Performance of CHROMagar MRSA medium for detection of methicillin-resistant Staphylococcus aureus

CHROMagar MRSA was evaluated for its ability to identify methicillin-resistant Staphylococcus aureus (MRSA). A well-defined collection consisting of 216 MRSA strains and 241 methicillin-susceptible Staphylococcus aureus isolates was used. The sensitivity of CHROMagar MRSA after 24 h of incubation was 95.4%, increasing to 100% after 48 h. The specificity was already 100% after 24 h.     

Regulation of gelatinase B in human monocytic and endothelial cells by PECAM-1 ligation and its modulation by interferon-beta.

Platelet endothelial cell adhesion molecule-1 (PECAM-1 or CD31) and gelatinase B are coexpressed at sites of inflammation, where an intense interaction occurs between leukocytes and endothelial cells. To investigate whether a functional link exists between PECAM-1 activation and gelatinase B production, the regulatory role of PECAM-1, IFN-gamma, IFN-beta, LPS, and PMA on the production of gelatinase B (MMP-9) was studied in vitro in normal human umbilical vein endothelial cells (HUVECs), human peripheral blood mononuclear cells (PBMCs), and in a human monocytic leukemia cell line. In THP-1 cells, progelatinase B levels were slightly up-regulated by immobilized PECAM-1-specific monoclonal antibody (mAb) and soluble recombinant PECAM-1 when compared with strong induction by LPS and PMA. IFN-beta inhibited the induced and basal gelatinase B production but had no modulating effect on the expression of PECAM-1. HUVECs mainly produced progelatinase A (proMMP-2). Treatment with LPS and triggering of the endothelial cells with PECAM-1 mAb or recombinant PECAM-1 had no effect on gelatinase A or B production, whereas PMA stimulated the production of progelatinase B. IFN-beta significantly up-regulated the expression of PECAM-1 in HUVECs but did not affect gelatinase secretion. Finally, in PBMCs, progelatinase B production was increased by soluble PECAM-1 mAb, recombinant PECAM-1, LPS, and PMA, whereas IFN-beta reduced gelatinase B secretion. IFN-beta did not alter PECAM-1 expression on PBMCs. Thus, PECAM-1 and gelatinase B are differently regulated in leukocytes and endothelial cells.     

Sedation in palliative care - a critical analysis of 7 years experience

BACKGROUND: The administration of sedatives in terminally ill patients becomes an increasingly feasible medical option in end-of-life care. However, sedation for intractable distress has raised considerable medical and ethical concerns. In our study we provide a critical analysis of seven years experience with the application of sedation in the final phase of life in our palliative care unit. METHODS: Medical records of 548 patients, who died in the Palliative Care Unit of GK Havelhoehe between 1995-2002, were retrospectively analysed with regard to sedation in the last 48 hrs of life. The parameters of investigation included indication, choice and kind of sedation, prevalence of intolerable symptoms, patients' requests for sedation, state of consciousness and communication abilities during sedation. Critical evaluation included a comparison of the period between 1995-1999 and 2000-2002. RESULTS: 14.6% (n = 80) of the patients in palliative care had sedation given by the intravenous route in the last 48 hrs of their life according to internal guidelines. The annual frequency to apply sedation increased continuously from 7% in 1995 to 19% in 2002. Main indications shifted from refractory control of physical symptoms (dyspnoea, gastrointestinal, pain, bleeding and agitated delirium) to more psychological distress (panic-stricken fear, severe depression, refractory insomnia and other forms of affective decompensation). Patients' and relatives' requests for sedation in the final phase were significantly more frequent during the period 2000-2002. CONCLUSION: Sedation in the terminal or final phase of life plays an increasing role in the management of intractable physical and psychological distress. Ethical concerns are raised by patients' requests and needs on the one hand, and the physicians' self-understanding on the other hand. Hence, ethically acceptable criteria and guidelines for the decision making are needed with special regard to the nature of refractory and intolerable symptoms, patients' informed consent and personal needs, the goals and aims of medical sedation in end-of-life care.     

Modulation of CD8 and CD3 by HIV or HIV antigens

To investigate whether human immunodeficiency virus (HIV)-1 and HIV-1 antigens modulate surface and cytoplasmic CD8 or CD3, as well as CD4, we used cell permeabilization reagents, surface/cytoplasmic fluorescent staining, multiparameter flow cytometric techniques and an in vitro culture system in which relatively few lymphocytes are actively infected with HIV. Human peripheral blood lymphocytes were: not stimulated, not stimulated but HIV-inoculated, phytohaemagglutinin (PHA)-stimulated, PHA/HIV-inoculated (PHA/HIV), or placed into media with soluble gp120, Rev or Nef. HIV inoculation and Nef had striking modulatory effects on CD8. The cytoplasmic CD8 median fluorescent intensity (MFI) of positive lymphocytes was lower for cells in unstimulated/HIV-infected cultures than unstimulated cultures (44 versus 62% of ex vivo value, P = 0.032) and lower for cells in PHA/HIV cultures than in PHA cultures (56 versus 100% of ex vivo, P = 0.041). The surface CD8 MFI values for Nef were significantly lower than the ex vivo value (75% of ex vivo, P = 0.006). At days 2-7 of culture, Rev was associated with slight reductions in surface CD4 MFI (58% of ex vivo versus 78% of ex vivo for unstimulated cultures, P = 0.047) and greater effects on cytoplasmic CD3 MFI (131 versus 179% of ex vivo for unstimulated cultures, P = 0.035), and surface CD8 MFI (70% of ex vivo, P = 0.006 versus ex vivo value). The globality of Rev's effects suggests these are related to a shared processing pathway, i.e. not due to direct interaction with CD3, CD4 and CD8; the effects of HIV inoculation and Nef on CD8 expression appear to be more CD8 specific. Because CD8 is essential for cytotoxic T-cell function, its down-modulation could inhibit this activity, including anti-HIV cytotoxicity. Given the critical roles of CD3 and CD8 in T-lymphocyte signal transduction and antigen responsiveness, the effects of HIV, Rev and Nef on these molecules have clinically significant implications concerning the pathogenesis and treatment of HIV.     

Expression of inducible nitric oxide synthase in skin lesions of patients with american cutaneous leishmaniasis

Cytokine-inducible (or type 2) nitric oxide synthase (iNOS) is indispensable for the resolution of Leishmania major or Leishmania donovani infections in mice. In contrast, little is known about the expression and function of iNOS in human leishmaniasis. Here, we show by immunohistological analysis of skin biopsies from Mexican patients with local (LCL) or diffuse (DCL) cutaneous leishmaniasis that the expression of iNOS was most prominent in LCL lesions with small numbers of parasites whereas lesions with a high parasite burden (LCL or DCL) contained considerably fewer iNOS-positive cells. This is the first study to suggest an antileishmanial function of iNOS in human Leishmania infections in vivo.     

Micronuclei containing whole chromosomes harbouring the selectable gene do not lead to mutagenesis

Loss of heterozygosity is one genetic change observed in manytumours. We do not know whether the loss of chromosomal materialthrough micronucleus formation is a viable mechanism associatedwith, and possibly leading to, genetic disease. Previously,we treated L5178Y mouse lymphoma cells with four aneugens. Althoughthese aneugens induced micronuclei containing predominantlywhole chromosomes, they did not induce mutations at Tk1, theselectable gene, under the same non-toxic conditions in whichthey induced micronuclei. This suggested that the inductionof micronuclei containing whole chromosomes was not an earlyevent leading to phenotypically expressed mutations in thesecells under the conditions used. However, it is possible thatchromosome 11, on which Tk1 resides, may be under-representedin the micronucleus population. To find out the frequency ofinduction of micronuclei containing chromosome 11, we appliedfluorescence in situ hybridization using a chromosome 11 paintto micronuclei induced by colcemid and vinblastine. We foundthat the numbers of micronuclei containing chromosome 11 aremore than sufficient to be detectable as mutations if thesemicronuclei lead to viable mutants. We conclude that the formationof micronuclei containing whole chromosomes does not lead toviable, dividing mutants in this system. ⁵To whom correspondence should be addressed     

Stage-specific protein synthesis by asexual blood stage parasites of Plasmodium falciparum

Highly synchronised cultures of cloned Plasmodium falciparum (clone T9-94) were metabolically radiolabelled with [35S]methionine during eight consecutive non-overlapping intervals, while parasites developed from young rings to mature schizonts. Analysis of equal amounts of trichloroacetic acid precipitable radioactivity from each interval by sodium dodecyl sulphate-polyacrylamide gel electrophoresis fluorography allowed the stage specificity of protein synthesis to be investigated. More than forty polypeptides with molecular weights of 20 000 to 200 000 can be distinguished. While some proteins are synthesised throughout erythrocytic schizogony many are shown to be stage-specific. Among these are a range of high molecular weight proteins synthesised only during nuclear division. Detailed morphological information permits correlations to be made between synthesis of particular polypeptides and parasite structure.