CD8+ T cells have an essential role in pulmonary clearance of nontypeable Haemophilus influenzae following mucosal immunization

A rodent respiratory experimental model has proved useful for investigating the immune mechanisms responsible for clearance of bacteria from the lungs. Immunohistochemical studies in immune and nonimmune rats have identified the cellular kinetics of response to bacterial pulmonary infection for CD8+, CD4+, and gammadelta+ T cells; B cells; and the expression of major histocompatibility complex class II (MHC-II). During the course of bacterial clearance, there was no apparent proliferation or extravasation of lymphocytes, nor was there increased expression of MHC-II in nonimmune animals despite an influx of polymorphonuclear leukocytes, whereas in immunized animals there was an early influx of CD8+ and gammadelta+ T cells, followed by enhanced expression of the MHC-II marker, cellular infiltration by polymorphonuclear leukocytes, and finally an increased number of CD4+ T cells. Depletion of CD8+ T cells confirmed their vital contribution in the preprimed immune response to pulmonary infection by significantly decreasing the animals' ability to clear bacteria following challenge.     

NADPH oxidase, Nramp1 and nitric oxide synthase 2 in the host antimicrobial response

Using highly conserved, complex enzyme systems, leukocytes utilize the toxic nature of free radical intermediates, derived from oxygen and nitrogen, to control microbial pathogens as part of the innate immune response. Upon activation, NADPH oxidase generates superoxide anion radicals, which in turn give rise to further reactive oxygen intermediates. Similarly, activated nitric oxide synthase 2 catalyses the production of nitric oxide radicals, which leads to the formation of reactive nitrogen intermediates. Nitrogen- and oxygen-centered reactive intermediates can interact to form further reactive species. In addition, presence of the cationic transporter, Nrampl, may exacerbate the effects of these toxic compounds on invading microbes. While each of these antimicrobial systems can operate independently, the combination of their activities is synergistic in the successful containment of almost all invading pathogens. These systems are activated and modulated by microbial products and a series of temporally expressed cytokines. They also feed directly into the initiation of the adaptive immune response, which culminates in lasting specific immunity. The effector molecules, generated in the early innate immune response, are not specific to the invading pathogen and may also cause damage to the host. It is the critical balance of these processes in the initial stages of infection that determines the outcome of infectious disease.     

Three-dimensional transesophageal echocardiography (TEE) and other future directions

As faster imaging systems enter the market, three-dimensional echocardiography is gearing up to become a useful tool in assisting the clinician to image the heart in many innovative projections. What started out as a novel idea of displaying a three-dimensional anatomic picture of the heart now provides a multitude of views of the heart and its structures. Information gained from anatomic and dynamic data has helped clinicians and surgeons in making clinical decisions. In the future, this imaging modality may become a routine imaging modality for assessing cardiac pathology and may serve to increase understanding of the dynamics of the heart.     

Advanced Cardiac Life Support guidelines 2011

The main emphasis in the Advanced Cardiac Life Support (ACLS) guidelines are in the areas of good quality chest compressions, ensuring normoventilation, removal of atropine from the cardiac arrest algorithm, removal of the use of the endotracheal route for drug administration, and renewed focus on the care provided after return of spontaneous circulation. In addition, the need for monitoring of quality of the various care procedures is emphasised. While the various ACLS procedures are being carried out, there is a need to minimise interruptions to chest compressions for maintenance of coronary perfusion pressures. In addition, the resuscitation team needs to continually look out for reversible causes of the cardiac arrest.     

1,N2-propanodeoxyguanosine adducts of the 1,3-butadiene metabolite, hydroxymethylvinyl ketone

1,3-Butadiene (BD) is a rodent and human carcinogen. While several epoxides formed during BD metabolism are mutagenic and may contribute to BD carcinogenicity, another proposed metabolite, hydroxymethylvinyl ketone (HMVK), could also be involved. A significant quantity of HMVK is likely to be formed since it is a proposed intermediate in the metabolism of 3-butene-1,2-diol (BD-diol) to 1,2-dihydroxy-4-(N-acetylcysteinyl)butane, the major mercapturic acid metabolite of BD in humans. In addition, BD-diol is a major BD metabolite in liver perfusion experiments in rodents. By analogy with other alpha,beta-unsaturated carbonyls, HMVK is likely to be mutagenic via formation of promutagenic 1,N(2)-propanodeoxyguanosine adducts. The objective of the current study was to investigate the formation of such adducts in vitro. The reaction between HMVK and dGuo yielded two major products shown to be identical by positive ion electrospray-MS, having protonated molecular ions with m/z consistent with HMVK-derived 1,N(2)-propanodeoxyguanosine (HMVK-dGuo). Rechromatography of each fraction yielded two fractions with retention times identical to those initially isolated, suggesting equilibration between two diastereomers. Two partially resolved sets of (1)H NMR signals were consistent with a 1:1 mixture of diastereomeric C-6-substituted adducts equilibrating slowly on an NMR time-scale. Following deglycosylation, C-6 substitution was verified by two-dimensional correlation NMR spectroscopy, indicating that the initial adducts were formed by Michael addition of dGuo-N1 to the terminal vinyl carbon followed by cyclization to the 1,N(2)-propano structure. Reactions with calf thymus DNA under physiological conditions yielded two sets of products. The first set had HPLC retention times and mass spectra identical to those of the previously characterized C-6-substituted HMVK-dGuo diastereomers. The second set had a molecular ion and fragmentation pattern identical to the C-6-substituted adducts and on this basis were assigned as the diastereomeric C-8 adducts. In addition to detecting HMVK-dGuo in treated DNA, the adducts were also present in control DNA. Overall, our research demonstrates that HMVK can form promutagenic DNA adducts and it therefore has the potential to play a role in BD-associated mutagenicity.     

Cytokines and immunity to viral infections

In this review, we discuss two broad approaches we have taken to study the role of cytokines and chemokines in antiviral immunity. Firstly, recombinant vaccinia viruses were engineered to exit encoding cytokines and chemokines of interest. Potent antiviral activity was mediated by many of these encoded factors, including IL-2, IL12. IFN-γ. TNF-α. CD40L. Mig and Crg-2, In some cases, liosi defense mechanisms were induced (IL-2, IL-t2. Mig and Crg-2), whilst for others, a direct antiviral effect was demonstrated (IFN-γ. TNF-α and CD40L), In sharp contrast, vector-directed expression of IL 4, a type 2 factor, greatly increased virus virulence, due 10 a downregulation of host type 1 immune responses. Our second experimental approach involved the use of strains of mice deficient for the production of particular cytokines or their receptors, often in combination with our engineered viruses. Mice deficient in either IFN-γ, IFN-γR, IFN-α/βR, TNFFRs, CD40 or IL-6 were, in general, highly susceptible to poxvirus infection. Surprisingly, not only the TNFR1, but also the TNFR2, was able to mediate the antiviral effects of TNF-α in viv, whilst the antiviral activity observed following CD40-CD40L interaction is a newly defined function which may involve apoptosis of infected cells. Through the use of perforin-deficient mice, we were able to demonstrate a requirement for this molecule in the clearance of some viruses. such as ectromelia virus, whilst for others, such as vaccinia virus, perforin was less important but IFN-γ was essential.     

Interferon gamma is involved in the recovery of athymic nude mice from recombinant vaccinia virus/interleukin 2 infection

Athymic nude mice recover from an infection with recombinant vaccinia virus (VV) encoding murine interleukin 2 (IL-2), but treatment with a mAb to IL-2 accentuated infection. Administration of a mAb against interferon gamma (IFN-gamma) to mice infected with the IL-2-encoding virus completely prevented the IL-2-induced mechanisms of recovery. Both asialo-GM1+ (NK) and asialo-GM1- (non-NK) cells were participants in the IFN-gamma-mediated recovery of nude mice from infection with the IL-2-encoding VV recombinant. Depletion of asialo-GM1+ cells exacerbated infection, though not as much as anti-IFN-gamma mAb. In vitro, both asialo-GM1+ and asialo-GM1- nude mouse splenocytes produced IFN-gamma in response to IL-2.     

Biosynthesis and Response of Zinc Oxide Nanoparticles against Periimplantitis Triggering Pathogens

Periimplantitis due to pathogenic bacteria is considered as a major cause for dental implants failures. Biogenic zinc oxide nanoparticles (ZnPs) are known to inhibit periimplantitis triggering pathogens. The current investigation intended to perform ZnPs biosynthesis and evaluation against periimplantitis triggering bacteria. The current study involved ZnPs biosynthesis using Andrographis paniculata leaves aqueous extract (APLAE), followed by optimization, stability, characterization, and in vitro evaluation against periimplantitis triggering bacteria. The experimental results indicated the success of ZnPs biosynthesis based on the optimization of zinc acetate (1.5 g), plant extract (5 mL), pH 12, and temperature (25 °C), and using the stability study (absorbance between 365–370 nm) and characterization data exhibiting broad and shifted bands (in FTIR spectrum), the size was found to be below 98.61 nm (determined by FESEM and XRD spectra) and 71.54% zinc was observed in the EDX spectrum. Biogenic ZnPs exhibited a high inhibitory activity against periimplantitis-triggering pathogens (E. coli and S. aureus). Based on the experimental results, the present study concludes that biogenic ZnPs possess a high inhibitory potential against periimplantitis-triggering bacteria, and it is established that the biosynthesis of ZnPs using APLAE is a useful method.     

Tape-strip sampling for measuring dermal exposure to 1,6-hexamethylene diisocyanate

OBJECTIVES: This study describes the development and evaluation of a method for sampling layers of the stratum corneum for the quantitation of dermal exposure to 1,6-hexamethylene diisocyanate (HDI). METHODS: HDI deposited on skin was collected by the removal of stratum corneum with adhesive tape, derivatized with 1-(2-methoxyphenyl)piperazine, and quantitated as the urea derivative (HDIU) by liquid chromatography-mass spectrometry (LC-MS). This LC-MS method was tested by analyzing tape spiked with HDI-containing products, then applied to tape samples collected from the skin of an auto-body shop worker exposed to polyurethane paint aerosols. RESULTS: The limits of detection and quantitation were 20 and 50 fmol per injection, respectively. The recovery of HDI from the tape was 99.3% [95% confidence interval (95% CI) 97.1-102]. HDIU was stable at -40 degrees C, degrading by 0.28% (95% CI 0.10-0.46) per day. Quantifiable amounts of HDI were observed in 42.6% of the first three successive tape-strip samples collected from 36 different sites on the skin of the worker. The amount of HDI recovered from the collection sites on skin, measured by summing the levels collected with three successive tape-strips, ranged from nondetectable to 1874 pmol. CONCLUSIONS: This study demonstrates that HDI on skin can be collected with tape-strips and quantified at occupational levels using LC-MS.     

Influenza virus inhibits amiloride-sensitive Na+ channels in respiratory epithelia

Many pathogens causing diarrhea do so by modulating ion transport in the gut. Respiratory pathogens are similarly associated with disturbances of fluid balance in the respiratory tract, although it is not known whether they too act by altering epithelial ion transport. Here we show that influenza virus A/PR/8/34 inhibits the amiloride-sensitive Na(+) current across mouse tracheal epithelium with a half-time of about 60 min. We further show that the inhibitory effect of the influenza virus is caused by the binding of viral hemagglutinin to a cell-surface receptor, which then activates phospholipase C and protein kinase C. Given the importance of epithelial Na(+) channels in controlling the amount of fluid in the respiratory tract, we suggest that down-regulation of Na(+) channels induced by influenza virus may play a role in the fluid transport abnormalities that are associated with influenza infections.