Image analysis versus flow cytometry for DNA ploidy quantitation of solid tumors: a comparison of six methods of sample preparation

With the availability of user-friendly interactive image analysis instruments for DNA analysis, there is a growing need for comparison with the established methodology of flow cytometry. We have compared the results of DNA ploidy quantitation in 12 solid tumors prepared by six different techniques of sample preparation: flow cytometry of fresh cell suspensions and of nuclei isolated from formalin-fixed, paraffin-embedded tissue; and image analysis of touch preparations, of disaggregated cells from paraffin-embedded tissue as well as of 3- and 7-microns-thick tissue sections. Complete agreement in DNA ploidy results obtained by the six methods was found in six out of 12 solid tumors. Image analysis of touch preparations detected most tetraploid and multiple aneuploid peaks. Sections of 7-microns-thick tissue gave better histogram quality than 3-microns-thick sections, however tetraploid peaks were not resolved in one case. Image analysis of disaggregated paraffin-embedded tumor showed comparable ploidy to fresh touch preparations in seven out of 12 cases, the discrepancies being due to loss of tetraploid or multiple aneuploid peaks. Flow cytometry gave good histograms, but tetraploid and multiple aneuploid peaks were occasionally not detected. Each method presents advantages and disadvantages. Flow cytometry and image analysis are complementary methods for DNA quantitation, and more than one method may be necessary to confirm the DNA content of solid tumors.

HLA-DR expression in bile duct damage in hepatitis C

Several investigations have demonstrated aberrant expression of HLA-DR on damaged bile duct epithelium of patients with primary biliary cirrhosis, liver allograft rejection, graft versus host disease, and AIDS. Since bile duct damage is a prominent feature of chronic hepatitis C, it may also be associated with HLA-DR induction. Therefore, we examined the expression of HLA-DR antigen in formalin-fixed, paraffin-embedded liver biopsy sections of 30 patients with chronic hepatitis C by the avidin-biotin peroxidase complex method using a monoclonal antibody to HLA-DR. HLA-DR was not detected on bile duct epithelium in any of the cases, although bile duct damage of varying degree was observed in 90% of the cases. HLA-DR was expressed by Kupffer cells; inflammatory infiltrates in portal tracts, and in areas of piecemeal necrosis and lobular necrosis; dendritic cells in portal and periportal areas; and occasionally hepatocytes. These observations suggest that the mechanism of bile duct injury in chronic hepatitis C may be different from that of other conditions such as primary biliary cirrhosis, liver allograft rejection, and graft versus host disease.

Stroke secondary to carotid occlusion in a young man with nephrotic syndrome: Case description and review of the literature

We report a case of hemispheric stroke and death secondary to thrombosis of the internal carotid artery in a young adult with minimal-change nephrotic syndrome. Thrombotic complications are common in patients with nephrotic syndrome and may be due to a hypercoagulable state. To our knowledge, this is the first report of cerebral infarction due to thrombosis in the extracranial vasculature in a patient with nephrotic syndrome. We review previous reports of cerebral infarction in association with nephrotic syndrome and discuss possible mechanisms of hypercoagulability in this setting.

DNA flow cytometric evaluation of serous and mucinous cystic neoplasms of the pancreas

There have been few reports of flow cytometric studies of pancreatic neoplasms, whether endocrine or exocrine. In this report, the DNA content of three mucinous and seven serous cystic tumors of the pancreas was evaluated by flow cytometry on formaldehyde solution-fixed, paraffin-embedded tissue. Two serous cystadenomas were aneuploid, with the remaining five serous and all three mucinous being diploid. All cases had a low S phase (ranging from 0.1% to 3.1%), indicating neoplasms with a low turnover. From these results, it appeared that DNA flow cytometry as an independent factor did not discriminate between the benign pancreatic serous cystadenomas and the more aggressive mucinous cystic neoplasms.