Treatment of post-prostatectomy rectourethral fistula with fibrin sealant (Quixil™) injection: a novel application.

Rectourethral fistulas in adults is a rare but potentially devastating postoperative condition requiring complex and demanding surgery. Fibrin glue treatment has been used with some success in anal and rectovaginal fistulas, and in the case we present here this indication has been extended to a postoperative rectourethral fistula following radical prostatectomy. For the first time, to our knowledge, a fibrin sealant (Quixil) was injected into the fistula tract, and a rectal mucosal flap was used to close the internal opening. The fistula healed in few weeks, and the patient is symptom free after 1 year of follow-up.

Solid-phase synthesis of MEN 11270, a new cyclic peptide kinin B2 receptor antagonist.

An efficient synthesis of the cyclic decapeptide MEN 11270 [H-DArg1-Arg2 Pro3-Hyp4-Gly5-Thi6-Dab7-DTic8-Oic9-Arg10 c(7gamma - 10alpha)] was developed. Two three-dimensional orthogonal strategies were applied and compared: Fmoc/Tos/Boc (procedure A) and Fmoc/Pmc/Dde (procedure B). Both resulted in a 23-step strategy comprising the stepwise solid-phase chain assembly of the linear protected peptide, partial deprotection, solution-phase cyclization and final full deprotection. The stepwise assembly of the linear peptide was optimized by double coupling and acylation time prolongation for critical residues (Tic, Dab, Thi, Pro). O-(7-azabenzotriazol-1-yl)-N,N,N',N' tetramethyluronium (HATU) was preferred as coupling reagent for Dab. In the cyclization step, the partial racemization of Arg10 (31% using 1-ethyl-3-(3'-dimethyl-aminopropyl) carbodiimide/1-hydroxybenzotriazole (EDC/HOBt) as activation system) was reduced to 3% with HATU. The final deprotection was performed in the presence of dimethylsulfide (procedure A) and thiocresol (procedure B) as scavengers, to avoid the sulfation of Hyp side chain. The final compound and the main by-products were characterized by mass spectroscopy (MS), nuclear magnetic resonance (NMR) and racemization test. Procedure B produced operationally simpler and more efficient results than A (28% overall yield versus 4%).

[Echodynamics of the cervical ureter junction]. / Ecodinamica della giunzione cervico uretrale.

Transrectal dynamic ultrasonography is a 3 dimensional study that identifies accurately bladder neck (B.N.) diseases during micturition, providing precise noninvasive images of the B.N. orifice and the posterior urethra. This technique requires a 7-10 Mhz high frequency linear transducer. Benign Prostaic Hyperplasia (BPH) may restrict the urethral lumen and deviate its intra prostate tract. The images obtained allow a detailed and precise analysis of the B.N. and intravesical development of the median lobe. The urethra classically has a stretched and elongated appearance. This technique is useful in the diagnosis and in the follow up of neuropathic bladder. It is also useful in morphological and dynamic study of the B.N. after TURP. Diagnosis of B.N. hypertrophy or sclerosis is easy if a posterior beak at internal meatus level and positive stop test are present. After radical prostatectomy or radical cystectomy with orthotopic neobladder, this technique is useful to evaluate the internal urethral meatus and voluntary skeletal sphincter providing to a continence mechanism. We believe dynamic transrectal echography should become a procedure to be included as a part of the routine pre-surgical investigation of the B.N. diseases, for its non invasive nature, easiness to perform, and highly useful information.

A model for the structure of a homodimeric prohormone: the precursor to the locust neuropeptide AKH I.

We have determined the structure in solution of a homodimeric protein that is a precursor to the locust neuropeptide adipokinetic hormone I using nuclear magnetic resonance spectroscopy. This precursor, called P1, is comprised of two 41 residue strands joined by a single inter-chain disulphide at Cys39. We have also determined the structure of an end product of P1 processing, called APRP1; this is a homodimer comprised of residues 14-41 of P1. Nuclear Overhauser Effect (nOe) data indicate that in both P1 and APRP1, residues 22-37 (numbered with respect to P1) form pairs of alpha-helices, with no evidence for any other secondary structure.