Long-read powered viral metagenomics in the oligotrophic Sargasso Sea

Dominant microorganisms of the Sargasso Sea are key drivers of the global carbon cycle. However, associated viruses that shape microbial community structure and function are not well characterised. Here, we combined short and long read sequencing to survey Sargasso Sea phage communities in virus- and cellular fractions at viral maximum (80 m) and mesopelagic (200 m) depths. We identified 2,301 Sargasso Sea phage populations from 186 genera. Over half of the phage populations identified here lacked representation in global ocean viral metagenomes, whilst 177 of the 186 identified genera lacked representation in genomic databases of phage isolates. Viral fraction and cell-associated viral communities were decoupled, indicating viral turnover occurred across periods longer than the sampling period of three days. Inclusion of long-read data was critical for capturing the breadth of viral diversity. Phage isolates that infect the dominant bacterial taxa Prochlorococcus and Pelagibacter, usually regarded as cosmopolitan and abundant, were poorly represented.

Developing an intervention package to optimise the management of vancomycin therapy using theory informed co-design

BACKGROUND

Optimising the management of vancomycin by achieving target therapeutic concentrations early during therapy has been associated with reduced mortality and morbidity. Despite the availability of guidelines and training, the management of vancomycin remains suboptimal.

OBJECTIVES

The primary outcome was the development of interventions and associated implementation strategies to optimise the management of vancomycin therapy. This paper describes how co-design process was used to build a theory informed intervention package, which was implemented across a wide range of in-patient hospital settings in Queensland, Australia.

METHODS

This multiple methods study was conducted in four phases: 1) a baseline audit to identify the nature of the problem and associated determinants informed by stakeholder interviews 2) mapping these findings to the Theoretical Domains Framework (TDF) to identify behavioural correlates and modifiers 3) prioritising the behavioural modifiers and associated implementation strategies to inform a protype of the intervention in a series of co-design sessions and 4) implementing and evaluating the intervention package. The study was conducted across the four teaching hospitals in a large Queensland Hospital and Health Service across multiple healthcare disciplines namely nurses, doctors, and pharmacists. This intervention package was subsequently implemented across Queensland Health with the support of the local champions under the guidance of the steering group.

RESULTS

Clinicians identified that a multifaceted intervention package and training which can be tailored to the health-care professional disciplines, would be best suited to shift clinician behaviour to align with guidelines. The findings from the co-design process aligned with theory-informed intervention package. Each of the intervention strategies varied in their frequency and popularity of use.

CONCLUSIONS

The use of theory-informed and participatory approach assisted with the intervention development process and aligned the intervention content with the priorities of stakeholders. The TDF provided a structured process for developing intervention content which is both acceptable and useful to stakeholders and may improve the management of vancomycin.

First impressions: A prospective evaluation of patient-physician concordance and satisfaction following the initial medical oncology consultation

BACKGROUND

An especially significant event in the patient-oncologist relationship is the initial consultation, where many complex topics-diagnosis, treatment intent, and often, prognosis-are discussed in a relatively short period of time. This study aimed to measure patients' understanding of the information discussed during their first medical oncology visit and their satisfaction with the communication from medical oncologists.

METHODS

Between January and August 2021, patients without prior systemic treatment of their gastrointestinal malignancy (GI) attending the Princess Margaret Cancer Centre (PMCC) were approached within 24 h of their initial consultation to complete a paper-based questionnaire assessing understanding of their disease (diagnosis, treatment plan/intent, and prognosis) and satisfaction with the consultation. Medical oncology physicians simultaneously completed a similar questionnaire about the information discussed at the initial visit. Matched patient-physician responses were compared to assess the degree of concordance.

RESULTS

A total of 184 matched patient-physician surveys were completed. The concordance rates for understanding of diagnosis, treatment plan, treatment intent, and prognosis were 92.9%, 59.2%, 66.8%, and 59.8%, respectively. After adjusting for patient and physician variables, patients who reported treatment intent to be unclear at the time of the consultation were independently associated with lower satisfaction scores (global p = 0.014). There was no statistically significant association between patient satisfaction and whether prognosis was disclosed (p = 0.08).

CONCLUSION

An in-depth conversation as to what treatment intent and prognosis means is reasonable during the initial medical oncology consultation to ensure patients and caregivers have a better understanding about their cancer.

Novel pelagiphage isolate Polarivirus skadi is a polar specialist that dominates SAR11-associated bacteriophage communities at high latitudes

The SAR11 clade are the most abundant members of surface marine bacterioplankton and a critical component of global biogeochemical cycles. Similarly, pelagiphages that infect SAR11 are ubiquitous and highly abundant in the oceans. Pelagiphages are predicted to shape SAR11 community structures and increase carbon turnover throughout the oceans. Yet, ecological drivers of host and niche specificity of pelagiphage populations are poorly understood. Here we report the global distribution of a novel pelagiphage called "Polarivirus skadi", which is the sole representative of a novel genus. P. skadi was isolated from the Western English Channel using a cold-water ecotype of SAR11 as bait. P. skadi is closely related to the globally dominant pelagiphage HTVC010P. Along with other HTVC010P-type viruses, P. skadi belongs to a distinct viral family within the order Caudovirales, for which we propose the name Ubiqueviridae. Metagenomic read recruitment identified P. skadi as one of the most abundant pelagiphages on Earth. P. skadi is a polar specialist, replacing HTVC010P at high latitudes. Experimental evaluation of P. skadi host range against cold- and warm-water SAR11 ecotypes supported cold-water specialism. Relative abundance of P. skadi in marine metagenomes correlated negatively with temperature, and positively with nutrients, available oxygen, and chlorophyll concentrations. In contrast, relative abundance of HTVC010P correlated negatively with oxygen and positively with salinity, with no significant correlation to temperature. The majority of other pelagiphages were scarce in most marine provinces, with a few representatives constrained to discrete ecological niches. Our results suggest that pelagiphage populations persist within a global viral seed bank, with environmental parameters and host availability selecting for a few ecotypes that dominate ocean viromes.

Combination of clinical, radiomic, and "delta" radiomic features in survival prediction of metastatic gastroesophageal adenocarcinoma

Objectives

To identify combined clinical, radiomic, and delta-radiomic features in metastatic gastroesophageal adenocarcinomas (GEAs) that may predict survival outcomes.

Methods

A total of 166 patients with metastatic GEAs on palliative chemotherapy with baseline and treatment/follow-up (8-12 weeks) contrast-enhanced CT were retrospectively identified. Demographic and clinical data were collected. Three-dimensional whole-lesional radiomic analysis was performed on the treatment/follow-up scans. "Delta" radiomic features were calculated based on the change in radiomic parameters compared to the baseline. The univariable analysis (UVA) Cox proportional hazards model was used to select clinical variables predictive of overall survival (OS) and progression-free survival (PFS) (p-value <0.05). The radiomic and "delta" features were then assessed in a multivariable analysis (MVA) Cox model in combination with clinical features identified on UVA. Features with a p-value <0.01 in the MVA models were selected to assess their pairwise correlation. Only non-highly correlated features (Pearson's correlation coefficient <0.7) were included in the final model. Leave-one-out cross-validation method was used, and the 1-year area under the receiver operating characteristic curve (AUC) was calculated for PFS and OS.

Results

Of the 166 patients (median age of 59.8 years), 114 (69%) were male, 139 (84%) were non-Asian, and 147 (89%) had an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1. The median PFS and OS on treatment were 3.6 months (95% CI 2.86, 4.63) and 9 months (95% CI 7.49, 11.04), respectively. On UVA, the number of chemotherapy cycles and number of lesions at the end of treatment were associated with both PFS and OS (p < 0.001). ECOG status was associated with OS (p = 0.0063), but not PFS (p = 0.054). Of the delta-radiomic features, delta conventional HUmin, delta gray-level zone length matrix (GLZLM) GLNU, and delta GLZLM LGZE were incorporated into the model for PFS, and delta shape compacity was incorporated in the model for OS. Of the treatment/follow-up radiomic features, shape compacity and neighborhood gray-level dependence matrix (NGLDM) contrast were used in both models. The combined 1-year AUC (Kaplan-Meier estimator) was 0.82 and 0.81 for PFS and OS, respectively.

Conclusions

A combination of clinical, radiomics, and delta-radiomic features may predict PFS and OS in GEAs with reasonable accuracy.

Systemic inflammatory prognostic scores in advanced pancreatic adenocarcinoma

BACKGROUND

Systemic inflammatory scores may aid prognostication and patient selection for trials. We compared five scores in advanced pancreatic adenocarcinoma (PDAC).

METHODS

Unresectable/metastatic PDAC patients enrolled in the Comprehensive Molecular Characterisation of Advanced Pancreatic Ductal Adenocarcinoma for Better Treatment Selection trial (NCT02750657) were included. Patients had pre-treatment biopsies for whole genome and RNA sequencing. CD8 immunohistochemistry was available in a subset. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio, Prognostic Nutritional Index, Gustave Roussy Immune Score (GRIm-S), and Memorial Sloan Kettering Prognostic Score (MPS) were calculated. Overall survival (OS) was estimated using Kaplan-Meier methods. Associations between inflammatory scores, clinical/genomic characteristics, and OS were analysed.

RESULTS

We analysed 263 patients. High-risk NLR, GRIm-S and MPS were poorly prognostic. The GRIm-S had the highest predictive ability: median OS 6.4 vs. 10 months for high risk vs. low-risk (P < 0.001); HR 2.26 (P < 0.001). ECOG ≥ 1, the basal-like subtype, and low-HRDetect were additional poor prognostic factors (P < 0.01). Inflammatory scores did not associate with RNA-based classifiers or homologous recombination repair deficiency genotypes. High-risk MPS (P = 0.04) and GRIm-S (P = 0.02) patients had lower median CD8 + tumour-infiltrating lymphocytes.

CONCLUSIONS

Inflammatory scores incorporating NLR have prognostic value in advanced PDAC. Understanding immunophenotypes of poor-risk patients and using these scores in trials will advance the field.

Comparison of Four Clinical Prognostic Scores in Patients with Advanced Gastric and Esophageal Cancer

BACKGROUND

Prognostic scores that can identify patients at risk for early death are needed to aid treatment decision-making and patient selection for clinical trials. We compared the accuracy of four scores to predict early death (within 90 days) and overall survival (OS) in patients with metastatic gastric and esophageal (GE) cancer.

METHODS

Advanced GE cancer patients receiving first-line systemic therapy were included. Prognostic risks were calculated using: Royal Marsden Hospital (RMH), MD Anderson Cancer Centre (MDACC), Gustave Roussy Immune (GRIm-Score), and MD Anderson Immune Checkpoint Inhibitor (MDA-ICI) scores. Overall survival (OS) was estimated using the Kaplan-Meier method. Cox proportional hazards models were used to analyze associations between prognostic scores and OS. The predictive discrimination was estimated using Harrell's c-index. Predictive ability for early death was measured using time-dependent AUCs.

RESULTS

In total, 451 patients with metastatic GE cancer were included. High risk patients had shorter OS for all scores (RMH high- vs. low-risk median OS 7.9 vs. 12.2 months, P < .001; MDACC 6.8 vs. 11.9 months P < .001; GRIm-Score 5.3 vs. 13 months, P < .001; MDA-ICI 8.2 vs. 12.2 months, P < .001). On multivariable analysis, each prognostic score was significantly associated with OS. The GRIm-Score had the highest predictive discrimination and predictive ability for early death.

CONCLUSIONS

The GRIm-Score had the highest accuracy in predicting early death and OS. Clinicians may use this score to identify patients at higher risk of early death to guide treatment decisions including clinical trial enrolment. This score could also be used as a stratification factor in future clinical trial designs.

Visualisation of microalgal-viral interactions by high-speed atomic force microscopy

Visualization of viruses and their hosts has been paramount to their study and understanding. The direct observation of the morphological dynamics of infection is a highly desired capability and the focus of instrument development across a variety of microscopy technologies. This study demonstrates progress that has been made in exploiting the capabilities offered by HS-AFM to characterise the interactions between coccolithoviruses and their globally important coccolithophore hosts. We observe whole Emiliania huxleyi Virus capsids, transient binding to Emiliania huxleyi derived supported lipid bilayers, and host-virus binding in real-time in an environmentally relevant, aqueous environment.

Molecular characterisation of pancreatic ductal adenocarcinoma with NTRK fusions and review of the literature

AIMS

The majority of pancreatic ductal adenocarcinomas (PDACs) harbour oncogenic mutations in KRAS with variants in TP53, CDKN2A and SMAD4 also prevalent. The presence of oncogenic fusions including NTRK fusions are rare but important to identify. Here we ascertain the prevalence of NTRK fusions and document their genomic characteristics in a large series of PDAC.

METHODS

Whole genome sequencing and RNAseq were performed on a series of patients with resected or locally advanced/metastatic PDAC collected between 2008 and 2020 at a single institution. A subset of specimens underwent immunohistochemistry (IHC) analysis. Clinical and molecular characterisation and IHC sensitivity and specificity were evaluated.

RESULTS

400 patients were included (resected n=167; locally advanced/metastatic n=233). Three patients were identified as harbouring an NTRK fusion, two EML4-NTRK3 (KRAS-WT) and a single novel KANK1-NTRK3 fusion. The latter occurring in the presence of a subclonal KRAS mutation. Typical PDAC drivers were present including mutations in TP53 and CDKN2A. Substitution base signatures and tumour mutational burden were similar to typical PDAC. The prevalence of NTRK fusions was 0.8% (3/400), while in KRAS wild-type tumours, it was 6.25% (2/32). DNA prediction alone documented six false-positive cases. RNA analysis correctly identified the in-frame fusion transcripts. IHC analysis was negative in the KANK1-NTRK3 fusion but positive in a EML4-NTRK3 case, highlighting lower sensitivity of IHC.

CONCLUSION

NTRK fusions are rare; however, with emerging therapeutic options targeting these fusions, detection is vital. Reflex testing for KRAS mutations and subsequent RNA-based screening could help identify these cases in PDAC.

A 17-year time-series of fungal environmental DNA from a coastal marine ecosystem reveals long-term seasonal-scale and inter-annual diversity patterns

Changing patterns in diversity are a feature of many habitats, with seasonality a major driver of ecosystem structure and function. In coastal marine plankton-based ecosystems, seasonality has been established through long-term time-series of bacterioplankton and protists. Alongside these groups, fungi also inhabit coastal marine ecosystems. If and how marine fungi show long-term intra- and inter-annual diversity patterns is unknown, preventing a comprehensive understanding of marine fungal ecology. Here, we use a 17-year environmental DNA time-series from the English Channel to determine long-term marine fungal diversity patterns. We show that fungal community structure progresses at seasonal and monthly scales and is only weakly related to environmental parameters. Communities restructured every 52-weeks suggesting long-term stability in diversity patterns. Some major marine fungal genera have clear inter-annual recurrence patterns, re-appearing in the annual cycle at the same period. Low relative abundance taxa that are likely non-marine show seasonal input to the coastal marine ecosystem suggesting land-sea exchange regularly takes place. Our results demonstrate long-term intra- and inter-annual marine fungal diversity patterns. We anticipate this study could form the basis for better understanding the ecology of marine fungi and how they fit in the structure and function of the wider coastal marine ecosystem.

Characterization of a Virally Encoded Flavodoxin That Can Drive Bacterial Cytochrome P450 Monooxygenase Activity

Flavodoxins are small electron transport proteins that are involved in a myriad of photosynthetic and non-photosynthetic metabolic pathways in Bacteria (including cyanobacteria), Archaea and some algae. The sequenced genome of 0305φ8-36, a large bacteriophage that infects the soil bacterium Bacillus thuringiensis, was predicted to encode a putative flavodoxin redox protein. Here we confirm that 0305φ8-36 phage encodes a FMN-containing flavodoxin polypeptide and we report the expression, purification and enzymatic characterization of the recombinant protein. Purified 0305φ8-36 flavodoxin has near-identical spectral properties to control, purified Escherichia coli flavodoxin. Using in vitro assays we show that 0305φ8-36 flavodoxin can be reconstituted with E. coli flavodoxin reductase and support regio- and stereospecific cytochrome P450 CYP170A1 allyl-oxidation of epi-isozizaene to the sesquiterpene antibiotic product albaflavenone, found in the soil bacterium Streptomyces coelicolor. In vivo, 0305φ8-36 flavodoxin is predicted to mediate the 2-electron reduction of the β subunit of phage-encoded ribonucleotide reductase to catalyse the conversion of ribonucleotides to deoxyribonucleotides during viral replication. Our results demonstrate that this phage flavodoxin has the potential to manipulate and drive bacterial P450 cellular metabolism, which may affect both the host biological fitness and the communal microbiome. Such a scenario may also be applicable in other viral-host symbiotic/parasitic relationships.

Bone density of the humeral condyle in Labrador retrievers with medial coronoid process disease

OBJECTIVES

To estimate, using CT imaging, differences in the regional bone density of the humeral condyle in Labrador retriever elbows with and without medial coronoid process disease.

MATERIALS AND METHODS

The elbows of Labrador Retrievers that had undergone CT were reviewed. Scans were divided into three categories: elbows without medial coronoid process disease; elbows with medial coronoid process disease involving fragmentation of the radial incisure; elbows with medial coronoid process disease involving fragmentation of the medial coronoid apex. A templating technique was employed to define the weight-bearing regions of the medial and lateral portion of the humeral condyle and estimates of volumetric bone density (defined by Hounsfield unit measurement) were compared across the three groups.

RESULTS

CT evaluation was performed on 122 elbows in 81 dogs. There was a higher mean Hounsfield unit measurement in the medial and lateral portions of the humeral condyles in elbows with medial coronoid process disease involving fragmentation of the medial coronoid apex compared with elbows with medial coronoid process disease involving fragmentation of the radial incisure.

CLINICAL SIGNIFICANCE

Dogs with apical fragmentation of the medial coronoid process exhibited significantly higher estimated bone mineral density within the medial portion of the humeral condyle when compared to dogs with radial incisure fragmentation. The medial portion of the humeral condyle may be associated with the pathogenesis of apical but not radial incisure medial coronoid process fragmentation in Labrador Retrievers.

Impact of sites of metastatic dissemination on survival in advanced gastroesophageal adenocarcinoma

Introduction

Metastatic gastroesophageal adenocarcinoma (GEA) is a heterogeneous disease with an overall poor prognosis. The impact of sites of metastatic dissemination on survival is not well characterized. This study aimed to evaluate whether certain sites of metastatic disease impacts survival.

Methods

A retrospective analysis of 375 patients with metastatic GEA treated at the Princess Margaret Cancer Centre from 2006 to 2016 was performed. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method. Cox proportional hazards regression models were used to assess the association between sites of metastases and OS adjusting for baseline patient characteristics.

Results

Median duration of follow-up was 47.8 months. Median OS in this cohort was 11.8 months (95% CI: 10.2–12.9 months). Patients with lymph node only disease, compared to those with other sites of metastases, had the longest median OS (20.4 vs. 10.6 months; p < 0.001) and PFS (11.4 vs. 6.3 months; p < 0.001). On multivariable analysis adjusting for relevant clinical factors including age, sex, and Eastern Cooperative Oncology Group performance status, the presence of lung (HR 1.67, 95% CI: 1.23–2.26; p < 0.001) or bone metastases (HR 1.84, 95% CI: 1.31–2.59; p < 0.001) were independently associated with shorter OS. The majority of patients (68%) were treated with palliative intent first-line platinum-based chemotherapy.

Discussion/Conclusion

Patients with metastatic GEA have an overall poor prognosis. The presence of lung or bone metastases is an independent risk factor for decreased survival. Prognostic models incorporating sites of metastasis should be considered in the clinical evaluation of metastatic GEA.

Comparison of four clinical prognostic scores in patients with advanced gastric and esophageal cancer

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Background: While several clinical scoring systems exist to aid prognostication and patient (pt) selection for clinical trials in oncology, none are standardly used. We compared the ability of four prognostic scores to predict overall survival (OS) in pts with advanced gastric and esophageal (GE) cancer. Methods: Pts with advanced (unresectable or metastatic) GE cancer receiving first-line palliative-intent systemic therapy at the Princess Margaret Cancer Centre from 2007 to 2020 were included. High prognostic risk pts were identified using four scoring systems: Royal Marsden Hospital (RMH), MD Anderson Cancer Centre (MDACC), Gustave Roussy Immune Score (GRIm-S) and MD Anderson Immune Checkpoint Inhibitor (MDA-ICI) score. OS was estimated using the Kaplan-Meier method and compared between risk groups (high vs. not-high) for each scoring system using the log-rank test. Cox proportional hazards models were used to analyze the association between each prognostic score and OS, adjusting for baseline clinical factors. Harrell’s c-index was used to evaluate predictive discrimination of the models. Time-dependent AUCs were used to measure predictive ability for early death (within 90 days). Results: In total, 451 pts with advanced GE cancer were included. The median age was 59 years, 68% were male, 51% had ECOG status 0-1, 63% presented with de novo metastatic disease. The proportion of pts categorized as high risk was: RMH 25% (N=113), MDACC 13% (N=95), GRIm-S 24% (N=109), MDA-ICI 26% (N=117). In all scoring systems, high risk pts had significantly shorter OS (median OS 7.9 versus 12.2 months for RMH high vs. low risk, p<0.001; 6.8 vs. 11.9 months p<0.001 for MDACC; 5.3 vs. 13 months p<0.001 for GRIm-S; 8.2 vs. 12.2 months p<0.001 for MDA-ICI). On multivariable analysis, each prognostic score was significantly associated with OS (Table). The GRIm-S had the highest predictive discrimination (c-index 0.645 [0.612-0.678]) and highest predictive ability for early death (AUC 0.754 [0.675-0.832]). Conclusions: All four prognostic scoring systems compared had reasonable accuracy in predicting OS for patients with advanced GE cancer. The higher accuracy for predicting early death may render the GRIm-S as preferable. These tools can aid oncologists in discussions about prognosis, therapeutic decision-making and patient selection for clinical trials.[Table: see text]

Comparison of systematic inflammatory prognostic scores in patients with advanced pancreatic adenocarcinoma

4149

Background: Systemic inflammatory scores have been developed as tools to aid clinicians in prognostication and patient (pt) selection for clinical trials. We compared the accuracy of five prognostic scores to predict overall survival (OS) in pts with advanced pancreatic adenocarcinoma (PDAC). Methods: Pts with advanced PDAC enrolled on the COMPASS trial (NCT02750657) from 2015 to 2020 were included. All pts had biopsies for whole genome and RNA sequencing prior to standard first-line chemotherapy in the advanced setting. Prognostic risk was calculated using: neutrophil-to-lymphocyte ratio (NLR; >5 = high), platelet-to-lymphocyte ratio (PLR; > 150 = high), Prognostic Nutritional Index (PNI = albumin + 5 x lymphocytes. PNI < 45 = high risk), Gustave Roussy Immune Score (GRIm-S; NLR>6 = 1 point, albumin <35 = 1 point, LDH > upper limit of normal [ULN] = 1 point. GRIm-S ≥2 = high risk), and Memorial Sloan Kettering Prognostic Score (MPS; NLR >4 and albumin < 40 = high risk). OS was estimated using the Kaplan-Meier method and compared between risk groups (high vs. not-high) for each scoring system using the log-rank test. Cox proportional hazards models were used to analyze the association between each prognostic score and OS, adjusting for baseline clinical and genomic factors. Results: In total, 263 pts with advanced PDAC cancer were included, with median follow up of 32.9 (95% CI 15.9-64.2) months. Median OS in the intention to treat population was 9.3 months (95% CI 8-10.2). PLR and PNI were not prognostic. High risk NLR (N=85, 32%), GRIm-S (N=47, 18%) and MPS (N=46, 17%) identified pts with poor prognosis. The GRIm-S and MPS were most significant: median OS in high vs low risk pts 6.4 vs. 10 months p<0.001 (GRIm-S) and 6.3 vs. 10 months p=0.002 (MPS). On multivariable analyses, high risk NLR, GRIm-Score and MPS were each associated with poor OS after adjusting for baseline clinical and genomic factors (Table). For all models, ECOG ≥1 (N=165, 63%); the basal-like Moffitt RNA subtype (N=49, 20% vs 80% classical) and low HRDetect scores (N=31, 13%) were significantly associated with poor OS. However these scores did not associate with RNA based classifiers or HRD scores and can therefore provide additional prognostic information. Conclusions: Both the GRIm-S and MPS are highly prognostic in PDAC and are scores easily used in the clinical setting and may help in clinical trial selection. Genotypic correlates are being explored.[Table: see text]

End-of-life intravenous chemotherapy administration patterns in the treatment of Queensland lung and pancreas cancer patients: a 10-year retrospective analysis

BACKGROUND

End-of-life (EOL) chemotherapy administration rates for solid tumours are 12-20% and are associated with a reduced quality of life, increased hospitalisation and incidence of death within an acute care facility.

AIM

We sought to determine the rate of EOL chemotherapy in government and private hospitals and determine the impact on hospitalisations and location of death in lung and pancreatic cancer patients.

METHODS

Data were obtained from the Queensland Oncology Repository between 2005 and 2014. Lung (n = 16 501) and pancreatic cancer (n = 4144) deaths were analysed. EOL chemotherapy was determined to be within 30 days of death. Demographics, location of treatment and death are reported.

RESULTS

Chemotherapy was administered to 6518 (40%) lung cancer and 1694 (41%) pancreatic cancer patients. A total of 1474 (9%) and 477 (12%) patients, respectively, received EOL chemotherapy. EOL chemotherapy was more common in males and those with distant metastatic disease, while less likely in the elderly and those with a lower socioeconomic status. EOL chemotherapy was more prevalent in large hospitals and was more common in private compared with government hospitals for pancreatic cancer (30 vs 26%; P < 0.001), while it was similar for lung cancer (24 vs 22%; P = 0.115). Death after EOL chemotherapy compared with all cancer deaths was more common in an acute care facility (lung cancer: 60 vs 37%; P < 0.001; pancreatic cancer: 53 vs 36%; P < 0.001).

CONCLUSIONS

EOL chemotherapy rates were similar to Australian yet marginally lower than international rates, with variation dependent on the size and type of facility and increased the rate of deaths within an acute care facility.

Preoperative and Postoperative Approaches to Gastroesophageal Cancer: What is All the Fuss About

Gastroesophageal cancers carry poor prognoses, and are a leading cause of cancer-related morbidity and mortality worldwide. Even in those with resectable disease, more than half of patients treated with surgery alone experience disease recurrence. Multimodality approaches using preoperative and postoperative chemotherapy and/or radiotherapy have been established, resulting in incremental improvements in outcomes. Globally, there is no standardized approach, and treatment varies with geographic location. The question remains of how to select the optimal perioperative treatment that will maximize benefit for patients while avoiding toxicities from unnecessary therapies. This article reviews currently available evidence supporting preoperative and postoperative therapy in gastroesophageal cancers, with an emphasis on recent practice-changing trials and ongoing areas of investigation, including the role of immune checkpoint inhibition and biomarker-guided treatment.

Prognostic ability of the Gustave Roussy Immune Score for patients with advanced pancreatic adenocarcinoma

469

Background: The Gustave Roussy Immune Score (GRIm-S) considers a composite of neutrophil to lymphocyte ratio (> 6 = 1), albumin (< 35 = 1) and LDH (> ULN = 1) and has been established as a prognostic score and may in aid in the selection of patients for phase 1 trials of immune checkpoint inhibitors. Methods: We explored the prognostic impact of the GRIm-S (high > 1) in patients enrolled on the COMPASS trial and correlated the score with genomic and clinical characteristics. Patients in this trial had biopsies for whole genomic and RNA sequencing prior to standard chemotherapy regimens in the advanced setting. Results: 252 patients were included in the analyses with a median follow-up time of 28 months. 16% of patients had a high GRIm-S with significantly shorter median overall survival (OS) of 4.1 months versus 10.0 months in those with a low score (HR 2.18, 95% CI 1.4-3.4, p < 0.0001). In the GRIm-S-high cohort, early progression with non-evaluable disease and disease progression were more common than in the GRIm-S low cohort (56% vs 31%, p = 0.003). In a multivariable analysis, a high GRIm-S was poorly prognostic (HR 1.6 95% CI 1.3-1.9, p < 0.001), whereas the classical RNA subtype (vs. basal-like) (HR 0.41, 95% CI 0.3-0.6, p < 0.001) and a high HRDetect score (HR 0.47 95% CI 0.3-0.7, p < 0.001) associated with superior OS. The GRIm-S did not correlate with RNA subtypes or with specific KRAS mutations. There were no differences in structural variant load or tumour mutational burden between groups. However those with a high GRIm-S did have a higher total target lesion diameter at baseline (p < 0.001). Conclusions: The GRIm-S identifies a subset of patients who have aggressive pancreas cancer and short life expectancy. This information may help clinicians in treatment decision making and selection for clinical trials.

Survival prediction using radiomic signatures in metastatic gastric and esophageal adenocarcinoma (GEA)

357

Background: Radiomic characterisation of tumour phenotypes can generate image-driven biomarkers that potentially aid in clinical decision-making. We sought to identify radiomic features in metastatic GEA that may be predictive for survival outcomes. Methods: A retrospective analysis between 2009-20 identified patients (pts) with metastatic GEA. All pts received chemotherapy (CTx), with a ‘baseline’ and 8-12 week ‘on-treatment’ contrast-enhanced CT chest/abdomen/pelvis performed. Radiomic analysis was performed with LIFEx (livexsoft.org). Population demographics and clinical outcomes were recorded. Univariable Cox proportional hazards model (UVA) assessed clinical variables (n=26) predictive of overall survival (OS) and progression-free survival (PFS) with p=0.05 indicating significance. Multivariable Cox model (MVA) was used to assess radiomic features (n=78) in the presence of clinical variables. Concordance index (C-index) was calculated to assess model performance (≥0.7 = high predictive accuracy). A ‘validation’ cohort analysis was performed to validate the model. Results: 166 pts were identified (primary cohort n=143; validation cohort n=23). 123 had de-novo metastatic disease, 43 recurrence following curative-intent therapy. In the primary cohort the median age was 58.1y, 101 (71%) were male, 120 (84%) were non-Asian and 131 (92%) were ECOG 0-1. Similar demographics were observed in the validation cohort. Both ‘baseline’ and ‘on-treatment’ scans UVA identified Her2 status, ethnicity, and the number of CTx cycles as predictive of PFS, while ECOG, brain metastases, neutrophil count (ANC), albumin and number of CTx cycles were predictive of OS. ‘Baseline’ model analysis for PFS and OS identified consistent radiomic features (HUskewness; HUpeakSphere), with an observed C-index 0.6 and 0.657 respectively. No radiomic features were identified on ‘on-treatment’ PFS analysis. ‘On-treatment’ OS analysis is shown in the table with 3 radiomic features (SHAPE Surface; SHAPE Compacity; PARAMS ZSpatial-Resampling) predictive for OS. The C-index is 0.76. Analysis of the validation cohort supported the model (C-index 0.815) for ‘on-treatment’ OS. Conclusions: Radiomic analysis identified a number of features associated with PFS and OS. The features specifically identified on ‘on-treatment’ scans were highly predictive for OS. Our analysis suggests radiomic features in addition to clinical variables can be predictive of outcome in patients with metastatic GEA receiving CTx.[Table: see text]

CANDIED: A Pan-Canadian Cohort of Immune Checkpoint Inhibitor-Induced Insulin-Dependent Diabetes Mellitus

Simple Summary

Immune checkpoint inhibitor-induced insulin-dependent diabetes mellitus (ICI-induced IDDM) is an emerging form of autoimmune diabetes. We describe the characteristics of 34 patients who developed ICI-induced IDDM across five Canadian cancer centres. We observed that presentation with hyperglycemic crisis is common and that patients treated with combination immunotherapy regimens develop ICI-induced IDDM earlier than those treated with monotherapy. Our results suggest that ICI-induced IDDM is irreversible but is associated with high tumor response rates and prolonged survival. The data generated by this study may help clinicians manage ICI-induced IDDM.

Abstract

Immune checkpoint inhibitor (ICI)-induced insulin-dependent diabetes mellitus (IDDM) is a rare but potentially fatal immune-related adverse event (irAE). In this multicentre retrospective cohort study, we describe the characteristics of ICI-induced IDDM in patients treated across five Canadian cancer centres, as well as their tumor response rates and survival. In 34 patients identified, 25 (74%) were male and 19 (56%) had melanoma. All patients received anti-programed death 1 (anti-PD1) or anti-programmed death ligand-1 (anti-PD-L1)-based therapy. From ICI initiation, median time to onset of IDDM was 2.4 months (95% CI 1.1–3.6). Patients treated with anti-PD1/PD-L1 in combination with an anti-cytotoxic T lymphocyte antigen 4 antibody developed IDDM earlier compared with patients on monotherapy (1.4 vs. 3.9 months, p = 0.05). Diabetic ketoacidosis occurred in 21 (62%) patients. Amongst 30 patients evaluable for response, 10 (33%) had a complete response and another 10 (33%) had a partial response. Median overall survival was not reached (95% CI NE; median follow-up 31.7 months). All patients remained insulin-dependent at the end of follow-up. We observed that ICI-induced IDDM is an irreversible irAE and may be associated with a high response rate and prolonged survival.

Genomic sequencing to inform therapy in advanced pancreatic cancer: A systematic review and meta-analysis of prospective studies

PURPOSE

Current guidelines recommend somatic genomic sequencing for patients with advanced pancreatic cancer to identify targetable alterations amenable to targeted therapy. The benefit of somatic genomic sequencing in pancreatic cancer remains unclear. This study aims to assess the evidence supporting genomic sequencing to inform treatment selection for patients with advanced pancreatic cancer.

METHODS

A systematic review identified prospective studies of exocrine pancreatic cancer patients published before August 2020 which conducted genomic sequencing to inform treatment selection. Outcomes of interest included the proportion of patients with targetable alterations, the proportion that received targeted treatments, and the impact of targeted treatments on overall survival. Meta-analysis for proportions and hazard ratios was performed using Dersimonian and Laird random effect models.

RESULTS

19 studies (representing 2048 pancreatic cancer patients) were included. Sequencing methodologies, definitions of targetable alterations, and approaches treatment selection varied across studies and were incompletely reported. 590 of 1382 sequenced patients harboured a targetable alteration (random effects meta-analysis estimate of the proportion 0.46, 95% confidence interval 0.32-0.61). The proportion of patients with targetable alterations was highly heterogenous between studies (I² 93%, P < 0.001). 91 of 1390 patients received a matched therapy based on their targetable alterations (random effects meta-analysis estimate of the proportion 0.12, 95% CI 0.06-0.23). One observational study reported an overall survival benefit of matched therapy.

CONCLUSIONS

Genomic sequencing frequently identifies targetable alterations in pancreatic cancers. Further research is required to standardize the definitions of targetable alterations, the approach to treatment matching, and quantify the benefit of targeted therapy.

Efficient dilution-to-extinction isolation of novel virus-host model systems for fastidious heterotrophic bacteria

Microbes and their associated viruses are key drivers of biogeochemical processes in marine and soil biomes. While viruses of phototrophic cyanobacteria are well-represented in model systems, challenges of isolating marine microbial heterotrophs and their viruses have hampered experimental approaches to quantify the importance of viruses in nutrient recycling. A resurgence in cultivation efforts has improved the availability of fastidious bacteria for hypothesis testing, but this has not been matched by similar efforts to cultivate their associated bacteriophages. Here, we describe a high-throughput method for isolating important virus-host systems for fastidious heterotrophic bacteria that couples advances in culturing of hosts with sequential enrichment and isolation of associated phages. Applied to six monthly samples from the Western English Channel, we first isolated one new member of the globally dominant bacterial SAR11 clade and three new members of the methylotrophic bacterial clade OM43. We used these as bait to isolate 117 new phages, including the first known siphophage-infecting SAR11, and the first isolated phage for OM43. Genomic analyses of 13 novel viruses revealed representatives of three new viral genera, and infection assays showed that the viruses infecting SAR11 have ecotype-specific host ranges. Similar to the abundant human-associated phage ɸCrAss001, infection dynamics within the majority of isolates suggested either prevalent lysogeny or chronic infection, despite a lack of associated genes, or host phenotypic bistability with lysis putatively maintained within a susceptible subpopulation. Broader representation of important virus-host systems in culture collections and genomic databases will improve both our understanding of virus-host interactions, and accuracy of computational approaches to evaluate ecological patterns from metagenomic data.

Predictors of survival after metastasectomy of oligometastatic recurrence following gastroesophageal cancer treatment

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Background: Recurrent gastroesophageal (GE) carcinomas carry a poor prognosis and are usually treated with palliative chemotherapy (CTX). However, recent studies suggest that certain patients with oligometastatic recurrence can have long term survival after metastasectomy. Appropriate patient selection for metastasectomy remains a challenge, as few predictors of overall survival (OS) after metastasectomy have been identified. Our primary aim was to identify predictors of OS following metastasectomy in GE cancers. Methods: We conducted a retrospective study of GE cancer patients treated from 2007 to 2015 using the Princess Margaret Hospital Cancer Registry. We included patients who underwent curative-intent surgery or definitive chemoradiation (CRT) for localized GE cancer who then had single organ recurrence treated with metastasectomy. The probability of OS from date of recurrence was estimated with the Kaplan Meier method. Predictors of OS after metastasectomy for isolated recurrence were determined using Cox proportional hazards analysis. Covariates included time to recurrence (interval from curative-intent surgery or completion of definitive CRT), site of recurrence (lung/non-lung), sex, age and race (Asian/Non-Asian). Within the multivariable model, predictors with a p-value less than 0.05 were deemed significant. Results: Of 44 patients, median age was 58 years (28-78), and 59% were male. Primary sites were: esophagus 25%, GE junction 41% and gastric 34%. Treatment of the primary was: surgery alone 13%, surgery and (neo)adjuvant CTX 76%, and CRT 11%. Recurrent sites were brain 22%, ovary 20%, lung 18%, bone 7%, adrenals 7%, liver 7%, distant lymph node 6%, and other 13%. The median follow up time was 38.9 months. The 1, 3 and 5-year (yr) OS following metastasectomy were 79% (95% CI 68-92%), 40% (27-58%) and 28% (16-49%). Univariable analysis revealed that time to recurrence greater than 1 yr (HR=0.45 95% CI 0.21-0.93, p=0.032) and lung site recurrence (HR=0.16 95% CI 0.04-0.67, p=0.012) were associated with longer OS. On multivariable analysis, only lung site recurrence was significant (HR=0.12 95% CI 0.03-0.54, p=0.0056). The 1, 3 and 5-yr OS for patients after resection of isolated lung recurrence were 100% (95% CI 100-100%), 86% (63-100%) and 69% (40-100%). Conclusions: In our study, patients with isolated pulmonary recurrences demonstrated prolonged overall survival following metastasectomy. These patients could be considered for resection following recurrence of GE cancer. [Table: see text]

Impact of lenvatinib (LEN) dose-intensity and starting dose on survival among patients with advanced hepatocellular carcinoma (HCC): Results from a Canadian multicenter database (HCC CHORD)

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Background: The REFLECT trial established LEN as a first-line treatment option for HCC. However, decreased LEN exposure is common due to adverse events leading to dose reductions and treatment discontinuations. The aim of this study was to evaluate whether starting dose or dose-intensity of LEN affects survival. To our knowledge, this is the first study to examine dosing of LEN and survival in HCC patients treated outside of Asia. Methods: From July 2018 to December 2019, HCC patients treated with first-line LEN from 10 different Canadian cancer centers were included. Overall survival (OS), progression-free survival (PFS), disease control rate (DCR) and objective response rate (ORR) were retrospectively analyzed and compared across different mean dose-intensities (> 66.7% vs <=66.7%) and starting dose groups (Full vs reduced). Survival outcomes were assessed with Kaplan-Meier curves and Cox proportional hazards models. DCR and ORR were determined radiographically according to the treating physician´s assessment in clinical notes and not RECIST 1.1 or mRECIST. Results: A total of 173 patients were included. Median age was 67 years, 77% were men and 23% East Asian. The most frequent causes of liver disease were hepatitis C (38%) and B (20%). 56% of patients received localized treatment prior to LEN. Of those, 24% had TACE, 6% TARE and 8% had liver transplant. Before starting LEN 31% of patients were ECOG 0 and 57% were ECOG 1. Most patients were Child-Pugh A (81%) and BCLC stage C (73%). Main portal vein invasion was present in 15% of the patients. Median follow-up was 4.5 months. LEN was started at full dose in 54% of patients and 60% had a mean dose intensity greater than 66.7%. ORR, PFS and OS results and their comparison between the different starting dose and dose-intensities are shown in the table. In a multivariate model that adjusted for age, gender, stage, ECOG, Child-Pugh, BCLC, cirrhosis, liver etiology disease (hepatitis B, C and non-viral), presence of tumor thrombus, prior transplant and localized treatment, dose intensity (>66.7 vs <=66.7% [HR 0.70, 95% CI 0.42-1.18; p=0.18]) was not a predictor of survival. Conclusions: In HCC patients starting LEN at a reduced dose does not appear to compromise survival. LEN dose-intensity of > 66.7% was associated with improved survival, but not after controlling for potential confounders.[Table: see text]

A Non-Destructive, Tuneable Method to Isolate Live Cells for High-Speed AFM Analysis

Suitable immobilisation of microorganisms and single cells is key for high-resolution topographical imaging and study of mechanical properties with atomic force microscopy (AFM) under physiologically relevant conditions. Sample preparation techniques must be able to withstand the forces exerted by the Z range-limited cantilever tip, and not negatively affect the sample surface for data acquisition. Here, we describe an inherently flexible methodology, utilising the high-resolution three-dimensional based printing technique of multiphoton polymerisation to rapidly generate bespoke arrays for cellular AFM analysis. As an example, we present data collected from live Emiliania huxleyi cells, unicellular microalgae, imaged by contact mode High-Speed Atomic Force Microscopy (HS-AFM), including one cell that was imaged continuously for over 90 min.

Gastric and gastroesophageal adenocarcinoma survival outcomes relative to completion of perioperative fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT): A single-center retrospective analysis

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Background: Perioperative FLOT is standard-of-care for locally advanced resectable gastric and gastroesophageal (GEJ) adenocarcinoma. Completion of perioperative chemotherapy (8 cycles) is potentially jeopardised by significant toxicity and intolerance. Only 46% of patients completed all cycles in the initial phase 2/3 trial (FLOT-AIO). We sought to determine the rate of treatment completion in a real-world population and any subsequent impact on survival of incomplete treatment. Methods: A retrospective analysis of gastric and GEJ adenocarcinoma patients treated with perioperative FLOT at Princess Margaret Cancer Centre, Toronto between September 2017 and July 2020 was performed. The rate of perioperative FLOT administration, disease-free survival (DFS) and overall survival (OS) was analysed, with outcomes compared between patients that completed perioperative FLOT and those that didn’t. Results: 32 patients were identified as receiving neoadjuvant FLOT. Mean age was 61.5y, 26 (81%) were male and 29 (91%) were non-Asian. All patients were ECOG 0-1. The median number of neoadjuvant cycles was 4. 29 (91%) had surgery (2 = disease progression; 1 = declined surgery). 10 (34%) patients had minimal/nil response upon resection (College of American Pathologists Tumour Regression Grading (TRG) Score 3), 5 of whom received adjuvant FLOT whilst 5 did not (p0.28). 10 (34%) patients did not receive adjuvant FLOT, 18 (62%) did and 1 received 8 cycles of neoadjuvant chemotherapy. Nil demographic differences were observed between ‘yes’ and ‘no’ adjuvant FLOT groups. The reasons for not having adjuvant chemotherapy were: metastatic disease diagnosed post-operatively (n = 2), TRG Score 3 (n = 4), patient declined further chemotherapy (n = 1), reduced performance status and/or toxicity (n = 2), and the patient requiring treatment for a second malignancy (n = 2). 10 (34%) patients completed perioperative chemotherapy. Median DFS was 12.5m (95% CI 7.9-12.5) for ‘no’ FLOT’ and was not-reached for ‘yes’ FLOT (p = 0.29). 18m DFS was 50% (95% CI 27-93) v 81% (95% CI 64-100) respectively. The median OS for ‘no’ adjuvant FLOT was 16.7m (95% CI 11.5-16.7) with 5 deaths. Zero deaths due to malignancy had occurred at 23.3m in those who received adjuvant FLOT (p0.00164). 1 death in the ‘yes’ group occurred due to interstitial lung disease. Conclusions: In our small population size 34% of patients completed perioperative FLOT. Whilst nil statistically significant difference was observed in mDFS, an improved mOS was observed in those that received adjuvant FLOT suggesting an importance in receiving the maximum number of cycles of chemotherapy. Given the challenges of administering adjuvant FLOT future trials into the feasibility and efficacy of 8 cycles of neoadjuvant FLOT should be considered.

Efficacy and safety of lenvatinib in the real-world treatment of hepatocellular carcinoma: Results from a Canadian multicenter database (HCC CHORD)

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Background: The REFLECT trial establishedlenvatinib (LEN) as a first-line treatment option for hepatocellular carcinoma (HCC). Compared to sorafenib (S), LEN has a higher objective response rate (ORR) and progression-free survival (PFS) with a slightly different toxicity profile. The aim of this study was to gather data regarding the efficacy and safety of LEN when used in the real-world treatment of HCC. To our knowledge, this is the first study to examine LEN use in HCC patients treated outside of Asia. Methods: HCC patients treated with LEN from 10 cancer centers in the Canadian provinces of British Columbia, Alberta, Ontario and Nova Scotia between July 2018 to July 2020 were included. Overall survival (OS), PFS, disease control rate (DCR) and ORR were retrospectively analyzed and compared across first- and second-to-fourth line use of LEN. ORR was determined radiographically according to the treating physician´s opinion in clinical notes and not RECIST 1.1 or mRECIST. Toxicities were also examined. Results: A total of 220 patients were included in this analysis. Median age was 67 years, 80% were men and 25.5% East Asian. The most frequent causes of liver disease were hepatitis C (37%) and B (26%). 62% of patients received any localized treatment before LEN, of those 26% had TACE, 15% TARE and 7.7% had liver transplant. Before starting LEN 29% of patients were ECOG 0 and 59% were ECOG 1. Most patients were Child-Pugh A (81%) and BCLC stage C (75.5%). Main portal vein invasion was present in 14% of the patients. Median follow-up was 4.5 months. A total of 173 patients (79%) received LEN as first line therapy and 47 patients (21%) were treated in second-to-fourth line. Of patients receiving LEN in first line, 22 (13%) started treatment with S, but switched to LEN before progression due to poor tolerance of S. ORR, DCR, PFS and OS are shown in the table. Toxicities occurred in 86% of patients and led to dose reductions in 76 (35%) patients and drug discontinuation in 53 (24%) patients. The most common side effects were fatigue (59%), hypertension (41%), decreased appetite (25%) and diarrhea (22%). Conclusions: Outcomes of HCC patients treated in Canada with LEN in the first line are comparable to those demonstrated in the REFLECT trial, despite the inclusion of Child-Pugh B and ECOG >1 patients. LEN use in second or later lines also showed similar outcomes, although more conclusions are difficult to draw due to the small numbers. LEN appears to be effective and safe in real world practice outside of Asia in first- and second-to-fourth line treatment of HCC. [Table: see text]

Prognostic significance of nutritional markers in metastatic gastric and esophageal adenocarcinoma

Background

Malnutrition and sarcopenia are poor prognostic factors in many cancers. Studies in gastric and esophageal (GE) cancer have focused on curative intent patients. This study aims to evaluate the prognostic utility of malnutrition and sarcopenia in de novo metastatic GE adenocarcinoma.

Methods

Patients with de novo metastatic GE adenocarcinoma seen at the Princess Margaret Cancer Centre from 2010 to 2016 with an available pre‐treatment abdominal computed tomography (CT) were included. Malnutrition was defined as nutritional risk index (NRI) <97.5. Skeletal muscle index (SMI) was measured at the L3 level (sarcopenia defined as SMI <34.4 cm²/m² in women and <45.4 cm²/m² in men). Patients receiving chemotherapy had NRI and SMI recalculated at the time of first restaging CT.

Results

Of 175 consecutive patients, 33% were malnourished and 39% were sarcopenic at baseline. Patients with pretreatment malnourishment had significantly shorter overall survival (OS; 5.8 vs. 10.9 months, p = 0.000475). Patients who became malnourished during chemotherapy had worse OS compared to those who maintained their nutrition (12.2 vs. 17.5 months p = 0.0484). On univariable analysis, ECOG (p < 0.001), number of metastatic sites (p = 0.029) and NRI (p < 0.001) were significant prognostic factors while BMI (p = 0.57) and sarcopenia (p = 0.19) were not. On multivariable analysis, ECOG (p < 0.001), baseline NRI (p = 0.025), and change in NRI during treatment (p < 0.001) were significant poor prognostic factors for OS.

Conclusions

In de novo metastatic GE adenocarcinoma patients, ECOG, pretreatment NRI and change in NRI were significant prognostic factors for OS while sarcopenia was not. Use of NRI at baseline and during treatment can provide useful prognostic information.

Retrospective analysis of hospital admissions due to immune checkpoint inhibitor-induced immune-related adverse events (irAE)

AIM

Hospital admissions secondary to immune-related adverse events (irAE) arising from immune checkpoint inhibitors (ICI) are likely to increase with increasing use of this class of drug. We sought to determine the characteristics and outcomes of hospital admissions due to irAE.

METHODS

A retrospective analysis of patients treated with ICI at two tertiary hospitals in Queensland (Australia) was performed. Patients who received at least one dose of ICI for a nonhaematological malignancy between the 1st January 2016 and 1st January 2017 were included. All subsequent hospital admissions were analyzed.

RESULTS

A total of 140 patients were included, with the most common malignancies being non-small-cell-cell lung cancer (41%) and melanoma (18%), and most patients received anti-PD1 treatment (78%). A sum of 76 patients accounted for 116 admissions. Comparing admissions due to irAE and non-irAE, those admitted for irAE had a significantly longer duration on ICI prior to admission (173 vs 105 days, P = 0.04) but durations of admissions were similar (9.0 vs 8.5 days, P = 0.85). Fifteen patients (11% overall cohort) accounted for 18 admissions attributable to 16 separate irAE. irAE was not considered as a differential diagnosis on admission in 7 patients (38%). In those patients, commencement of corticosteroids was delayed (1.5 days, P = 0.01) but this did not translate into adverse outcomes such as prolonged admissions, prolonged steroid use or long-term complications. All patients with irAE were managed with high-dose corticosteroids. One death resulted from irAE (pneumonitis).

CONCLUSIONS

A sum of 11% patients receiving ICI required hospital admission for irAE. The relatively high rate of irAE as a missed differential diagnosis on admission suggests a need for improved cross-discipline awareness, education, and institutional management guidelines.

Prognostic significance of nutritional markers in metastatic gastric and esophageal adenocarcinoma

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Background: Malnutrition and sarcopenia (defined as low skeletal muscle mass) are recognized as poor prognostic factors in many cancers. Studies to date in gastroesophageal cancer have largely focused on patients (pts) undergoing curative intent surgery. This study aims to evaluate the prognostic utility of nutritional markers and sarcopenia in pts with de novo metastatic gastric and esophageal adenocarcinoma (GEA). Methods: Pts with de novo metastatic GEA seen at the Princess Margaret Cancer Centre from 2010-2016 with available pre-treatment abdominal computed tomography imaging were identified from an institutional database. Nutritional index (NRI) was calculated using weight and albumin, with moderate/severe malnutrition defined as NRI < 97.5. Skeletal muscle index (SMI) normalized by height was calculated at the L3 level using Slice-O-Matic software. Sarcopenia was defined as SMI < 34.4cm2/m2 in women and < 45.4cm2/m2 in men based on previously established consensus. Results: Of 175 consecutive pts, median age was 61, 69% were male, 79% had ECOG performance status 0-1, and 71% received chemotherapy. Median BMI was 24.2 (range 15.7-39.8), 70% of pts had > 5% weight loss in the preceding 3 months, and 29% had moderate/severe malnutrition. 68 pts (39%) were sarcopenic, of whom 46% were malnourished. Median overall survival (OS) was 9.3 months (95% CI 7.3-11.4) for all pts. OS was significantly worse in malnourished pts (5.5 vs 10.9 months, p = 0.000475) and displayed a non-significant trend in sarcopenic pts (7.8 vs 10.6 months, p = 0.186). On univariable Cox proportional hazards (PH) analysis, ECOG (p < 0.001), number of metastatic sites (p = 0.029) and NRI (p < 0.001) were significant prognostic factors, while BMI (p = 0.57) and sarcopenia (p = 0.19) were not. On multivariable Cox PH analysis, ECOG (p < 0.001) and NRI (p = 0.025) remained significant as poor prognostic factors for OS. Conclusions: This study demonstrates in a large cohort of de novo metastatic GEA pts that ECOG and NRI were significantly associated with poor OS. NRI was superior to BMI alone. Early identification of malnourished pts using NRI may allow for supportive interventions to optimize nutritional status. Further study is needed to determine whether these factors can be modified to improve prognosis in these pts.

Outcomes relative to paclitaxel dose-intensity when administered with ramucirumab in gastric and gastroesophageal junction (GEJ) adenocarcinoma

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Background: Combination paclitaxel (PTX) and ramucirumab (RAM) is standard second-line treatment for gastric and GEJ cancers. Peripheral neuropathy (PN) is considered a potential obstacle to administering a maximal dose of PTX, potentially limiting efficacy. We sought to determine the dose-intensity and outcomes for patients receiving this treatment. Methods: A retrospective analysis of gastric and GEJ cancer patients treated at Princess Margaret Cancer Centre (2012-2017) was performed identifying all patients who received PTX and RAM during their treatment course. The primary objective was to determine the dose-intensity of PTX administration. Secondary objectives included identification of the reason for dose-reduction (DR), and comparing progression-free survival (PFS) and overall survival (OS) in relation to PTX DR. Results: 45 patients were included in the study. Mean age was 57.2y, 34 (76%) were male, 7 (16%) were Asian, 5 (11%) patients were her2 positive. 42 (93%) patients received first-line treatment containing a potential neuro-toxic agent (cisplatin, oxaliplatin, docetaxel or paclitaxel). 22 (49%) subjects required PTX DR. The median number of cycles administered for subjects not requiring a DR and those with dose-reduced PTX was 3 v 6 (p < 0.001) respectively, with the median number of PTX doses administered 8 v 15 (p0.0022). The mean dose-intensity was 100 v 83% (p < 0.001). PN was the reason for DR in 32% (n = 7) of subjects, whilst neutropenia was 41% (n = 9). The reason for treatment cessation was disease progression in 91% of subjects, irrespective of whether they required a DR or not. Median PFS was 2.8m (95% CI 2.1-4.8) (100% dose PTX) and 5.5m (95% CI 4.8-8.6) in those requiring a DR (p0.0006). Median OS, measured from the initial diagnosis of incurable/metastatic disease was 16.4m (95% CI 13.7-22.9) and 18.5m (95% CI 14.9-47.5) respectively (p0.0953). Conclusions: Approximately half of the patients required a PTX DR, of whom a clinically significant 32% were DR due to PN, slightly less than those DR due to neutropenia. PFS was longer in those requiring a DR, which may reflect that those on treatment longer are more likely to experience toxicity and require a subsequent DR. PTX DR did not significantly affect OS, thus whilst PTX toxicity remains a clinical concern we did not identify that a DR resulted in an appreciable difference in treatment efficacy.

Coproducts of algae and yeast-derived single cell oils: A critical review of their role in improving biorefinery sustainability

Oleaginous microalgae and yeast are of increasing interest as a renewable resource for single cell oils (SCOs). These have applications in fuels, feed and food products. In order to become cost competitive with existing terrestrial oils, a biorefinery approach is often taken where several product streams are valorised alongside the SCO. Whilst many life cycle assessment (LCA) and Techno-economic (TEA) studies have employed this biorefinery approach to SCO production, a systematic analysis of their implications is missing. This review evaluates the economic and environmental impacts associated with the use of coproducts. Overall, protein production plays the greatest role in determining viability, with coproduct strategy crucial to considering in the early stages of research and development.

Short communication: trends in biometeorology publishing: a case study of climate and Human Health Commission members

The International Journal of Biometeorology (IJB) has been the flagship journal in the field for the past 60+ years. However, given its interdisciplinary nature, biometeorology research has appeared in numerous publication outlets other than the IJB. This study compiles the most popular of these journals, so that early-career biometeorologists might be able to be exposed to more literature that the field has to offer. In focusing on where members of the International Society of Biometeorology's (ISB) Climate and Human Health Commission (CHH) members publish, journals with a general focus on fields such as climate, the environment, and health stand out. Many of these journals have impact factors much higher than the IJB, potentially making them more attractive for dissemination of results to a larger audience. With this paper, the authors hope that the interest in biometeorology is broadened through an expansion of known available literature, specifically with early-career researchers.

Improving electrocoagulation floatation for harvesting microalgae

Electro-coagulation floatation (ECF) is a foam-floatation dewatering method that has been shown to be a highly effective, rapid, and scalable separation methodology. In this manuscript, an in-depth analysis of the gas and flocculant levels observed during the process is provided, with microbubbles observed in the 5-80 μm size range at a concentration of 102-103 bubbles mL-1. Electrolysis of microalgae culture was then observed, demonstrating both effective separation using aluminium electrodes (nine microalgal species tested, 1-40 μm size range, motile and non-motile, marine and freshwater), and sterilisation of culture through bleaching with inert titanium electrodes. Atomic force microscopy was used to visualise floc formation in the presence and absence of algae, showing nanoscale structures on the magnitude of 40-400 nm and entrapped microalgal cells. Improvements to aid industrial biotechnology processing were investigated: protein-doping was found to improve foam stability without inducing cell lysis, and an oxalate buffer wash regime was found to dissolve the flocculant whilst producing no observable difference in the final algal lipid or pigment profiles, leaving the cells viable at the end of the process. ECF separated microalgal culture had an algal biomass loading of 13% and as such was ideal for direct down-stream processing through hydrothermal liquefaction. High bio-crude yields were achieved, though this was reduced slightly on addition of the Al(OH)3 after ECF, with carbon being distributed away to the aqueous and solid residue phases. The amenability and compatibility of ECF to integration with, or replacement of, existing centrifugation and settling processes suggests this process may be of significant interest to the biotechnology industry.

The Mortality Response to Absolute and Relative Temperature Extremes

While the impact of absolute extreme temperatures on human health has been amply studied, far less attention has been given to relative temperature extremes, that is, events that are highly unusual for the time of year but not necessarily extreme relative to a location's overall climate. In this research, we use a recently defined extreme temperature event metric to define absolute extreme heat events (EHE) and extreme cold events (ECE) using absolute thresholds, and relative extreme heat events (REHE) and relative extreme cold events (RECE) using relative thresholds. All-cause mortality outcomes using a distributed lag nonlinear model are evaluated for the largest 51 metropolitan areas in the US for the period 1975-2010. Both the immediate impacts and the cumulative 20-day impacts are assessed for each of the extreme temperature event types. The 51 metropolitan areas were then grouped into 8 regions for meta-analysis. For heat events, the greatest mortality increases occur with a 0-day lag, with the subsequent days showing below-expected mortality (harvesting) that decreases the overall cumulative impact. For EHE, increases in mortality are still statistically significant when examined over 20 days. For REHE, it appears as though the day-0 increase in mortality is short-term displacement. For cold events, both relative and absolute, there is little mortality increase on day 0, but the impacts increase on subsequent days. Cumulative impacts are statistically significant at more than half of the stations for both ECE and RECE. The response to absolute ECE is strongest, but is also significant when using RECE across several southern locations, suggesting that there may be a lack of acclimatization, increasing mortality in relative cold events both early and late in winter.

Long-read viral metagenomics captures abundant and microdiverse viral populations and their niche-defining genomic islands

Marine viruses impact global biogeochemical cycles via their influence on host community structure and function, yet our understanding of viral ecology is constrained by limitations in host culturing and a lack of reference genomes and 'universal' gene markers to facilitate community surveys. Short-read viral metagenomic studies have provided clues to viral function and first estimates of global viral gene abundance and distribution, but their assemblies are confounded by populations with high levels of strain evenness and nucleotide diversity (microdiversity), limiting assembly of some of the most abundant viruses on Earth. Such features also challenge assembly across genomic islands containing niche-defining genes that drive ecological speciation. These populations and features may be successfully captured by single-virus genomics and fosmid-based approaches, at least in abundant taxa, but at considerable cost and technical expertise. Here we established a low-cost, low-input, high throughput alternative sequencing and informatics workflow to improve viral metagenomic assemblies using short-read and long-read technology. The 'VirION' (Viral, long-read metagenomics via MinION sequencing) approach was first validated using mock communities where it was found to be as relatively quantitative as short-read methods and provided significant improvements in recovery of viral genomes. We then then applied VirION to the first metagenome from a natural viral community from the Western English Channel. In comparison to a short-read only approach, VirION: (i) increased number and completeness of assembled viral genomes; (ii) captured abundant, highly microdiverse virus populations, and (iii) captured more and longer genomic islands. Together, these findings suggest that VirION provides a high throughput and cost-effective alternative to fosmid and single-virus genomic approaches to more comprehensively explore viral communities in nature.

Organic waste as a sustainable feedstock for platform chemicals

Biorefineries have been established since the 1980s for biofuel production, and there has been a switch lately from first to second generation feedstocks in order to avoid the food versus fuel dilemma. To a lesser extent, many opportunities have been investigated for producing chemicals from biomass using by-products of the present biorefineries, simple waste streams. Current facilities apply intensive pre-treatments to deal with single substrate types such as carbohydrates. However, most organic streams such as municipal solid waste or algal blooms present a high complexity and variable mixture of molecules, which makes specific compound production and separation difficult. Here we focus on flexible anaerobic fermentation and hydrothermal processes that can treat complex biomass as a whole to obtain a range of products within an integrated biorefinery concept.

Host-hijacking and planktonic piracy: how phages command the microbial high seas

Microbial communities living in the oceans are major drivers of global biogeochemical cycles. With nutrients limited across vast swathes of the ocean, marine microbes eke out a living under constant assault from predatory viruses. Viral concentrations exceed those of their bacterial prey by an order of magnitude in surface water, making these obligate parasites the most abundant biological entities in the ocean. Like the pirates of the 17th and 18th centuries that hounded ships plying major trade and exploration routes, viruses have evolved mechanisms to hijack microbial cells and repurpose their cargo and indeed the vessels themselves to maximise viral propagation. Phenotypic reconfiguration of the host is often achieved through Auxiliary Metabolic Genes - genes originally derived from host genomes but maintained and adapted in viral genomes to redirect energy and substrates towards viral synthesis. In this review, we critically evaluate the literature describing the mechanisms used by bacteriophages to reconfigure host metabolism and to plunder intracellular resources to optimise viral production. We also highlight the mechanisms used when, in challenging environments, a 'batten down the hatches' strategy supersedes that of 'plunder and pillage'. Here, the infecting virus increases host fitness through phenotypic augmentation in order to ride out the metaphorical storm, with a concomitant impact on host substrate uptake and metabolism, and ultimately, their interactions with their wider microbial community. Thus, the traditional view of the virus-host relationship as predator and prey does not fully characterise the variety or significance of the interactions observed. Recent advances in viral metagenomics have provided a tantalising glimpse of novel mechanisms of viral metabolic reprogramming in global oceans. Incorporation of these new findings into global biogeochemical models requires experimental evidence from model systems and major improvements in our ability to accurately predict protein function from sequence data.

Engineering the unicellular alga Phaeodactylum tricornutum for high-value plant triterpenoid production

Plant triterpenoids constitute a diverse class of organic compounds that play a major role in development, plant defence and environmental interaction. Several triterpenes have demonstrated potential as pharmaceuticals. One example is betulin, which has shown promise as a pharmaceutical precursor for the treatment of certain cancers and HIV. Major challenges for triterpenoid commercialization include their low production levels and their cost-effective purification from the complex mixtures present in their natural hosts. Therefore, attempts to produce these compounds in industrially relevant microbial systems such as bacteria and yeasts have attracted great interest. Here, we report the production of the triterpenes betulin and its precursor lupeol in the photosynthetic diatom Phaeodactylum tricornutum, a unicellular eukaryotic alga. This was achieved by introducing three plant enzymes in the microalga: a Lotus japonicus oxidosqualene cyclase and a Medicago truncatula cytochrome P450 along with its native reductase. The introduction of the L. japonicus oxidosqualene cyclase perturbed the mRNA expression levels of the native mevalonate and sterol biosynthesis pathway. The best performing strains were selected and grown in a 550-L pilot-scale photobioreactor facility. To our knowledge, this is the most extensive pathway engineering undertaken in a diatom and the first time that a sapogenin has been artificially produced in a microalga, demonstrating the feasibility of the photo-bio-production of more complex high-value, metabolites in microalgae.

Algal Viruses: The (Atomic) Shape of Things to Come

Visualization of algal viruses has been paramount to their study and understanding. The direct observation of the morphological dynamics of infection is a highly desired capability and the focus of instrument development across a variety of microscopy technologies. However, the high temporal (ms) and spatial resolution (nm) required, combined with the need to operate in physiologically relevant conditions presents a significant challenge. Here we present a short history of virus structure study and its relation to algal viruses and highlight current work, concentrating on electron microscopy and atomic force microscopy, towards the direct observation of individual algae⁻virus interactions. Finally, we make predictions towards future algal virus study direction with particular focus on the exciting opportunities offered by modern high-speed atomic force microscopy methods and instrumentation.

Red cell distribution width and neutrophil to lymphocyte ratio as predictors of outcomes in acute pancreatitis: A retrospective cohort study

BACKGROUND

Acute pancreatitis is a commonly encountered emergency but accurately predicting that subset of patients who will become systemically unwell has proven difficult. Simple haematological prognostic markers, such as red cell distribution width (RDW) and neutrophil to lymphocyte ratio (NLR), could identify such patients. The aim of this study was to assess the usefulness of RDW and NLR measured on admission as predictors of mortality and intensive care (ICU) or high dependency unit (HDU) admission in patients with acute pancreatitis.

MATERIALS AND METHODS

All patient who presented to our institution with acute pancreatitis between August 2013 and August 2016 were retrospectively identified using the prospectively maintained Hospital In-Patient Enquiry (HIPE) discharge audit. Data on survival, admission to HDU or ICU, length of stay and haematological parameters including RDW and NLR on presentation to the emergency department were collected.

RESULTS

A total of 185 patients with acute pancreatitis were included of which 23 (12%) patients had a RDW above the upper limit of normal (ULN), which was associated with a significantly increased likelihood of admission to ICU or HDU (RR3.5; p = 0.01); 117 (63%) patients had a NLR above 5 on presentation, which also increased the risk of ICU or HDU admission (RR 8.1; p = 0.01). Patients who had both a RDW above the ULN and a raised NLR had an increased risk of inpatient mortality (RR 9.9; p = 0.04).

CONCLUSION

RDW and NLR can identify patients at increased risk of severe acute pancreatitis on presentation to the Emergency Department.

Poloxamer 188 decreases membrane toxicity of mutant SOD1 and ameliorates pathology observed in SOD1 mouse model for ALS

Here we report a gain in function for mutant (mt) superoxide dismutase I (SOD1), a cause of familial amyotrophic lateral sclerosis (FALS), wherein small soluble oligomers of mtSOD1 acquire a membrane toxicity. Phosphatidylglycerol (PG) lipid domains are selectively targeted, which could result in membrane damage or "toxic channels" becoming active in the bilayer. This PG-selective SOD1-mediated membrane toxicity is largely reversible in vitro by a widely-available FDA-approved surfactant and membrane-stabilizer P188. Treatment of G93ASOD1 transgenic mice with P188 significantly delayed symptoms onset, extended survival and decreased motoneuron death. The use of P188 or an analogue, which targets mtSOD1 misfolding-induced membrane toxicity, may provide a new direction for ALS treatment.

Mortality risks during extreme temperature events (ETEs) using a distributed lag non-linear model

This study investigates the relationship between all-cause mortality and extreme temperature events (ETEs) from 1975 to 2004. For 50 U.S. locations, these heat and cold events were defined based on location-specific thresholds of daily mean apparent temperature. Heat days were defined by a 3-day mean apparent temperature greater than the 95th percentile while extreme heat days were greater than the 97.5th percentile. Similarly, calculations for cold and extreme cold days relied upon the 5th and 2.5th percentiles. A distributed lag non-linear model assessed the relationship between mortality and ETEs for a cumulative 14-day period following exposure. Subsets for season and duration effect denote the differences between early- and late-season as well as short and long ETEs. While longer-lasting heat days resulted in elevated mortality, early season events also impacted mortality outcomes. Over the course of the summer season, heat-related risk decreased, though prolonged heat days still had a greater influence on mortality. Unlike heat, cold-related risk was greatest in more southerly locations. Risk was highest for early season cold events and decreased over the course of the winter season. Statistically, short episodes of cold showed the highest relative risk, suggesting unsettled weather conditions may have some relationship to cold-related mortality. For both heat and cold, results indicate higher risk to the more extreme thresholds. Risk values provide further insight into the role of adaptation, geographical variability, and acclimatization with respect to ETEs.

Posttranslational Amelogenin Processing and Changes in Matrix Assembly during Enamel Development

The extracellular tooth enamel matrix is a unique, protein-rich environment that provides the structural basis for the growth of long and parallel oriented enamel crystals. Here we have conducted a series of in vivo and in vitro studies to characterize the changes in matrix shape and organization that take place during the transition from ameloblast intravesicular matrices to extracellular subunit compartments and pericrystalline sheath proteins, and correlated these changes with stages of amelogenin matrix protein posttranslational processing. Our transmission electron microscopic studies revealed a 2.5-fold difference in matrix subunit compartment dimensions between secretory vesicle and extracellular enamel protein matrix as well as conformational changes in matrix structure between vesicles, stippled materials, and pericrystalline matrix. Enamel crystal growth in organ culture demonstrated granular mineral deposits associated with the enamel matrix framework, dot-like mineral deposits along elongating initial enamel crystallites, and dramatic changes in enamel matrix configuration following the onset of enamel crystal formation. Atomic force micrographs provided evidence for the presence of both linear and hexagonal/ring-shaped full-length recombinant amelogenin protein assemblies on mica surfaces, while nickel-staining of the N-terminal amelogenin N92 His-tag revealed 20 nm diameter oval and globular amelogenin assemblies in N92 amelogenin matrices. Western blot analysis comparing loosely bound and mineral-associated protein fractions of developing porcine enamel organs, superficial and deep enamel layers demonstrated (i) a single, full-length amelogenin band in the enamel organ followed by 3 kDa cleavage upon entry into the enamel layer, (ii) a close association of 8–16 kDa C-terminal amelogenin cleavage products with the growing enamel apatite crystal surface, and (iii) a remaining pool of N-terminal amelogenin fragments loosely retained between the crystalline phases of the deep enamel layer. Together, our data establish a temporo-spatial correlation between amelogenin protein processing and the changes in enamel matrix configuration that take place during the transition from intracellular vesicle compartments to extracellular matrix assemblies and the formation of protein coats along elongating apatite crystal surfaces. In conclusion, our study suggests that enzymatic cleavage of the amelogenin enamel matrix protein plays a key role in the patterning of the organic matrix framework as it affects enamel apatite crystal growth and habit.

Supporting sustainability initiatives through biometeorology education and training

The International Society of Biometeorology (ISB) has covered significant breadth and depth addressing fundamental and applied societal and environmental challenges in the last 60 years. Biometeorology is an interdisciplinary science connecting living organisms to their environment, but there is very little understanding of the existence and placement of this discipline within formal educational systems and institutions. It is thus difficult to project the ability of members of the biometeorological community-especially the biometeorologists of the future-to help solve global challenges. In this paper, we ask: At present, how we are training people to understand and think about biometeorology? We also ask: What are the current tools and opportunities in which biometeorologists might address future challenges? Finally, we connect these two questions by asking: What type of new training and skill development is needed to better educate "biometeorologists of the future" to more effectively address the future challenges? To answer these questions, we provide quantitative and qualitative evidence from an educationally focused workshop attended by new professionals in biometeorology. We identify four common themes (thermal comfort and exposures, agricultural productivity, air quality, and urbanization) that biometeorologists are currently studying and that we expect to be important in the future based on their alignment with the United Nations Sustainable Development Goals. Review of recent literature within each of these thematic areas highlights a wide array of skill sets and perspectives that biometeorologists are already using. Current and new professionals within the ISB have noted highly varying and largely improvised educational pathways into the field. While variability and improvisation may be assets in promoting flexibility, adaptation, and interdisciplinarity, the lack of formal training in biometeorology raises concerns about the extent to which continuing generations of scholars will identify and engage with the community of scholarship that the ISB has developed over its 60-year history.

Sixty years of the International Journal of Biometeorology

The International Journal of Biometeorology (IJB) has continuously evolved since its first publications in 1957. In this paper, we examine these changes using a database that includes all manuscript titles and author information. A brief history considers the development of the journal and shifts over time. With an interdisciplinary focus, publications draw on a wide array of subdisciplines. Using content analysis, we evaluate the themes found within IJB. Some research themes have maintained prominence throughout the journal's history, while other themes have waxed or waned over time. Similarly, the most influential manuscripts throughout the past 60 years reveal that human biometeorological papers, particularly regarding thermal comfort, have been influential throughout the journal's history, with other themes, including phenology and animal biometeorology, more concentrated in specific periods. Dominated by North America and Europe in the early years, publication authorship has shifted over the last decade to be more globally representative. Recent inclusion of special issues devoted to regional biometeorological issues, as well as to Students and New Professionals, offer insight into the future direction of the IJB.

Oncologic doses of zoledronic acid induce site specific suppression of bone modelling in rice rats

OBJECTIVES

To examine the effect of zoledronic acid (ZOL) on cortical bone modelling and healing of extraction sockets in the jaw bones of a rodent model. We hypothesized ZOL suppresses both the bone formation in the modelling mode in the jaw bones and alters the extraction site healing.

MATERIAL & METHODS

Rice rats were administered saline solution and two dose regimens of ZOL: 0.1 mg/kg, twice a week, for 4 weeks (n=17, saline=8 & ZOL=9) and a higher dose of 0.4 mg/kg, weekly, for 9 weeks (n=30, saline=15 & ZOL=15). Two pairs of fluorochrome bone labels were administered. Extraction of maxillary teeth was performed in maxilla. Mineral apposition rate, mineralizing surface and bone formation rate (BFR) were quantified on periodontal (PDL), alveolar and basal bone surfaces, and in the trabecular bone of proximal tibia. Bone volume (BV) was evaluated at extraction sockets. Multivariate Gaussian models were used to account for repeated measurements, and analyzes were conducted in SAS V9.3.

RESULTS

ZOL suppressed bone modelling (BFR/BS) at the PDL surfaces in the mandible (P<.05), but its effect was not significant at the periosteal surfaces of both jaws. BV for the healing sockets of ZOL treated animals was not significantly different (P=.07) compared to the saline group. ZOL suppressive effect was higher in the tibia compared to the jaws.

CONCLUSION

ZOL severely suppresses coupled remodelling in the tibia, and the suppression of bone formation in the modelling mode in the jaws demonstrates the site specific effects of ZOL in rice rats.