Reduction of healthcare-associated infections in a long-term care brain injury ward by replacing regular linens with biocidal copper oxide impregnated linens.

BACKGROUND: Contaminated textiles in hospitals contribute to endogenous, indirect-contact, and aerosol transmission of nosocomial related pathogens. Copper oxide impregnated linens have wide-spectrum antimicrobial, antifungal, and antiviral properties. Our aim was to determine if replacing non-biocidal linens with biocidal copper oxide impregnated linens would reduce the rates of healthcare-associated infections (HAI) in a long-term care ward. METHODS: We compared the rates of HAI in two analogous patient cohorts in a head injury care ward over two 6-month parallel periods before (period A) and after (period B) replacing all the regular non-biocidal linens and personnel uniforms with copper oxide impregnated biocidal products. RESULTS: During period B, in comparison to period A, there was a 24% reduction in the HAI per 1000 hospitalization-days (p<0.05), a 47% reduction in the number of fever days (>38.5°C) per 1000 hospitalization-days (p<0.01), and a 32.8% reduction in total number of days of antibiotic administration per 1000 hospitalization-days (p<0.0001). Accordingly there was saving of approximately 27% in costs of antibiotics, HAI-related treatments, X-rays, disposables, labor, and laundry, expenses during period B. CONCLUSIONS: The use of biocidal copper oxide impregnated textiles in a long-term care ward may significantly reduce HAI, fever, antibiotic consumption, and related treatment costs.

Improvement of facial skin characteristics using copper oxide containing pillowcases: a double-blind, placebo-controlled, parallel, randomized study.

Copper plays a key role in several processes of skin formation and regeneration. Copper has been shown to be absorbed through intact skin. We hypothesized that sleeping on fabrics containing copper-impregnated fibres would have a positive cosmetic effect on the skin. The aim of this study was to confirm our hypothesis. A 4-week, double blind, parallel, randomized study was carried out in which 57 volunteers aged 40-60 years used either copper oxide containing pillowcases (0.4% weight/weight) or control pillowcases not containing copper. Photographs were taken by a professional photographer of each participant at the beginning of the study and at 2 and 4 weeks after the commencement of the study. Two expert graders (a dermatologist and a cosmetologist) evaluated the pictures for the effect on several cosmetic facial skin characteristics. The copper-containing pillowcases had a positive effect for the following facial characteristics: reduction of wrinkles (P < 0.001) and crow's feet/fine lines (P < 0.001) and improvement of general appearance (P < 0.001) at both 2 and 4 weeks. The differences were statistically significant (Wilcoxon scores and chi-squared tests). Consistent sleeping for 4 weeks on copper oxide containing pillowcases caused a significant reduction in the appearance of facial wrinkles and crow's feet/fine lines and significant improvement in the appearance of facial skin. In most trial participants, this effect was already noticeable within 2 weeks of using the copper oxide containing pillowcases.

HIV and helminth co-infection: is deworming necessary?

We have previously suggested that helminth infections play a major role in the pathogenesis of HIV-1 infection in Africa and other developing areas, due to their profound effects on the host immune system, which make those infected more susceptible to HIV-1 infection and less able to cope with it. Chronic immune activation with a dominant Th2 profile, and anergy, are the hallmarks of chronic helminth infection, and may therefore account for most of these effects. In the present review, we summarize the studies that have addressed these issues and argue that despite some conflicting results, the cumulative immunological and epidemiological evidence is in favour of deworming as a preventive and possible therapeutic measure vis-à-vis HIV-1 infection. We suggest that it should be at least tested on a wider and larger scale than has been done until now, because of its immense potential impact on the still raging AIDS epidemic in developing countries.

Multi-targeting the entrance door to block HIV-1.

The multistep nature of HIV-1 entry provides multisite targeting at the entrance door of HIV-1 to cells. Blocking HIV-1 entry to its host cells has clear advantages over blocking subsequent stages in the life cycle of the virus. Indeed, potent cooperative and synergistic inhibition of HIV-1 proliferation has been observed in in vitro studies with several entry inhibitor combinations, interacting with different steps of the HIV-1-cell entry cascade. Targeting a compound to several steps of the viral-cell entry and also to subsequent steps in the viral life cycle promises an even more effective therapeutic, by reducing the probability of HIV-1 to develop resistance. Using one drug that can target multiple sites and/or steps in the viral life cycle will have obvious advantages in clinical use. In this article we review the multistep process of HIV-1 cell entry and the current repertoire of inhibitors of this critical stage in the viral life cycle, and introduce an example of multisite HIV-1 targeting of the cell entry and subsequent critical steps in the viral life cycle.

Neomycin B-arginine conjugate, a novel HIV-1 Tat antagonist: synthesis and anti-HIV activities.

HIV-1 transactivating protein Tat is essential for virus replication and progression of HIV disease. HIV-1 Tat stimulates transactivation by binding to HIV-1 transactivator responsive element (TAR) RNA, and while secreted extracellularly, it acts as an immunosuppressor, an activator of quiescent T-cells for productive HIV-1 infection, and by binding to CXC chemokine receptor type 4 (CXCR4) as a chemokine analogue. Here we present a novel HIV-1 Tat antagonist, a neomycin B-hexaarginine conjugate (NeoR), which inhibits Tat transactivation and antagonizes Tat extracellular activities, such as increased viral production, induction of CXCR4 expression, suppression of CD3-activated proliferation of lymphocytes, and upregulation of the CD8 receptor. Moreover, Tat inhibits binding of fluoresceine isothiocyanate (FITC)-labeled NeoR to human peripheral blood mononuclear cells (PBMC), indicating that Tat and NeoR bind to the same cellular target. This is further substantiated by the finding that NeoR competes with the binding of monoclonal Abs to CXCR4. Furthermore, NeoR suppresses HIV-1 binding to cells. Importantly, NeoR accumulates in the cell nuclei and inhibits the replication of M- and T-tropic HIV-1 laboratory isolates (EC(50) = 0.8-5.3 microM). A putative model structure for the TAR-NeoR complex, which complies with available experimental data, is presented. We conclude that NeoR is a multitarget HIV-1 inhibitor; the structure, and molecular modeling and dynamics, suggest its binding to TAR RNA. NeoR inhibits HIV-1 binding to cells, partially by blocking the CXCR4 HIV-1 coreceptor, and it antagonizes Tat functions. NeoR is therefore an attractive lead compound, capable of interfering with different stages of HIV infection and AIDS pathogenesis.

Helminths, human immunodeficiency virus and tuberculosis.

Helminth infections affect over a quarter of the world's population, especially in the developing countries. These long-lasting parasitic infections cause widespread immune activation and dysregulation, a dominant Th2 cytokine immune profile and an immune hyporesponsiveness state. Considering these profound immune changes and the similar geographic distributions of helminthic infections, HIV and tuberculosis (TB), we suggest that helminthic infections play a major role in the pathogenesis of AIDS and TB. They apparently make the host more susceptible to infection by HIV and Mycobacterium tuberculosis, and impair his/her ability to generate protective immunity against both infections. The implication of these ideas is that without eradication of helminth infections and/or modulation of the immune changes that they cause, HIV and TB vaccines may fail to confer protection against their respective infections in helminth-endemic areas.

Immune activation correlates better than HIV plasma viral load with CD4 T-cell decline during HIV infection.

This study addressed the role of T-cell immune activation in determining HIV-1 plasma viral load and CD4+ T-cell blood levels during HIV-1 infection. A decrease of blood CD4 levels and CD4/CD8 ratios and an increase of CD8 levels in both treated (n = 35) and untreated (n = 19) HIV-positive individuals were more strongly correlated to immune activation (log percentage of HLA-DR+CD3+ cells; R = -0.78, R = -0.77, and R = 0.58, respectively; p <.0001) than to CD4 T-cell proliferation (log percentage of Ki-67+CD4+ cells; R = -0.57 [p <.0001], R = -0.48 [p <.001], and R = 0.37 [p <.01], respectively) or to viral load (R = -0.36 [p <.01], R = -0.23 [p =.09], R = 0.13 [p =.35], respectively). Because almost half of the Ki-67+CD4+ cells were also positive for CTLA-4 (a marker for activated nonproliferating cells), the correlation of CD4 levels to Ki-67 expression is only partially related to cell proliferation and more likely represents mainly immune activation of the cells without proliferation. Taken together, these results suggest that immune activation is the major determinant of CD4 decline and should therefore be considered central for the monitoring of HIV infection and its outcome after antiviral treatment.

Increased CCR5 and CXCR4 expression in Ethiopians living in Israel: environmental and constitutive factors.

HIV coreceptors play a major role in determining susceptibility and HIV cell tropism. The present work studied whether the high expression of these coreceptors found on lymphocytes and monocytes of Ethiopian immigrants to Israel (ETH) is the result of environmental and/or constitutive genetic factors. The study of 26 ETH shortly after their arrival to Israel (new ETH), 22 ETH in Israel over 7 years (old ETH), and 20 Caucasian Israelis (non-ETH) enabled us to address this issue. The new ETH had elevated levels of activated HLA-DR+CD4+ and CD38+CD8+ cells in comparison with both old ETH and non-ETH groups (P < 0.01), most probably related to chronic helminthic infections. Surface CCR5 expression, i.e., the percentage of CCR5+ cells and the number of CCR5 molecules/cell, was higher (2- to 3- and 8- to 31-fold, respectively) in activated than in nonactivated CD4+ cells, in all groups. However, CCR5 expression, in both activated and nonactivated CD4+ cells, was higher in both ETH groups than in the non-ETH group. CXCR4 expression was higher in nonactivated CD4+ cells in all groups and was also higher in both ETH groups, in both activated and nonactivated CD4+ cells, than in the non-ETH group. These findings suggest that constitutive factors, in addition to immune activation caused by environmental factors, account for the elevated expression of CCR5 and CXCR4 on CD4+ cells of ETH. This increased HIV coreceptor expression may make ETH more susceptible to HIV infection and may account in part for the rapid spread of AIDS in Ethiopia and the rest of Africa as well.

Induction of antigen-specific Th1-biased immune responses by plasmid DNA in schistosoma-infected mice with a preexistent dominant Th2 immune profile.

A requisite for vaccines to confer protection against intracellular infections such as Human Immunodeficiency Virus or Mycobacterium tuberculosis is their capacity to induce Th1 immune responses. However, they may fail to do so in Africa and South East Asia, where most individuals have a dominant preexistent Th2 immune profile, due to persistent helminthic parasitic infections, which may undermine any Th1 response. It is well established that DNA vaccines induce strong Th1 biased immune responses against an encoded antigen, depending on the route and mode of immunization. Here, we demonstrate that intradermal immunization with plasmid DNA encoding beta-gal (pCMV-LacZ) of Schistosoma-infected mice, with preexistent dominant Th2 immune background, induce a strong Th1 anti-beta-gal response, as opposed to immunized with beta-gal only. Importantly, the established protective Th2 immune response to schistosomes was not disrupted. These findings strongly support the possibility of using plasmid DNA as a Th1 inducing adjuvant when immunizing populations with a strong preexistent Th2 immune profile.

Chronic immune activation associated with intestinal helminth infections results in impaired signal transduction and anergy.

Helminthic parasites cause widespread, persistent infections in humans. The immigration of Ethiopians to Israel (a group denoted here by "Eth."), many of them infested with helminths and in a chronic immune-activation state, enabled us to investigate the effects of such immune activation on immune responses. We studied the immune profile and immune functions of 190 Eth. and Israeli non-Eth. (Isr.) highly, partially, or non-immune-activated individuals. Immune cells from highly immune-activated individuals were defective in several signaling responses, all of which were restored gradually following anti-helminthic treatment. These cells showed poor transmembrane signaling, as seen by the phosphorylation of various tyrosine kinases and of the MAPK kinases, ERK1/2 and p38; deficient degradation of phosphorylated IkappaBalpha; increased expression of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), which appears to block proliferative responses in these cells; decreased beta-chemokine secretion by CD8(+) cells after stimulation; and reduced proliferation to recall antigen stimulation. Highly immune-activated individuals also showed decreased delayed-type skin hypersensitivity responses to recall antigen before deworming. These findings support the notion that chronic helminthic infections cause persistent immune activation that results in hyporesponsiveness and anergy. Such impaired immune functions may diminish the capacity of these individuals to cope with infections and to generate cellular protective immunity after vaccination.

Increased CCR5 expression with decreased beta chemokine secretion in Ethiopians: relevance to AIDS in Africa.

OBJECTIVE: This study was undertaken to determine the contribution of HIV co-receptors and beta chemokine secretion to the increased susceptibility for human immunodeficiency virus (HIV) infection of peripheral blood mononuclear cells (PBMC) obtained from HIV-seronegative Ethiopian immigrants in Israel (ETH). STUDY DESIGN: Immune activation markers and HIV co-receptor expression on lymphocytes and monocytes, and beta chemokine secretion by CD8+ cells, were compared between ETH and non-Ethiopian Israeli (IS) HIV-negative individuals. RESULTS: The percentage of lymphocytes and monocytes expressing CCR5 was 1.6 and 3.0 times higher in ETH (n = 83) than in IS (n = 45), respectively (P < .001), whereas RANTES and MIP-1alpha secretion was 0.5 and 0.7 times lower (P < .01 and P < .05). The percentage of CCR5-expressing cells and RANTES secretion were inversely correlated (r = -0.7; P < .002). No differences were found in the proportion of CXCR4-expressing cells. No correlation between CCR5 expression and cell activation profile in the whole ETH population was found. However, in highly activated individuals (HLA-DR/CD3 > 7%), a significant decrease in CCR5 expression was observed. CONCLUSIONS: An increased proportion of CCR5-expressing cells with decreased beta chemokine secretion observed in ETH may account for the increased susceptibility to HIV infection of cells obtained from this group. These findings may partly explain the higher susceptibility for HIV infection in Africa and thus the rapid spread of acquired immunodeficiency syndrome (AIDS) in that continent.

Selective lysis of virus-infected cells by cobra snake cytotoxins: A sendai virus, human erythrocytes, and cytotoxin model.

By using a Sendai virus-human erythrocyte model, this work found that virus-infected cells were 10-fold more susceptible to lysis in two of five examined cobra venoms. Four cytotoxins were isolated from the venom of the cobra Naja nigricollis that also showed 10-fold higher cytotoxicity toward virus-infected cells than to untreated cells. As selective destruction of virus-infected cells is of immense importance in clinical practice, this work demonstrates the potential of cobra cytotoxins to serve as leading compounds for the generation of derivatives or fractions with high cytotoxic specificity toward virus-infected cells.

Infection by different HIV-1 subtypes (B and C) results in a similar immune activation profile despite distinct immune backgrounds.

We compared the immune activation profile of 46 HIV-negative and 75 HIV-positive Israelis infected with HIV-1 subtype B, with 85 HIV-negative and 102 HIV-positive Ethiopian immigrants to Israel, who were infected with HIV subtype C. The HIV-negative Ethiopians had exceedingly high blood levels of eosinophils, immunoglobulin E (IgE), and p75s tumor-necrosis factor receptors (p75sTNFR); secretion of interleukin-4 (IL-4) and IL-10 by peripheral blood mononuclear cells (PBMC); proportion of human leukocyte antigen (HLA)-DR+ cells within CD3+, CD4+, and CD8+ T-cell subsets; and proportion of CD45RO+ CD4+ cells; while having significantly lower secretion of interferon-gamma (IFN-gamma) by PBMC and percentage of CD45RA+ CD4+ and CD28+ CD8+ cells. HIV infection in both populations was associated with reduced IL-2, IL-4, IL-10, and IL-12 secretion, number of CD28+ and CD45RA+ CD8+ cells, and increased number of HLA-DR+-CD3+, CD4+, and CD8+ cells, and CD45RO+ CD8+ cells. Thus, infection with HIV-1 subtypes B and C of studied Israelis and Ethiopians, respectively, results in a similar immune activation profile at all stages of the infection when living in the same environment, despite the striking different immune profile observed in the HIV-negative Israeli and Ethiopian populations. Together with our previous observations, this indicates that HIV subtype is not a major determinant in the natural course of HIV infection.

The thiocarboxanilide nonnucleoside inhibitor UC781 restores antiviral activity of 3'-azido-3'-deoxythymidine (AZT) against AZT-resistant human immunodeficiency virus type 1.

N-[4-Chloro-3-(3-methyl-2-butenyloxy)phenyl]-2-methyl-3-furanca rbothioamide (UC781) is an exceptionally potent nonnucleoside inhibitor of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase. We found that a 1:1 molar combination of UC781 and 3'-azido-3'-deoxythymidine (AZT) showed high-level synergy in inhibiting the replication of AZT-resistant virus, implying that UC781 can restore antiviral activity to AZT against AZT-resistant HIV-1. Neither the nevirapine plus AZT nor the 2',5'-bis-O-(t-butyldimethylsilyl)-3'-spiro-5"-(4"-amino-1",2"-oxathi ole- 2",2"-dioxide plus AZT combinations had this effect. Studies with purified HIV-1 reverse transcriptase (from a wild type and an AZT-resistant mutant) showed that UC781 was a potent inhibitor of the pyrophosphorolytic cleavage of nucleotides from the 3' end of the DNA polymerization primer, a process that we have proposed to be critical for the phenotypic expression of AZT resistance. Combinations of UC781 plus AZT did not act in synergy to inhibit the replication of either wild-type virus or UC781-resistant HIV-1. Importantly, the time to the development of viral resistance to combinations of UC781 plus AZT is significantly delayed compared to the time to the development of resistance to either drug alone.

Phenotypic mechanism of HIV-1 resistance to 3'-azido-3'-deoxythymidine (AZT): increased polymerization processivity and enhanced sensitivity to pyrophosphate of the mutant viral reverse transcriptase.

The multiple mutations associated with high-level AZT resistance (D67N, K70R, T215F, K219Q) arise in two separate subdomains of the viral reverse transcriptase (RT), suggesting that these mutations may contribute differently to overall resistance. We compared wild-type RT with the D67N/K70R/T215F/K219Q, D67N/K70R, and T215F/K219Q mutant enzymes. The D67N/K70R/T215F/K219Q mutant showed increased DNA polymerase processivity; this resulted from decreased template/primer dissociation from RT, and was due to the T215F/K219Q mutations. The D67N/K70R/T215F/K219Q mutant was less sensitive to AZTTP (IC50 approximately 300 nM) than wt RT (IC50 approximately 100 nM) in the presence of 0.5 mM pyrophosphate. This change in pyrophosphate-mediated sensitivity of the mutant enzyme was selective for AZTTP, since similar Km values for TTP and inhibition by ddCTP and ddGTP were noted with wt and mutant RT in the absence or in the presence of pyrophosphate. The D67N/K70R/T215F/K219Q mutant showed an increased rate of pyrophosphorolysis (the reverse reaction of DNA synthesis) of chain-terminated DNA; this enhanced pyrophosphorolysis was due to the D67N/K70R mutations. However, the processivity of pyrophosphorolysis was similar for the wild-type and mutant enzymes. We propose that HIV-1 resistance to AZT results from the selectively decreased binding of AZTTP and the increased pyrophosphorolytic cleavage of chain-terminated viral DNA by the mutant RT at physiological pyrophosphate levels, resulting in a net decrease in chain termination. The increased processivity of viral DNA synthesis may be important to enable facile HIV replication in the presence of AZT, by compensating for the increased reverse reaction rate.

Physicochemical and biochemical properties of 2',5'-linked RNA and 2',5'-RNA:3',5'-RNA "hybrid" duplexes.

In recent publications, oligonucleotides joined by 2',5'-linkages were found to bind to complementary single-stranded RNA but to bind weakly, or not at all, to single-stranded DNA [e.g., P. A. Giannaris and M. J. Damha (1993) Nucleic Acids Res. 21, 4742-4749]. In this work, the biochemical and physicochemical properties of 2',5'-linked oligoribonucleotides containing mixed sequences of the four nucleobases (A, G, C, and U) were evaluated. CD spectra of RNA:2', 5'-RNA duplexes were compared with the spectra of DNA:DNA, RNA:RNA, and DNA:RNA duplexes of the same base sequence. The CD results indicated that the RNA:2',5'-RNA duplex structure more closely resembles the structure of the RNA:DNA hybrid, being more A-form than B-form in character. The melting temperature (Tm) values of the backbone-modified duplexes were compared with the Tm values of the unmodified duplexes. The order of thermal stability was RNA:RNA > DNA:DNA approximately RNA:DNA approximately DNA:RNA > RNA:2',5'-RNA > 2',5'-RNA:2',5'-RNA >> DNA:2',5'-RNA (undetected). RNA:2',5'-RNA duplexes are not substrates of the enzyme RNase H (Escherichia coli, or HIV-1 reverse transcriptase), but they can inhibit the RNase H-mediated cleavage of a natural DNA:RNA substrate. Structural models that are consistent with the selective association properties of 2',5'-linked oligonucleotides are discussed.