[First clinical experiences with a new cementless knee endoprosthesis for the dog]. / Erste klinische Erfahrungen mit einer neuen zementlosen Knie-Endoprothese für den Hund.

OBJECTIVE: This paper reports on the clinical application and first experiences of a newly developed cementless knee endoprosthesis for dogs. MATERIAL AND METHODS: The GenuSys knee-endoprosthesis was implanted in 23 knees of 22 dogs with severe gonarthritis and a history of pain. Their body weight ranged from 28 to 55 kg, their age between 5 and 12 years. This knee implant for dogs is a cementless "mobile bearing prosthesis". An additional fixation with one screw is necessary in the femoral component. Currently, there are four standard sizes of the prosthesis available. RESULTS: At the end of the study, 16 of 22 controlled patients (72.7%) were fully weightbearing on the operated limb or only showed a discreet lameness. We observed no complications in 12 cases (54.5%). In 10 cases problems in the course of healing were detected and made or would have made reoperation necessary. The complications noted were subluxation (n = 6, 27.3%), wound infection (n = 3, 13.6%) and a serious decrease in the range of motion (n = 1, 4.5%). Four of these 10 patients (40%) were subsequently healed through surgery. The remaining six dogs (27.3%) were euthanized or underwent arthrodesis of the leg. CONCLUSION AND CLINICAL RELEVANCE: Sixteen of 22 dogs (72.2%) showed much better weightbearing and an increased quality of life after endoprosthesis of the knee. Although the complication rate was high, we expect better results in the future due to improvements in the equipment and surgical procedure. A definitive conclusion can only be made based on the results of a long-term study.

Slit-lamp-adapted fourier-domain OCT for anterior and posterior segments: preliminary results and comparison to time-domain OCT.

PURPOSE: To evaluate the diagnostic potential of a slit-lamp (SL)-adapted Fourier-domain (= spectral radar, SR) optical coherence tomography (OCT)-SL-SR-OCT-instrument as an in vivo imaging device for use in examinations of the anterior and posterior segments. MATERIALS AND METHODS: In a pilot study, 88 eyes from 70 healthy volunteers and patients were examined using a prototype Fourier-domain SL-SR-OCT system. Results were compared to those from the following commercially available systems: the 1310-nm SL-OCT (Heidelberg Engineering, Heidelberg, Germany) for anterior segment and the Stratus OCT (Zeiss Meditec, Jena, Germany) for posterior segment imaging. Our SL-SR-OCT provides 1025 axial scans, 5000 Hz line-scan frequency, scan length of up to 8 mm, axial depth in air of 3.5 mm, and resolution of 9 mum. For posterior visualization, a hand-held 78-diopter ophthalmoscopic lens was used. RESULTS: Our SL-SR-OCT system allowed simultaneous scanning with direct biomicroscopic and SL imaging of anterior and posterior segment structures. Anatomical structures and pathological changes were displayed with high resolution and excellent contrast. Measurements of corneal and retinal thickness were possible. In comparison to images obtained by the SL-OCT, our SL-SR-OCT boasted a higher resolution, thus providing more clinically relevant details of the corneal epithelium, internal structure of filtering blebs, etc. Complete imaging of the chamber angle was limited, however, due to the backscattering properties of the sclera at 830 nm. For posterior segment imaging, excellent delineation of the macula and optic nerve head details, with a distinct portrayal of macular pathology and retinal edema, was possible with SL-SR-OCT. CONCLUSION: SL-SR-OCT enables detailed imaging of physiological and pathological anterior and posterior segment structures. As a multi-purpose device, it offers a wide spectrum of applications, with high-quality OCT-imaging, in a comfortable setting without the need to move the patient.

Towards multi-directional OCT for speckle noise reduction.

Multi-directional optical coherence tomography (MD-OCT) applies and extends the concept of angular compounding for speckle noise reduction to the area of OCT imaging. OCT images are acquired from a wide range of angles of view. Averaging of the rotated images therefore requires compensation of the parallax which is achieved by simple image registration for image reconstruction. Test measurements of a sample structure in a low and highly scattering environment show that the method improves the signal-to-noise ratio by a factor of 4 and hence reduces speckle noise significantly. Experimental results also show that the proposed averaging increases the performance of common edge-detection algorithms.

The genotoxicity of lead.

Lead has been tested for genotoxic potential in a range of mutagenicity assays. Such studies report varying effects, and the results are equivocal. The reasons for this may be related to problems of the solubility of many lead compounds, their inability to dissolve in biological fluids, chemical interferences resulting in conflicting observations, the nonspecificity of the assays used, the delivery of toxic doses to specific genetic processes or the mediation of genotoxicity through indirect mechanisms. Occupational and environmental exposures to lead have also been associated with increases in chromosomal damage in humans at moderate to high exposures, although this evidence is contradictory. Where positive findings have been reported, many are related to exposure. The possibility that lead is genotoxic is by no means clear, but evidence is still accumulating.

Mutagenic activity of heated potato/oil systems.

Mutagens detected with Salmonella typhimurium strain TA 98 in the presence of liver S9 mix were extracted from potato slices, but not pure potato starch, after frying in oil. No mutagenic activity was detected using strain TA 100, in the presence or absence of S9 mix with either fried potato slices or potato starch. Mutagenic activity was detected at frying temperatures of 140 degrees C and above. The mutagenic activity was limited to the outer portion of the fried potato slices and increased with frying time and temperature. Mutagenic activity ratios for extraction with both (NH4)2SO4/NH4OH and Na2SO4/NaOH were similar.