Preimplantation genetic diagnosis on in vitro fertilization clinic websites: presentations of risks, benefits and other information.

Objective: To examine information on preimplantation genetic diagnosis (PGD) presented on IVF clinic websites.

Design: We systematically sampled every third IVF clinic on the 2004 Centers for Disease Control provider list.

Setting: The Internet.

Experiences with lithotripters: measurements of standardized fragmentation.

A comparison of lithotripters in terms of the fragmentation efficacy was established by using artificial stones. Two hundred pulses were applied to identical calcium sulphate cubes at varied energy levels of different lithotripters. In the cubics the shock waves formed regular craters, which could be analyzed with regard to depth, diameter, and volume.

[New trends in extracorporeal shockwave lithotripsy].

Extracorporeal shock wave lithotripsy has become an established and successful treatment modality for urinary and biliary calculi. However, shock wave technology and corresponding device designs are still at an innovative stage. Three trends are discussed in this paper.

Pressure distribution and energy flow in the focal region of two different electromagnetic shock wave sources.

In extracorporeal shock wave lithotripsy there is still a lack of knowledge about the basic physical terms that are essential for a scientific comparison of lithotripters with different technologies. The main goal of this article is to introduce the relation between pressure distribution, acoustic energy flow and intensity. The procedure of how these data can be achieved quantitatively is described.

The mechanisms of stone disintegration by shock waves.

Through interpretation of high-speed films at 10,000 frames per second of shock wave action on kidney stones and gallstones, the mechanism of stone destruction was analyzed in detail. This shows that the interaction of the shock wave with the targets firstly produces fissures in the stone material. Liquid then enters these small cracks.

First experience with a modified Siemens Lithostar shock wave system.

A Siemens Lithostar shock wave system was modified and investigated clinically. The modified system yields increased focal pressure and energy density. The first clinical experience in renal calculi shows a significant reduction in shock wave numbers per treatment.

Pressure-optimized lithotripsy with the Siemens Lithostar: successful and tissue-protecting treatment of urinary stones.

With the Siemens Lithostar all kinds of urinary stones can be successfully treated at significantly lower pressure levels than with other commercially available lithotripters. Experimental and clinical experience indicates that for urinary stones there exists a pressure region between 200 and 400 bar (20-40 MPa) where lithotripsy can be performed successfully and the tissue can be protected. By calculation of isobar zones the pressure distribution of different lithotripters can be compared quantitatively.

Value of in-line and out-of-line ultrasound targeting in extracorporeal shock wave lithotripsy.

Acoustic inhomogeneities of body tissue may deflect diagnostic ultrasound waves as well as therapeutic shock waves. The influence of incorrect ultrasound targeting and shock wave application due to these deflection effects has been examined quantitatively by means of a two-dimensional physical model. The accuracy of in-line and out-of-line targeting has been determined.