Membrane-derived particles shed by PSMA-positive cells function as pro-angiogenic stimuli in tumors

Cell membrane-derived particles (Mp) are rounded membrane-enclosed particles that are shed from tumor cells. Mp are formed from tumor membranes and are capable of tumor targeting and immunotherapeutic agents because they share membrane homology with parental cells; thus, they are under consideration as a drug delivery vehicle. Prostate-specific membrane antigen (PSMA), a transmembrane glycoprotein with enzymatic functionality, is highly expressed in Mp and extracellular vesicles (EV) from prostate cancer (PCa) with poor clinical prognosis. Although PSMA expression was previously shown in EV and Mp isolated from cell lines and from the blood of patients with high-grade PCa, no pathophysiological effects have been linked to PCa-derived Mp. Here, we compared Mp from PSMA-expressing (PSMA-Mp) and PSMA-non-expressing (WT-Mp) cells side by side in vitro and in vivo. PSMA-Mp can transfer PSMA and new phenotypic characteristics to the tumor microenvironment. The consequence of PSMA transfer to cells and increased secretion of vascular endothelial growth factor-A (VEGF-A), pro-angiogenic and pro-lymphangiogenic mediators, with increased 4E binding protein 1 (4EBP-1) phosphorylation.

Hydrodynamic and ecological 3D modeling in tropical lakes

Conservation and improvement of water quality in water bodies is an important matter to maintain all of its uses as well as other human necessities like microclimate regulation and leisure. Lakes and reservoirs have a complex circulation behavior with vertical temperature profiles changes along the time, resulting in differences in water density and a vertical stratification condition. This characteristic can directly affect the water quality conditions perturbing its main indicators. This study aims to evaluate the quasi-3D models' capacity to represent the hydrodynamic behavior of a tropical lake and its effects on the main variables that characterize its water quality. To achieve this objective, high-frequency monitoring data were collected, the lake was represented in a quasi-3D model, and the accuracy of the result was evaluated by applying statistical indices. The evaluation showed good agreement between field measures and simulated results when compared with other applications. The connections between hydrodynamic behavior and water quality were seen with the simulations results analysis, which showed that mixing events and long stratification periods perturb the water quality, the first with re-suspended bed material and the second blocking the surface and bottom exchanges. The application of a 3D model gives the capacity to reproduce the reservoir spatial variability and its vertical profiles, which is necessary to study the constituents' distributions across the water column. Therefore, the hydrodynamic and water quality behavior of lakes was accurately represented by the model, as well as the importance of improving high-frequency monitoring techniques.

Oral Lesions in Dogs with Visceral Leishmaniosis

Canine visceral leishmaniosis (CVL) is an important zoonotic disease, which is endemic in Brazil and several other parts of the world. The disease may affect multiple organs, but lesions in the oral cavity are considered uncommon. Twenty-three cases of oral lesions compatible with CVL were diagnosed from 2015 to 2018 in the Federal District, Brazil. Six cases were confirmed to be CVL based on histopathology, immunohistochemistry and polymerase chain reaction amplification of Leishmania infantum kDNA. Most of the affected dogs were >9 years of age, of mixed breed and were classified as having stage C of the disease. The most important gross findings were ulcerated nodular lesions in the tongue, lip, gingiva and hard palate. Microscopically, there was lymphoplasmacytic to granulomatous inflammation that was diffuse, moderate to severe and associated with ulceration. CVL should be considered in the differential diagnosis of nodular and ulcerative oral lesions in dogs.

Effect of thermally deposited siloxane-methacrylate coating on bonding to glass fibre posts

AIM

To evaluate the alterations promoted by a thermally deposited siloxane-methacrylate coating on the surface of glass fibre posts and their effect on the bond strength of resin-core materials to the posts.

METHODOLOGY

Fibre post surfaces were treated with experimental thermally deposited siloxane-methacrylate coatings or clinically available treatments (i.e. hydrogen peroxide and methylene chloride); nontreated posts were used as controls. The contact angles formed between the post surface and the water/adhesive were measured with a tensiometer. Scanning electron microscopy and electron dispersive spectroscopy were used to examine the topographies and chemical changes in the post surfaces following treatment. Surface roughness was evaluated with laser interferometry. Core resin was bonded to the fibre posts, and microtensile bond strength testing was subsequently performed. The data were individually submitted to anova and Tukey's tests (α = 0.05).

RESULTS

The water contact angle was reduced significantly (P < 0.05) by the thermally deposited siloxane-methacrylate coating. All treatments significantly increased the adhesive contact angle (P ≤ 0.016) compared to the control as well as the surface roughness (P ≤ 0.006) and the amount of Si on post surfaces. Greater percentages of Si were observed for the thermally deposited coating. The bond strength to the posts was significantly improved by the thermally deposited coating (P < 0.05), whereas the other treatments did not differ from the control.

CONCLUSION

Treating the surface of glass fibre posts with a thermally deposited siloxane-methacrylate coating improved the bond strength to resin-based materials. The coating could be performed by manufacturers of glass fibre posts in order to reduce the number of clinical steps required for luting posts into root canals.

Abstract 4550: Antiproliferative activity of 8-methoxypsoralen without UV light irradiation: A new perspective for cancer therapy

The furanocoumarin-derivative 8-methoxypsoralen (8-MOP) is commonly used combined with UV light irradiation for treatment of skin diseases. We have recently demonstrated that 8-MOP inhibits GST-P1 in tumor cells and acts as chemosensitizer. These new data show direct antitumor activity of this compound without photoactivation in an in vitro model of glioma, the most common and lethal primary malignant brain tumor. Rat glioma C6 cells and human glioblastoma GL-15 cells were submitted to treatment with 8-MOP, as well as primary rat astrocytes cultures for comparison. Cell viability was measured by MTT assay; phase contrast microscopy and quantification of total protein content were also performed. The trypan blue dye exclusion assay and colony formation test were used to analyze cell proliferation. Flow cytometry was used for cell cycle analyses. Morphological changes were accessed by electron microscopy and proteins expression was studied by using immunolabeling techniques. As main results, 8-MOP reduced cell viability and cellularity, time- and dose-dependently, more efficiently in tumor than in normal cells. The compound also showed considerable antiproliferative effect against tumor cells and induced cell death by apoptosis when used at high concentration. However, 8-MOP did not promote cell cycle arrest and also did not increase labeling of markers associated to bad prognostic. Additional tests with cell lines from other tumors (breast cancer, colorectal cancer and lymphoma) showed that they respond differently to 8-MOP treatment, pointing to a pathway-specificity of its action. A qualitative structure-activity relationship study was also performed using coumarin derivatives structurally related to 8-MOP, from these experiments it was possible to suggest the relevance of each part of 8-MOP molecular structure for antiproliferative action. These results point furanocoumarin derivatives as a possible new class of anticancer agents.

Note: This abstract was not presented at the meeting.

Citation Format: Diêgo M. de Oliveira, Rute M F Lima, Eudes S. Velozo, Ilza A. Amorim, Tales H A Mota, Silvia L. Costa, Fabio P. Silva, Ramon S. El-Bachá. Antiproliferative activity of 8-methoxypsoralen without UV light irradiation: A new perspective for cancer therapy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4550. doi:10.1158/1538-7445.AM2015-4550

Etching a Fiber Post Surface with High-concentration Bleaching Agents

Introduction

Commonly, resin composites/cements fail to achieve proper bonding to fiber posts when their surfaces have not been previously etched. This study evaluated the effect of the concentration and application mode of hydrogen peroxide on the surface topography and bond strength of resin composite to glass-fiber posts.

Methods and Materials

Fiber posts were immersed in 24% or 35% solutions (a high-concentration bleaching agent) of hydrogen peroxide (H2O2), or these solutions were applied over the post surface using a microbrush (n=10). Posts without any treatment were used as a control. After etching, the posts were silanated and an adhesive was applied. The posts were positioned in a mold, and a resin composite was incrementally inserted and light-cured. The post/resin assembly was serially sectioned into several beams that were subjected to a tensile bond strength test. The data were subjected to the two-way analysis of variance and Tukey test (α=0.05). The Dunnet's test was used to compare the experimental conditions to the control. The surface topography was analyzed using scanning electronic microscopy.

Results

The non-etched post presented a relatively smooth surface without fiber exposure. Except for the application of 24% H2O2, the other experimental conditions increased the number of exposed fibers and bond strength in relation to the control. Although immersion resulted in higher values for the 24% H2O2 application, the mode of application did not alter bond strength when 35% H2O2 was used.

Conclusions

The effect of the mode of application of H2O2 depended on its level of concentration. A high-concentration bleaching agent improved the bond strength of the resin composite to the post surface, regardless of which mode was used.

On the quaternary structure of a C-type lectin from Bothrops jararacussu venom--BJ-32 (BjcuL)

BJ-32 (also known as BjcuL) is a C-type lectin from the venom of Bothrops jararacussu with specificity for beta-galactosides and a remarkable ability to agglutinate several species of trypanosomatids. Our objective was to study the oligomerization state of native BJ-32 by using different biophysical and computational methods. Small-angle X-ray light scattering (SAXS) experiments disclosed a compact, globular protein with a radius of gyration of 36.72+/-0.04A and molecular weight calculated as 147.5+/-2.0kDa. From analytical ultracentrifugation analysis, it was determined that the BJ-32 sedimentation profile fits nicely to a decamer model. The analysis of the intrinsic emitted fluorescence spectra for BJ-32 solutions indicated that association of subunits in the decamer is accompanied by changes in the environment of Tryptophan residues. Both ab initio and comparative models of BJ-32 supported the resemblance of the decamer in the crystallographic structure from a close homologue, the rattlesnake venom lectin (RSL) from Crotalus atrox.

Simple affinity chromatographic procedure to purify β-galactoside binding lectins

Affinity chromatography based on the commercial resin Sepharose CL-6B was used to isolate new C1-beta-type lectins from crude preparations of snake venoms (Bothrops jararaca, Bothrops jararacussu, Bothrops newiedi, Bothrops moojeni, Lachesis muta rhombeata). Most of the C-type lectins could be eluted with almost 100% recovery using the competitor isopropyl-beta-D-thiogalactoside (IPTG) or through Ca2+ sequestration with EDTA. The lectin yield varied considerably among the different snake species, but B. newiedi venom was a particularly rich source of lectin, retaining 2.7 mg of lectin by milliliter of resin in saturating conditions. C1-alpha-lectins from Crotalus durisus terrificus venom, from the jack fruit (jacalin) and from bread fruit seeds extract (frutalin) had no affinity, either with or without Ca2+ added, for Sepharose CL-6B, showing that the resin is specific for C1-beta-type lectins. Sepharose CL-6B used as galactose-affinity chromatography provides a simple and fast method for isolating C-type beta-galactoside binding lectins from crude sample preparations.

TIPUH1 encodes a novel KRAB zinc-finger protein highly expressed in human hepatocellular carcinomas

To achieve a better understanding of mechanisms that underlie hepatocarcinogenesis and to identify novel target molecules for diagnosis and therapy of hepatocellular carcinoma (HCC), we previously analysed gene-expression profiles of 20 HCC tissues on a cDNA microarray. Among the genes upregulated in the tumor tissues compared with their nontumor counterparts, we focused on a novel gene termed transcription-involved protein upregulated in HCC (TIPUH1) that putatively encoded a 500-amino-acid protein containing 12 zinc-finger domains and a Kruppel-associated box domain. Multiple-tissue northern blot analysis revealed it's testis- and placenta-specific expression in normal tissues. Colony-formation assay in soft agar showed that TIPUH1 conferred anchorage-independent growth to NIH3T3 cells, suggesting its oncogenic activity. Conversely, specific siRNA for TIPUH1 knocked down its expression in HCC cells, which resulted in their growth inhibition. We identified four TIPUH1-interacting proteins including TIF1beta, a transcription-intermediary protein, and three involved in pre-mRNA processing (hnRNPU, hnRNPF, and Nucleolin), suggesting that overexpressed TIPUH1 may play a role in hepatocarcinogenesis by regulating transcription and/or RNA processing of growth control genes. These data may contribute to a better understanding of liver neoplasia, and to the development of novel strategy for treatment of HCCs.

Biochemical and molecular modeling analysis of the ability of two p-aminobenzamidine-based sorbents to selectively purify serine proteases (fibrinogenases) from snake venoms

Snake venoms contain several trypsin-like enzymes with equivalent physicochemical characteristics and similar inhibition profiles. These are rather difficult to separate by classical purification procedures and therefore constitute a good model for affinity chromatography analysis. Some of these trypsin homologues present fibrinogenase activity, mimicking one or more features of the central mammalian coagulation enzyme, thrombin. It was previously demonstrated that a number of amidine derivatives are able to interact specifically with some of these serine proteases. To understand the enzyme-sorbent interactions we have investigated the ability of two commercially available benzamidine affinity matrices to purify thrombin-like serine proteases (TLSP) with similar biological properties from two snake venoms (Bothrops jararacussu and Lachesis muta rhombeata). Curiously, each sorbent retained a single but distinct TLSP from each venom with high yield. Molecular modeling analysis suggested that hydrophobic interactions within a specific region on the surface of these enzymes could be generated to explain this exquisite specificity. In addition, it was demonstrated that a specific tandem alignment of the two benzamidine sorbents enables the purification of three other enzymes from B. jararacussu venom.

Anti-herpes simplex virus effect of a seed extract from the tropical plant Licania tomentosa (Benth.) Fritsch (Chrysobalanaceae)

Incubation of acyclovir-resistant herpes simplex virus type 1 (ACVr-HSV1), during infection of the HEp-2 cell culture, with an extract prepared from the seeds of Licania tomentosa (Benth.) Fritsch (Chrysobalanaceae) species impaired the productive replication of this virus in a concentration-dependent manner. The extract was able to inhibit extracellular virus (virucidal effect) and also interfered with a very early event of cell infection, at a non-cytotoxic concentration.

Exploring the subsite specificity of Schistosoma mansoni aspartyl hemoglobinase through comparative molecular modelling

Blood flukes of the genus Schistosoma currently infect millions of people in tropical and subtropical countries. An enzyme playing a major role in hemoglobin (Hb) degradation by Schistosoma mansoni has been cloned and shown to be highly similar to the human cathepsin D aspartyl proteinase, although presenting a distinct substrate specificity from the latter. Investigating the structural features responsible for this difference has a major application in the design of selective anti-schistosomal drugs. In order to achieve this goal a homology model for the S. mansoni aspartyl hemoglobinase was constructed and then used to simulate the complexes formed with two transition state analogues of Hb-derived octapeptide substrates. Comparison with human cathepsin D showed that different pocket volumes and surface electrostatic potentials arise from substitutions in residues comprising the S4, S3, S2 and S3' subsites. Since the primary specificity of the S. mansoni enzyme resembles that of HIV-1 protease, we have discussed the applicability of current retroviral protease inhibitors as leads for the design of new anti-schistosomal drugs.

Acute renal failure due to abdominal compartment syndrome: report on four cases and literature review

We report on 4 cases of abdominal compartment syndrome complicated by acute renal failure that were promptly reversed by different abdominal decompression methods. Case 1: A 57-year-old obese woman in the post-operative period after giant incisional hernia correction with an intra-abdominal pressure of 24 mm Hg. She was sedated and curarized, and the intra-abdominal pressure fell to 15 mm Hg. Case 2: A 73-year-old woman with acute inflammatory abdomen was undergoing exploratory laparotomy when a hypertensive pneumoperitoneum was noticed. During the surgery, enhancement of urinary output was observed. Case 3: An 18-year-old man who underwent hepatectomy and developed coagulopathy and hepatic bleeding that required abdominal packing, developed oliguria with a transvesical intra-abdominal pressure of 22 mm Hg. During reoperation, the compresses were removed with a prompt improvement in urinary flow. Case 4: A 46-year-old man with hepatic cirrhosis was admitted after incisional hernia repair with intra-abdominal pressure of 16 mm Hg. After paracentesis, the intra-abdominal pressure fell to 11 mm Hg.