Approaching prosthesis infection environment: Development of an innovative in vitro Staphylococcus aureus biofilm model.

The major role and implication of bacterial biofilms in the case of bone and prosthesis infections have been highlighted and often linked to implant colonization. Management strategies of these difficult-to-treat infections consist in surgeries and antibiotic treatment, but the rate of relapse remains high, especially if Staphylococcus aureus, a high-virulent pathogen, is involved. Therapeutic approaches are not adapted to the specific features of biofilm in bone context whereas infectious environment is known to importantly influence biofilm structure. In the present study, we aim to characterize S. aureus SH1000 (methicillin-sensitive strain, MSSA) and USA300 (methicillin-resistant strain, MRSA) biofilm on different surfaces mimicking the periprosthetic environment. As expected, protein adsorption on titanium enhanced the number of adherent bacteria for both strains. On bone explant, USA300 adhered more than SH1000. The simultaneous presence of two different surfaces was also found to change the bacterial behaviour. Thus, proteins adsorption on titanium and bone samples (from bank or directly recovered after an arthroplasty) were found to be key parameters that influence S. aureus biofilm formation: adhesion, matrix production and biofilm-related gene regulation. These results highlighted the need for new biofilm models, more relevant with the infectious environment by using adapted culture medium and presence of surfaces that are representative of in situ conditions to better evaluate therapeutic strategies against biofilm.

Altered frontocortical, cerebellar, and basal ganglia activity in adjuvant-treated breast cancer survivors 5-10 years after chemotherapy.

PURPOSE: To explore the relationship of regional cerebral blood flow and metabolism with cognitive function and past exposure to chemotherapy for breast cancer. PATIENTS AND METHODS: Subjects treated for breast cancer with adjuvant chemotherapy remotely (5-10 years previously) were studied with neuropsychologic testing and positron emission tomography (PET), and were compared with control subjects who had never received chemotherapy. [O-15] water PET scans was acquired during performance of control and memory-related tasks to evaluate cognition-related cerebral blood flow, and [F-18] fluorodeoxyglucose (FDG) PET scans were acquired to evaluate resting cerebral metabolism. PET scans were analyzed by statistical parametric mapping and region of interest methods of analysis. RESULTS: During performance of a short-term recall task, modulation of cerebral blood flow in specific regions of frontal cortex and cerebellum was significantly altered in chemotherapy-treated subjects. Cerebral activation in chemotherapy-treated subjects differed most significantly from untreated subjects in inferior frontal gyrus, and resting metabolism in this area correlated with performance on a short-term memory task previously found to be particularly impaired in chemotherapy-treated subjects. In examining drug-class specific effects, metabolism of the basal ganglia was significantly decreased in tamoxifen + chemotherapy-treated patients compared with chemotherapy-only breast cancer subjects or with subjects who had not received chemotherapy, while chemotherapy alone was not associated with decreased basal ganglia activity relative to untreated subjects. CONCLUSION: Specific alterations in activity of frontal cortex, cerebellum, and basal ganglia in breast cancer survivors were documented by functional neuroimaging 5-10 years after completion of chemotherapy.

Assessing the impact of cancer: development of a new instrument for long-term survivors.

OBJECTIVE: To develop and evaluate a new instrument that measures aspects of long-term survivorship not measured by existing tools. METHODS: In qualitative interviews, 47 long-term cancer survivors (LTS) detailed ways that cancer has impacted their lives. Content analysis resulted in the creation of 325 candidate items for inclusion in a new Impact of Cancer (IOC) instrument. Following expert review, item reduction and pilot testing, 81 items were administered with other established health status and quality of life (QOL) instruments to 193 LTS of breast, prostate, colorectal cancers and lymphoma. Internal consistency reliability and validity of newly-derived scales was assessed. RESULTS: Factor analysis of items using a priori QOL domains resulted in the derivation of ten new and specific subscales: Health Awareness, Body Changes, Health Worries, Positive and Negative Self-Evaluation, Positive and Negative Life Outlook, Social Life Interferences, Relationships, and Meaning of Cancer. Internal consistency measurements for these subscales ranged from 0.67 to 0.89. Expected associations within and among the IOC subscales and standardized measures of health status and QOL were observed, as were some unexpected findings. CONCLUSIONS: Psychometric analysis indicated that this initial version of the Impact of Cancer instrument measures distinct and relevant constructs for LTS. Future work is necessary to confirm the factor structure, responsiveness and further validation of the instrument.

Neurocognitive performance in breast cancer survivors exposed to adjuvant chemotherapy and tamoxifen.

The primary aim of the current study was to examine whether neurocognitive functioning among breast cancer survivors (BCS) exposed to systemic adjuvant chemotherapy differs from that seen among BCS who did not receive chemotherapy. The performance of each of these BCS groups was compared to a demographically matched comparison group without history of breast cancer, a group not included in the majority of previous cognitive functioning studies. We also sought to explore whether usage of the anti-estrogen drug tamoxifen, a common component of breast cancer treatment, was related to neurocognitive functioning. Finally, we wished to examine the relationship between subjective report of cognitive functioning and objective performance on neurocognitive measures among BCS. Fifty-three survivors of breast cancer (all between 2-5 years after diagnosis and initial surgical removal of cancerous tissue) and 19 healthy non-BCS comparison subjects were administered a comprehensive neurocognitive battery, and measures of mood, energy level, and self-reported cognitive functioning. Those BCS who received adjuvant chemotherapy performed significantly worse in the domains of verbal learning, visuospatial functioning, and visual memory than BCS treated with surgery only. Those who received both chemotherapy and tamoxifen showed the greatest compromise. Although patients who received chemotherapy (with and without tamoxifen) performed worse than those treated with surgery only on several domains, neither group was significantly different from demographically matched comparison subjects without a history of breast cancer. Finally, we found no relationship between subjective cognitive complaints and objective performance, although cognitive complaints were associated with measures of psychological distress and fatigue. We highlight ways in which these data converge with other recent studies to suggest that systemic chemotherapy, especially in combination with tamoxifen, can have adverse yet subtle effects on cognitive functioning.