A mouse model of persistent brain infection with recombinant Measles virus

Measles virus (MV) nucleocapsids are present abundantly in brain cells of patients with subacute sclerosing panencephalitis (SSPE). This invariably lethal brain disease develops years after acute measles as result of a persistent MV infection. Various rodent models for MV infection of the central nervous system (CNS) have been described in the past, in which the detection of viral antigens is based on histological staining procedures of paraffin embedded brains. Here, the usage of a recombinant MV (MV-EGFP-CAMH) expressing the haemagglutinin (H) of the rodent-adapted MV-strain CAM/RB and the enhanced green fluorescent protein (EGFP) is described. In newborn rodents the virus infects neurons and causes an acute lethal encephalitis. From 2 weeks on, when the immune system of the genetically unmodified animal is maturating, intracerebral (i.c.) infection is overcome subclinically, however, a focal persistent infection in groups of neurons remains. The complete brain can be analysed in 50 or 100 microm slices, and infected autofluorescent cells are readily detected. Seven and 28 days post-infection (p.i.) 86 and 81% of mice are infected, respectively, and virus persists for more than 50 days p.i. Intraperitoneal immunization with MV 1 week before infection, but not after infection, protects and prevents persistence. The high percentage of persistence demonstrates that this is a reliable and useful model of a persistent CNS infection in fully immunocompetent mice, which allows the investigation of determinants of the immune system.

Einheimische Helminthosen

Worldwide an estimated 1.5-2 billion people are infested with helminths. Over the last decades, in industrialized countries prevalence rates of human helminthic infections were decreased by means of wastewater and food control. In this article, we review the geographic distributions as well as the impact on the public health system of the most prevalent helminthiases. Special emphasis is given to Echinococcus, Enterobiasis, and Toxocariasis. Intestinal larvae or eggs of helminths can be detected in faeces. Pinworms are collected with a strip of cellophane tape with the sticky side towards the anus. Tissue helminthosis, like Toxocariasis or Trichinosis are associated with eosinophilia and can be diagnosed with sensitive immunological methods or by biopsy. Infection with Echinococcus multilocularis is the most serious parasitic disease in central Europe. Although current therapeutic options are limited, 5 year survival rates were markedly improved by the combination of medical and surgical treatment.

[Tropical and subtropical helminthoses]

Human helminthic infestations are extraordinarily common in tropical regions and represent a significant burden for those countries and their populations. The risk of intestinal helminthoses is further increased by poverty. Particularly in children helminthoses lead to malnutrition (ascariasis etc) or iron and protein deficiency (ancylostomiasis). Tropical helminthoses like schistosomiasis and filariasis can cause severe organ damage, starvation, and early death. In contrast, returning travellers very rarely acquire tropical helminthoses, if they follow simple hygienic rules. Furthermore, the worm burden in returning travelers hardly ever is high enough to cause severe illness. Therefore, tropical helminthosis is more common in immigrants from endemic areas compared to returning travelers.

CD9-dependent regulation of Canine distemper virus-induced cell-cell fusion segregates with the extracellular domain of the haemagglutinin

Antibodies to CD9, a member of the tetraspan transmembrane-protein family, selectively inhibit Canine distemper virus (CDV)-induced cell-cell fusion. Neither CDV-induced virus-cell fusion nor cell-cell fusion induced by the closely related morbillivirus Measles virus (MV) is affected by anti-CD9 antibodies. As CDV does not bind CD9, an unknown, indirect mechanism is responsible for the observed inhibition of cell-cell fusion. It was investigated whether this effect was restricted to only one viral glycoprotein, either the haemagglutinin (H) or the fusion (F) protein, which form a fusion complex on the surface of virions and infected cells, or whether it is dependent on both in transient co-transfection assays. The susceptibility to CD9 antibodies segregates with the H protein of CDV. By exchanging portions of the H proteins of CDV and MV, it was determined that the complete extracellular domain, including the predicted stem structure (stem 1, barrel strand 1 and stem 2) and globular head domain, of the CDV-H protein mediates the effect. This suggests that interaction of the CDV-H protein with an unknown cellular receptor(s) is regulated by CD9, rather than F protein-mediated membrane fusion.

Antibacterial essential oils in malodorous cancer patients: clinical observations in 30 patients

Malodorous necrotic ulcers in cancer patients are of major concern as it leads to social isolation and poor quality of life. Current medications and topical therapies have proven inadequate in their ability to reduce foul smell to acceptable levels. We report the positive experience we have had in using antibacterial essential oils in patients with incurable head and neck cancer and associated malodorous necrotic ulcers. All patients received a standard course of therapy with oral or systemic antibiosis. In addition, we rinsed the ulcers with an antibacterial essential oil mix (mainly based on Eucalyptus oil) twice a day. All patients experienced complete resolution of the foul smell by only the third or fourth day of therapy. As a secondary effect we saw that besides smell reduction the oils had anti-inflammatory effects on neoplastic ulcers. In some patients ulcers started to heal and achieved complete re-epithiliazation. The patients experienced great personal relief upon resolution of their malodorous conditions. Quality of life improved significantly with the resulting reintroduction of social contact with friends and relatives.

Effect of pH on the in vitro activity of and propensity for emergence of resistance to fluoroquinolones, macrolides, and a ketolide

Antibiotic activity against common respiratory pathogens can be affected by the pH of the medium (in vitro) or the bodily fluid (in vivo) in which bacteria are present. The ionized fraction of an antibiotic is not able to efficiently penetrate bacterial or mammalian membranes, reducing the quantity of molecules able to exert their antibacterial effect resulting in elevated MIC values This study shows that the activity of macrolide antibiotics is particularly sensitive to acidic conditions, whereas a ketolide and fluoroquinolones are much less affected. Furthermore, induction of spontaneous and multistep macrolide resistance is greatly increased in acidic medium. In contrast, telithromycin and moxifloxacin did not induce resistance at any pH. Antibiotics which are less likely to induce resistance in vitro may also be less likely to induce the development of resistance in patients with respiratory tract infections.

Pharmacodynamics of moxifloxacin and levofloxacin simulating human serum and lung concentrations

Fluoroquinolones are known to penetrate well into the infectious foci such as lung mucosa, epithelial lining fluid and alveolar macrophages achieving higher target site concentrations than the corresponding serum levels. In order to integrate the in vitro antibacterial activity and pharmacokinetics of moxifloxacin and levofloxacin, their bactericidal efficacy was assessed by simulating human serum and lung tissue concentrations using Streptococcus pneumoniae, Staphylococcus aureus and Klebsiella pneumoniae as indicator organisms. The bacteria were exposed to fluctuating moxifloxacin and levofloxacin concentrations simulating the drug levels in serum, lung mucosa, epithelial lining fluid and alveolar macrophages. The following parameters were deduced from the kill curves: area under the bactericidal kill curve normalized to the initial inoculum (AUBKC norm), the time needed to reduce the inoculum by 3 log(10) titers, and the initial bactericidal activity. In general, all these three parameters were for all the bacterial isolates having been exposed to moxifloxacin concentration dependent. In contrast, beyond a levofloxacin concentration of optimal bactericidal effect, higher drug concentrations did not further augment the bactericidal activity of levofloxacin. These data demonstrate that not all fluoroquinolones share the same pharmacodynamic targets needed to maximize their antibacterial effect.

Advantages of C2 Monitoring to Avoid Acute Rejection in Pediatric Heart Transplant Recipients

BACKGROUND

Inadequate cyclosporine (CsA) blood levels are a major risk factor for acute rejection in transplant recipients. The CsA trough level (C0 level) measured just before the next dose is commonly used to adjust the oral dosage. However, the 2-hour post-CsA dose concentration (C2 level) is favored as the best single-point correlate of CsA area-under-the-curve concentration and may better reflect the immunosuppressive effect of CsA. Because an adequate C2 level has not yet been defined, this study was performed to assess the value of C2 monitoring for the prevention of acute rejection and to define target levels in pediatric heart transplant recipients.

METHODS

C2 levels were assessed in 50 pediatric heart transplant patients with oral CsA therapy and compared with trough C0 levels using full blood sampling, mass spectrometry and a blinded analysis. Acute graft rejection was detected using intramyocardial electrocardiogram (IMEG) and serial conventional and tissue Doppler echocardiography (TDE). Rejection was confirmed or excluded by endomyocardial biopsy.

RESULTS

C2 and not C0 levels were significantly reduced in patients with acute graft rejection (ISHLT Grade > or =2). Patients with a C2 level <600 ng/ml had a significantly higher risk of developing acute rejection (100% sensitivity and 82% specificity). Patients with impaired CsA absorption were identified with C2 monitoring and switched to another calcineurin inhibitor.

CONCLUSIONS

Monitoring of the C2 rather than the C0 level better reflects immunosuppressive efficiency and identifies patients at increased risk of acute rejection. A C2 level of >600 ng/ml should be the target to prevent acute rejection.

Central diabetes insipidus in a patient with malaria tropica

Up to 21% of severe cases of malaria tropica are associated with polyuria and are life-threatening. We describe a 39-yr-old man with malaria tropica who developed disseminated intravascular coagulation, polyuria, and a pituitary lesion. Empiric treatment with vasopressin improved the polyuria. This is the first case of malaria tropica in which central diabetes insipidus has been documented.

Self–fabricated fenestrated Amplatzer occluders for transcatheter closure of atrial septal defect in patients with left ventricular restriction: midterm results

To avoid left ventricular failure after transcatheter closure of atrial septal defects in elderly patients with restrictive left ventricular physiology, partial occlusion by fenestrated devices may be an option. If complete defect closure is not possible in these patients, significant reduction of left to right shunting usually results in clinical benefit. We report two patients in whom deterioration of left ventricular function could be avoided by implantation of self-fabricated fenestrated Amplatzer Septal Occluders (ASO) in patients with ongoing restrictive left ventricular physiology. We describe technical preparation of the standard occluder, the specific implantation technique, and the initial and the intermediate term results up to 24 months.

Kinetics and Quantification of Antibacterial Effects of Beta-Lactams, Macrolides, and Quinolones against Gram-Positive and Gram-Negative RTI Pathogens

Traditionally, the in vitro activity of antibacterial agents is characterized by their minimal inhibitory concentrations. However, these endpoints are, by nature, discrete and do not provide information on time-dependent killing of the bacteria during the incubation period. Nevertheless, the pharmacodynamic characteristics of antibacterial agents are almost always defined by correlating a static endpoint describing the antibacterial activity of an agent with the pharmacokinetics, describing the time-dependent fluctuation of drug concentrations. This approach is basically a contradiction in itself. Therefore, it would be more logical to correlate pharmacokinetics to in vitro parameters describing the time- and concentration-dependent antibacterial action of an agent. Thus, experimental methods and mathematical models quantifying the decrease in growth rate of a bacterial population due to the action of an antibacterial agent as a function of time and drug concentration have been applied to quantitate their pharmacodynamics. The effect of nine antibacterial agents representing drug classes of penicillins, cephalosporins, penems, macrolides, and fluoroquinolones were mathematically analyzed by using three different but related models. The kill rate, maximal kill, the 50%-effective concentration (EC50), the Hill coefficient, and concentrations and times needed to obtain a 1,000-fold decrease of the initial number of viable counts were calculated. Both the phenotypic description of the time-kill curves and these five parameters mirror the bacteriostatic or bactericidal activity of all nine agents studied as a function of time and concentration. Therefore, it would be more logical to correlate a parameter quantifying the kinetics of antibacterial in vitro activity with the pharmacokinetics of the drug, thus, replacing static endpoints like minimal inhibitory concentrations.