Effects of diets high in saturated fat and cholesterol on the lipid composition of canine platelets

The phospholipid composition of platelets from dogs on various experimental diets was determined. Thyroidectomized foxhounds were fed a control diet or the control diet supplemented with (1) beef tallow, (2) beef tallow and cholesterol, or (3) beef tallow, cholesterol, and safflower oil for 23 weeks prior to isolation of platelets. Platelets from animals fed the control diet contained 36.7% phosphatidylcholine (PC), 22.8% phosphatidylethanolamine (PE), 18.4% sphingomyelin (Sph), 11.8% phosphatidylserine (PS), 6.3% phosphatidylinositol (PI), and 2.2% lysophosphatidylcholine. The PE was 77.6% in the plasmalogen form. No highly significant changes in the phospholipid class composition resulted from the experimental diets. Cholesterol supplementation of the diets, however, caused consistent alterations in the fatty acid compositions of the platelet phospholipids including increases in the percentages of 18∶1ω9 (oleic acid), 18∶2ω6 (linoleic acid), and 20∶3ω6 (homo-gamma linolenic acid) and a decrease in the percentage of 20∶4ω6 (arachidonic acid). Addition of safflower oil to the tallow-cholesterol diet partially reversed these effects. These cholesterol-induced alterations in fatty acid composition could be due to exchange with plasma lipids, de novo synthesis, or altered platelet metabolism. The mechanism remains to be determined. Der. Nelson’s current affiliation is the Lipid Metabolism Branch, Division of Heart and Vascular Diseases, National Heart, Lung, and Blood Institute.     

Wound healing and the immune response in swine treated with a hemostatic bandage composed of salmon thrombin and fibrinogen

We investigated the inflammatory response in pigs exposed to salmon fibrinogen/thrombin dressings. Animals were exposed to the material in 3 ways: (a) thrombin and fibrinogen were injected intravenously, (b) dual full-thickness skin lesions were surgically created on the dorsal aspect of the swine and treated with the fibrinogen/thrombin bandage and a commercial bandage or (c) a fibrinogen/thrombin bandage was inserted through an abdominal incision into the peritoneal cavity. Blood was collected twice weekly and animals were sacrificed at 7, 10 or 28 days. Animals in the 28-day dermal lesion group were given an injection of salmon fibrinogen/thrombin at the 10 day point to simulate a second bandage application. The immune response manifested itself as induction of germinal centers in mesenteric lymph nodes and in the white pulp of the spleen. Examination of the histology of the skin and organs showed a cellular inflammatory response with granulation tissue and signs of edema that resolved by the 28-day stage. Antibodies reactive to salmon and human thrombin and fibrinogen were detected, but fibrinogen levels and coagulation processes were not affected. In conclusion, animals treated with salmon fibrinogen/thrombin bandages demonstrated a smooth recovery course in terms of both tissue healing and the immune response without adverse effects from the exposure to the fish proteins.     

Functional maturation of the primate fetal adrenal in vivo: 3. Specific zonal localization and developmental regulation of CYP21A2 (P450c21) and CYP11B1/CYP11B2 (P450c11/aldosterone synthase) lead to integrated concept of zonal and temporal steroid biosynthesis

Previous studies in the primate fetal adrenal gland have indicated that the gland is comprised of three functional zones: 1) the inner fetal zone (FZ), which has the enzymes necessary for dehydroepiandrosterone sulfate (DHEAS) production beginning early in gestation; 2) the transitional zone (TZ), which possesses enzymes necessary for cortisol production; and 3) the outer, definitive zone (DZ), which appears to function as a reservoir of progenitor cells that may populate the remainder of the gland and does not acquire a steroidogenic phenotype with the capacity to produce mineralocorticoids until near term. The enzymes CYP21A2 (P450 21 hydroxylase, or P450c21), CYP11B1 (11beta hydroxylase or P450c11) and CYP11B2 (aldosterone synthase) are necessary for glucocorticoid and mineralocorticoid synthesis but have not been localized previously in an ontogenic manner in the primate fetal adrenal gland. Therefore, we used immunocytochemistry (ICC) to assess specific zonal localization and developmental regulation of CYP21A2 and CYP11B1/CYP11B2 in the human (13-24 weeks' gestation) and rhesus monkey (109 d-term) fetal adrenal gland. In the fetal rhesus, ICC was performed with and without metyrapone administration to the fetus to assess the effects of endogenously increased fetal ACTH. In the human fetal adrenal, CYP21A2 immunoreactivity (IR) was present in only a few isolated cells in the DZ but was detectable in almost all cells in the TZ and FZ. In the fetal rhesus, CYP21A2-IR was present in cells throughout the DZ and TZ and, to a lesser degree, in the FZ. Staining intensity increased with advancing gestational age and was up-regulated in the DZ and TZ, but not the FZ, of the metyrapone-treated fetuses. In the human fetal adrenal gland, CYP11B1/CYP11B2-IR was absent in the DZ but present in the TZ and FZ. In the fetal rhesus monkey adrenal, CYP11B1/CYP11B2-IR was present in all cells of the TZ and FZ but was absent from the DZ until near term. After metyrapone, CYP11B1/CYP11B2-IR was induced in the DZ and was up-regulated in the TZ and FZ. Taken together, these data indicate that in the primate fetal adrenal gland, the FZ has the capacity to synthesize DHEA and DHEAS beginning early in development, the TZ has the capacity to synthesize cortisol after midgestation, and the DZ has the capacity to synthesize mineralocorticoids, but not until near term. The spatial localization of steroid metabolizing enzymes and steroid products in the human and rhesus monkey fetal adrenal suggests analogies of the three functional zones of the fetus (DZ, TZ, and FZ) to their adult counterparts (zona glomerulosa, zona fasciculata, and zona reticularis) and their steroid products (mineralocorticoids, glucocorticoids and androgens, respectively), although the reason for the presence of CYP11B1/CYP11B2- and CYP21A2-IR in the FZ remains to be elucidated.     

Reticulum cell neoplasms of lymph nodes: a clinicopathologic study of 11 cases with recognition of a new subtype derived from fibroblastic reticular cells

Lymph nodes contain nonlymphoid accessory cells including follicular dendritic cells (FDCs), interdigitating dendritic cells (IDCs) and fibroblastic reticular cells (FBRCs). Neoplasms derived from FDCs are uncommon, and those of IDC origin are even more rare. We report the clinicopathologic features of 11 reticulum cell neoplasms, including 2 of FBRC origin. There were seven male patients and four female patients ranging in age from 13 to 73 years. All cases involved lymph nodes (cervical or supraclavicular-6 cases), (abdominal--2 cases), epitrochlear (1 case); two had more than one site of involvement (cervical lymph node and mediastinum--1 case, cervical and abdominal lymph nodes--1 case). One case of FDC tumor had concomitant Castleman's disease, plasma cell variant. Each neoplasm showed similar histology with oval-to-spindle-shaped cells in a storiform or fascicular pattern. Based on immunophenotypic findings, the neoplasms were classified as FDC (five cases), IDC (two cases), FBRC (three cases), and reticulum cell neoplasm, not otherwise specified (one case). The FDC tumors showed immunoreactivity for CD21 or CD35, vimentin, and CD68. The IDC tumors showed strong positivity for S-100 protein and variable positivity for CD68 and CD1a. The cases derived from FBRCs were positive for vimentin, desmin, and smooth-muscle actin. The neoplasm classified as reticulum cell neoplasm, not otherwise specified had similar morphologic features but showed only equivocal positivity for CD68 and vimentin. Follow-up was available for 9 of 11 (82%) cases with a mean of 3.5 years. Four of five patients with FDC tumors were alive with disease when last seen; the fifth is alive and well with no evidence of disease at 4-year follow-up. One patient with IDC tumor had a recurrence in a different nodal site. Two patients with FBRC tumor were disease free at follow-up of 2 years and 8 years, respectively. The patient with reticulum cell neoplasm, not otherwise specified, was alive and disease free 8 years after diagnosis.     

Pathological findings in human autoimmune lymphoproliferative syndrome

The defects in lymphocyte apoptosis that underlie the autoimmune lymphoproliferative syndrome (ALPS) are usually attributable to inherited mutations of the CD95 (Fas) gene. In this report, we present the histopathological and immunophenotypic features seen in the lymph nodes (n = 16), peripheral blood (n = 10), bone marrow (n = 2), spleen (n = 3), and liver (n = 2) from 10 patients with ALPS. Lymph nodes showed marked paracortical hyperplasia. Interfollicular areas were expanded and populated by T cell receptor-alphabeta CD3+ CD4-CD8- (double-negative, DN) T cells that were negative for CD45RO. CD45RA+ T cells were increased in all cases studied. The paracortical infiltrate was a result of both reduced apoptosis and increased proliferation, as measured by in situ detection of DNA fragmentation and staining with MIB-1, respectively. The paracortical proliferation may be extensive enough to suggest a diagnosis of malignant lymphoma. Many of the paracortical lymphocytes expressed markers associated with cytotoxicity, such as perforin, TIA-1, and CD57. CD25 was negative. In addition, most lymph nodes exhibited florid follicular hyperplasia, often with focal progressive transformation of germinal centers; in some cases, follicular involution was seen. A polyclonal plasmacytosis also was present. The spleens were markedly enlarged, more than 10 times normal size. There was expansion of both white pulp and red pulp, with increased DN T cells. DN T cells also were observed in liver biopsies exhibiting portal triaditis. In the peripheral blood, the T cells showed increased expression of HLA-DR and CD57 but not CD25. CD45RA+ T cells were increased in the four cases studied. Polyclonal B cell lymphocytosis with expansion of CD5+ B cells was a characteristic finding. Taken together, the histopathological and immunophenotypic findings, particularly in lymph nodes and peripheral blood, are sufficiently distinctive to suggest a diagnosis of ALPS. Of note, two affected family members of one proband developed lymphoma (T-cell-rich B-cell lymphoma and nodular lymphocyte predominance Hodgkin's disease, respectively).     

Lymphangiomatosis with splenic involvement

Severe splenomegaly and anemia developed in a 5-year-old girl with diffuse lymphangiomatosis of the upper part of the body. Radioisotope scanning and celiac angiography demonstrated lymphangiomatosis of the spleen, a rare but diagnosable condition. Intractable infection in areas of ulcerated skin led to her death from overwhelming sepsis.     

Population-based incremental interactive concept learning for image retrieval by stochastic string segmentations

We propose a method for concept-based medical image retrieval that is a superset of existing semantic-based image retrieval methods. We conceive of a concept as an incremental and interactive formalization of the user's conception of an object in an image. The premise is that such a concept is closely related to a user's specific preferences and subjectivity and, thus, allows to deal with the complexity and content-dependency of medical image content. We describe an object in terms of multiple continuous boundary features and represent an object concept by the stochastic characteristics of an object population. A population-based incrementally learning technique, in combination with relevance feedback, is then used for concept customization. The user determines the speed and direction of concept customization using a single parameter that defines the degree of exploration and exploitation of the search space. Images are retrieved from a database in a limited number of steps based upon the customized concept. To demonstrate our method we have performed concept-based image retrieval on a database of 292 digitized X-ray images of cervical vertebrae with a variety of abnormalities. The results show that our method produces precise and accurate results when doing a direct search. In an open-ended search our method efficiently and effectively explores the search space.     

Selective detection and identification of sugar nucleotides by CE-electrospray-MS and its application to bacterial metabolomics

A novel method employing CE-ESMS and precursor ion scanning was developed for the selective detection of nucleotide-activated sugars. By using precursor ion scanning for fragment ions specific to the different nucleotide carriers, i.e., ions at m/z 322 for cytidine monophosphate, m/z 323, 385, and 403 for uridine diphosphate, m/z 362, 424, and 442, for guanosine diphosphate, and m/z 346, 408, and 426 for adenosine diphosphate, it was possible to selectively detect sugar nucleotides involved in the biosynthesis of glycoconjugates such as glycoproteins and lipopolysaccharides. Enhancement of sensitivity was achieved using N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) as a sample stacking buffer and provided detection limits between 0.2 and 3.8 pmol.mL(-)(1). The present CE-ESMS method provided linear dynamic ranges over the concentrations 0.2-164 nM (r(2) = 0.952-0.997) for different nucleotide sugar standards. The application of this method is demonstrated for the identification of intracellular pools of sugar nucleotides in wild type and isogenic mutants from the bacterial pathogen Campylobacter jejuni. By using product ion scanning (with and without front-end collision-induced dissociation), it was possible to determine the precise nature of unexpected sugar nucleotides involved in the biosynthesis of pseudaminic acid, a sialic acid-like sugar previously observed on the flagellin of some pathogenic bacteria.