Targeted therapies and hypoxia imaging

Hypoxia-specific cytotoxins have long exhibited considerable promise for treating hypoxic tumors, however recent negative results in large scale clinical trials have highlighted the importance of selecting patients who are most likely to respond using hypoxia imaging methods. This review looks at the available hypoxia-specific cytotoxins and describes how existing hypoxia imaging methods can be best used to predict which tumors will respond. It then surveys prior studies which combine hypoxia-selective cytotoxin treatment with hypoxia imaging, and finally concludes with a discussion of what lessons can be learnt from previous experiences in order to improve the use of these cytotoxic agents in future clinical evaluations.

Neuroblastoma cells injected into experimental mature teratoma reveal a tropism for embryonic loose mesenchyme

Embryonic neural tumors are responsible for a disproportionate number of cancer deaths in children. Although dramatic improvements in survival for pediatric malignancy has been achieved in previous years advancements seem to be slowing down. For the development of new enhanced therapy and an increased understanding of the disease, pre-clinical models better capturing the neoplastic niche are essential. Tumors of early childhood present in this respect a particular challenge. Here, we explore how components of the embryonic process in stem‑cell induced mature teratoma can function as an experimental in vivo microenvironment instigating the growth of injected childhood neuroblastoma (NB) cell lines. Three human NB cell lines, IMR-32, Kelly and SK-N-BE(2), were injected into mature pluripotent stem cell‑induced teratoma (PSCT) and compared to xenografts of the same cell lines. Proliferative NB cells from all lines were readily detected in both models with a typical histology of a poorly differentiated NB tumor with a variable amount of fibrovascular stroma. Uniquely in the PSCT microenvironment, NB cells were found integrated in a non‑random fashion. Neuroblastoma cells were never observed in areas with well-differentiated somatic tissue i.e. bone, muscle, gut or areas of other easily identifiable tissue types. Instead, the three cell lines all showed initial growth exclusively occurring in the embryonic loose mesenchymal stroma, resulting in a histology recapitulating NB native presentation in vivo. Whether this reflects the 'open' nature of loose mesenchyme more easily giving space to new cells compared to other more dense tissues, the rigidity of matrix providing physical cues modulating NB characteristics, or if embryonic loose mesenchyme may supply developmental cues that attracted or promoted the integration of NB, remains to be tested. We tentatively hypothesize that mature PSCT provide an embryonic niche well suited for in vivo studies on NB.

Multiple antigen peptide containing B and T cell epitopes of F1 antigen of Yersinia pestis showed enhanced Th1 immune response in murine model

Yersinia pestis is a facultative bacterium that can survive and proliferate inside host macrophages and cause bubonic, pneumonic and systemic infection. Apart from humoral response, cell-mediated protection plays a major role in combating the disease. Fraction 1 capsular antigen (F1-Ag) of Y. pestis has long been exploited as a vaccine candidate. In this study, F1-multiple antigenic peptide (F1-MAP or MAP)-specific cell-mediated and cytokine responses were studied in murine model. MAP consisting of three B and one T cell epitopes of F1-antigen with one palmitoyl residue was synthesized using Fmoc chemistry. Mice were immunized with different formulations of MAP in poly DL-lactide-co-glycolide (PLGA) microspheres. F1-MAP with CpG oligodeoxynucleotide (CpG-ODN) as an adjuvant showed enhanced in vitro T cell proliferation and Th1 (IL-2, IFN-γ and TNF-α) and Th17 (IL-17A) cytokine secretion. Similar formulation also showed significantly higher numbers of cytokine (IL-2, IFN-γ)-secreting cells. Moreover, F1-MAP with CpG formulation showed significantly high (P < 0.001) percentage of CD4(+) IFN-γ(+) cells as compared to CD8(+) IFN-γ(+) cells, and also more (CD4- IFN-γ)(+) cells secrete perforin and granzyme as compared to (CD8- IFN-γ)(+) showing Th1 response. Thus, the study highlights the importance of Th1 cytokine and existence of CD4(+) and CD8(+) immune response. This study proposes a new perspective for the development of vaccination strategies for Y. pestis that trigger T cell immune response.

A randomised controlled trial of sublingual buprenorphine-naloxone film versus tablets in the management of opioid dependence

BACKGROUND

Buprenorphine-naloxone sublingual film was introduced in 2011 in Australia as an alternative to tablets. This study compared the two formulations on subjective dose effects and equivalence, trough plasma levels, adverse events, patient satisfaction, supervised dosing time, and impact upon treatment outcomes (substance use, psychosocial function).

METHODS

92 buprenorphine-naloxone tablet patients were recruited to this outpatient multi-site double-blind double-dummy parallel group trial. Patients were randomised to either tablets or film, without dose changes, over a 31 day period.

RESULTS

No significant group differences were observed for subjective dose effects, trough plasma buprenorphine or norbuprenorphine levels, adverse events and treatment outcomes. Buprenorphine-naloxone film took significantly less time to dissolve than tablets (173±71 versus 242±141s, p=0.007, F=7.67).

CONCLUSIONS

The study demonstrated dose equivalence and comparable clinical outcomes between the buprenorphine-naloxone film and tablet preparations, whilst showing improved dispensing times and patient ratings of satisfaction with the film.

An overview of electronic apex locators: part 1

To effectively carry out root canal therapy, the clinician must accurately determine the apical limit of the root canal system as well as the position of the canal terminus. Its position can be estimated using a variety of techniques, including radiographs, tactile feedback from endodontic instruments and electronic apex locators. This article describes the micro-anatomy of the apical terminus, different methods of measuring root canal system length and how a tooth can function as an electrical capacitor. This capacitor model represents a starting point upon which all apex locators are based. An understanding of this model can help the practitioner to optimise the use of apex locators, understand their limitations and avoid errors that can occur.

Cancer outcomes and all-cause mortality in adults allocated to metformin: systematic review and collaborative meta-analysis of randomised clinical trials

AIMS/HYPOTHESIS

Observational studies suggest that metformin may reduce cancer risk by approximately one-third. We examined cancer outcomes and all-cause mortality in published randomised controlled trials (RCTs).

METHODS

RCTs comparing metformin with active glucose-lowering therapy or placebo/usual care, with minimum 500 participants and 1-year follow-up, were identified by systematic review. Data on cancer incidence and all-cause mortality were obtained from publications or by contacting investigators. For two trials, cancer incidence data were not available; cancer mortality was used as a surrogate. Summary RRs, 95% CIs and I (2)statistics for heterogeneity were calculated by fixed effects meta-analysis.

RESULTS

Of 4,039 abstracts identified, 94 publications described 14 eligible studies. RRs for cancer were available from 11 RCTs with 398 cancers during 51,681 person-years. RRs for all-cause mortality were available from 13 RCTs with 552 deaths during 66,447 person-years. Summary RRs for cancer outcomes in people randomised to metformin compared with any comparator were 1.02 (95% CI 0.82, 1.26) across all trials, 0.98 (95% CI 0.77, 1.23) in a subgroup analysis of active-comparator trials and 1.36 (95% CI 0.74, 2.49) in a subgroup analysis of placebo/usual care comparator trials. The summary RR for all-cause mortality was 0.94 (95% CI 0.79, 1.12) across all trials.

CONCLUSIONS/INTERPRETATION

Meta-analysis of currently available RCT data does not support the hypothesis that metformin lowers cancer risk by one-third. Eligible trials also showed no significant effect of metformin on all-cause mortality. However, limitations include heterogeneous comparator types, absent cancer data from two trials, and short follow-up, especially for mortality.

Nutritional evaluation of distillery sludge and its effect as a substitute of canola meal on performance of broiler chickens

The study was conducted to investigate the chemical composition of distillery yeast sludge and its inclusion in broiler diets to replace canola meal. Raw distillery yeast sludge was washed with water using water and sludge in the ratio 6:1, respectively. Proximate analysis of raw distillery yeast sludge and washed distillery sludge was carried out for crude protein (CP), true protein (TP), ether extract (EE), ash, acid insoluble ash and nitrogen free extract (NFE) determination. Mineral contents and amino acid profile of raw distillery yeast sludge and washed distillery sludge were also determined. After chemical evaluation, four iso-caloric and iso-nitrogenous broiler starter and finisher diets were prepared in mash form using 0 (control), 4, 8 and 12% levels of washed distillery sludge replacing canola meal. One hundred and twenty day-old broiler chicks were randomly distributed into 12 experimental units in such a way that each diet was offered to three experimental units, each comprising of 10 chicks. It was observed that washing affected the nutrients either by decreasing or increasing their concentration. It decreased the total mineral contents whereas CP, TP, EE and NFE contents increased. Washing also increased amino acid profile. Average feed intake and weight gain were higher in birds fed diet containing 8% washed distillery sludge and lower in birds fed diet containing 0% washed distillery sludge. Feed cost per kg live weight gain decreased significantly as the level of washed distillery sludge was increased in the diet. Average heart, liver and pancreas weights decreased with increased level of washed distillery sludge in the diet. The study revealed that after washing, distillery yeast sludge can be used successfully in broiler diets up to the level of 8% without any adverse effect on broiler’s performance.

P2-16-13: Life after Mastectomy without Breast Reconstruction – Are the Needs of Caribbean Women Different?

Aim: The standard of care in the United States and United Kingdom for women undergoing mastectomy is to be offered breast reconstruction surgery (BRS), either immediate or delayed. In Trinidad, for a variety of reasons, patients are not routinely offered this option. We undertook a study to determine the impact of breast surgery without reconstruction on their perception of sexuality, body image, relationships and quality of life. The aim is to establish a benchmark for the planning and incorporation of reconstructive options into the care pathway of patients requiring oncoplastic surgery in the Caribbean.

Method: A questionnaire was administered to post surgery breast cancer patients in a public oncology clinic in Trinidad. These patients had no BRS and had surgery at various institutions in Trinidad, where the primary surgical service was General Surgery. Data was collected prospectively and analysed using SPSS software.

Results: Of 130 questionnaires administered to date, 80(61.5%) of those collected were adequate for analysis. 46.1%(n=35) of patients were less than fifty years of age; 44%(n=24) were Afro-Caribbean and 55.6% (n=30) East Indian-Caribbean; 61.1%(n=44) had mastectomies and 38.9%(n=28) had breast conserving surgery (BCS). Of all patients, 90%(n=70) felt attractive, feminine and satisfied with their bodies before surgery, however postoperatively, all who had BCS remained satisfied with their bodies but a significant proportion of patients in the mastectomy group were dissatisfied(p=0.006) and found it harder to look at themselves naked(p=0.025) and be seen naked by their partners (42.9%, n=15). East Indian-Caribbean women felt less attractive after surgery compared to Afro-Caribbean patients(p=0.024). Among all patients, 19.2% felt shy to go out in public after surgery, 28.8% left their house less and 35% (n=25) had fewer social interactions. When analysed by ethnicity, East Indian-Caribbean women were more likely to avoid public events(p=0.003) and had fewer social interactions(p=0.028) than Afro-Caribbean patients. This effect persisted in mastectomy patients(p=0.007), especially in the East Indian-Caribbean group(p=0.0017). 69% of patients were willing to undergo BRS, but it was offered to only 32.5%(n=13) of mastectomy patients. The interest in BRS was similar in all races, age groups and surgery types.

Conclusion: This study explores the experiences and needs of Caribbean women with breast cancer in Trinidad. We found from this data that their needs mirror those of women in other countries where BRS is incorporated into the core care pathway. Our data demonstrates that even with ethnic differences, there is deterioration in self esteem and feminity with breast cancer surgery, with lasting effects. Subtle differences appear to be present in body image perception amongst East Indian-Caribbean women versus Afro-Caribbean and may be a useful template when assessing patient needs with a view to how we individualize care in the Caribbean setting. This data also emphasizes the potential benefit in incorporating an Oncology-Plastic Surgery Team approach in our setting and supports the view that providing BRS to patients as early as possible can help to maintain a positive outlook in personal and social interactions.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-16-13.