Cyclosporin A-mediated killing of <Emphasis Type="Italic">Leishmania major</Emphasis> by macrophages is independent of reactive nitrogen and endogenous TNF-α and is not inhibited by IL-10 and 13

Murine macrophages were treated with various doses of cyclosporin A (CsA) to enhance the killing of Leishmania major parasites. CsA reduced the rate of infected cells from 75% in non-treated controls to less than 15% with 1 micro g CsA/ml in a dose-dependent manner. The leishmanicidal effect was also observed when CsA was added 48 h after the infection of macrophages. In contrast, FK506, another structural non-related immunosuppressive drug with antiparasitic activities, showed no effect on the ability of macrophages to kill intracellular Leishmania parasites. Since nitric oxide has been identified as a key molecule for the leishmanicidal function of macrophages, we analyzed the role of this molecule. There was no influence on the leishmanicidal effect of CsA when L- N-(1-iminoethyl)lysine, a potent and selective inhibitor of mouse inducible nitric oxide synthase, was added. Furthermore, the presence of the macrophage-inhibiting cytokines interleukin (IL)-10 and IL-13 simultaneously or prior to CsA did not inhibit leishmania killing, while both cytokines completely prevented parasite killing by macrophages activated with gamma interferon and tumor necrosis factor (TNF). CsA was fully active on macrophages from TNF-receptor p55 knockout mice arguing against autocrine activation by TNF. We therefore conclude that the antileishmanial effect of CsA is independent of effector mechanisms employed by macrophage-activating cytokines.     

Characterisation of non-multiresistant methicillin-resistant Staphylococcus aureus (including EMRSA-15) in Kuwait Hospitals

This study characterised non-multiresistant methicillin-resistant Staphylococcus aureus (nmMRSA) isolates from Kuwait hospitals to ascertain whether they were community-acquired MRSA (CA-MRSA). Forty-two nmMRSA isolates obtained between July 2001 and October 2003 were analysed by staphylococcal cassette chromosome mec (SCCmec) typing, bacteriophage typing, production of Panton-Valentine leukocidin (PVL), urease and staphylococcal enterotoxins A, B, C and D, TSST-1, and by pulsed-field gel electrophoresis (PFGE). Forty-one isolates were SCCmec type IV, and one isolate was SCCmec type III. The isolates belonged to six PFGE patterns, with two types, A and D, distributed in six and four hospitals, respectively. Most (n = 26; 61.9%) isolates produced urease. These isolates were mainly from wound and skin infections, showed low-level methicillin resistance (MIC 8-48 mg/L), and nine carried genes for PVL. These characteristics, together with their carriage of the type-IV SCCmec, identified the isolates as CA-MRSA. Ten of the 16 urease-negative isolates produced staphylococal enterotoxin C; 12 reacted weakly with phage 75, and were resistant to clindamycin and/or erythromycin, which are characteristics of EMRSA-15. Thus, this study identified the co-existence of two types of nmMRSA, i.e., CA-MRSA and EMRSA-15, in Kuwait hospitals.     

Effects of glycine and GABA,and blocking actions of strychnine and picrotoxin in the hypoglossus nucleus

Summary Neutral ω-amino acids were applied iontophoretically in the hypoglossus nucleus. Intracellular recordings revealed inhibitory actions involving hyperpolarization and conductance increase of the membrane. The antidromic field potential was reduced most effectively by glycine, as judged by the comparison of iontophoretic currents. Picrotoxin, ejected electrophoretically, clearly interfered with the action of GABA, glycine effects being reduced only with rather high currents. Strychnine had very specific blocking ability against glycine actions. Supported by the Deutsche Forschungsgemeinschaft (Br 242/7).     

Convergence in the Reciprocal la Inhibitory Pathway of Excitation from Descending Pathways and Inhibition from Motor Axon Collaterals

With intracellular recording from motoneurones and utilizing the technique of spatial facilitation it has been investigated if those la inhibitory interneurones which receive excitation from supraspinal centres also can be inhibited from recurrent motor axon collaterals. For each motoneurone the stimulation strengths were chosen so that separate stimulation of either the supraspinal system or la afferents did not evoke any 1PSP while a combined stimulation at suitable intervals gave a large IPSP. When preceded by stimulation of ventral roots this test IPSP was abolished or decreased. This was found in about 100 motoneurones belonging to different hindlimb muscles in which an IPSP appeared after facilitation from vestibulo-, rubro-or cortico-spinal tracts. It is thus concluded that a convergence of supraspinal excitation and recurrent inhibition occurs on the same la inhibitory interneurones.     

Identification of a Thymidylate Synthase Gene within the Genome of Chilo Iridescent Virus

The thymidylate synthase (TS, EC 2.1.1.45) is essential for the de novo synthesis of dTMP in pro- and eucaryotic organisms. Consequently it plays a major role in the replication of the DNA genome of a cell or a DNA virus. The gene encoding the TS of Chilo iridescent virus (CIV) was identified by nucleotide sequence analysis of the viral genome and was mapped within the EcoRI CIV DNA fragments G and R. Computer assisted analysis of the DNA nucleotide sequence between the genome coordinates 0.482 and 0.489 revealed an open reading frame (ORF) of 885 nucleotides. This ORF was found to encode a polypeptide of 295 amino acid residues (33.9 kDa) that showed significant homologies to known TS of different species including mammals, plants, fungi, protozoa, bacteria, and DNA viruses. The highest amino acid homologies were found between the CIV-TS and the TS of herpesvirus ateles (54.0%), Saccharomyces cerevisiae (51.8%), herpesvirus saimiri (51.0%), rhesus monkey rhadinovirus (50.7%), mouse (50.5%), rat (50.2%), varicella-zoster virus (50.2%), equine herpesvirus 2 (50.0%), and the human TS (48.4%). The CIV-TS contains six amino acid domains that are highly conserved in the TS of other species. Within these domains the major amino acid residues are present for which a functional role has been reported. The CIV-TS was found to be more closely related to the TS of eucaryotes than to the TS of procaryotes indicating the phylogenetic origin of the CIV-TS gene. The identification of a TS gene in the genome of CIV is the first report of a viral TS that is not encoded by a herpesvirus or a bacteriophage.     

A novel 5q35.3 subtelomeric deletion syndrome

We observed a novel 3.5 Mb 5q subtelomeric deletion in a 3-year-old girl with developmental delay, hypotonia and multiple minor anomalies. Comparison of her phenotype with the few published patients with terminal 5q35 deletions revealed several overlapping features, but also showed remarkable differences such as shortness of stature versus macrosomia. After the report of 5q35.3 microdeletions in Sotos syndrome we integrated the published BACs into the public draft sequence and exactly mapped the deletion size in our patient by FISH analysis with 15 BAC probes. We demonstrated that the deletion in our patient is immediately adjacent to the reported Sotos syndrome deletion site. Subtracting the symptoms of Sotos syndrome from the published patients with larger 5q35.3 deletions allowed us to delineate a distinct phenotype of prenatal lymphedema with increased nuchal translucency, pronounced muscular hypotonia and delay of reaching motor milestones, but speech development within normal limits, wide fontanels, failure to thrive with postnatal short stature, and multiple minor anomalies such as mildly bell-shaped chest, minor congenital heart disease, and a distinct facial gestalt, associated with the novel 3.5 Mb cryptic deletion. We further showed in our patient that the deletion of the LCT(4) synthase gene results in a reduction of cysteinyl leukotriene synthesis to about 65% compared to normal values. The prenatal nuchal lymphedema associated with this deletion syndrome my be related to the deletion of the FLT4 gene causing autosomal dominant primary lymphedema and contributes to the differential diagnosis of increased fetal nuchal translucency.     

PCR assays for identification of Coccidioides posadasii based on the nucleotide sequence of the antigen 2/proline-rich antigen

A conventional nested PCR and a real-time LightCycler PCR assay for detection of Coccidioides posadasii DNA were designed and tested in 120 clinical strains. These had been isolated from 114 patients within 10 years in Monterrey, Nuevo Leon, Mexico, known to be endemic for coccidioidomycosis. The gene encoding the specific antigen 2/proline-rich antigen (Ag2/PRA) was used as a target. All strains were correctly identified, whereas DNA from related members of the family Onygenaceae remained negative. Melting curve analysis by LightCycler and sequencing of the 526-bp product of the first PCR demonstrated either 100% identity to the GenBank sequence of the Silveira strain, now known to be C. posadasii (accession number AF013256), or a single silent mutation at position 1228. Length determination of two microsatellite-containing loci (GAC and 621) identified all 120 isolates as C. posadasii. Specific DNA was amplified by conventional nested PCR from three microscopically spherule-positive paraffin-embedded tissue samples, whereas 20 human tissue samples positive for other dimorphic fungi remained negative. Additionally, the safety of each step of a modified commercially available DNA extraction procedure was evaluated by using 10 strains. At least three steps of the protocol were demonstrated to sufficiently kill arthroconidia. This safe procedure is applicable to cultures and to clinical specimens.     

Direct detection and differentiation of Legionella spp. and Legionella pneumophila in clinical specimens by dual-color real-time PCR and melting curve analysis

A dual-color LightCycler PCR assay targeting the 16S rDNA gene of Legionella spp. was established. By using two pairs of hybridization probes, Legionella spp. and Legionella pneumophila could be detected and differentiated simultaneously. With 26 culture-positive and 42 culture-negative respiratory specimens from patients with atypical pneumonia, 100% sensitivity and specificity was observed for L. pneumophila.     

Characterization of Mycobacterium tuberculosis complex DNAs from Egyptian mummies by spoligotyping

Bone and soft tissue samples from 85 ancient Egyptian mummies were analyzed for the presence of ancient Mycobacterium tuberculosis complex DNA (aDNA) and further characterized by spoligotyping. The specimens were obtained from individuals from different tomb complexes in Thebes West, Upper Egypt, which were used for upper social class burials between the Middle Kingdom (since ca. 2050 BC) and the Late Period (until ca. 500 BC). A total of 25 samples provided a specific positive signal for the amplification of a 123-bp fragment of the repetitive element IS6110, indicating the presence of M. tuberculosis DNA. Further PCR-based tests for the identification of subspecies failed due to lack of specific amplification products in the historic tissue samples. Of these 25 positive specimens, 12 could be successfully characterized by spoligotyping. The spoligotyping signatures were compared to those in an international database. They all show either an M. tuberculosis or an M. africanum pattern, but none revealed an M. bovis-specific pattern. The results from a Middle Kingdom tomb (used exclusively between ca. 2050 and 1650 BC) suggest that these samples bear an M. africanum-type specific spoligotyping signature. The samples from later periods provided patterns typical for M. tuberculosis. This study clearly demonstrates that spoligotyping can be applied to historic tissue samples. In addition, our results do not support the theory that M. tuberculosis originated from the M. bovis type but, rather, suggest that human M. tuberculosis may have originated from a precursor complex probably related to M. africanum.