Emeritus Professor Tim Roberts

Background. Passage of bacterial cells through filter pores has been reported for a number of bacterial species. In this investigation, we tested the filterability of staphylococcal cultures that were exposed to several environmental stress conditions by passing them through 0.22 and 0.45 m sterile filters, which are industry standards. Findings. Results showed repeated passage of viable staphylococcal cells through both pore sizes, although more passage was seen through the 0.45 m pore size. Of the three staphylococcal species, S. lugdunensis showed the best passage at relatively higher numbers regardless of the treatment, while both S. aureus and S. epidermidis showed limited passage or complete inhibition. Conclusion. The data showed that staphylococcal bacteria were capable of passing through sterile filters in a viable state. There was better passage through 0.45 m sterile filters than through the 0.22 m sterile filters. Application of a stress condition did not appear to enhance filterability of these bacterial cultures. © 2010 Roberts et al; licensee BioMed Central Ltd.

Objective: To elute placental bound immunoglobulin G (IgG) in situ. Design: Laboratory based experimentation. Setting: Biological Sciences Department, The University of Newcastle Australia and the Department of Biochemistry, University of Nairobi, Kenya. Subjects: Twelve pregnant ewes 10 to 15 days before the onset of natural parturition. Results: Placental eluates were rich in IgG 1 and IgG2. The relative molecular weigh of placental IgG was estimated at 158kDa by gel filtration chromatography. Analysis of eluate by SDS PAGE revealed the heavy and light chains of IgG at 57 and 27kDa respectively together giving a relative molecular weight of 168kDa. Conclusion: Placental bound IgG may be crucial in immunology of pregnancy and together with the cognate antigen thereof may be useful as models for the study of maternal-fetal interaction in human pregnancy and in the development of experimental immunotherapy to immunologically compromised pregnancies in humans and livestock.

A previous investigation of a cohort of 20 chronic fatigue syndrome (CFS) patients revealed an increased urinary excretion of an unusual metabolite, tentatively identified as amino-hydroxy-N-methyl-pyrrolidine (coded CFSUM1) and ß-alanine, compared with 45 control subjects. The relative abundances of both CFSUM1 and ß-alanine were positively associated with the core diagnostic symptoms of CFS and associated changes in amino and organic acid excretion. The psychological attributes of these CFS patients and controls were assessed in this study by using the Symptom Check List-90- revised (SCL-90-R) psychological inventory. The CFS patients had increases in the SCL-90-R somatization, obsessive compulsive, depression, anxiety and phobic anxiety dimension scores. Nineteen of 20 CFS patients had somatization T-scores = 63 (P < 0.0001), suggestive of a somatization disorder. Multiple regression analysis indicated that somatization was the most important SCL- 90-R-defined dimension discriminating CFS from control subjects. Depression and anxiety were not found to be important inter-group determinants. The dimension scores were each related to specific changes in the urinary excretion of organic and amino acids, suggesting that each is biochemically distinct and has an organic basis. Cluster analysis of dimension profiles revealed that the profile with increased prevalence (P < 0.0001) in CFS patients was associated with increased excretion of CFSUM1 (P < 0.005) and had increases in somatization, obsessive compulsion and depression dimension scores. The PSDI as a measure of SCL-90-R symptom severity was positively correlated with CFSUM1 (model P < 0.003). CFSUM1 was also the primary correlate for the somatization dimension (model P < 0.0008), but was not associated with any other SCL-90-R-defined dimension. Another unidentified urinary metabolite, coded UM15, was the primary correlate for depression (model P < 0.0004) and was associated with multiple dimension elevations by both cluster and logistic regression analysis; the excretion of this compound was unrelated to CFSUM1. These results indicated that, in this CFS cohort, the SCL-90-R defined psychological changes were strongly associated with changes in the biochemical homeostasis of patients, suggestive of an organic basis to CFS.

A study was undertaken to assess the ability of the erythrocyte to provide protection to other tissues against oxidative damage, Radiolabelled (51Cr) human umbilical vein endothelial cells (HUVEC) were incubated with erythrocytes and neutrophils activated with phorbol myristate acetate (PMA). Damage to the endothelial cells was indicated by release of radioactivity into the suspending medium. We found that the co-incubation of HUVEC with an increasing range of erythrocyte concentrations resulted in a dose dependent reduction in the release of radioactivity. These data suggest that the erythrocytes afforded some protection against endothelial cell damage by the activated neutrophils. When PMA-activated neutrophils were incubated with erythrocytes, the erythrocytes had reduced levels of 2,3-diphosphoglycerate (p < 0.01) and glutathione (p < 0.01) compared with erythrocytes incubated alone, indicating utilisation of antioxidant potential. The same erythrocytes had increased concentrations of the oxidative damage products, malondialdehyde (p < 0.02) and methaemoglobin (p < 0.002). These data support the hypothesis that erythrocytes can provide antioxidant protection to other tissues.

We have recently proposed that the eiythran acts as a major deactivate! of reactive free radical species in vivo in addition to its recognised role of gas transport (1). The expendable nature of the individual erythrocyte would be a desirable attribute for such a detoxification unit As a consequence of this function, the labile components of individual erythrocytes would suffer oxidative damage over a period of time leading to biochemical and structural changes. The alterations, including those to membrane integrity, would be reflected by changes in shape and function. To test this hypothesis, radiolabelled ("Cor) human umbilical vein endothelial cells (HUVEQ, were incubated with neutrophils activated with phorbol myristate acetate (PMA) and red cells. Damage to the endothelial cells, indicated by release of radioactivity into the suspending medium, was proportionately reduced by increasing concentrations of erythrocytes. Erythrocytes, modified so that Superoxide was unable to cross the membrane or so that the glutathione or catalase mechanism was inactive, were less efficient at preventing release of radioactivity. Erythrocytes incubated with PMA activated neutrophils contained less 2,3-diphosphoglycerate (2,3-DPG) (p=0.01), less glutathione (p=0.01), more malondialdehyde (p=0.02) and more methaemoglobin (p=0.002) than those incubated alone or with unactivated neutrophils. The depleted 2,3-DPG and glutathione are presumably the result of the acute oxidative stress in this environment We have found increased levels of these metabolites in erythrocytes from chronically stressed environments such as rheumatoid arthritis or renal dialysis presumably to compensate for the increased demand. These findings demonstrate that erythrocytes undergo biochemical changes in environments of high oxidative stress and support our hypothesis that they behave as free radical scavengers under certain conditions.

A visual analog pain scale and scalar responses to 13 pain/symptom indicator Symptom Checklist-90-Revised (SCL-90-R) questions were used to assess symptom prevalence and pain severity in 43 chronic orofacial muscle pain patients and 40 control subjects. The orofacial muscle pain group reported pain in an axial skeletal distribution; neurocognitive, gastrogenitourinary, and musculoskeletal symptoms; infectious events at or preceding onset; similar symptoms in sexual partners; and low prevalence of trauma. Sudden onset was reported by 30.2% of pain patients. Strong associations were found between chronic orofacial muscle pain and (1) onset-related infectiouslike events (67.4%); (2) a higher prevalence of history of respiratory and gastrogenitourinary infectious events; and (3) high prevalences of similar pain symptoms in long-term sexual partners. The SCL-90-R somatization scores (> 62) had a higher prevalence in the chronic pain group. No prevalence differences or associations with pain/symptom indicators were found for depression or anxiety dimension scores. These data suggest that patients with recurrent systemic infectious events have a higher prevalence of reporting of chronic orofacial muscle pain compared with control subjects, and these infectious events are associated with the onset of chronic orofacial muscle pain in 67% of patients.

The rosette inhibition test was used to monitor the activity of an early pregnancy factor (EPF) in sera collected from 18 healthy women who were attempting to conceive. Serial blood samples collected during the luteal phase of 21 menstrual cycles demonstrated the appearance of EPF in 14 of the cycles, of which six showed only transient EPF activity over a 5-10 day period following ovulation. These results indicate a 67% rate of fertilization and a 36% rate of early conceptus losses.