CD150 (SLAM) is a receptor for measles virus but is not involved in viral contact-mediated proliferation inhibition

Measles virus (MV) interacts with cellular receptors on the surface of peripheral blood lymphocytes (PBL) which mediate virus binding and uptake. Simultaneously, the direct contact of the viral glycoproteins with the cell surface induces a negative signal blocking progression to the S phase of the cell cycle, resulting in a pronounced proliferation inhibition. We selected a monoclonal antibody (MAb 5C6) directed to the surface of highly MV-susceptible B cells (B95a), which inhibits binding to and infection of cells with MV wild-type and vaccine strains. By screening a retroviral cDNA library from human splenocytes (ViraPort; Stratagene) with this antibody, we cloned and identified the recognized molecule as signaling lymphocytic activation molecule (SLAM; CD150), which is identical to the MV receptor recently found by H. Tatsuo et al. (Nature 406:893-897, 2000). After infection of cells, and after surface contact with MV envelope proteins, SLAM is downregulated from the cell surface of activated PBL and cell lines. Although anti-SLAM and/or anti-CD46 antibodies block virus binding, they do not interfere with the contact-mediated proliferation inhibition. In addition, the cell-type-specific expression of SLAM does not correlate with the sensitivity of cells for proliferation inhibition. The data indicate that proliferation inhibition induced by MV contact is independent of the presence or absence of the virus-binding receptors SLAM and CD46.     

Evolution of plant defense mechanisms. Relationships of phenylcoumaran benzylic ether reductases to pinoresinol-lariciresinol and isoflavone reductases

Pinoresinol-lariciresinol and isoflavone reductase classes are phylogenetically related, as is a third, the so-called "isoflavone reductase homologs." This study establishes the first known catalytic function for the latter, as being able to engender the NADPH-dependent reduction of phenylcoumaran benzylic ethers. Accordingly, all three reductase classes are involved in the biosynthesis of important and related phenylpropanoid-derived plant defense compounds. In this investigation, the phenylcoumaran benzylic ether reductase from the gymnosperm, Pinus taeda, was cloned, with the recombinant protein heterologously expressed in Escherichia coli. The purified enzyme reduces the benzylic ether functionalities of both dehydrodiconiferyl alcohol and dihydrodehydrodiconiferyl alcohol, with a higher affinity for the former, as measured by apparent Km and Vmax values and observed kinetic 3H-isotope effects. It abstracts the 4R-hydride of the required NADPH cofactor in a manner analogous to that of the pinoresinol-lariciresinol reductases and isoflavone reductases. A similar catalytic function was observed for the corresponding recombinant reductase whose gene was cloned from the angiosperm, Populus trichocarpa. Interestingly, both pinoresinol-lariciresinol reductases and isoflavone reductases catalyze enantiospecific conversions, whereas the phenylcoumaran benzylic ether reductase only shows regiospecific discrimination. A possible evolutionary relationship among the three reductase classes is proposed, based on the supposition that phenylcoumaran benzylic ether reductases represent the progenitors of pinoresinol-lariciresinol and isoflavone reductases.     

The "Goldilocks Effect" in Cystic Fibrosis: identification of a lung phenotype in the <Emphasis Type="Italic">cftr</Emphasis> knockout and heterozygous mouse

Background  

Cystic Fibrosis is a pleiotropic disease in humans with primary morbidity and mortality associated with a lung disease phenotype. However, knockout in the mouse of cftr, the gene whose mutant alleles are responsible for cystic fibrosis, has previously failed to produce a readily, quantifiable lung phenotype.     

Extent of measles virus spread and immune suppression differentiates between wild-type and vaccine strains in the cotton rat model (Sigmodon hispidus)

Infection of humans with wild-type measles virus leads to strong immune suppression and secondary infections, whereas immunization with an attenuated vaccine strain does not. Using the cotton rat model (Sigmodon hispidus), we investigated whether vaccine and wild-type viruses differ in viral spread and whether this is correlated with inhibition of of proliferation of spleen cells ex vivo after mitogen stimulation. After intranasal infection of cotton rats with wild-type and vaccine strains, it was found that wild-type virus replicates better in lung tissue, spreads to the mediastinal lymph nodes, and induces a more pronounced and longer-lasting inhibition of proliferation of spleen cells ex vivo after mitogen stimulation than does vaccine virus. To induce the same degree of proliferation inhibition, 1,000-fold less wild-type virus was required than vaccine virus. With this system, the virulence of various measles virus isolates and recombinant viruses was tested. Four (in humans and/or monkeys) highly pathogenic virus strains were immunosuppressive, whereas viruses of vaccine virus genotype A were not. Using virus pairs which, due to passage on fibroblasts versus lymphoid cells or due to a point mutation in the hemagglutinin (N481 --> Y), differed in their usage of the two receptor molecules CD46 and CD150 on human cells, it was found that viruses using exclusively CD150 in vitro spread to mediastinal lymph nodes and induced strong immune suppression. These data demonstrate that important parameters of virulence seen in humans, such as viral spread and immune suppression, are reflected in the cotton rat model.     

Multiple Ca(2+)-dependent modulators mediate alkalosis-induced vasodilation in newborn piglet lungs

We previously found that alkalosis-induced vasodilation was mediated by endothelium-derived nitric oxide (EDNO) in newborn piglet pulmonary artery and vein rings precontracted with the thromboxane mimetic U-46619. In contrast, prostacyclin or K(+) channel activation contributed to the response in other preparations. This study was undertaken to determine whether EDNO alone also mediates alkalosis-induced pulmonary vasodilation in piglet lungs vasoconstricted with hypoxia and, if not, to identify the mediator(s) involved. Responses to alkalosis were measured during hypoxia under control conditions after blocking nitric oxide synthase (N(omega)-nitro-L-arginine), cyclooxygenase (meclofenamate), or both endothelium-derived modulators (Dual); after blocking voltage-dependent (4-aminopyridine), ATP- dependent (glibenclamide), or Ca(2+)-dependent K(+) (K(Ca); tetraethylammonium) K(+) channels; and after blocking both endothelium-derived modulators and K(Ca) channels (Triple). Vasodilator responses measured after 20 min of alkalosis were blunted in Dual and tetraethylammonium lungs and abolished in Triple lungs. Thus alkalosis-induced vasodilation in hypoxic lungs appeared to be mediated by three Ca(2+)-dependent modulators: EDNO, prostacyclin, and K(Ca) channels. In addition, a transient, unidentified modulator contributed to the nadir of the vasodilator response measured at 10 min of alkalosis. Future studies are needed to identify factors that contribute to the discordance between isolated vessels and whole lungs.     

Standardizing digital photography: it's not all in the eye of the beholder

Advances in digital photography have made it an efficient and economically appealing alternative to conventional photography. Nevertheless, as objective observers and clinical photographers, we must realize that all digital cameras are not created equal. Different digital cameras frequently used in plastic surgery practices (Olympus 600DL, Olympus 2500, Sony DSC-D700, Nikon Coolpix 950, and Nikon D1) were evaluated, using a subject photographed with each camera in the identical lighting conditions, to determine inherent differences in quality, color, and contrast of the resultant photographs. Three different lighting conditions were examined: single soft-box lighting, dual studio flash boxes, and operating room lighting with on-camera flash. The same digital settings (program mode, ISO camera default setting, high quality setting with JPEG compression) were used. Each camera was digitally color balanced using an 18 percent gray card. Raw and color-balanced images were viewed side-by-side. The macro-image capabilities of each camera were also examined. Conventional 35-mm photographs using a 105 macro-lens on Kodachrome and Ektachrome slide film were obtained for comparison. All of the digital cameras performed with noticeable differences, but they maintained consistency in the three different lighting conditions. Digital photographs differed most greatly with respect to quality and contrast, which was especially obvious once color balancing was performed. Marked differences in quality and ability were observed with respect to macro-image capabilities. Inherent differences in features among digital cameras produce dramatically different photographic results with regard to color, contrast, focus, and overall quality. With the increasing use of digital photography in plastic surgery journals and presentations, it must be recognized that digital cameras do not all display photographs of similar quality, especially when used to evaluate skin appearance. To standardize digital photography, the surgeon must realize that switching digital cameras is akin to switching film types. Standardization of digital photographs should include image resolution between 1.5 and 2.7 million pixels, ISO default setting, color balancing with an 18 percent gray card and software, consistency in focal distance, JPEG compression of medium-to-high quality, and backgrounds of medium blue or 18 percent gray.     

Measles virus induced immunosuppression: targets and effector mechanisms

A profound, transient suppression of immune functions during and after the acute infection is the major cause of more than one million cases of infant deaths associated with measles worldwide. Concommittant with the generation of an efficient measles virus (MV) specific immunity, immune responses towards other pathogens are strongly impaired and provide the basis for the establishment and severe course of opportunistic infections. The molecular basis for MV-induced immunosuppression has not been resolved as yet. Similar to other immunosuppressive viruses, MV is lymphotropic and viral nucleic acid and proteins are detectable in peripheral blood mononuclear cells (PBMC). It is considered central to MV-induced immunosuppression that PBMC isolated from patients largely fail to proliferate in response to antigen specific and polyclonal stimulation. The low abundancy of MV-infected PBMC suggests that MV-induced immunosuppression is not directly caused by infection-mediated cell loss or fusion, but rather by indirect mechanisms such as deregulation of cytokines or surface contact-mediated signaling which may lead to apoptosis or impair the proliferative response of uninfected PBMC. Evidence for a role of any of these mechanisms was obtained in vitro, however, much has still to be learned about the tropism of MV and its interactions with particular host cells such as dendritic cells in vivo.     

Optimization of the chiral separation of some 2-arylpropionic acids on an avidin column by modeling a combined response

The enantiomeric separation of some nonsteroidal antiinflammatory drugs was investigated on an avidin column. An experimental design approach (central composite design) was used to evaluate the effects of three method parameters (pH, concentration of organic modifier, and buffer concentration) on the analysis time and the resolution, as well as to model these responses. This revealed that the organic modifier concentration and sometimes the pH are significant parameters to control because of their influence on both analysis time and resolution. Furthermore, the central composite design results were combined in a multicriteria decision-making approach in order to obtain a set of optimal experimental conditions leading to the most desirable compromise between resolution and analysis time.     

Increased expression of HSP27 protects canine myocytes from simulated ischemia-reperfusion injury

Previous studies have shown that adult rat myocytes can be protected from simulated ischemia-reperfusion (I/R) injury by small heat shock proteins (sHSPs). However, to date the cardioprotective effect of sHSPs has not been confirmed in adult myocytes from a large animal species. Left ventricular myocytes from adult dogs were cultured and infected with a replication-deficient adenovirus designed to increase expression of the human form of HSP27. The response to simulated I/R injury was compared using morphologic criteria. Virus-infected myocytes expressed two- to threefold more HSP27 and sustained less injury in response to simulated I/R than control cells (P < 0.001; paired t-test). Canine myocytes can be isolated, cultured, and induced to increase the expression of a foreign protein without significant effects on differentiation and/or viability. Increased expression of HSP27 provides significant protection from simulated I/R injury in adult canine myocytes. Determining the mechanism by which sHSPs protect from lethal cell injury will provide important new insights into the mechanism of irreversible cell injury in adult myocardium.