROK-induced Ca(2+) sensitization, HA-1077 and Y-27632, inhibited BE-induced force by approximately 50%, and in combination with LOE-908, nearly abolished force. 6. These data suggest that two principal muscarinic receptor-stimulated detrusor contractile mechanisms include NSCC activation, that elevates [Ca(2+)]i and ROK activation, that sensitizes cross bridges to Ca(2+).

Injury to the genitourinary tract and functional reconstruction of the urethra.

In the field of trauma and reconstruction, some aspects have changed significantly, whereas others continue to refine concepts that have developed over recent years. In urethral reconstruction, procedures are becoming more complex. The morbidity of the lithotomy position has been recognized for years. Recent literature has clarified the argument over the 'best stirrup', and time in lithotomy has been identified as a significant contributor to morbidity. Implantation of the AMS-800 sphincter has been examined in irradiated patients. The complication and revision rate is higher but not so high as to preclude consideration of its use. A number of articles have examined the use of cystoscopy in all cases of complicated pelvic surgery and in specific urethral suspension procedures. This has been recognized by urologists for years; it is a new concept in the gynecology literature. Cystoscopy continues to be routinely used, as many 'routine cases' when examined with cystoscopy are found to be associated with complications to the genitourinary tract. The non-operative management of renal trauma is expanded to select blunt grade 5 renal injuries. A series examined the use of computed tomography scan for bladder injuries and found it to be both sensitive and specific.

Management of penile amputation injuries.

Penile amputation is an uncommon injury resulting from self-mutilation, felonious assault, or accidental trauma. Management requires resuscitation and stabilization of the patient with particular attention to underlying psychiatric illness. Amputated tissue can be preserved under hypothermic conditions in preparation for surgical replantation. Current replantation techniques rely on microsurgical approximation of the dorsal structures and cavernosal arteries with uniformly good results. Phallic replacement may be necessary when the amputated segment is lost. Microsurgical free forearm flap phalloplasty is the current mainstay of penile replacement surgery. Although urethral complications remain problematic, the results continue to be acceptable with regard to appearance and function. A unique subset of patients sustaining amputation injury is children. Both replantation and phallic construction have been successful in children and represent an alternative to gender reassignment.

The effect of colonoscopy on serum prostate specific antigen levels.

OBJECTIVE: To evaluate, in a prospective trial, the effect of colonoscopy on serum prostate specific antigen (PSA) levels (which are known to increase after cystoscopy and prostatic needle biopsy) in men aged 50-70 years, as they commonly undergo colonoscopy and PSA screening together. SUBJECTS AND METHODS: Twenty-four consecutive men (mean age 61 years, range 37-78) were enrolled in the study. All subjects had their serum PSA measured 24-72 h before undergoing colonoscopy. Further values were obtained 24 h, 7 and 30 days after the procedure. The values before and after colonoscopy were compared to evaluate the effect of colonoscopy on serum PSA levels. RESULTS: Of 24 patients, seven (35%) had insignificant increases at 24 h after colonoscopy; 12 (50%) patients had an insignificant increase in PSA level 30 days after the procedure. None of the 24 patients had a significant increase after colonoscopy when compared with baseline values. CONCLUSION: Flexible colonoscopy does not adversely affect serum PSA levels. Although individuals may have a 30% daily fluctuation in serum values, this study detected no significant change in serum PSA levels after prolonged transrectal prostatic manipulation with a colonoscope.

Urethral calculus extraction using a penile ring block anesthetic.

Urethral calculi are rare and usually originate from the kidney or bladder. Classically, they are extracted endoscopically under anesthesia. We present two cases of impacted distal urethral calculi extracted using a penile ring block and forceps.