Hemofiltration and double high flux dialysis: risks and benefits

Patients with systemic lupus erythematosus require adequate information (sun avoidance, fair compliance, smoking discontinuation, adequate contraception and diet, pregnancy planning). Nonsteroidal antiinflammatory drugs and antimalarials are effective in patients presenting with skin and articular involvement. Visceral lesions and hemocytopenias require the use of steroids, alone or in association with immunosuppressive agents. Long-term anticoagulation with an INR of 3-3.5 achieves the prevention of recurrent thrombotic events. Experimental data suggest that more specific treatments and even regimens aimed at eradication of human lupus might soon arise.     

Efficacy of perichondrium and a trabecular demineralized bone matrix for generating cartilage

A pedicled auricular perichondrial flap wrapped around trabecular demineralized bovine bone matrix can generate an autologous cartilage graft. In earlier experimental studies, it was demonstrated that this graft could be used for nasal and cricoid reconstruction. It was assumed that the vascularization of the perichondrial flap was obligatory, but it was never proven that the flap should be pedicled. Moreover, for clinical use, the dimensions of the auricle would set restrictions to the size of the graft generated. Therefore, the possibility to generate cartilage with a composite graft of a free perichondrial flap wrapped around demineralized bovine bone matrix, by using young New Zealand White rabbits, was studied. This composite graft was implanted at poorly (subcutaneously in the abdominal wall; n = 12), fairly (subcutaneously in the pinna; n = 12), and well-vascularized sites (quadriceps muscle; n = 12). As a control, trabecular demineralized bovine bone matrix was implanted without perichondrial cover. Half of these grafts (n = 6) were harvested after 3 weeks, and the remaining grafts (n = 6) after 6 weeks of implantation. In histologic sections of these grafts, the incidence of cartilage formation was scored. Furthermore, the amount of newly formed cartilage was calculated by computerized histomorphometry. Trabecular demineralized bovine bone matrix without perichondrial cover demonstrated early resorption; no cartilage or bone was formed. In demineralized bovine bone matrix wrapped in perichondrium, early cartilage formed after 3 weeks at well- and fairly vascularized sites. No cartilage could be detected in grafts placed at a poorly vascularized site after 3 weeks; minimal cartilage formed after 6 weeks. In summary, the highest incidence of cartilage formed when trabecular demineralized bovine bone matrix was wrapped either in a pedicled auricular perichondrial flap or in a free perichondrial flap, which was placed at a well-vascularized site. Second, a significantly higher percentage of the total area of the graft was cartilaginized at well-vascularized sites after 3 weeks. The newly generated cartilage contained collagen type II and proteoglycans with hyaluronic acid binding regions, whereas collagen type I was absent, indicating the presence of hyaline cartilage. This study demonstrates that new cartilage suitable for a graft can be generated by free perichondrial flaps, provided that the site of implantation is well vascularized. Consequently, the size of such a graft is no longer limited to the dimensions of the auricle.     

Tolerance and immunity to MUC1 in a human MUC1 transgenic murine model

A sensitive assay of the 2H-enrichment of water based on the isotopic exchange between the hydrogens of water and of acetone in alkaline medium is described and validated. For low 2H-enrichments (0.008 to 0.5%), the sample is spiked with [U-13C3]acetone and NaOH. After exchange, 2H-enriched [U-13C3]acetone is extracted with chloroform and assayed by gas chromatography-mass spectrometry. With some instruments, ion-molecule reactions, resulting in increased baseline enrichment, are minimized by lowering the electron ionization energy from the usual 70 to 10 eV. The 2H-enrichment of water is amplified nearly sixfold in the M4/M3 ratio of [U-13C3]acetone. For high 2H-enrichments (0.25 to 100%), the use of unlabeled acetone suffices. After exchange, the mass isotopomer distribution of acetone is analyzed, yielding the 2H-enrichment of water. The assay with [U-13C3]acetone allows measuring the 2H-enrichment of water even in biological samples containing acetone. This technique is more rapid and economical than the classical isotope ratio mass spectrometric assay of the enrichment of hydrogen gas derived from the reduction of water.     

More sensitive high-pressure liquid-chromatographic determiantion of theophylline in serum

We present procedures for determining theophylline in 50 mul of serum. The drug is extracted into a small volume of solvent that contains an internal standard, 8-chlorotheophylline. The extract is Analyzed by isocratic reversedphase chromatography, with measurement of eluted theophylline at 273 nm. Day-to-day reproducibility within 5% is attainable for the concentration range 5--20 mg/liter. Other xanthines and related metabolites do not interfere. Sensitivity is 1 mg/liter. The correlation coefficient, when results by a spectrophotometric procedure were compared, was 0.989. Amobarbital, secobarbital, phenobarbital, and diphenylhydantoin do not interfere. Total analysis time for a single sample is 15 min.     

Analysis of pointing errors reveals properties of data representations and coordinate transformations within the central nervous system

The execution of a simple pointing task invokes a chain of processing that includes visual acquisition of the target, coordination of multimodal proprioceptive signals, and ultimately the generation of a motor command that will drive the finger to the desired target location. These processes in the sensorimotor chain can be described in terms of internal representations of the target or limb positions and coordinate transformations between different internal reference frames. In this article we first describe how different types of error analysis can be used to identify properties of the internal representations and coordinate transformations within the central nervous system. We then describe a series of experiments in which subjects pointed to remembered 3D visual targets under two lighting conditions (dim light and total darkness) and after two different memory delays (0.5 and 5.0 s) and report results in terms of variable error, constant error, and local distortion. Finally, we present a set of simulations to help explain the patterns of errors produced in this pointing task. These analyses and experiments provide insight into the structure of the underlying sensorimotor processes employed by the central nervous system.     

The preparation of field electron/field-ion emitters by ion etching

A new technique is described for the fabrication and resharpening of field emitters. This technique employs an ion gun and uses methods analogous to those used to produce thin foils for the transmission electron microscope. In this way it has proved possible to produce reliably sharp emitters of both metal and semiconducting materials and the technique is particularly useful when dealing with those materials normally difficult to electropolish or chemically etch. Applications lie not only in field electron emission and field-ion microscopy, but may also be relevant to the development of high current electron sources for use in electron microscopy.     

Design Features of a Positron Tomograph with 2.4 MM Resolution

A design is presented for a positron tomograph having 2.4 mm spatial resolution. This resolution is achieved by using small plastic scintillators in ten detector rings, the light from the scintillators being transmitted to photomultipliers through optical fibers. By proper arrangement of the fibers the light signals are coded so that only 200 photomultipliers are required for the system. By using 10 rings the sensitivity of the tomograph is increased so that it is better than that of present tomographs having design resolutions of 6 mm.     

Determination of cell origin after marrow transplantation in canines by polymerase chain reaction and quantitation of the ZFY/ZFX genes

BACKGROUND: In order to follow the course of bone marrow engraftment in dogs, and to determine the presence, and percentage, of donor-derived cells in other canine tissues, a simple and fast method of determining cell origin after sex-mismatched bone marrow transplantation was developed. METHODS: Using universal primers, fragments from genomic DNA corresponding to ZFX and ZFY genes were amplified by polymerase chain reaction. A restriction fragment length polymorphism, combined with densitometric analysis, was then used to distinguish and quantitate ZFY and ZFX sequences. Unknown samples were analyzed against standards of known mixtures of male and female DNA. RESULTS: Canine ZFY and ZFX genes were clearly resolved after amplification, digestion with HaeIII, and denaturing polyacrylamide gel electrophoresis. Microchimerism could be detected in male and female dog DNA samples derived from a range of fresh and frozen tissues including spleen, testicle, and the central nervous system. The levels of chimerism determined using this method were in either agreement with results obtained by karyotyping or more sensitive, with a detection limit of 0.4% compared with 1-2%. CONCLUSIONS: Polymerase chain reaction/restriction fragment length polymorphism detection of the ZFY and ZFX genes was found to be simple, accurate, and reliable for assessing engraftment in dogs. When compared with cytogenetic analysis, this method was found to be faster to perform, more capable of detecting lower levels of microchimerism, and useful for detecting donor-derived cells in stored specimens and in tissues other than peripheral blood or bone marrow.     

Undiagnosed scleroderma in a patient with a difficult airway

BACKGROUND: We report one case of symptomatic aneurysm of infrarenal abdominal aorta in a patient symptomatic for acute abdomen. METHODS: The patient was accepted at the Emergency Care Unit and the routine admission tests were taken. US of the abdomen revealed a (SVI) disposition of the organs and an aneurysm of the abdominal aorta below the renal arteries. Patient underwent an aorto-aortic straight graft CONCLUSIONS: In this case-report we show SVI cannot be considered a problem in the surgical treatment of symptomatic abdominal aortic aneurysms.