Enantioselectivity in random deposition processes on template surfaces.

A molecular model is proposed to study the enantioselective adsorption of chiral species on metallic surfaces modified through the preadsorption of another chiral species, known as template surfaces. It is found that anisotropic and exclusive interactions among adsorbed species are essential factors in the enantioselective process. It is shown how the formation of compact structures explains the fact that an enantiomer of species B having the same symmetry as the template species A can be preferentially adsorbed with respect to the other enantiomer of species B, thus producing enantioselectivity. The model predicts enantioselectivity peaks on a limited range of the template coverage, as typically observed experimentally in some systems.

Soft-tissue applications of the holmium:YAG laser in urology.

The holmium:YAG laser possesses both ablative and hemostatic properties and in preliminary clinical use has demonstrated many potential urologic applications. We review our initial experience in treating a variety of soft-tissue lesions of the urinary tract with this laser. A total of 51 patients underwent 53 procedures including superficial bladder tumor ablation (25), incision of ureteral stricture (15), incision of urethral stricture (6), relief of ureteropelvic junction obstruction (3), incision of bladder neck contracture (2), and ureteral tumor ablation (2). Procedures were considered successful, with no further intervention or alternative energy source required, in 81% of the cases. The laser demonstrated precise hemostatic cutting and warrants further investigation as a multipurpose urologic laser.

Preliminary experience with holmium: YAG laser lithotripsy.

Lithotripsy with the pulsed-dye laser has been shown to be a safe and effective method of intracorporeal urinary stone fragmentation. Recently, a new device, the holmium: YAG laser, has been developed with both soft tissue and lithotripsy applications. We present our preliminary experience with the Ho:YAG laser for lithotripsy of urinary calculi. Ureteroscopy and lasertripsy resulted in successful fragmentation of ureteral stones in 92% of 21 patients when the laser was used alone or in combination with electrohydraulic lithotripsy. One complication directly related to the use of the laser occurred, a ureteral perforation, when the device was utilized under fluoroscopic control. In four patients undergoing percutaneous flexible nephrolithotripsy, the laser demonstrated utility in fragmenting caliceal stones remote from the nephrostomy tract. In summary, the Ho:YAG laser has demonstrated its efficacy as a method of intracorporeal lithotripsy. The tissue effects of this device, as well as the optimal energy/pulse and frequency settings, need further evaluation in order to minimize the risks of tissue injury.

Presentation of ureteral colic in a patient with a ureteroinguinal hernia.

The presence of ureter within an inguinal hernia is an uncommon occurrence. We report on the presentation of a patient with ureteral colic and subsequent discovery of a herniated ueter in the inguinal canal. Surgeons must be aware of this condition in order to carefully preserve ureteral integrity and avoid complications during hernia repair.

[The use of Wagner's external fixator in the treatment of septic fractures of the femoral shaft (author's transl)]. / Le fixateur de Wagner dans le traitement des fractures septiques du fémur.

The authors have treated 10 cases of septic fracture of the femoral shaft by the following technique. In the first stage, necrotic and infected tissues were excised at the fracture site including soft tissue and bone. The importance of a large excision is emphasised. The fracture was then immobilised by an external fixator. In the second stage, the shaft was reconstructed by grafting using bone chips and sometimes massive cancellous bone autografts. The fixators were left until solid bone union had been achieved. 9 excellent results were observed. In one case, the bone refractured with recurrence of sepsis.

Dynamic effects of promoters on associative desorption.

The kinetics of the associative desorption of A(2) in the presence of coadsorbed promoter species B is studied under conditions of nonequilibrium by the analysis of thermal desorption spectra obtained by Monte Carlo simulation. A rich variety of behaviors is found and discussed with regard to the interplay between the concentrations of promoter species, the surface mobility of A and B, and the interparticle interactions.

Intracorporeal lithotripsy with the holmium:YAG laser.

PURPOSE: Preliminary evaluations of the holmium:YAG laser have demonstrated a variety of potential urological applications, including ablation of soft tissue lesions as well as stone fragmentation. We present our experience with the holmium:YAG laser for intracorporeal lithotripsy of urinary calculi. MATERIALS AND METHODS: During a 24-month period 75 patients underwent 79 laser procedures, including retrograde ureteroscopy for ureteral calculi (71) and fragmentation of caliceal stones remote from the nephrostomy tract during percutaneous nephrolithotripsy (8). RESULTS: Complete stone fragmentation without need for additional procedures or lithotripsy was achieved in 85% of the cases. Treatment failures included 1 case of stone migration, 7 incomplete fragmentation requiring other lithotripsy devices and 3 laser malfunction. One ureteral perforation occurred when the laser was activated without direct visual guidance. CONCLUSIONS: The holmium:YAG laser has demonstrated its efficacy as a method of intracorporeal lithotripsy. Advantages include ability to fragment stones of all composition, and the multipurpose, multispecialty applications of the holmium wavelength. This laser has potential soft tissue effects, and careful attention to technique during lithotripsy is required to avoid ureteral wall injury.

Simultaneous subluxation of the metacarpophalangeal joints of all four fingers: a case report.

Simultaneous subluxation of the metacarpophalangeal joints of all four fingers is rare, and we have found no cases in the literature. A 45-year-old construction worker fell and dislocated the metacarpophalangeal joints of all the fingers of his left hand. Closed reduction by manipulation was successfully accomplished, and the patient returned to work within 5 months of his accident. He had a full range of motion 1 year later.