[Engine-driven preparation of curved root canals: a platform to assess physical parameters]. / Maschinelle Aufbereitung gekrümmter Wurzelkanäle: Messaufbau zur Darstellung physikalischer Parameter.

The number of engine-driven rotary instruments available on the market is steadily increasing. These instruments enable clinicians to prepare better shaped root canals, however, rotary instruments have a higher risk for fracture than hand instruments. Unfortunately, the stresses placed on engine-driven rotary instruments in curved canals are insufficiently studied. The aim of this study was to develop a device which could measure more accurately the physical parameters influencing rotary instruments in curved canals. For this purpose, a specially designed machine was constructed to measure the torque which develops between the rotary instrument and the motor. Apical forces and penetration depths could also be directly measured in real time. A variety of other measurements was also possible because of other special set-ups integrated into the device. In the current study torque was assessed for GT-Files, size 35 with a .12 and sizes 20 with a .12 to .06 taper. In additions to preparations in simulated canals in plastic blocks, the "ISO 3630-1 specification for fracture moment" and "number of cycles till fatigue fracture" was measured. The findings indicated that when instruments were used for preparations, torques up to 40 Nmm were present. This exceeded the static fracture load, which was less than than 13 Nmm for the size 20 with .12 taper. In contrast, the number of rotations were more than 10 times lower when shaping canals in plastic blocks with a 5 mm radius of curvature than the number of rotations to fracture in the "cyclic fatigue test". This suggests that a GT-instrument could be used in ten canals. The apical force was always greater than 1 N and occasionally, 8 N or more was recorded. Further studies on natural teeth with varying canal geometries are required using the specially developed torsional machine to reduce the incidence of instrument fracture. In this way an efficient clinical potential can be confirmed for engine-driven rotary instruments in canal preparation.

Autologous T cells control B-chronic lymphocytic leukemia tumor progression in human-->mouse radiation chimera.

B-chronic lymphocytic leukemia (B-CLL) is characterized by the clonal accumulation of CD5+ B cells. It has been suggested that CLL cells may be regulated by inhibitory and growth-promoting signals exerted by autologous T cells. We have recently described a model for human B-CLL in which peripheral blood mononuclear cells (PBMCs) are transplanted into the peritoneal cavity of lethally irradiated mice radioprotected with bone marrow from mice with severe combined immunodeficiency. In this model, adoptive transfer of low-stage PBMCs leads to marked engraftment of T cells or combined T and CLL cell engraftment, whereas infusion of high-stage PBMCs leads to dominance of CLL cells with a miniscule level of T-cell engraftment. This mutual exclusive pattern of engraftment indicated that T cells might control the expansion of tumor cells in the peritoneum of recipient BALB/c mice. In the present study, we further investigated this question and we demonstrate that in vivo T-cell depletion, using OKT3 antibody, markedly enhances the engraftment of B-CLL cells from patients with early-stage disease. In mice receiving PBMCs from 11 donors with advanced-stage disease, the results were more heterogeneous. In five patients the results were similar to those observed in early stage, whereas in two cases no CLL cell engraftment was found in the absence of T cells. The addition of purified T cells to PBMCs led to a substantial decrease of CLL engraftment in three advanced-stage cases. These results strengthen the working hypothesis that autologous T cells can actively suppress the expansion of the pathological cells in human-->mouse radiation chimera. This effect is prominent in early-stage disease, whereas in advanced stage suppressive and/or stimulatory effects may occur in different patients. The interaction of T cells with tumor cells and the potential of autologous T cell/immune-therapy in CLL can be further explored in this model.

Kinetics and proposed mechanism of the reaction of an immunoinhibition, particle-enhanced immunoassay.

We report kinetic studies on the reaction of a latex agglutination immunoassay used to quantify phenytoin in serum. In this assay, polystyrene particles with a covalently attached analog of phenytoin react with an antiphenytoin monoclonal antibody to form light-scattering aggregates, with the rate of this reaction being decreased by addition of phenytoin from sample. In the absence of free (sample) phenytoin, this reaction did not exhibit a maximum rate of agglutination in the presence of excess antibody, i.e., an equivalence point. Furthermore, agglutination was inhibitable by free phenytoin even when the latter was added after agglutination of particles with antibody had begun. Most significantly, the immunoagglutination proceeded in an identical fashion with monovalent F(ab) fragment. These data are consistent with low-affinity immunospecific particle-antibody complexation, which then induces colloidal aggregation, without requiring immunospecific bridging by antibody molecules. The described mechanism is not generalizable to all latex agglutination immunoassays, although disturbance of colloidal stability may be a component in most assays.

[A new method for 3-dimensional wear measurement]. / Eine neue Methode zur dreidimensionalen Verschleissmessung.

This study described a custom-made three-coordinate measuring system. It was based on a mechanical digital measuring device, a measuring and overlapping software and special specimen holders. The x-/y-measuring area was 100,000 x 100,000 microns and the vertical measuring range was 30,000 microns. The measurements were reproducible within the resolution of 1.0 microns over the entire measuring range. The maximum measurable tilt relative to the horizontal plane was < 59 degrees. The total accuracy of the system, which was influenced by the resolution of the measuring device, the reproducibility of the measurements, the accuracy of the test sample reposition and the measuring/overlapping software was better than 1.0 microns. For the graphic presentation of the data commercial software was adopted. Its capabilities were demonstrated on selected examples. The measuring system is an efficient device, which is extremely well adopted to the problem of quantitative wear measurement in dentistry.

Release of preventive agents from pacifiers in vitro. An introduction to a novel preventive measure.

Clinical data show that the later primary teeth are colonized by mutans streptococci (MS), the less caries will develop, if at all. Since up to 90% of teething children develop a sucking habit, pacifiers were designed to release preventive agents into the mouth. Simultaneous use of sodium fluoride and xylitol increases the enamel fluoride content. Xylitol affects specifically growth and metabolism of mutans streptococci. The aim of this study was to determine the release of fluoride, xylitol and sorbitol from pacifiers in vitro. A disintegration apparatus was designed to test the dissolution of tablets containing NaF resp. 0.25 mg F, 160 mg xylitol and 150 mg sorbitol from the pacifiers. Six pacifiers were agitated simultaneously with a standardised pump movement, 30 strokes/min, in 15 ml normal saline at +37 degrees C for 2, 5, 10, 20, 40, 60 and 90 min. The released fluoride was determined in 1 ml samples of saline to which 1 ml Tisab was added using a combined F-ion electrode. Xylitol and sorbitol were analyzed by using an ion chromatograph with a pulsed-amperometric detector. A linear slow release of fluoride, xylitol and sorbitol from the pacifiers could be observed up to 90 min. After 2700 strokes the residual saline in the suction chambers (vol. approximately 0.4 ml) was equally analyzed, where all 3 ingredients could still be detected.

The zeta sedimentation ration (ZSR) as the routine monitor of disease activity in a general hospital.

Nine hundred eighty-one requests for sedimentation rates in a clinical laboratory were received and the zeta sedimentation ratio (ZSR) test was performed. The results were correlated with the patients' diagnoses and disease activity. This test was found to be a useful monitor of disease activity in a clinical setting. Substitution of the ZSR for the standard erythrocyte sedimentation rates (ESR) appears to be acceptable. The test is simple, rapidly performed, and reproducible.

Studies on the action of myelin basic protein (MBP) in rat brain.

The specificity of I125-MBP uptake and subcellular distribution on a discontinuous sucrose density gradient, compared to those of histone H 4 and cytochrome c, showed a high affinity of MBP for mitochondria and heavy synaptosomes, and of histone H 4 for lighter synaptosomes. One heavier synaptosomal subpopulation was almost equally labelled by both proteins. Cytochrome c showed only a low uptake into particular material. Receptor interaction studies of MBP with H3-labelled 5-hydroxytryptamine and naloxone gave negative results.

Endometrial carcinoma of prostatic utricle with osseous metastases.

Endometrial carcinoma of the prostatic utricle is a rare pupillary prostatic tumor arising in the region of the prostatic urethra and verumontanum. Since the first description by Melicow and Pachter in 1967, 8 additional cases have been reported. This case is the tenth reported, and the first in which metastases to bone have been proved by biopsy. Transurethral resection of the tumor with postoperative radiation therapy to the prostatic region and metastases has resulted in clinical improvement. The importance of accurate diagnosis of this neoplasm is emphasized to avoid unnecessary delay in the appropriate choice of therapeutic modalities.

Zeta sedimentation ratio in rheumatic disease. Comparison of the zeta sedimentation ratio with the Wintrobe and Westergren sedimentation rates.

The zeta sedimentation ratios (ZSR) of 104 normal subjects and 106 rheumatology clinic patients were compared with their Westergren and Wintrobe erythrocyte sedimentation rates (ESR). The mean ZSR for normal subjects was 49.42 +/- 3.75%. The rheumatology clinic patients were separated into noninflammatory and inflammatory disease groups. The mean ZSR values for these groups were: noninflammatory, 51.60 +/- 5.33%; inflammatory, 59.43 +/- 7.32% (t = 5.5, p less than 0.001). The correlation between ZSR and ESR values was excellent. The ZSR determination has several advantages over the standard ESR in that it can be performed on blood anticoagulated with EDTA and need not be corrected for age, sex or packed cell volume. The ZSR is a rapid, reproducible test correlating well with rheumatic disease activity.

Genitourinary aspects of disseminated coccidioidomycosis.

Genitourinary involvement is common in disseminated coccidioidomycosis. Urologic evaluation should include careful examination, cultures and radiograms. The radiographic features of renal coccidioidomycosis parallel those of renal tuberculosis, with feathery, moth-eaten calices, infundibular constriction and caliceal ballooning, and eventual calcification of granulomas. Coccidioidal epididymitis may be chronic, with long asymptomatic intervals. A patient with a 15-year interval between episodes of right and left coccidioidal epipidymitis is described. Complement fixation titers should be used to determine the activity of genitourinary coccidioidomycosis. In 3 of 12 patients dissemination of coccidioidomycosis occurred during treatment with immunosuppressive medications. Renal transplant patients should be evaluated for active coccidioidomycosis prior to transplantation.