Angiotropic large cell lymphoma of the prostate gland: an immunohistochemical study

Malignant angioendotheliomatosis (MAE) is a rare disorder characterized by the intravascular proliferation of neoplastic mononuclear cells. Until recently, the cell of origin was uncertain; some investigators reported MAE to be lymphomatous in nature, while others claimed it to be of endothelial derivation. In the present unusual case, MAE was an incidental findings in the prostate of a patient with prostatic adenocarcinoma; it is shown to be a lymphoma of B-cell origin.     

CD40 promotes the development of early diabetic retinopathy in mice

Aims/hypothesis

Microangiopathy is a leading complication of diabetes that commonly affects the retina. Degenerate capillaries are a central feature of diabetic retinopathy. An inflammatory process has been linked to the development of diabetic retinopathy but its regulation is incompletely understood. Cluster of differentiation (CD) 40 is a member of the TNF receptor superfamily that promotes the development of certain inflammatory disorders. The role of CD40 in diabetic microangiopathy is unknown.

Methods

B6 and Cd40 ^?/? mice were administered streptozotocin to induce diabetes. Leucostasis was assessed using fluorescein isothiocyanate-conjugated concanavalin A. Retinal Icam1 and Cd40 mRNA levels were examined using real-time PCR. Protein nitration was assessed by immunohistochemistry. Histopathology was examined in the retinal vasculature. CD40 expression was assessed by flow cytometry and immunohistochemistry. Intercellular adhesion molecule 1 (ICAM-1) and nitric oxide synthase 2 (NOS2) were examined by immunoblot and/or flow cytometry. Nitric oxide production was examined by immunoblot and Griess reaction.

Results

In mouse models of diabetes, Cd40 ^?/? mice exhibited reduced retinal leucostasis and did not develop capillary degeneration in comparison with B6 mice. Diabetic Cd40 ^?/? mice had diminished ICAM-1 upregulation and decreased protein nitration. Cd40 mRNA levels were increased in the retinas of diabetic B6 mice compared with non-diabetic controls. CD40 expression increased in retinal Müller cells, endothelial cells and microglia of diabetic animals. CD40 stimulation upregulated ICAM-1 in retinal endothelial cells and Müller cells. CD40 ligation upregulated NOS2 and nitric oxide production by Müller cells.

Conclusions/interpretation

CD40-deficient mice were protected from the development of diabetic retinopathy. These mice exhibited diminished inflammatory responses linked to diabetic retinopathy. CD40 stimulation of retinal cells triggered these pro-inflammatory responses.     

Pharmacological blockade of TRPV1 receptors modulates the effects of 6‐OHDA on motor and cognitive functions in a rat model of Parkinson's disease

TRPV1 receptors and cannabinoid system are considered as important modulators of basal ganglia functions, and their pharmacologic manipulation represents a promising therapy to alleviate Parkinson‐induced hypokinesia. Recent evidence suggests that the blockade of cannabinoid receptors might be beneficial to alleviate motor deficits observed in Parkinson's disease. In the present study, we have evaluated the effects of AMG₉₈₁₀, a selective antagonist of TRPV1 receptors, on the motor and cognitive functions in a rat model of Parkinson's disease generated by an intracerebroventricular injection of 6‐ hydroxydopamine (6‐OHDA) (200 μg per animal). The injection of 10 nmol of AMG₉₈₁₀ for a single dose (AMG1) and for 2 weeks (AMG14) partially attenuated the hypokinesia shown by these animals in motor function evaluation tests, whereas chronic administration of AMG had destructive effects on learning and memory in 6‐OHDA‐treated rats. Animals in the AMG 1 and AMG 14 groups showed an increased latency to fall in rotarod and grasping tests in each trials compared with 6‐OHDA‐treated rats (P < 0.01) and DMSO 1 and 14 groups (P < 0.05). Our data indicate that pharmacological blockade of TRPV1 receptors by AMG ₉₈₁₀ attenuates the hypokinetic effects of 6‐OHDA and that TRPV1 receptors play an important role in 6‐OHDA‐induced hypokinesia, athough elucidation of the neurochemical substrate involved in this process remains a major challenge for the future.     

Genotype and phenotype: a practical approach to the immunogenetic analysis of lymphoproliferative disorders

Determination of cell lineage and clonality in lymphoproliferative disorders (LPD) is greatly enhanced by molecular genetic analysis in conjunction with morphologic and immunologic techniques. We now report on a technique in which we used cryostat-cut, fresh-frozen sections (CCFFS) prepared from tissues in a manner that allows DNA hybridization studies to be coordinated readily with routine morphologic and immunohistologic studies. Thirty-seven cases representing a broad spectrum of reactive and malignant LPD were examined with this method. Samples of DNA were extracted from frozen sections, subjected to Southern blot hybridization, and probed for rearrangements of the immunoglobulin (Ig) heavy-chain and the kappa and lambda light-chain genes, as well as for the T-cell receptor beta-chain gene. We also evaluated the effects of (1) diagnostic category of LPD, (2) volume of the tissue sample, and (3) fibrosis, necrosis, and ice crystal artifacts in the sample on the recovery of DNA. Ice artifact and sample size had the greatest negative impacts on the quantity and condition of DNA recovered. Of 19 samples involved by B-cell LPD, the results of immunogenetic studies were consistent with the immunophenotypes in all but one case. Of the T-cell lymphomas from which sufficient DNA was available (three out of five of the T-cell cases), all showed rearrangements of the T-cell beta-chain gene. In order to reduce sample processing time, we evaluated alternate blot hybridization methods, rapid alkaline transfers, and direct hybridization of synthetic oligonucleotides in dried agarose gels, and found that they decreased the time required for hybridization studies. In summary, the use of CCFFS as the source of DNA allows study of gene rearrangements and, at the same time, preserves frozen-tissue blocks in tumor banks for further immunologic studies. The development of time-effective methods will make the routine use of molecular-genetic analysis more practical in the diagnostic hematopathology laboratory.     

Calcitriol is a potent inhibitor of retinal neovascularization

PURPOSE: Vitamin D compounds inhibit the growth of a variety of tumors in preclinical and clinical studies. Among the mechanisms suggested for this inhibition is antiangiogenesis. Retinal angiogenesis is the basis for vision loss in several major blinding diseases. The purpose of this study was to evaluate the antiangiogenic activity of calcitriol (1,25-dihydroxyvitamin D(3)) in vivo and its effect on retinal endothelial cell (EC) proliferation, migration, and capillary morphogenesis in vitro. METHODS: The mouse oxygen-induced ischemic retinopathy (OIR) model was used to assess the antiangiogenic activity of calcitriol. Ocular VEGF levels were determined by Western blot analysis of whole eye extracts from postnatal day (P) 15 mice during OIR. The effects of calcitriol on retinal EC proliferation, migration, and capillary morphogenesis were also assessed in vitro. RESULTS: Calcitriol-treated animals demonstrated a significant decrease in retinal neovascularization compared with control animals. This effect was dose dependent, and retinal neovascularization was significantly inhibited in calcitriol-treated mice. Although no deaths occurred, calcitriol administration was associated with increased serum calcium and a lack of increase in body weight in a dose-independent manner. The ocular level of VEGF was similar in control and calcitriol-treated animals. At a lower concentration of calcitriol, retinal EC capillary morphogenesis in solubilized basement membrane was inhibited without a significant inhibitory effect on EC proliferation and migration. The concentration of calcitriol required to inhibit retinal EC proliferation was significantly higher than that required to inhibit EC capillary morphogenesis. CONCLUSIONS: These data suggest calcitriol is a potent inhibitor of retinal neovascularization and may be of benefit in the treatment of a variety of eye diseases with a neovascular component.     

Monocytoid B lymphocytes: their relation to the patterns of the acquired immunodeficiency syndrome (AIDS) and AIDS-related lymphadenopathy

It was shown recently that monocytoid cells express B-cell-restricted antigens and polyclonal surface immunoglobulins, and the term monocytoid B lymphocytes (MBL) has thus been offered as a more appropriate designation. Although most commonly seen in toxoplasmic lymphadenitis, MBL have been observed in a variety of reactive and neoplastic conditions involving lymph nodes. In the present study MBL were found in 17 of 22 lymph nodes from 20 patients with the acquired immunodeficiency syndrome (AIDS) and AIDS-related lymphadenopathy. In all 17 samples, the MBL were found in lymph nodes with florid reactive follicular hyperplasia, and they were geographically close to the hyperplastic lymphoid follicles. However, MBL were not detected in lymph nodes showing involuted follicles or lymphocyte depletion. The disappearance of MBL apparently parallels the progressive involution of secondary follicles. Leu-3+/Leu-2+ (T-helper/T-suppressor) ratios were studied in 14 lymph node cell suspension samples and ten peripheral blood samples. The lymph node Leu-3+/Leu-2+ ratios were significantly lower in AIDS-related lymphadenopathy than in non-AIDS-related reactive follicular hyperplasia (P less than 0.001); the peripheral blood ratios were decreased in nine of the ten cases. The diminished T-helper status in patients with AIDS and AIDS-related lymphadenopathy may be relevant to the immunopathogenesis of follicular involution and, indirectly, to the disappearance of MBL.     

Enhanced proangiogenic signaling in thrombospondin-1-deficient retinal endothelial cells

Thrombospondin-1 (TSP1) is an endogenous inhibitor of angiogenesis, which limits blood vessel density in normal tissues and curtails tumor growth. Previous studies of the molecular and cellular effects of TSP1 in angiogenesis have been contradictory. Here, we show that retinal endothelial cells (REC) prepared from TSP1-deficient (TSP1-/-) mice are more proliferative and migratory compared to the wild type REC. We observed up-regulation of the cell cycle regulators, including cyclin A, D1, and Cdk2, as well as the enhanced sequential activities of Src, PI3-kinase, Akt/PKB, Rac1/Cdc42 GTPases, and p38 MAP kinase in TSP1-/- REC. The increased levels of fibronectin and active Akt/PKB were also observed in retinal vasculature of TSP1-/- mice in vivo. Inhibition of Src/PI3-kinase/P38 MAP kinase activities in TSP1-/- REC resulted in decreased migration. Furthermore, TSP1-/- REC showed decreased intracellular levels of active Fyn and JNK2 without affecting caspase-3 activity. Thus, our results demonstrate that in the absence of TSP1, the proangiogenic signaling is enhanced, possibly through up-regulation of fibronectin expression. The enhanced signaling further promotes EC proliferation, migration, and survival. These novel observations support the TSP1's role as an endogenous inhibitor of angiogenesis whose endothelium expression promotes a quiescent, differentiated phenotype.