CD31 immunoreactivity in mesenchymal neoplasms of the skin and subcutis: report of 145 cases and review of putative immunohistologic markers of endothelial differentiation.

CD31 has recently been reported as a specific marker of endothelial differentiation among non-hematopoietic human neoplasms. In order to address this contention in particular regard to tumors of the skin and subcutis, the authors undertook a comparative study that surveyed 145 mesenchymal lesions. The antibodies used were directed against CD31 (clone JC/70A) and CD34 (clone My10), and these were compared with binding of Ulex europaeus I agglutinin (UEA). Proliferations that were included in the category of vascular tumors included cavernous and capillary hemangiomas (17 cases); lymphangiomas (8); epithelioid ("histiocytoid") hemangiomas (3), papillary endovascular hemangioendothelioma (1), angiosarcoma (7), and Kaposi's sarcoma of the mixed angiomatoid and spindle-cell type (17). CD31-immunoreactivity was observed in 35 of 53 vascular lesions; the neoplastic cells in a single angiosarcoma and the spindle cells in each case of Kaposi's sarcoma (KS) were not labeled. In all of the latter tumors, however, staining for CD31 was identified in the endothelia of angiomatoid areas and non-neoplastic blood vessels. These results compared favorably with those seen with anti-CD34, which decorated 36 of 53 vascular tumors--including 8 of 17 KS cases--and UEA, which bound to the neoplastic cells of 36 lesions. In contrast, all of 92 non-endothelial tumors included in this study (34 nerve sheath tumors [30 benign; 4 malignant]; 39 fibrohistiocytic neoplasms [11 benign; 28 malignant]; 9 smooth muscle tumors [6 benign; 3 malignant]; 7 glomus tumors; and 3 giant cell fibroblastomas) were negative for CD31. UEA labeled 3 non-vascular neoplasms, whereas 38 lesions of that type were CD34-positive.(ABSTRACT TRUNCATED AT 250 WORDS)

Diffuse microscopic angiodysplasia--a previously unreported variant of angiodysplasia. Report of a case.

PURPOSE: The entity of diffuse microscopic angiodysplasia is described, and a patient with severe gastrointestinal hemorrhage because of this submucosal source of bleeding is reported. METHOD: Case records of a patient with severe gastrointestinal hemorrhage were reviewed, and histologic findings were compared with colonoscopic and operative findings. The patient received 51 units of packed red blood cells over 3.5 months and remained undiagnosed, despite an exhaustive evaluation, until autopsy. RESULTS: Ectatic veins, venules, and capillaries were present within the submucosa in virtually every section of the small and large intestine examined (79 of 86 sections). Histologic evidence of bleeding from these submucosal vessels was identified in three sites (colon, jejunum, and ileum). The absence of endoscopically visible lesions was explained by findings that vessels did not traverse the muscularis mucosa and that mucosal depth was normal. This case of diffuse microscopic angiodysplasia, therefore, represents a unique variant, because the vascular findings were so diffuse and the mucosa remained histologically and endoscopically uninvolved, despite severe bleeding. CONCLUSION: Gastrointestinal bleeding from angiodysplasia is generally assumed to arise from endoscopically recognizable vascular ectasia within the mucosa. Thus, this case helps provide an explanation for some cases in which occult or massive bleeding is assumed to be secondary to angiodysplasia, even when endoscopic verification is not possible. Recognition of this disease process may require segmental resection or deep biopsy of endoscopically normal intestine.

Renal dysfunction and intravascular coagulation with aprotinin and hypothermic circulatory arrest.

High-dose aprotinin was used in 20 patients undergoing primary or repeat operations on the thoracic or thoracoabdominal aorta using cardiopulmonary bypass and hypothermic circulatory arrest. The activated clotting times immediately before the establishment of hypothermic circulatory arrest exceeded 700 seconds in all but 1 patient. Three patients (15%) required reoperation for bleeding. Seven patients died during hospitalization, and 5 had postmortem examination. Platelet-fibrin thrombi were present in multiple organs including the coronary arteries of 4 patients with myocardial infarction or failure, the pulmonary arteries of 2 patients, 1 of whom died of acute right ventricular failure, the brains of 2 patients who sustained a stroke, and the kidneys of 4 patients, 3 of whom had development of renal dysfunction. Renal dysfunction occurred in 13 patients (65%), and all were 65 years of age or older. Five of these patients required hemodialysis. Among 20 age-matched patients who had similar operations without aprotinin, there was one hospital death (5%) from myocardial infarction, and renal dysfunction developed in 1 patient (5%), who did not require dialysis. None of these 20 patients required reoperation for bleeding. Although aprotinin has been shown to reduce blood loss in patients having cardiac operations employing cardiopulmonary bypass, this benefit was not attained in this group of patients with thoracic aortic disease in whom hypothermic circulatory arrest was used. Use of aprotinin in elderly patients undergoing these procedures was associated with an increased risk of renal dysfunction and failure, and of myocardial infarction and death.

Co-transcription pattern of an introgressed operon in the maize chloroplast genome comprising four ATP synthase subunit genes and the ribosomal rps2.

Several examples of the introduction of a gene from one gene complex into another (introgression) are found when chloroplast RP gene clusters are compared to those in Escherichia coli or cyanobacteria. Here we describe the transcript pattern of one such cluster from maize (Zea mays) that includes the genes for 4 subunits of the thylakoid ATP synthase (atpI, H, F, A) and the rps2 gene. Twelve transcript species covering the size range from 7,000 to 800 nt were identified in RNA isolated from dark-grown and greening maize seedlings, and several of them were characterized by reverse transcription analysis. A major species of 6,200 nt, with its 5' end at 181 nt upstream of the initiating ATG of rps2, contained the transcripts of all the 5 genes. Two further sets of transcripts having their 5' ends ca. 120 and 50 nt upstream of the initiation codons of the atpI and atpH genes were also identified. Thus, this plastid gene cluster in maize is functionally organized as an operon with additional regulatory features to allow for increased accumulation of mRNAs for the thylakoid components.

Cutinase is not required for fungal pathogenicity on pea.

Cutinase, a fungal extracellular esterase, has been proposed to be crucial in the early events of plant infection by many pathogenic fungi. To test the long-standing hypothesis that cutinase of Nectria haematococca (Fusarium solani f sp pisi) is essential to pathogenicity, we constructed cutinase-deficient mutants by transformation-mediated gene disruption of the single cutinase gene of a highly virulent N. haematococca strain. Four independent mutants were obtained lacking a functional cutinase gene, as confirmed by gel blot analyses and enzyme assays. Bioassays of the cutinase-deficient strains showed no difference in pathogenicity and virulence on pea compared to the wild type and a control transformant. We conclude that the cutinase of N. haematococca is not essential for the infection of pea.