Nonactivated titanium-dioxide nanoparticles promote the growth of Chlamydia trachomatis and decrease the antimicrobial activity of silver nanoparticles.

AIMS: Chlamydia trachomatis and herpes simplex virus (HSV) are the most prevalent bacterial and viral sexually transmitted infections. Due to the chronic nature of their infections, they are able to interact with titanium-dioxide (TiO2 ) nanoparticles (NPs) applied as food additives or drug delivery vehicles. The aim of this study was to describe the interactions of these two prevalent pathogens with the TiO2 NPs. METHODS AND RESULTS: Chlamydia trachomatis and HSV-2 were treated with nonactivated TiO2 NPs, silver NPs and silver decorated TiO2 NPs before infection of HeLa and Vero cells. Their intracellular growth was monitored by quantitative PCR. Unexpectedly, the TiO2 NPs (100 µg ml-1 ) increased the growth of C. trachomatis by approximately fourfold, while the HSV-2 replication was not affected. Addition of TiO2 to silver NPs decreased their antimicrobial activity against C. trachomatis up to 27·92-fold. CONCLUSION: In summary, nonactivated TiO2 NPs could increase the replication of C. trachomatis and decrease the antimicrobial activity of silver NPs. SIGNIFICANCE AND IMPACT OF THE STUDY: The food industry or drug delivery use of TiO2 NPs could enhance the growth of certain intracellular pathogens and potentially worsen disease symptoms, a feature that should be further investigated.

Impact of antiseptics on Chlamydia trachomatis growth.

UNLABELLED: Bacterial vaginosis is a frequent dysbiosis, where the normal lactobacillus-dominated flora is replaced by an anaerob/aerob polymicrobial flora. Bacterial vaginosis increases the risk of acquiring sexually transmitted infections (STI) including the most frequent Chlamydia trachomatis infections. Intravaginal antiseptics are part of the bacterial vaginosis treatment, and ideally they should also inhibit the bacterial vaginosis-related STI. Therefore, we tested the antichlamydial activity of four antiseptics: iodine aqueous solution, povidone-iodine, chlorhexidine and borax. First, we measured the impact of antiseptics on the viability of the HeLa cervical epithelial cells, and calculated the maximum nontoxic concentrations. Next, we infected the cells with C. trachomatis preincubated for 1 h with the particular antiseptic. The chlamydial growth was measured by direct quantitative PCR (qPCR) of the infected cells. The minimal inhibitory concentrations (MIC) of chlorhexidine and povidone-iodine were 3·91 and 97 µg ml(-1) respectively; however, the MIC of chlorhexidine was close to its maximum nontoxic concentration. The iodine aqueous solution and the borax showed no antichlamydial activity. Our in vitro studies showed that chlorhexidine and particularly povidone-iodine are potentially able to limit the bacterial vaginosis-related C. trachomatis infection. SIGNIFICANCE AND IMPACT OF THE STUDY: We measured the antichlamydial effects of various antiseptics. These antiseptics are being used for the treatment of bacterial vaginosis, but their effect on the bacterial vaginosis-related sexually transmitted infections, particularly the most frequent Chlamydia trachomatis (C. trachomatis) infections has not been investigated. We showed that povidone-iodine (Betadine) inhibited the chlamydial growth in concentrations that was not toxic to the epithelial cells. We concluded that due to its additional antichlamydial effect, povidone-iodine could be a preferable antiseptic in bacterial vaginosis treatment.

Inflammatory- and immune responses in relation to bacterial replication in mice following re-infections with Chlamydophila pneumoniae.

OBJECTIVE: Investigation of chronic infections with Chlamydophila pneumoniae. METHODS: BALB/c mice were repeatedly infected with C. pneumoniae and tested during a 1-year period. Production of histamine, IFN-gamma, IL-6 and antibodies was monitored by ELISA. Live bacteria were cultured and DNA was detected by PCR. Cellular immunity was tested by ELISPOT. RESULTS: After re-infections, culture positivity and persistence of DNA in lungs and blood were shorter. Detection of DNA at late time points indicated persistent infection in a few mice. Histamine was produced after primary and re-infections, and the level correlated with the number of viable bacteria in lung. IFN-gamma, IL-6 levels, IgG2/IgG1 ratio, IgA titres, and level of chlamydial heat-shock protein antibodies were higher after re-infections. IgM antibodies were demonstrated even after re-infections. High number of IFN-gamma-producing splenocytes was observed after the third inoculation. CONCLUSION: These results promote an understanding of the patho- and immune mechanisms after C. pneumoniae re-infections.

Chronic infections and histamine, CRP and IL-6 levels after percutaneous transluminal coronary angioplasty.

OBJECTIVE AND DESIGN: Our hypothesis was that percutaneous transluminal coronary angioplasty (PTCA) reactivates certain pathogens that contribute to inflammatory processes after the intervention. SUBJECTS: We determined the levels of antibodies to human Hsp60 and levels of histamine, CRP and IL-6 in sera from 28 patients of unstable angina prior to and on days 4 and 14 after PTCA. We compared the presence of Chlamydophila pneumoniae (Cpn) and human cytomegalovirus (HCMV) DNA in peripheral blood, and levels of antibodies to Cpn, HCMV, herpes simplex virus, Epstein-Barr virus and mycobacterial Hsp65 in the serum. RESULTS: Higher prevalence of Cpn and HCMV DNA was demonstrated after PTCA than before, but titers of antibodies to the pathogens did not increase. Levels of histamine, CRP and IL-6 were enhanced after PTCA. There was no association between the levels of histamine, CRP and IL-6 and the rate of pathogen DNA, or antibody titers to the pathogens, except an association between Cpn IgA and histamine levels before PTCA. CONCLUSIONS: Reactivation of Cpn and HCMV and inflammatory change characterized by increased levels of histamine, CRP and IL-6 following PTCA are suggested. An association might exist between Cpn IgA antibody and histamine levels in patients of unstable angina.

A soluble factor(s) released by MRC-5 cells early and late after human cytomegalovirus infection induces maturation of monocyte-derived dendritic cells.

A human cytomegalovirus (HCMV) strain passaged 10 times on MRC-5 human fibroblast cells failed to express immediate early (IE) antigens in immature dendritic cells (iDCs) after infection. However, both the early and the late HCMV conditioning medium, harvested from MRC-5 cells at 24 h or 7-9 days after infection, respectively, induced a higher ratio of DCs expressing maturation markers (CD40, CD83, CD86 and HLA-DR) on the surface of the cells. HCMV conditioning medium, ultracentrifuged to remove virus particles, exhibited a similarly enhanced expression of DC maturation markers. DCs treated with HCMV conditioning medium harvested late after infection increased the percentages of autologous CD4+ and CD8+ cells of seropositive donors to produce IFN-gamma and stimulated HCMV-specific lymphoproliferative responses. The early HCMC conditioning medium was also able to induce the functional maturation of DCs, as demonstrated by supplementing this medium with a Chlamydia pneumoniae antigen.

The interactions between human dendritic cells and microbes; possible clinical applications of dendritic cells.

The dendritic cells comprise several subsets that induce and regulate the immune responses against foreign and self-antigens, and that can therefore function as initiators of protective immunity and inducers of central or peripheral tolerance. The different subpopulations of dendritic cells interact with and also influence other cell populations of the immune system, such as T and B lymphocytes and natural killer cells. The factors that determine the given dendritic cell functions depend on the state of maturation and the local microenvironment. The interactions between dendritic cells and microorganisms are rather complex, but progress in the past few years has shed light on several aspects of these interactions. This review lays emphasis on the interactions between human dendritic cells, important components of the intima of arterial specimens at areas predisposed to atherosclerotic lesions, and Chlamydia pneumoniae and cytomegalovirus, the human pathogens most strongly implicated in the development of atherosclerosis. In addition, several examples of the potential clinical applications of dendritic cells are described.

Chlamydia pneumoniae exacerbates aortic inflammatory foci caused by murine cytomegalovirus infection in normocholesterolemic mice.

Inflammatory foci induced by murine cytomegalovirus infection in normocholesterolemic mice were present temporarily in the aortic wall, but some of these foci developed into advanced lesions that persisted late after infection. The early foci induced by virus infection were significantly exacerbated following a single inoculation with Chlamydia pneumoniae.

Chlamydia pneumoniae in atherosclerotic middle cerebral artery.

BACKGROUND AND PURPOSE: Atherosclerotic middle cerebral arteries are frequent sites of thrombosis, leading to stroke. Previous studies have suggested a role for Chlamydia pneumoniae in the pathogenesis of atherosclerosis. However, the presence of this pathogen in atherosclerotic middle cerebral arteries has heretofore not been documented. In the present study, we analyzed atheromatous plaques from middle cerebral arteries for the presence of C pneumoniae. METHODS: Atherosclerotic middle cerebral arteries from 15 cadavers who died of natural causes and corresponding nonatherosclerotic arteries from 4 otherwise healthy trauma victims were examined. Assays for C pneumoniae DNA were carried out by nested polymerase chain reaction (nPCR) specific for the C pneumoniae ompA gene. The presence of the bacterium was assessed by transmission electron microscopy. RESULTS: Five of the 15 atherosclerotic arterial samples and none of the control tissues were positive for C pneumoniae by nPCR. Particles similar in morphology and size to C pneumoniae elementary bodies were detected by transmission electron microscopy in 4 of the 5 nPCR-positive atherosclerotic samples. CONCLUSIONS: The demonstration of C pneumoniae in atherosclerotic middle cerebral arteries is consistent with the hypothesis that this bacterium is involved in acute and chronic cerebrovascular diseases.

Optimization of DNA immunization against human cytomegalovirus.

The immune responses of mice injected with plasmids VR-gB and VR-gB Delta tm expressing the full-length membrane-anchored, or secreted forms of human cytomegalovirus (HCMV)-glycoprotein B (gB), respectively, and VR-pp65 expressing the HCMV-phosphoprotein 65 (pp65) were analyzed. Pretreatment of mice with the local anesthetic bupivacaine did not enhance antibody production, and IFN-alpha co-expressed with the immunizing plasmids induced a moderate increase in the antibody response. However, antibody response was higher in mice inoculated at three sites in the musculus quadriceps than in mice inoculated at one site with the same dose and in the same muscle. pVR-gB Delta tm induced significantly higher antibody titers than the construct expressing the membrane-anchored form of gB, and priming with pVR-gB Delta tm followed by boosting with the gB subunit resulted in high-titer antibody responses. Immunization with VR-pp65 induced dose-dependent CTL responses in about 50% of the mice at a dose of 50 microg. Co-expression of IFN-alpha did not affect the number of responding mice. These findings might be important for optimization of humoral and cellular immune responses to HCMV after DNA vaccination.

Independent and joint effects of antibodies to human heat-shock protein 60 and Chlamydia pneumoniae infection in the development of coronary atherosclerosis.

BACKGROUND: Studies have suggested that the prevalence of antibodies against heat-shock proteins (HSPs), Chlamydia pneumoniae (CPN), and cytomegalovirus (CMV) is associated with coronary artery disease (CAD), but the independent or joint effects of human (h) HSP60 antibodies and these pathogens in patients have not been fully elucidated. METHODS AND RESULTS: A total of 405 subjects (276 patients with CAD and 129 control individuals) were tested for serum antibodies to hHSP60, CPN, and CMV immediate-early-1 (IE1) antigens. Patients were also assessed for serum cholesterol, triglyceride levels, and smoking habit. Significantly elevated levels of antibodies to hHSP60 and CPN but not to CMV-IE1 antigens were documented in CAD patients. Multiple logistic regression analysis and subanalyses of selected subjects showed that these associations were independent of age, sex, smoking, and serum lipid levels. Antibodies to hHSP60 and CPN did not correlate quantitatively; however, the relative risk of disease development was substantially increased in subjects with high antibody levels to both hHSP60 and CPN:, reaching an odds ratio of 82.0 (95% CI 10.6 to 625.0). CONCLUSIONS: High levels of antibodies to hHSP60 and CPN: are independent risk factors for coronary atherosclerosis, but their simultaneous presence substantially increases the risk for disease development.

Chronic infections and atherosclerosis.

The inability of traditional risk factors such as hypercholesterolemia, hypertension, and smoking to explain the incidence of atherosclerosis (AT) in about 50% of the cases prompted a search for additional putative risk factors involved in the development of the disease. Infectious agents have long been suspected to initiate/contribute to the process of AT. It has also been suggested that inflammation, either related to infectious agents or independent from infection, may mediate the atherogenic process [1, 2].

Cytotoxic T lymphocyte (CTL) responses to human cytomegalovirus pp65, IE1-Exon4, gB, pp150, and pp28 in healthy individuals: reevaluation of prevalence of IE1-specific CTLs.

The prevalence of human cytomegalovirus (HCMV) pp65-, pp150-, IE1-exon4-, gB- and pp28-specific cytotoxic T lymphocyte (CTL) responses was compared among 34 healthy individuals, grouped by neutralizing antibody titers. Moderately and highly seropositive donors showed predominantly pp65- and IE1-exon4-specific CTL responses (92% and 76% of the donors, respectively), with similar precursor frequencies in the 2 donors tested. In addition, highly seropositive and a few moderately seropositive donors showed CTL responses to gB and pp150 (33% and 30% of the donors, respectively). No individual recognized pp28 as a target in the CTL assay. Phenotypic analysis revealed a mixed effector population of CD4+ and CD8+ (1 donor) or only CD8+ cells for pp65-specific effectors (2 donors). IE1-exon4- and pp150-specific effectors were CD8+ (2 donors and 1 donor, respectively), whereas gB-specific CTLs were CD4+ (1 donor). These data may help to design a cellular immunity-based vaccine effective against HCMV diseases.

The Vienna Cochlear Implant in patients with obliteration of the cochlea.

Twelve deaf patients with obliterated or ossified cochleas received the extracochlear version of the Vienna Cochlear Implant. Four patients, 1 of them a child, developed open speech comprehension. Obliteration of the cochlea could not always be predicted by conventional tomography of the temporal bone. Short duration of deafness, wide dynamic range, and good ability of time resolution (small temporal difference limen [TDL]) are predictors for good postoperative results. Obliteration or ossification of the cochlea per se is no contraindication to cochlear implantation.

[Current status of electrostimulation of auditory nerve fibers with cochlear implants]. / Derzeitiger Stand der Elektrostimulation der Hörnervenfasern mit Cochlearimplantaten.

Under the observance of a few selection criteria electrostimulation of the cochlea nerve with cochlea implants is a suitable method to supply totally deafs with a hearing ability and in about the half of the patients even with speech understanding. The technology of the Vienna Cochlea Implant, selection criteria, surgical technique as well as the rehabilitation procedure and the results are discussed.

[Management of cochlear implants in children--methods and results]. / Cochlearimplantatversorgung bei Kindern--Methoden und Ergebnisse.

Selection criteria, basic principles of auditory training, development of an auditory test battery for children and results of 15 children between 4 and 14 years are presented and discussed. To summarize, results range from acoustic attention to tones and sounds and recognition of environmental sounds to the use of supra-segmental and segmental features of speech. Some children are able to recognize words and phrases from a closed list. One of the children has postlingual deafness and has had also a very short duration of deafness before implantation. This child shows better results than the pre and perilingually deaf children. Because of the fact that the patient group is small and there are also many intervening variables like age, duration of deafness and use of two different test instruments, it is difficult to find a relationship between the results and all other variables. The auditory test battery for children, which consists of seven subtests, measuring acoustic orientation and auditory speech perception on different linguistic levels, is much more suitable for the evaluation of auditory performance for this age group than the auditory test battery for adults (Eisenwort and Burian 1988).

[Evaluating speech perception of children with the cochlear implant: approaches to a new test procedure]. / Zur Evaluierung der Sprachperzeption bei Kindern mit Cochlearimplantat: Ansätze zu einem neuen Testverfahren.

The Auditory Test Battery for children, a test instrument for the German language, which measures acoustic orientation and speech perception on different linguistic levels, is described. Speech perception data for each subject, gathered from 8 implanted children, are presented.

First behind the ear-wearable speech processor for the Vienna cochlear prosthesis. A preliminary report.

A behind the ear-wearable speech processor for the Vienna cochlear prosthesis has been designed. In a comparative study 6 patients used the new device for 1 week and were then tested. The results from the auditory test battery and a speech tracking were about the same, only the perception of speech from an open list was better when the patients used the conventional processor. It is possible to reduce the size of a speech processor substantially by modifying the speech-processing strategy without major decrease of the performance. More patients have to be tested after using the device for a longer time.

[The cochlear implant and its psychosocial effects in 36 patients]. / Das Cochlearimplantat und seine psychosozialen Auswirkungen bei 36 Patienten.

In a study on 36 cochlear implant patients questionnaires answered pre- and postsurgically were analyzed. One year after implantation patients demonstrated significant changes on some of the test items. Although results show that the patients accept their device, some of their wishes and hopes remain unsatisfied.