Skin squames contribute to ammonia and volatile fatty acid production from bacteria colonizing in air-cooling units with odor complaints

One of the most notable Indoor Air Quality problems is odor emission. This study investigated the potential contribution of skin squames to the production of ammonia (NH₃ ) and volatile organic acids (VFAs) by 7 bacteria isolated from air-cooling (AC) units with complaints of urine and body odors. Our previous study showed that keratinolytic activity is higher in AC units with odor complaints than those without. In the offices where these units are located, the most likely source of keratins is from human skin squames. Most bacteria can produce NH₃ and VFAs in the skin squame culture. Some correlations between the levels of NH₃ , NH4+, VFAs, and keratinolytic activity were found. The odor production pathway with skin squames was proposed. Staphylococcus haemolyticus was abundant in the AC units with odor problems and had a high level of keratinolytic activity in addition to odor production. For long-term odor control, it is important to reduce the level of skin squames entering the AC units.

Spontaneous resolution of acute rejection and tolerance induction with IL-2 fusion protein in vascularized composite allotransplantation

Vascularized composite allotransplantation (VCA) has emerged as a treatment option for treating nonlife-threatening conditions. Therefore, in order to make VCA a safe reconstruction option, there is a need to minimize immunosuppression, develop tolerance-inducing strategies and elucidate the mechanisms of VCA rejection and tolerance. In this study we explored the effects of hIL-2/Fc (a long-lasting human IL-2 fusion protein), in combination with antilymphocyte serum (ALS) and short-term cyclosporine A (CsA), on graft survival, regulatory T cell (Treg) proliferation and tolerance induction in a rat hind-limb transplant model. We demonstrate that hIL-2/Fc therapy tips the immune balance, increasing Treg proliferation and suppressing effector T cells, and permits VCA tolerance as demonstrated by long-term allograft survival and donor-antigen acceptance. Moreover, we observe two distinct types of acute rejection (AR), progressive and reversible, within hIL-2/Fc plus ALS and CsA treated recipients. Our study shows differential gene expression profiles of FoxP3 versus GzmB, Prf1 or interferon-γ in these two types of AR, with reversible rejection demonstrating higher Treg to Teff gene expression. This correlation of gene expression profile at the first clinical sign of AR with VCA outcomes can provide the basis for further inquiry into the mechanistic aspects of VCA rejection and future drug targets.

Direct incorporation of the NKT-cell activator α-galactosylceramide into a recombinant Listeria monocytogenes improves breast cancer vaccine efficacy

Background:

Immune suppression in the tumour microenvironment remains a major limitation to successful immunotherapy of cancer. In the current study, we analysed whether the natural killer T cell-activating glycolipid α-galactosylceramide could overcome immune suppression and improve vaccination against metastatic breast cancer.

Methods:

Mice with metastatic breast cancer (4T1 model) were therapeutically treated with a Listeria monocytogenes-based vaccine expressing tumour-associated antigen Mage-b followed by α-galactosylceramide as separate agents, or as a complex of α-galactosylceramide stably incorporated into Listeria-Mage-b. Effects on metastases, tumour weight, toxicity and immune responses were determined.

Results:

Sequential treatments of mice with established 4T1 breast carcinomas using Listeria-Mage-b followed by α-galactosylceramide as a separate agent was highly effective at reducing metastases, but was accompanied by severe liver toxicity. In contrast, combined therapy using Listeria-Mage-b modified by incorporation of α-galactosylceramide resulted in nearly complete elimination of metastases without toxicity. This was associated with a significant increase in the percentage of natural killer T cells in the spleen, and an increase in natural killer cell activity and in T cell responses to Mage-b.

Conclusions:

Our results suggest that direct incorporation of α-galactosylceramide into a live bacterial vaccine vector is a promising non-toxic new approach for the treatment of metastatic breast cancer.

Vascularized osteomyocutaneous allografts are permissive to tolerance by induction-based immunomodulatory therapy

Vascularized composite allografts (VCAs) are unique among transplanted organs in that they are composed of multiple tissues with disparate antigenic and immunologic properties. As the predominant indications for VCAs are non-life-threatening conditions, there is an immediate need to develop tolerance induction strategies and to elucidate the mechanisms of VCA rejection and tolerance using VCA-specific animal models. In this study, we explore the effects of in vitro induced donor antigen-specific CD4(-) CD8(-) double negative (DN) Treg-based therapy, in a fully MHC mismatched mouse VCA such as a vascularized osteomyocutaneous as compared to a non-VCA such as a full thickness skin (FTS) transplantation model to elucidate the unique features of VCA rejection and tolerance. We demonstrate that combined therapy with antigen-induced CD4 derived DN Tregs and a short course of anti-lymphocyte serum, rapamycin and IL-2/Fc fusion protein results in donor-specific tolerance to VCA, but not FTS allografts. Macrochimerism was detected in VCA but not FTS allograft recipients up to >60 days after transplantation. Moreover, a significant increase of CD4(+) Foxp3(+) Tregs was found in the peripheral blood of tolerant VCA recipients. These data suggest that VCA are permissive to tolerance induced by DN Treg-based induction therapy.

Construction and evaluation of high-quality n-ZnO nanorod/p-diamond heterojunctions

Vertically-aligned ZnO nanorods (NRs) arrays were synthesized by a low-temperature solution method on boron-doped diamond (BDD) films. The morphology, growth direction, and crystallinity of the ZnO NRs were studied by scanning electron microscopy, X-ray diffraction and cathodoluminescence. Electrical characterization of the ZnO NR/BBD heterostructures revealed characteristic p-n junction properties with an on/off ratio of about 50 at +/- 4 V and a small reverse leakage current approximately 1 microA. Moreover, the junctions showed an ideality factor around 1.0 at a low forward voltage from 0 to 0.3 V and about 2.1 for an increased voltage ranging from 1.2 to 3.0 V, being consistent with that of an ideal diode according to the Sah-Noyce-Shockley theory.

Adoptive cell therapy using antigen-specific CD4⁻CD8⁻T regulatory cells to prevent autoimmune diabetes and promote islet allograft survival in NOD mice

AIMS/HYPOTHESIS

A new differentiation pathway for CD4(-)CD8(-) (DN) T cells has recently been identified that exhibits the potent function of peripheral converted DN T cells in suppressing immune responses and provides the potential to treat autoimmune diseases. The aim of this study was to determine if the DN T cells converted from CD4(+) T cells of NOD mice retain the antigen-specific regulatory capacity and prevent autoimmune diabetes in vivo. We also sought to determine if the combination of DN T cells with rapamycin promotes islet allograft survival in autoimmune diabetic NOD recipients.

METHODS

NOD CD4(+) T cells were converted to DN T cells in an in vitro mixed-lymphocyte reaction, with or without GAD65 peptide, as previously reported. The antigen-specific DN T cells were adoptively transferred to NOD/SCID mice, new-onset diabetic NOD mice or islet-allograft-recipient NOD mice as the part of cell-based therapy. The development of diabetes and allograft survival was assessed by monitoring blood glucose levels.

RESULTS

NOD CD4(+) T cells were converted in vitro to DN T cells at a rate of 50% and expressed unique cell features. The DN T cells from NOD donors blocked autoimmunity and prevented diabetes in NOD models, and these effects were even greater for GAD65-peptide-primed DN T cells. DN T cells acted in conjunction with rapamycin to suppress alloantigen-triggered T cell proliferation, promoted apoptosis and prolonged islet allograft survival in NOD recipients.

CONCLUSIONS/INTERPRETATION

Administration of the islet beta cell antigen-specific DN T cells can prevent the development of autoimmune diabetes and promote islet allograft survival in NOD mice.

Prospects of Wannier functions in investigating photonic crystal all-optical devices for signal processing

Wannier functions derived from Bloch functions have been identified as an efficient means of analyzing the properties of photonic crystals in which localized functions have now opened the door for 2D and 3D structures containing defects to be investigated. In this paper, based on the Maxwell equations in diagonalized form and utilizing Bloch waves we have obtained an equivalent system of algebraic equations in eigenform. By establishing and exploiting several distinct properties of the resulting eigenpairs, we demonstrate an ability to construct Wannier functions associated with the simplest one-dimensional photonic structure. More importantly, the numerical investigation of the inner- and intra-band orthonormality conditions as well as Hilbert space partitioning features shows a capability for multi-resolution analysis that will make all-optical signal processing devices with photonic crystal structures feasible.

Observation of dynamic samples using simple coverslip fluidics

The ability to observe samples undergoing controlled fluid flow under the microscope is important for studying biochemical processes and motion dynamics. We describe here a simple method to achieve this using coverslips shaped using a fiber scribe. Testing showed good directional flow control within the test range of 0-1 ml/min flow rate and an ability to sustain a flow rate up to approximately 1 ml/min. Testing with a sealed T-channel coverslip demonstrated the ability to construct fluid network branches with this scheme. We also demonstrated the usefulness of this procedure in motion dynamic studies of Dunaliella algae swimming under fluid flow.

Epidemiology of suspected elderly mistreatment in Singapore

INTRODUCTION

In our Asian society, respect for our elderly is deeply entrenched and highly valued. However, a previous study had shown that physical mistreatment of the elderly exists in the local population. This present descriptive study aims to evaluate the other types of elderly mistreatment and epidemiology of suspected victims in the local population.

METHODS

Over a period of 12 months, from June 2005 to May 2006, doctors of the Emergency Department (ED) were trained to look for clinical features of mistreatment in patients aged 65 years and above. A specially-developed evaluation form was used to help the staff in assessing suspected cases; these were then referred to medical social workers for further evaluation.

RESULTS

42 cases of suspected mistreatment were detected, with almost three times more female than male patients. The average age of suspected victims was 78.8 years. There were 27 cases of possible physical mistreatment, 25 of possible neglect, six of possible psychological mistreatment, two of possible financial mistreatment, one of possible abandonment and one of possible self-neglect. Most suspected perpetrators were family members, and more than half were the victims' sons. 37 suspected victims had to be warded after ED consultation and eight died within six months of presentation.

CONCLUSION

Mistreatment of the elderly in the local population is more prevalent than expected and victims can suffer adverse outcomes. Understanding of this problem is still incomplete and more research is required. Increased awareness of this problem in the community and the medical fraternity can better identify such patients.

Inexpensive color evaluation of dye-based pressure-sensitive films for plantar studies

Dye-based pressure-sensitive films are advantageous in plantar pressure studies due to their ease of use, cost-effectiveness, and ability to produce measurements within the shoe. To circumvent the use of proprietary equipment and software to relate the dye-stained film to load, an alternative approach of using a conventional flatbed scanner and generic image processing software is attempted here instead. The technique revealed high linear increasing and decreasing trends for the respective red and blue normalized intensities (R(2) > 0.95) and low standard deviation in all readings (<0.06) overall. By subtracting the blue from the red normalized intensity, it was discovered that the measurement sensitivity could be doubled. The results here confirm the viability of using a conventional flatbed scanner and generic image processing software to relate the dye-stained pressure films to load. The adoption of this approach promises substantial cost savings.

The optical mouse as an inexpensive region-of-interest position recorder in optical microscopy

In optical microscopy, the microscopic features of interest typically have to be derived from regions that are spatially distributed over the sample. While the features to be analyzed may be minute, the regions from where they must be obtained from may be located quite far apart from one another. If the features are not distinct enough to allow easy visual discrimination, it would be tedious and time-consuming to attempt to recall and revisit these regions of interest. One method to overcome this difficulty would be to note and record the graduated markings on the microscope, or to use built-in position encoders. The former is tedious while the latter is generally expensive. Here, a region-of-interest position-recording implement based on the use of an optical mouse is presented. It is inexpensive and easily adaptable to the manual stage of any optical microscope.

Derivation of retardation phase in computer-aided photoelasticity by using carrier fringe phase shifting

Previous phase-shifting schemes in computer-aided photoelasticity required the processing of six fringe patterns to derive the phase difference due to retardation. A technique in which a carrier fringe is used is demonstrated to reduce to four the number of fringe patterns required. The use of fewer fringe patterns lowers the computation time and the number of phase-step errors. The basis of the technique is outlined in detail, and experimental results are presented as well.

Photoelastic illumination by using cathode-ray-tube displays

The need to perform computer-aided fringe-analysis schemes in photoelasticity for automated stress analysis has necessitated further developments in specimen illumination. Commonly available cathode-ray-tube color displays are investigated for such a purpose.

Derivation of phase in computer-aided photoelasticity

Phase-shifting techniques have been successfully implemented to yield the phase from sinusoidally modulated intensity fields in interferometry. However, when the intensity fields are that of squared sinusoidal modulation, as in the case of photoelasticity, implementation of existing phase-shift operations will result in error. An operation is outlined to derive faultlessly the phase in computer-aided photoelasticity.

Object illumination angle measurement in speckle interferometry

Errors in measurement of the object illumination angle affect fringe interpretation accuracies in speckle interferometry. To measure the object illumination angle we propose a method based on the moiré effect. The technique is easy to implement and was found to yield fast and accurate measurements.

White-light reconstruction setup for shearograms using optical-fiber waveguides

A white-light reconstruction setup for shearograms using optical-fiber waveguides is presented. The setup is compact, is not susceptible to dust and scratches, and enables the two-dimensional fringe pattern on shearograms to be viewed directly under uniform and enhanced illumination with minimal image distortion.

Using gradient-index lenses for laser-beam expansion in interferometry

The use of gradient-index lenses, which inherently have fewer surface defects than conventional convex lenses, for laser-beam expansion in interferometry results in improved fringe visibility without loss of light intensity and the need for stringent alignment requirements.

Age-dependent choice of sexual partners and the transmission dynamics of HIV in Sub-Saharan Africa

A mathematical model of the transmission of HIV-1 within heterosexual populations in Sub-Saharan Africa is described and its properties analysed. The model incorporates epidemiological and demographic processes and extends previous work in this area via the inclusion of age and sex dependency in rates of sexual partner change, and sexual partner choice dependent on age. Parameter assignments are made on the basis of current data on the transmission dynamics of HIV-1 and the demography of human populations in Africa. Both age-dependent rates of sexual activity and the sexual contact of males with females younger than themselves act to enhance the predicted demographic impact. With realistic parameter values, the model suggests AIDS is able to reverse the sign of population growth rates from positive to negative values over a timescale of a few decades. The sensitivity of this prediction is examined in relation to changes in the pattern of sexual contact between different age classes of females and males, different patterns of change in the age-dependent rate of sexual partner change, different assumptions concerning the doubling time of the epidemic in its early stages, and the relative efficiencies of viral transmission between men and women, and vice versa. The impact AIDS is predicted to have on the number of young and elderly persons as a fraction of the number of productive adults (the dependancy ratio) is examined under various assumptions concerning the weighting to be applied to mirror the burden imposed by the care of those with AIDS. The paper includes an assessment of the influence of the timing of changes in sexual behaviour, or the promotion of the use of condoms, on the predicted course of the epidemic. The paper concludes with a discussion of data needs and the model refinements required to more accurately mirror current understanding of the epidemiology of HIV-1.

Reducing the spread of HIV infection in sub-Saharan Africa: some demographic and economic implications

Any reduction in the rate of spread of HIV infection has consequences for the incidence and demographic effects of AIDS. In this paper, output from a published mathematical model of the dynamics of HIV transmission through heterosexual contact is used to study the implications of reducing HIV transmission on demographic patterns and national health budgets in sub-Saharan Africa. The major conclusion is that both the timing and the effectiveness of reducing HIV transmission are non-linearly related to their potential demographic and economic effects. The analysis emphasizes the benefits to be gained from a concerted effort to reduce the spread of HIV infection as early as possible in the time course of the epidemic.

The influence of different sexual-contact patterns between age classes on the predicted demographic impact of AIDS in developing countries

A model is developed to describe the spread of HIV within heterosexual communities and the demographic impact of AIDS. The model combines epidemiologic and demographic processes and is designed to mirror the impact of AIDS in sub-Saharan Africa. Refinements on past work in this area include unequal probabilities for transmission from females to males and from males to females, the inclusion of an age- and sex-dependent sexual-partner choice function and distributed incubation plus infectious periods. Numerical studies suggest that unequal transmission probabilities (weighted to a greater probability from males to females than vice versa), and the tendency of males to choose sexual partners of the opposite sex younger than themselves, both act to increase the demographic impact of AIDS over that predicted with equal transmission between the sexes and partner choice restricted within given age classes. Analyses support the conclusions of past work that the epidemic will only have a small detrimental impact on the dependency ratio of a population (the ratio of dependents to working adults) even when a weighting is added to take account of the extra burden imposed by the care of adult AIDS patients. However, a small increase in the ratio can imply a significant rise in the number of dependents within the population. Stimulation studies of the impact of changes in behavior to reduce transmission highlight to the need to induce such changes as early as possible in the course of the epidemic in order to minimize its impact. Directions for future research are discussed emphasizing the need to acquire quantitative data on sexual habits and to construct models to represent heterogeneity in sexual behavior.

Studies on the interaction of propranolol with erythrocyte membranes

The interaction of propranolol with erythrocyte membranes at concentrations stabilizing intact erythrocytes against hypotonic hemolysis produced corresponding perturbations in membrane protein and particularly membrane phospholipid components as monitored by increases in the reactivity of membrane amino and sulfhydryl groups towards trinitrobenzenesulfonic acid and 5,5'-dithio-bis(2-nitro-benzoic acid), respectively. Membrane-propranolol interactions were also analyzed in terms of alterations produced in the kinetic properties of membrane enzymes. These experiments provided evidence that propranolol-induced perturbations were sufficiently generalized as to influence the activity of enzymatic processes associated with both inner and outer membrane surfaces. Configurational changes in membrane phospholipids were implicated in these effects of propranolol, which included alterations in functionally significant membrane-cation interactions, It is suggested that the findings described here may provide a basis for understanding molecular aspects of membrane stabilization in other systems.

Synthesis of Some New Phosphino Acetylenes

The synthesis and characterization of the new phosphino acetylenes (C6H5)2PC≡CCF3, (C6H5)2PC≡CC(CH3)3, (C6H5)2PC≡CP(C6F5)2, (C6F5)2PC≡CCH3, (C6F5)2PC≡CC6H5, (C6H5)2PC≡CP[N-(C2H5)2]2, the mixed arsine–phosphine (C6H5)2PC≡CAs(C6H5)2 and the arsino acetylene (C6H5)2AsC≡CCF3, are reported.

Some new diphosphine-bridged nickel carbonyl and cyclopentadienyl compounds

The binuclear diphosphine bridged monocarbonyl compound [Ni(CO)]2(DPPA)3 has been obtained by reaction of Ni(CO)4 with bis(diphenylphosphino)acetylene (DPPA) under mild conditions and by displacement of π-cyclopentadienyl groups from [π-C5H5Ni(CO)]2 at room temperature. The latter reaction suggests a possible route to other monocarbonyl nickel phosphine compounds not available by direct reaction of Ni(CO)4 with phosphines. The preparation and characterization of the binuclear compounds [Ni(CO)2]2(DPPA)2, [Ni(CO)3]2(DPPA), and (π-C5H5NiI)2(DPPA) are also described.