Detection and identification of putative bacterial endosymbionts and endogenous viruses in tick cell lines

As well as being vectors of many viral, bacterial, and protozoan pathogens of medical and veterinary importance, ticks harbour a variety of microorganisms which are not known to be pathogenic for vertebrate hosts. Continuous cell lines established from ixodid and argasid ticks could be infected with such endosymbiotic bacteria and endogenous viruses, but to date very few cell lines have been examined for their presence. DNA and RNA extracted from over 50 tick cell lines deposited in the Roslin Wellcome Trust Tick Cell Biobank (http://tickcells.roslin.ac.uk) were screened for presence of bacteria and RNA viruses, respectively. Sequencing of PCR products amplified using pan-16S rRNA primers revealed the presence of DNA sequences from bacterial endosymbionts in several cell lines derived from Amblyomma and Dermacentor spp. ticks. Identification to species level was attempted using Rickettsia- and Francisella-specific primers. Pan-Nairovirus primers amplified PCR products of uncertain specificity in cell lines derived from Rhipicephalus, Hyalomma, Ixodes, Carios, and Ornithodoros spp. ticks. Further characterisation attempted with primers specific for Crimean-Congo haemorrhagic fever virus segments confirmed the absence of this arbovirus in the cells. A set of pan-Flavivirus primers did not detect endogenous viruses in any of the cell lines. Transmission electron microscopy revealed the presence of endogenous reovirus-like viruses in many of the cell lines; only 4 of these lines gave positive results with primers specific for the tick Orbivirus St Croix River virus, indicating that there may be additional, as yet undescribed ‘tick-only’ viruses inhabiting tick cell lines.     

Candida arthritis in an immunocompetent patient without predisposing factors

Candida arthritis is infrequent in patients who are not intravenous drug users. We describe a patient who was not an intravenous drug user and without other predisposing factors who developed knee arthritis caused byCandida albicans. We believe that this is the first report of such a case.     

Inotropic and Chronotropic Effects of 4-(4′-n-Butylaniline)-7,8-dimethoxy-5H-pyrimido[5,4–b]indole in Guinea-pig Atria

Cardiotonic effect of 4-(4′-n-butylaniline)-7,8-dimethoxy-5H-pyrimido[5,4-b)]indole (B₁₁) was investigated in isolated cardiac tissue preparations. The action of this agent on force of contraction, beating frequency and cyclic nucleotide phosphodiesterase (PDE) activity was studied. Amrinone was used for comparison. B₁₁ produced concentration-dependent (5 × 10^?6-1 × 10^?4m) positive inotropic and positive chronotropic responses in guinea-pig atrial tissues. The potency of B₁₁ was greater than that of amrinone. The cardiotonic effects of B₁₁ were not modified by β-adrenoceptor blockade. Carbachol inhibited the positive inotropic effect of B₁₁. The activity of B₁₁ was increased in desensitized left atrial tissues. B₁₁ inhibited the activities of PDE isoenzymes (type I, II, IV and V) from dog heart ventricle and PDE type IV from guinea-pig heart ventricle nonselectively. It is concluded that B₁₁ possesses potent positive inotropic activity in guinea-pig atria, and the effect is probably mediated by a non-selective inhibition of PDE activity.     

Air pollution and mortality in Madrid, Spain: a time-series analysis

To assess the relationship, if any, between air pollutant (sulfur dioxide and total suspended particulate) levels and mortality in the city of Madrid during the period 1986–1992, controlling for weather, season, and influenza epidemics. Methods: Daily death counts were obtained from the Regional Mortality Registry. Pollution data were supplied by the Municipal Monitoring Network. Time-series analysis methodology was used to assess the link between non-accidental as well as circulatory- and respiratory-disease mortality, on the one hand, and mean daily concentrations of SO₂ and total suspended particulate (TSP), on the other. Multivariate autoregressive integrated moving-average (ARIMA) models were used to adjust for season, temperature, relative humidity, and influenza. A␣sensitivity analysis was run to assess the robustness of the estimators. Results: Graphical analysis revealed a linear relationship between mortality and TSP. The relationship was logarithmic in the case of SO₂. TSP lagged 1 day and SO₂ lagged 3 days with an independent effect on mortality. This relationship was produced without the detection of a minimal threshold in emission values. Conclusions: These results support the hypothesis of an association between pollution levels and mortality between 1986–1992 in Madrid. Additional measures designed to reduce pollution levels without compromising thermal comfort should be implemented. Received: 28 January 1998 / Accepted: 6 July 1998     

Surgical experience with arteriovenous malformations in children

The authors report their surgical experience with 15 cases of arteriovenous malformations in children operated on in the last decade. Subarachnoid hemorrhage was the main clinical manifestation in 12 patients. Epilepsy was a secondary feature in 3 of these. Cortical areas were involved in 7 cases while the other 8 had the malformation in medial or deep structures of the brain. No mortality occurred from surgery. A radical excision was achieved in 12 cases, while in 3 cases remnants of the lesion were shown by postoperative angiography. Nine patients recovered from surgery without neurological impairment. Two children with left-sided arteriovenous malformations showed mild speech disturbances and 2 others with midline lesions suffered from hypotonus and ataxia.     

Cross-reaction of lupus anti-dsDNA antibodies with protein translation factor EF-2

This report elucidates a new cross-reactive intracellular target of anti-dsDNA antibodies. Previous experiments have demonstrated that some anti-dsDNA antibodies penetrate cells grown in tissue culture and all inhibit in vitro translation. Data implicate a cross-reactive antigen directly involved in protein synthesis: elongation factor-2 (EF-2). EF-2 was identified by N-terminal sequencing of a band identified with an antibody to the ribosomal protein S1 from Leuconostoc lactis in Western blot assay. Anti-DNA antibodies bind directly to purified EF-2 from bovine liver in dot blot assays. Anti-dsDNA antibodies were shown to inhibit in vitro translation. This inhibiting effect of anti-dsDNA antibodies was partially restored by EF-2 and abrogated by dsDNA, suggesting this cross-reactive specificity. These data demonstrate a cross-reaction between anti-dsDNA antibodies and EF-2 which may lead to cellular dysfunction, as evidenced by inhibition of protein synthesis, and provide a direct pathogenic role for cell penetrating anti-dsDNA antibodies.