Oncolytic viruses and histone deacetylase inhibitors—A multi-pronged strategy to target tumor cells

Oncolytic viruses (OVs) have shown promise as cancer therapeutics in pre-clinical and clinical testing; however, it is unlikely that OVs will constitute a stand-alone treatment. Histone deacetylase inhibitors (HDIs) represent a class of anticancer agents known to influence epigenetic modifications of chromatin, alter gene expression and manipulate a variety of signaling pathways, in some cases blunting the cellular antiviral response. Recent studies have shown that combining OV therapy with HDI treatment enhances viral replication and synergistically induces the killing of cancer cells in vitro and in vivo, an effect that has now been demonstrated in variety of virus/HDI combinations. This review discusses the results obtained with the different OV/HDI combinations, the rationale supporting these combinations and the advantages for oncolytic virus therapy.     

A nationwide population-based skin cancer screening in Germany: Proceedings of the first meeting of the International Task Force on Skin Cancer Screening and Prevention (September 24 and 25, 2009)

Skin cancer incidence is increasing worldwide in white populations and mortality rates have not declined throughout most of the world. An extraordinarily high proportion of at-risk individuals have yet to be screened for melanoma but guidelines from esteemed bodies do not currently endorse population-based screening. Evidence for the effectiveness of skin cancer screening is imperative. To this end, scientists in Germany have launched a nationwide skin cancer screening campaign. Herein, we review pilot screening data from Schleswig-Holstein, discuss the launch of the major new national initiative, review issues related to evaluation of that program, and propose seven recommendations from the International Task Force on Skin Cancer Screening and Prevention that was held in Hamburg, Germany, on September 24 and 25, 2009.     

Enterococcus faecalis Endocarditis Severity in Rabbits Is Reduced by IgG Fabs Interfering with Aggregation Substance

Background

Enterococcus faecalis is a significant cause of infective endocarditis, an infection of the heart endothelium leading to vegetation formation (microbes, fibrin, platelets, and host cells attached to underlying endothelial tissue). Our previous research determined that enterococcal aggregation substance (AS) is an important virulence factor in causation of endocarditis, although endocarditis may occur in the absence of AS production. Production of AS by E. faecalis causes the organism to form aggregates through AS binding to enterococcal binding substance. In this study, we assessed the ability of IgGs and IgG Fabs against AS to provide protection against AS⁺ E. faecalis endocarditis.

Methodology/Principal Findings

When challenged with AS⁺ E. faecalis, 10 rabbits actively immunized against AS⁺ E. faecalis developed more significant vegetations than 9 animals immunized against AS⁻ E. faecalis, and 9/10 succumbed compared to 2/9 (p<0.005), suggesting enhanced aggregation by IgG contributes significantly to disease. IgG antibodies against AS also enhanced enterococcal aggregation as tested in vitro. In contrast, Fab fragments of IgG from rabbits immunized against purified AS, when passively administered to rabbits (6/group) immediately before challenge with AS⁺ E. faecalis, reduced total vegetation (endocarditis lesion) microbial counts (7.9×10⁶ versus 2.0×10⁵, p = 0.02) and size (40 mg versus 10, p = 0.05). In vitro, the Fabs prevented enterococcal aggregation.

Conclusions/Significance

The data confirm the role of AS in infective endocarditis formation and suggest that use of Fabs against AS will provide partial protection from AS⁺ E. faecalis illness.     

Localization of zinc in the thymic reticulum of mice by electron-probe microanalysis

Summary Thymulin, a thymic hormone, is a nonapeptide requiring zinc for biological activity. It has been shown that epithelial cells, forming part of the thymic reticulum, secrete this hormone and/or store it within cytoplasmic vacuoles. X-ray electron-probe microanalysis (EPMA) has been used to detect zinc in the thymus. Low concentrations of zinc have been demonstrated in the dense granules contained in clear vacuoles of some epithelial cells in normal and ZnCl₂-injected mouse thymuses, thus suggesting that the metal may be coupled to the peptide before the secretion of the hormone from the cells.     

The physical characteristics of open flow and closed flow taste delivery apparatus

Comparisons between the intended duration of stimulus presentationand the measured duration were made for two types of liquiddelivery apparatus: an open flow apparatus, where liquid flowsonto the anterior dorsal surface of the tongue, and a closedflow apparatus, where the tongue acts as the missing wall segmentof a tube. Durations were measured from the conductivity offlowing liquids using recognition and detection threshold criteria.The closed flow delivery apparatus produced measured durationsthat exceeded the intended durations by as little as 2%, andno more than 112%, for either 2 mM NaSac or 500 mM NaCl at intendeddurations of 1000, 500, 200 and 100 ms, while the open flowdelivery apparatus durations exceeded the intended durationsby a minimum of 46% and as much as 1332%, for the same concentrationsand durations. Power function equations fitted all data, withr²>0.920, thus allowing predictions of measured durations.     

Factors affecting cholesterol monohydrate crystal nucleation time in model systems of supersaturated bile

We explored the influence of several compositional factors considered capable of influencing the nucleation time of model biles supersaturated in cholesterol. In addition to the classical techniques, e.g., electron microscopy and quasielastic light scattering, employed for size measurement and structural assessment, we employed a novel technique, i.e., video-enhanced microscopy, for particle evaluation in these polydisperse systems which often may simultaneously contain isolated small vesicles, their complex aggregates, and small cholesterol monohydrate crystals. The factors we studied included dilution, degree of cholesterol supersaturation, bile salt/lecithin molar ratio, and Ca2+ concentration. Dilution markedly raised the degree of cholesterol saturation, prolonged nucleation time for cholesterol monohydrate crystals, and favored formation of metastable small unilamellar vesicles. Increasing the degree of cholesterol supersaturation as an independent variable in more concentrated systems both shortened the nucleation time and favored spontaneous formation of a relatively small number of isolated vesicles. A decrease in bile salt/lecithin molar ratio within the physiologically relevant range was accompanied by a prolonged nucleation time and favored spontaneous vesicle formation. Large numbers of small unilamellar vesicles were observed even in concentrated model bile solutions (total lipids: 20 g/dl) when the bile salt/lecithin molar ratio was 1.9 or less. At physiological concentrations, Ca2+ promoted nucleation of cholesterol monohydrate crystals only in vesicle-containing solutions. Taken together, the following conclusions can be drawn. First, spontaneous vesicle formation in dilute systems prolongs solid cholesterol crystal nucleation. It can thus provide a supplementary non-micellar mode of cholesterol transport in micellar systems of supersaturated human bile. Second, dilution, degree of cholesterol supersaturation, and a decrease in bile salt/lecithin ratio prolong cholesterol crystal nucleation time and favor spontaneous vesicle formation. With increasing calcium concentrations, opposite effects are observed. Third, the presence of vesicles may help to account for the frequently observed and otherwise unexplained remarkable degree of metastable supersaturation and prolonged metastability (delayed nucleation time) for cholesterol in human bile.     

Identification of antigens and antibodies specific for Pneumocystis carinii

To increase understanding of Pneumocystis carinii and its interaction with its hosts, Ag specific for rodent and human P. carinii were identified by the immunoblot method after PAGE of P. carinii organism extracts. The m.w. of the major Ag of rat P. carinii were 45,000, 110,000, and a broad band of 49,000 to 64,000, and of human P. carinii were 22,000, 24,000, and a broad band of 35,000 to 45,000 daltons. Human and rat pneumocystis were not antigenically identical. Specific antibodies against rat P. carinii Ag were found in 18 of 79 rats by the immunoblot method. Specific antibodies against human P. carinii Ag were found in 32 of 33 adult human sera, but in only 1 of 8 sera from infants and children. Specific antibodies were found in sera of 13 of the 14 adults with no history of P. carinii pneumonia, and all 19 patients with recently diagnosed P. carinii pneumonia, including 9 patients with P. carinii pneumonia associated with AIDS. The results of this study support previous suggestions that a large proportion of adults have been exposed to P. carinii and provide a basis for the further investigations of host-P. carinii interactions.     

Supramicron-sized particle clearance from alveoli: route and kinetics

Particles inhaled and deposited in the alveoli of the lung, i.e., distal to the tracheobronchial mucociliary escalator, may theoretically be cleared by several routes, including solubilization, lymphatic drainage, and the mucociliary pathway. We studied the clearance routes and kinetics of an inert insoluble carbonized polystyrene particle of supramicron size (2.85 micron count median diameter) tagged with 57Co (half-life 270 days) in the adult unanesthetized sheep. The rate of particle clearance, assessed by gamma scintillation camera of the whole lung, showed a three-exponential function, comprising a rapid initial phase in the first 44 h of clearance for tracheobronchial deposition followed by a slower phase of mostly alveolar clearance in the next 30 days and a final phase of very slow relatively pure alveolar clearance. A balance study of particle route during clearance and autopsy of regional thoracic lymph nodes, blood, liver, and spleen demonstrated that this supramicron-sized particle cleared from alveoli predominantly via the mucociliary escalator of the tracheobronchial tree. Whole-lung lavage studies showed particle and macrophage recovery rates suggesting a sequestered state for alveolar-deposited particles, which may partly account for their slow clearance rates. The failure to find interstitial penetration by alveolar-deposited particles indicates that the macrophages engulfing these particles, at low particle burdens, travel normally in only one direction, i.e., from interstitium to alveolus and then to the mucociliary escalator.     

Production of antibodies against rhodopsin after immunization with beta gamma-subunits of transducin: evidence for interaction of beta gamma-subunits of guanosine 5'-triphosphate binding proteins with receptor

The light-detecting system of retinal rod outer segments is regulated by a guanyl nucleotide binding (G) protein, transducin, which is composed of alpha-, beta-, and gamma-subunits. Transducin couples rhodopsin to the intracellular effector enzyme, a cGMP phosphodiesterase. The beta gamma complex (T beta gamma) is required for the alpha-subunit (T alpha) to interact effectively with the photon receptor rhodopsin. It is not clear, however, whether T beta gamma binds directly to rhodopsin or promotes T alpha binding to rhodopsin only by binding to T alpha. We have found that serum from rabbits immunized with T beta gamma contained a population of antibodies that were reactive against rhodopsin. These antibodies could be separated from T beta gamma antibodies by absorbing the latter on immobilized transducin. Binding of purified rhodopsin antibodies was inhibited by T beta gamma, suggesting that the rhodopsin antibodies and T beta gamma bound to the same site on rhodopsin. We propose that the rhodopsin antibodies act both as antiidiotypic antibodies against the idiotypic T beta gamma antibodies and as antibodies against rhodopsin. This hypothesis is consistent with the conclusion that T beta gamma interacts directly with the receptor. It is probable that in an analogous way, G beta gamma interacts directly with receptors of the adenylate cyclase system.