Use of computed tomography sinography for evaluation of draining tracts in 27 dogs and one cat.

OBJECTIVES: To describe the clinical findings, imaging findings and outcome in patients in which CT sinography was performed, and assess to what degree this technique adds information about the extent of a tract or increases the accuracy of diagnosis of foreign bodies on CT. MATERIALS AND METHODS: Retrospective review of medical records of 27 dogs and one cat with draining tracts that had CT sinography. Pre- and post-intravenous (IV) contrast CT series were compared with CT sinography in each patient. RESULTS: Median duration of clinical signs before referral was 85 days (range 2 to 1478 days). The most common reported clinical signs were swelling (14/28, 50%) and regional pain (5/28, 18%). CT sinography revealed a more extensive tract than post-IV contrast CT in 21% cases. On post-IV contrast CT, 31% of foreign bodies were detected compared to 23% on CT sinography. All four foreign bodies detected by CT were observed in the non-contrast images. Surgery was performed after CT in 22 (79%) cases. Thirteen (46%) draining tracts resolved after surgery, three (11%) resolved without surgery, six (21%) persisted or recurred after surgery, and six (21%) were lost to follow-up. CLINICAL SIGNIFICANCE: CT sinography provides limited additional information about the extent of draining tracts compared to pre- and post-IV contrast CT images and did not increase the number of foreign bodies identified.

A prospective microbiologic surveillance program to detect and prevent the transfusion of bacterially contaminated platelets.

After two patients received bacterially contaminated platelet transfusions, a prospective surveillance program was instituted to perform Gram staining and microbiologic culturing of platelets at the time of transfusion. In 12 months, 3141 random-donor platelet pools (prepared from 14,481 units) and 2476 single-donor apheresis units were cultured. All single-donor apheresis units were sterile, but 6 (0.19%) of the random-donor pools were found to be bacterially contaminated, with 1 unit of 5 in the pool being the source in each case. Contaminants were Staphylococcus epidermidis (4 cases), Bacillus cereus (1), and Staphylococcus aureus (1) at counts of 0.5 x 10(2) to 10(11) colony-forming units per mL in platelet pools and 10(3) to 10(13) colony-forming units per mL in source units. The contamination rate for units transfused at < or = 4 days (1.8/10,000) was significantly lower than that at 5 days (11.9/10,000; p < 0.05), as was the magnitude of contamination (p < 0.05). Use of the pretransfusion Gram stain on 4- and 5-day-old platelet pools was 100 percent sensitive (4/4 true positives) and 99.93 percent specific (1 false positive) in detecting contaminated pools. These data define the extent and magnitude of platelet bacterial contamination and demonstrate the efficacy of the pretransfusion Gram stain on platelet units stored for 4 and 5 days in preventing the transfusion of heavily contaminated units. It is concluded that the risk of platelet contamination is related to the duration of component storage.(ABSTRACT TRUNCATED AT 250 WORDS)

Individual microglia move rapidly and directly to nerve lesions in the leech central nervous system.

Small cells called microglia, which collect at nerve lesions, were tracked as they moved within the leech nerve cord to crushes made minutes or hours before. The aim of this study was to determine whether microglia respond as a group and move en masse or instead move individually, at different rates, and whether they move along axons directly to the lesion or take another route, such as along the edges of the nerve cord. Cell nuclei in living nerve cords were stained with Hoechst 33258 dye and observed under dim ultraviolet illumination using fluorescence optics, a low-light video camera, and computer-assisted signal enhancement. Muscular movements of the cord were selectively reduced by bathing in 23 mM MgCl2. Regions of nerve cord within 300 microns of the crush were observed for 2-6 hr. Only a fraction of microglia, typically less than 50%, moved at any time, traveling toward the lesion at speeds up to 7 microns/min. Cells were moving as soon as observation began, within 15 min of crushing, and traveled directly toward the lesion along axons or axon tracts. Movements and roles of leech microglia are compared with their vertebrate counterparts, which are also active and respond to nerve injury.

Development of identified glia that ensheathe axons in Hirudo medicinalis.

Interaction between neurons and glia may contribute to the formation of characteristic nerve bundles formed by axon elongation along stereotypic pathways. This study reports the temporal and spatial distribution of identified ensheathing glia during embryonic development in the leech. The development of connective glia was followed 1) using an immunohistochemical probe (monoclonal antibody Lan3-13), which recognized connective glia, and 2) using electron microscopy. Embryonic glia were initially located in the medial region of the lateral connectives and contained intermediate filaments. Glia cells continued to develop throughout embryogenesis; the number and size of glial processes increased, and they ensheathed smaller bundles of axons. The glial cell recognized by Lan3-13 first appeared after axons had already begun to form the connectives. This suggests that these particular glial cells may not function in the initial guidance of axons along stereotypic pathways. However, another cell that contained small bundles of intermediate filaments and glycogen granules was present at early stages of connective formation. These cells may be undifferentiated or transient glia, which could contribute to the formation of characteristic nerve bundles.

Postmortem diagnosis of meningococcemia by detection of capsular polysaccharides.

Detection of specific meningococcal capsular polysaccharide (CPS) in postmortem blood permits rapid diagnosis of meningococcemia and differentiation from pneumococcemia and septicemia caused by Haemophilus influenzae Type b. We present studies validating application of latex agglutination assay for CPS on blood samples collected at autopsy, delineate the circumstances when CPS testing is indicated, and illustrate the usefulness of this procedure by several recent cases. Blood samples from victims dying of injury or disease other than infection were examined to determine whether the postmortem interval, bacterial contamination, anticoagulants, or delay in testing would result in false positive assays. Series 1 samples, collected so as to minimize bacterial contamination, were immediately submitted for assay. Series 2 evaluated the effect of adverse conditions of collection, anticoagulation, and prolonged sample storage. Despite extended postmortem intervals of up to 14 days, heavy bacterial contamination, prolonged storage at 4 degrees C, deep hemolysis, and presence of anticoagulants, false positive assays were seldom observed.