Biomedical subjects

T C Sorrell

Publications and source records attributed to T C Sorrell.

94 records · Page 6Linked to original sources

PubMedDate not supplied

Inhibition of the human platelet cyclooxygenase response by the naturally occurring phenazine derivative, 1-hydroxyphenazine.

The phenazine derivative, 1-hydroxyphenazine (OHP), is produced in vivo by Pseudomonas aeruginosa, an organism that colonises the airways of patients with cystic fibrosis. While known to inhibit leukotriene production by human neutrophils, the effects of OHP on cyclooxygenase pathways have not previously been reported. We used [3H] arachidonic acid (AA) under conditions of concurrent labelling-stimulation or pre-labelling for one hour followed by stimulation to determine the effects of OHP on the production of cyclooxygenase metabolites by human platelets stimulated with the calcium ionophore, A23187. Thromboxane B2 (TxB2) and 12-hydroxyheptadecatrienoic acid (HHT) production was inhibited in a dose-dependent manner by OHP using either pre-labelled or concurrently labelled platelets. However, production of 12-hydroxyeicosatetraenoic acid (12-HETE) was not diminished. Determination of the amount of total free label (AA+non-esterified AA metabolites) after stimulation of pre-labelled platelets indicated a dose-dependent inhibition of the release of AA from phospholipid by OHP. This was reflected in a corresponding increase in phospholipid AA content. These data indicate that phenazine derivatives of bacterial origin exhibit complex interactions with pathways of arachidonic acid metabolism in host cells. These effects may prove to be of pharmacological importance.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

PubMedDate not supplied

Cryptococcus neoformans var. gattii infection in northern Australia: existence of an environmental source other than known host eucalypts.

The 2 known host trees of Cryptococcus neoformans var. gattii, Eucalyptus camaldulensis and E. tereticornis, do not occur naturally in the 'Top End' of the Northern Territory (NT) of Australia. Nine clinical isolates of C. neoformans var. gattii from the NT were analysed by random amplification of polymorphic deoxyribonucleic acid (RAPD) and polymerase chain reaction 'fingerprinting'. Two isolates were assigned to RAPD profile VGI, previously established as the common RAPD profile. The remaining 7 were assigned to profile VGII; 6 of these isolates were recovered from individuals living in the 'Top End'. The results strongly support the existence of an alternative environmental niche for C. neoformans var. gattii, as all isolates from Eucalyptus spp. in Australia to date have been of RAPD profile VGI.

Cryptococcosis↗

PubMedDate not supplied

Cellulitis due to Pseudomonas putrefaciens: possible production of exotoxins.

Pseudomonas putrefaciens has been described as a rare cause of both lower-limb cellulitis and septicemic illness with significant morbidity. We report a case of P. putrefaciens infection in a patient with refractory lower-limb cellulitis and ulceration complicated by thrombocytopenia, hypotension, and mental obtundation in the apparent absence of bacteremia. This scenario raises the possibility of significant production of exotoxins by P. putrefaciens in vivo.

Aged↗

PubMedDate not supplied

Antimicrobial therapy and prevention of spontaneous bacterial peritonitis.

Spontaneous bacterial peritonitis is a frequent and serious infection in cirrhotic patients with ascites. A high index of suspicion is required for early diagnosis and rapid institution of treatment. The common micro-organisms involved in SBP are the aerobic Gram-negative bacilli and Gram-positive cocci that inhabit the intestine. Empiric antibiotic therapy active against these organisms should be instituted as soon as possible to improve survival. Third generation cephalosporins are very effective and safe as the initial empiric antibiotic regimen. Alternatives include beta-lactam-clavulanic acid combinations and other broad-spectrum antibiotics, although cost benefit considerations are important in selection. If cultures and susceptibility tests allow, antibiotic therapy should be altered to provide optimum narrow-spectrum and cost-effective treatment. Recent evidence suggests that (at least in the case of cefotaxime), 5-day treatment is equally effective as 10-day treatment. Except in patients awaiting liver transplantation, antibiotic prophylaxis of SBP is not recommended at present, as the few trials performed have not been able to demonstrate superior results for survival, hospital admissions or cost-effectiveness, over prompt diagnosis and therapy of individual episodes of SBP.

Anti-Bacterial Agents↗