Repeat duplex ultrasound scanning in suspected Deep Vein Thrombosis (DVT): putting the onus back on the referring clinician.

Duplex scanning is utilised by many departments in the investigation of suspected DVT. NICE Guideline CG144 recommended repeat scanning for patients in whom the initial Wells score was 'likely' in the presence of a raised D-Dimer, following a normal first scan. Following implementation of this recommendation in our department there was a dramatic rise in the number of repeat scans being undertaken, all of which were negative for DVT. Introduction of an electronic message to the report, placing the onus back on the referring clinician to arrange repeat scan if deemed appropriate resulted in a fall in the number of scans being undertaken without impacting on patient outcome.

Reticuloendotheliosis in captive greater and Attwater's prairie chickens.

Reticuloendotheliosis in captive greater (Tympanuchus cupido pinnatus) and Attwater's (T. cupido attwateri) prairie chickens is reported for the first time. Between September 1993 and August 1994, two adult female wild-caught greater prairie chickens housed at Texas A&M University (College Station, Texas, USA) were observed with multiple subcutaneous nodules. Both birds were euthanatized. Complete necropsy examinations revealed lesions limited to the skin of each bird. Histopathologic examination of lesions revealed pleomorphic lymphoreticular cells suggestive of reticuloendotheliosis and reticuloendotheliosis virus (REV) was demonstrated in tumor tissue by polymerase chain reaction and virus isolation. Between September 1994 and June 1995, five additional greater prairie chickens and two Attwater's prairie chickens were euthanatized or found dead with evidence of lymphoreticular neoplasia in multiple organ systems. Initial testing of the captive flock in December 1994 for evidence of viremia and antibody to reticuloendotheliosis virus revealed over 50% of the tested birds were viremic, but none developed antibodies. Subsequent testing between January 1995 and January 1996 indicated that once infected with reticuloendotheliosis virus, Attwater's prairie chickens tended to remain outwardly healthy despite persistent viremia compared to infected greater prairie chickens which had higher morbidity and mortality rates within 60 to 90 days after initial detection of viremia and did not usually develop persistent viremia. Antibodies to REV were detected in only three captive greater prairie chickens and only in 1995. Six of the nine birds that were euthanatized or found dead due to reticuloendotheliosis developed viremia prior to death; three birds were not tested prior to death. Testing of free-ranging greater and Attwater's prairie chickens for reticuloendotheliosis is recommended prior to translocation or release.

Nitric oxide production by lymphatic endothelial cells in vitro.

The present study demonstrates that confluent monolayer cultures of lymphatic endothelial cells produce and secrete NO. Immunofluorescent studies showed that eNOS activity can be stimulated with Ca ionophore to enhance the production of NO. Cells exposed to LPS and various cytokines stimulated the production of iNOS which showed the greatest increase in activity at 4 hrs and declined at 18 and 24 hrs. These studies provide evidence that, within the lymphatic vascular lumen, nitric oxide may be produced by the lymphatic endothelium which interact with various vasoactive substances to regulate lymphatic vascular tone. In addition, the production of NO by LEC may be important in the regulation of lymphatic vascular tone in order to more readily accommodate sudden fluctuations in lymph flow and pressure that normally occur during the process of lymph formation and propulsion.