Primary synovial chondromatosis: an elemental investigation of a rare skeletal pathology.

BACKGROUND: Primary synovial chondromatosis (PSC) is a rare idiopathic pathology characterised by the formation of osseocartilaginous nodules within synovial joints, tendons, or bursae. The mineralisation pattern of PSC nodules is poorly understood and has yet to be investigated using elemental analysis. Mapping this pattern could elucidate the progression of the disease. MATERIALS AND METHODS: Primary synovial chondromatosis nodules discovered during dissection of a formalin fixed donor were analysed. Scanning electron microscopy paired with energy dispersive X-ray spectroscopy (SEM-EDS) was used to quantify calcium and phosphorus levels to distinguish mineralised components from cartilage, indicated by increased carbon and oxygen concentrations. RESULTS: Nine nodules with average dimensions 1.76 cm × 1.25 cm were identified in the semimembranosus bursa. SEM-EDS demonstrated increased calcium phosphate levels in nodular cores, while outer margins contained primarily carbon and oxygen. Quantification of these elements revealed nodular peripheries to contain 68.0% carbon, 30.2% oxygen, 0.8% calcium, and 1.0% phosphate, while cores were comprised of 38.1% carbon, 42.1% oxygen, 14.1% calcium, and 5.7% phosphate. CONCLUSIONS: Nodules were found to have mineralised cores embedded within a cartilaginous matrix. This pattern suggests disease progression is facilitated by endochondral ossification, opening the potential for new therapeutic techniques.

Lidar system model for use with path obscurants and experimental validation.

When lidar pulses travel through a short path that includes a relatively high concentration of aerosols, scattering phenomena can alter the power and temporal properties of the pulses significantly, causing undesirable effects in the received pulse. In many applications the design of the lidar transmitter and receiver must consider adverse environmental aerosol conditions to ensure the desired performance. We present an analytical model of lidar system operation when the optical path includes aerosols for use in support of instrument design, simulations, and system evaluation. The model considers an optical path terminated with a solid object, although it can also be applied, with minor modifications, to cases where the expected backscatter occurs from nonsolid objects. The optical path aerosols are characterized by their attenuation and backscatter coefficients derived by the Mie theory from the concentration and particle size distribution of the aerosol. Other inputs include the lidar system parameters and instrument response function, and the model output is the time-resolved received pulse. The model is demonstrated and experimentally validated with military fog oil smoke for short ranges (several meters). The results are obtained with a lidar system operating at a wavelength of 0.905 microm within and outside the aerosol. The model goodness of fit is evaluated using the statistical coefficient of determination whose value ranged from 0.88 to 0.99 in this study.

Intermittent sequential pneumatic compression in prevention of venous stasis associated with pneumoperitoneum during laparoscopic cholecystectomy.

OBJECTIVES: To determine whether pneumoperitoneum and reverse Trendelenburg's position used during laparoscopy impede common femoral venous flow and whether calf-length intermittent sequential pneumatic compression (ISPC) overcomes this impedance. DESIGN: Using Doppler ultrasonography, peak systolic velocities in the common femoral vein were measured in patients undergoing laparoscopic cholecystectomy with peritoneal insufflation of carbon dioxide. Measurements were obtained during three intervals: preoperatively with the patients in the supine position; after induction of general anesthesia with the patients in the supine position; and after insufflation to 13 to 15 mm Hg with the patients in the 30 degrees reverse Trendelenburg position (both with and without ISPC). Mean arterial pressure and heart rate were obtained concurrently. Measurements of preoperative and postoperative calf and thigh circumferences were obtained. SETTING: A tertiary care center. PATIENT PARTICIPANTS: A consecutive sample of 20 patients 30 to 70 years of age (15 women and five men) who underwent laparoscopic cholecystectomy and met the inclusion criteria. MAIN OUTCOME MEASURES: Peak systolic velocity, mean arterial pressure, heart rate, and calf and thigh circumferences. RESULTS: The combination of pneumoperitoneum to 13 to 15 mm Hg and a 30 degrees reverse Trendelenburg position significantly decreased peak systolic velocity in the common femoral vein from a preoperative mean of 0.24 +/- 0.025 m/s to 0.14 +/- 0.011 m/s, or a 42% decrease. Intermittent sequential pneumatic compression reversed that effect, returning peak systolic velocity to 0.27 +/- 0.021 m/s. The mean difference between preoperative peak systolic velocity and peak systolic velocity with a combination of pneumoperitoneum, reverse Trendelenburg's position, and ISPC was 0.03 +/- 0.03 m/s but was not significant. Anesthesia alone caused a mean increase in preoperative peak systolic velocity from 0.24 +/- 0.025 m/s to 0.3 +/- 0.032 m/s. Mean arterial pressure levels, heart rate, and calf and thigh circumferences did not change significantly. CONCLUSIONS: This study demonstrated a significant reduction in common femoral venous flow during laparoscopic cholecystectomy coincident with pneumoperitoneum and reverse Trendelenburg's position. Intermittent sequential pneumatic compression reversed that effect, returning peak systolic velocity to normal.

Defective CD2 pathway T cell activation in systemic lupus erythematosus.

CD2 (T11; sheep erythrocyte receptor) is the surface component of an alternative, antigen-independent pathway of human T cell activation. The response to certain anti-CD2 antibodies is relatively independent of accessory cell signals and therefore provides a direct measurement of T cell function. The CD2 pathway may be important in the differentiation of thymocytes, on which the expression of CD2 precedes the appearance of the CD3-T cell receptor complex. In view of the impaired T cell regulation of immune responses in patients with systemic lupus erythematosus (SLE), we examined the activation of peripheral blood lymphocytes by anti-CD2 antibodies in 57 SLE patients and 32 normal control subjects. The CD2 pathway response was lower in the SLE patients (P less than 0.0001); 18 of the 57 SLE patients had a lower response than any of the control subjects. The SLE low-responder patients did not differ from the normal-responder patients in terms of disease activity or use of antiinflammatory and immunosuppressive medications. Low responses to anti-CD2 were corrected to normal by the coaddition of a submitogenic amount of phorbol myristate acetate (1 ng/ml). In some low-responder patients, the responses were normalized by the removal of non-T cells. The data indicate that some SLE patients have impaired responses to CD2 pathway activation and that this may reflect intrinsic T cell defects and/or regulatory influences of non-T cells.

Activation pathways of synovial T lymphocytes. Expression and function of the UM4D4/CDw60 antigen.

Accumulating evidence implicates a central role for synovial T cells in the pathogenesis of rheumatoid arthritis, but the activation pathways that drive proliferation and effector function of these cells are not known. We have recently generated a novel monoclonal antibody against a rheumatoid synovial T cell line that recognizes an antigen termed UM4D4 (CDw60). This antigen is expressed on a minority of peripheral blood T cells, and represents the surface component of a distinct pathway of human T cell activation. The current studies were performed to examine the expression and function of UM4D4 on T cells obtained from synovial fluid and synovial membranes of patients with rheumatoid arthritis and other forms of inflammatory joint disease. The UM4D4 antigen is expressed at high surface density on about three-fourths of synovial fluid T cells and on a small subset of synovial fluid natural killer cells; in synovial tissue it is present on more than 90% of T cells in lymphoid aggregates, and on approximately 50% of T cells in stromal infiltrates In addition, UM4D4 is expressed in synovial tissue on a previously undescribed population of HLA-DR/DP-negative non-T cells with a dendritic morphology. Anti-UM4D4 was co-mitogenic for both RA and non-RA synovial fluid mononuclear cells, and induced IL-2 receptor expression. The UM4D4/CDw60 antigen may represent a functional activation pathway for synovial compartment T cells, which could play an important role in the pathogenesis of inflammatory arthritis.

The mechanism of activation of 4-hydroxycyclophosphamide.

4-Hydroxycyclophosphamide (2/3) of unknown stereochemistry is the initial metabolite formed after administration of cyclophosphamide (1). Ultimate conversion to the cytotoxic metabolite phosphoramide mustard (6) is initiated by ring opening of 4-hydroxycyclophosphamide to produce aldophosphamide (4). The ring-opening reaction and subsequent equilibration of 2-4 are subject to general-acid catalysis, and the equilibrium composition is independent of buffer structure and pH. In contrast, formation of 6 from 4 proceeds by general-base-catalyzed beta-elimination. trans-4-Hydroxycyclophosphamide undergoes ring opening ca. 4 times faster than the cis isomer, and cyclization of 4 favors the trans isomer by a factor of ca. 3 over the cis isomer. The rapid equilibration of 2-5 and the absence of elimination to give 6 at pH approximately 5 provides a convenient method to prepare a stable equilibrium mixture of activated cyclophosphamide metabolites suitable for in vitro use.