Manufacturing of CD34 + HPC-enriched, high-purity mononuclear cell products from umbilical cord blood.

The purpose of this study was to explore methods of selectively enriching CD34 + haematopoietic progenitor cells (HPC) in mononuclear cell (MNC) preparations, and to outline a procedure for cryopreservation and thawing of manufactured material. Density gradient centrifugation of umbilical cord blood was achieved using Ficoll-Paque™ media at 1.077 g/mL and 1.065 g/mL densities and Leucosep preparation tubes. Post-process samples were analysed for CD34 + and MNC content. Finally, MNCs were frozen down at a concentration of 8.5 × 106 cells/mL in CryoStor CS10 using an Asymptote VIAFreeze controlled rate freezer at a rate of - 2 °C per minute, then thawed and analysed for viability and recovery. Processing with 1.065 g/mL media selectively depleted non-HPC cell types, producing an approximately fourfold increase in CD34 + frequency (M ± 1SD = 1.4 ± 1.3%, P < 0.01) relative to the pre-process sample (M ± 1SD = 0.4 ± 0.3%), whereas 1.077 g/mL media produced only a twofold enrichment (0.7 ± 0.6, P < 0.01). This was not accompanied by any significant forfeit of CD34 + recovery (79 ± 32% vs. 78 ± 32% respectively; P = 0.87). The MNCs generated by the 1.065 g/mL procedure were of greater purity (96 ± 2%) than in the 1.077 g/mL procedure (80 ± 7%, P < 0.01). Post-thaw, MNC viability was 95 ± 1% and CD34 + viability was 98 ± 1%. Ultra-pure MNCs rich in CD34 + HPCs can be generated with a simple, inexpensive modification to Ficoll-Paque™ media. These products can be easily cryopreserved using a simple controlled rate freezing procedure.

A retrospective study comparing postoperative opioid prescribing practices in an academic medical centre.

Background: In the midst of the North American opioid crisis, identifying and intervening on drivers of high-risk opioid prescriptions is an important step towards reducing iatrogenic harm. Objectives: We aimed to identify factors associated with variations in high-risk opioid discharge prescriptions, following select surgical procedures, to guide future quality improvement initiatives. Methods: This retrospective cohort study analyzed 1322 patients who underwent select open pelvic and open abdominal surgeries between January 1 and December 31, 2017, in a tertiary health care centre in Montreal. Results: Patients who underwent open abdominal surgeries were prescribed significantly higher daily doses of morphine milligram equivalents (MME) (45 mg; interquartile range, 30-60), than patients who underwent either a caesarean delivery (20 mg, 20-20) or a hysterectomy (30 mg, 22-30). After adjustment for multiple potential confounders, abdominal surgery was associated with 4 times the odds of receiving more than 50 MME at hospital discharge compared with pelvic surgeries (odds ratio, 3.96; 95% confidence interval, 1.31-11.97). The availability of postoperative preprinted order sets with fixed high doses of opioids was also highly associated with the outcome. Conclusion: In our institution, some surgeries were more likely to receive high-risk opioid prescriptions at discharge. Efforts to optimize safer prescribing practices should address the creation and/or updating of preprinted order sets to reflect current best practice guidelines. This initiative could be overseen by hospital pharmacy and therapeutics committees.

The MedSafer Study-Electronic Decision Support for Deprescribing in Hospitalized Older Adults: A Cluster Randomized Clinical Trial.

IMPORTANCE: Scalable deprescribing interventions may reduce polypharmacy and the use of potentially inappropriate medications (PIMs); however, few studies have been large enough to evaluate the impact that deprescribing may have on adverse drug events (ADEs). OBJECTIVE: To evaluate the effect of an electronic deprescribing decision support tool on ADEs after hospital discharge among older adults with polypharmacy. DESIGN, SETTING, AND PARTICIPANTS: This was a cluster randomized clinical trial of older (≥65 years) hospitalized patients with an expected survival of more than 3 months who were admitted to 1 of 11 acute care hospitals in Canada from August 22, 2017, to January 13, 2020. At admission, participants were taking 5 or more medications per day. Data analyses were performed from January 3, 2021, to September 23, 2021. INTERVENTIONS: Personalized reports of deprescribing opportunities generated by MedSafer software to address usual home medications and measures of prognosis and frailty. Deprescribing reports provided to the treating team were compared with usual care (medication reconciliation). MAIN OUTCOMES AND MEASURES: The primary outcome was a reduction of ADEs within the first 30 days postdischarge (including adverse drug withdrawal events) captured through structured telephone surveys and adjudicated blinded to intervention status. Secondary outcomes were the proportion of patients with 1 or more PIMs deprescribed at discharge and the proportion of patients with an adverse drug withdrawal event (ADWE). RESULTS: A total of 5698 participants (median [range] age, 78 [72-85] years; 2858 [50.2%] women; race and ethnicity data were not collected) were enrolled in 3 clusters and were adjudicated for the primary outcome (control, 3204; intervention, 2494). Despite cluster randomization, there were group imbalances, eg, the participants in the intervention arm were older and had more PIMS prescribed at baseline. After hospital discharge, 4989 (87.6%) participants completed an ADE interview. There was no significant difference in ADEs within 30 days of discharge (138 [5.0%] of 2742 control vs 111 [4.9%] of 2247 intervention participants; adjusted risk difference [aRD] -0.8%; 95% CI, -2.9% to 1.3%). Deprescribing increased from 795 (29.8%) of 2667 control to 1249 (55.4%) of 2256 intervention participants [aRD, 22.2%; 95% CI, 16.9% to 27.4%]. There was no difference in ADWEs between groups. Several post hoc sensitivity analyses, including the use of a nonparametric test to address the low cluster number, group imbalances, and potential biases, did not alter study conclusions. CONCLUSIONS AND RELEVANCE: This cluster randomized clinical trial showed that providing deprescribing clinical decision support during acute hospitalization had no demonstrable impact on ADEs, although the intervention was safe and led to improvements in deprescribing. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03272607.

Proton pump inhibitor use and risk for recurrent Clostridioides difficile infection: a systematic review and meta-analysis.

OBJECTIVES: Proton pump inhibitor (PPI) therapy is a potentially modifiable risk factor for recurrent Clostridioides difficile infection (CDI). Citing an absence of clinical trials, many guidelines do not provide recommendations for addressing PPI management. Our aim was to perform an updated systematic review and meta-analysis evaluating the association between PPI use and recurrent CDI addressing prior methodological limitations. METHODS: Data sources were MEDLINE and EMBASE. Eligible studies were cohort and case-control studies; there were no restrictions on study setting or duration of follow-up. Participants were adults with prior CDI who did or did not receive PPI therapy and were assessed for recurrent CDI. Summary (unadjusted) odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random effects model. Prespecified subgroup analyses were performed to explore heterogeneity including study design, study quality, duration of follow-up, adjustment for confounders, and outcome definition. RESULTS: Sixteen studies were included in the meta-analysis, comprising 57 477 patients with CDI, of whom 6870 (12%) received PPIs. The rate of recurrent CDI was 24% in patients treated with PPIs versus 18% in those who were not. A meta-analysis that pooled unadjusted odds ratios demonstrated higher odds of recurrent CDI in patients who received PPIs (OR 1.69, 95%CI 1.46-1.96) versus those who did not. There was moderate heterogeneity between studies (I2 56%); however, a sensitivity analysis restricted to studies with 56 days of follow-up substantially reduced the heterogeneity (OR 1.59, 95%CI 1.36-1.85; I2 12%). An analysis restricted to multivariate studies that combined adjusted ORs also demonstrated higher odds of recurrent CDI in patients who received PPIs (OR 1.49, 95%CI 1.12-2.00). No publication bias was identified. CONCLUSIONS: We found significantly higher odds of recurrent CDI among users of PPIs that persisted across multiple sensitivity analyses. These results support stronger recommendations for PPI stewardship at CDI diagnosis.

Proton Pump Inhibitors Versus Histamine-2 Receptor Antagonists Likely Increase Mortality in Critical Care: An Updated Meta-Analysis.

BACKGROUND: Upper gastrointestinal bleeding is common among the critically ill. Recently, the Proton Pump Inhibitors (PPIs) vs. Histamine-2 Receptor Blockers for Ulcer Prophylaxis Therapy in the Intensive Care Unit (PEPTIC) trial suggested PPIs might increase mortality. We performed an updated meta-analysis to further inform discussion. METHODS: We leveraged 2 recent systematic reviews to identify randomized controlled trials directly comparing PPIs and H-2 Receptor Antagonists (H2RAs) for stress ulcer prophylaxis in critically ill patients and reporting mortality. We extracted mortality data from each study and meta-analyzed them with the PEPTIC trial using a random effects model. RESULTS: Of 28,559 total patients, 14,436 (50.5%) were allocated to PPI and 14,123 to H2RAs (49.5%). Compared to H2RAs, the pooled relative risk for mortality was 1.05 (95% confidence interval 1.00-1.10) with an estimated risk difference for mortality of 9 additional deaths per 1000 patients exposed to PPI (95% confidence interval 0-18); heterogeneity was low (I2 = 0%; P = 0.826). CONCLUSIONS: Stress ulcer prophylaxis with PPIs likely increases mortality compared to H2RAs. Whether stress ulcer prophylaxis is beneficial in critical care remains open to further study.

COVID-SAFER: Deprescribing Guidance for Hydroxychloroquine Drug Interactions in Older Adults.

BACKGROUND/OBJECTIVES: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes high morbidity and mortality in older adults with chronic illnesses. Several trials are currently underway evaluating the antimalarial drug hydroxychloroquine as a potential treatment for acute infection. However, polypharmacy predisposes patients to increased risk of drug-drug interactions with hydroxychloroquine and may render many in this population ineligible to participate in trials. We aimed to quantify the degree of polypharmacy and burden of potentially inappropriate medications (PIMs) that older hospitalized adults are taking that would interact with hydroxychloroquine. METHODS: We reanalyzed data from the cohort of patients 65 years and older enrolled in the MedSafer pilot study. We first identified patients taking medications with potentially harmful drug-drug interactions with hydroxychloroquine that might exclude them from participation in a typical 2019 coronavirus disease (COVID-19) therapeutic trial. Next, we identified medications that were flagged by MedSafer as potentially inappropriate and crafted guidance around medication management if contemplating the use of hydroxychloroquine. RESULTS: The cohort contained a total of 1,001 unique patients with complete data on their home medications at admission. Of these 1,001 patients, 590 (58.9%) were receiving one or more home medications that could potentially interact with hydroxychloroquine, and of these, 255 (43.2%) were flagged as potentially inappropriate by the MedSafer tool. Common classes of PIMs observed were antipsychotics, cardiac medications, and antidiabetic agents. CONCLUSION: The COVID-19 pandemic highlights the importance of medication optimization and deprescribing PIMs in older adults. By acting now to reduce polypharmacy and use of PIMs, we can better prepare this vulnerable population for inclusion in trials and, if substantiated, pharmacologic treatment or prevention of COVID-19. J Am Geriatr Soc 68:1636-1646, 2020.

Gram-Negative Pneumonia Augments Non-Small Cell Lung Cancer Metastasis through Host Toll-like Receptor 4 Activation.

INTRODUCTION: Surgery is essential for cure of early-stage non-small cell lung cancer (NSCLC). Rates of postoperative bacterial pneumonias, however, remain high, and clinical data suggests that post-operative infectious complications confer an increased risk for metastasis. Toll-like receptors (TLRs) mediate the inflammatory response to infection by recognizing evolutionarily conserved bacterial structures at the surface of numerous pulmonary cell types; yet, little is known about how host TLR activation influences NSCLC metastasis. TLR4 recognizes gram-negative bacterium lipopolysaccharide activating the innate immune system. METHODS: C57BL/6 and TLR4 knockout murine airways were inoculated with Escherichia coli or lipopolysaccharide. Hepatic metastasis assays and intravital microscopy were performed. Bronchoepithelial conditioned media was generated through coincubation of bronchoepithelial cells with TLR4 activating Escherichia coli or lipopolysaccharide. Subsequently, H59 NSCLC were stimulated with conditioned media and subject to various adhesion assays. RESULTS: We demonstrate that gram-negative Escherichia coli pneumonia augments the formation of murine H59 NSCLC liver metastases in C57BL/6 mice through TLR4 activation. Additionally, infected C57BL/6 mice demonstrate increased H59 NSCLC in vivo hepatic sinusoidal adhesion compared with negative controls, a response that is significantly diminished in TLR4 knockout mice. Similarly, intratracheal injection of purified TLR4 activating lipopolysaccharide increases in vivo adhesion of H59 cells to murine hepatic sinusoids. Furthermore, H59 cells incubated with bronchoepithelial conditioned medium show increased cell adhesion to in vitro extracellular matrix proteins and in vivo hepatic sinusoids through a mechanism dependent on bronchoepithelial TLR4 activation and interleukin-6 secretion. CONCLUSION: TLR4 is a viable therapeutic target for NSCLC metastasis augmented by gram-negative pneumonia.

EMPOWERing Hospitalized Older Adults to Deprescribe Sedative Hypnotics: A Pilot Study.

OBJECTIVES: To distribute the EMPOWER patient education brochure and use hospitalization as an opportunity to reduce inappropriate sedatives. DESIGN: Participants were sequentially recruited until we achieved 30-day follow-up telephone and pharmacy records for 50 individuals. The proportion meeting the primary outcome was compared with that of a control cohort and with rates of cessation achieved in the community. SETTING: Fifty-two-bed medical clinical teaching unit in Montréal, Canada. PARTICIPANTS: Inpatients aged 65 and older who were chronic, regular sedative users. MEASUREMENTS: The primary outcome was short-term sustained cessation 30-days after discharge. As a secondary outcome, we compared self-reported sleep disturbance before and after the intervention. RESULTS: Sedatives were deprescribed in 32 of 50 (64%) participants who received the EMPOWER brochure, which was significantly higher than our historical rate of 21% (p<.001). Participants did not report significant worsening in their quality of sleep after sedative cessation. CONCLUSION: Hospitalized individuals are willing to deprescribe, and contact with the healthcare system provides the opportunity to initiate the process with educational brochures. This type of intervention requires few resources and is feasible and inexpensive.

Trauma care and referral patterns in Rwanda: implications for trauma system development.

BACKGROUND: Trauma remains a leading cause of death worldwide. The development of trauma systems in low-resource settings may be of benefit. The objective of this study was to describe operative procedures performed for trauma at a tertiary care facility in Kigali, Rwanda, and to evaluate geographical variations and referral patterns of trauma care. METHODS: We retrospectively reviewed all prospectively collected operative cases performed at the largest referral hospital in Rwanda, the Centre Hospitalier Universitaire de Kigali (CHUK), between June 1 and Dec. 1, 2011, for injury-related diagnoses. We used the Pearson χ² and Fisher exact tests to compare cases arising from within Kigali to those transferred from other provinces. Geospatial analyses were also performed to further elucidate transfer patterns. RESULTS: Over the 6-month study period, 2758 surgical interventions were performed at the CHUK. Of these, 653 (23.7%) were for trauma. Most patients resided outside of Kigali city, with 337 (58.0%) patients transferred from other provinces and 244 (42.0%) from within Kigali. Most trauma procedures were orthopedic (489 [84.2%]), although general surgery procedures represented a higher proportion of trauma surgeries in patients from other provinces than in patients from within Kigali (28 of 337 [8.3%] v. 10 of 244 [4.1%]). CONCLUSION: To our knowledge, this is the first study to highlight geographical variations in access to trauma care in a low-income country and the first description of trauma procedures at a referral centre in Rwanda. Future efforts should focus on maturing prehospital and interfacility transport systems, strengthening district hospitals and further supporting referral institutions.

CONTEXTE: Les traumatismes demeurent l'une des principales causes de décès dans le monde. La mise au point de systèmes de traumatologie dans des milieux défavorisés pourrait toutefois contribuer à améliorer la situation. Notre étude avait pour objectif de décrire les interventions chirurgicales pratiquées sur les victimes de traumatismes dans un établissement de soins tertiaires de Kigali, au Rwanda, et d'évaluer les variations géographiques et les habitudes d'orientation des patients dans le domaine de la traumatologie. MÉTHODES: Nous avons évalué rétroactivement les données recueillies de façon prospective sur l'ensemble des interventions réalisées au plus grand centre hospitalier régional du Rwanda, le Centre hospitalier universitaire de Kigali (CHUK), du 1er juin au 1er décembre 2011 pour les diagnostics liés à des blessures. Nous avons eu recours au test χ² de Pearson et au test exact de Fisher pour comparer les cas issus de la province de Kigali à ceux provenant d'autres provinces. Nous avons en outre effectué des analyses géospatiales afin de mieux comprendre les habitudes d'orientation des patients. RÉSULTATS: Au cours des 6 mois de l'étude, 2758 interventions chirurgicales ont été pratiquées au CHUK, dont 653 (23,7 %) pour des traumatismes. La majorité des patients résidaient à l'extérieur de la capitale : 337 (58,0 %) d'entre eux avaient été transférés d'autres provinces, et 244 (42,0 %), d'ailleurs dans la province. Si la plupart des interventions chirurgicales étaient orthopédiques (489, soit 84,2 %), les patients d'autres provinces ont plus souvent subi des interventions générales que leurs compatriotes de la province de Kigali (28 sur 337, soit 8,3 %, par rapport à 10 sur 244, soit 4,1 %). CONCLUSION: À notre connaissance, il s'agit de la première étude mettant en lumière les variations géographiques de l'accès aux soins en traumatologie dans un pays à faible revenu et de la première description des interventions chirurgicales pratiquées sur des victimes de traumatismes dans un centre régional du Rwanda. Les travaux à venir devraient être axés sur le développement des systèmes de transport avant l'hospitalisation et entre les établissements, le renforcement des hôpitaux de district et l'augmentation du soutien aux centres régionaux.

Acute care surgery in Rwanda: Operative epidemiology and geographic variations in access to care.

BACKGROUND: Surgical management of emergent, life-threatening diseases is an important public health priority. The objectives of this study were to (1) describe acute care general surgery procedures performed at the largest referral hospital in Rwanda and (2) understand the geographic distribution of disease presentations and referral patterns. METHODS: We performed a retrospective review of prospectively collected acute care surgery cases performed at the Centre Hospitalier Universitaire de Kigali (CHUK) in Rwanda between June 1 and December 1, 2011. Using Pearson's χ(2) test and the Fisher exact test, we compared cases originating from within Kigali and transfers from other provinces. Geospatial analyses also were used to further describe transfer patterns. RESULTS: During the study period, 2,758 surgical interventions were performed, of which 25.6% (707/2,758) were general surgery operations. Of these, 45.4% (321/707) met the definition of acute care surgery. Only about one-third-32.3% (92/285)-of patients resided within Kigali, whereas about two-thirds-67.7% (193/285)-were transferred from other provinces. Most patients transferred from other provinces were younger than 18 years of age (40.4%; 78/193), and 83.0% (39/47) of patients older than 50 years of age originated from outside of Kigali. Specific operative indications and surgical procedures varied substantially between patients from Kigali and patients transferred from other provinces. CONCLUSION: Emergency surgical conditions remain important contributors to the global burden of disease, particularly in low- and middle-income countries. Geographic variations exist in terms of operative diagnoses and procedures, which implies a need for improved access to surgical care at the district level with defined transfer mechanisms to greater-level care facilities when needed.

Comparative in vitro evaluation of transportability and toxicity of capecitabine and its metabolites in cells derived from normal human kidney and renal cancers.

The goal of this study was to understand roles of nucleoside and nucleobase transport processes in capecitabine pharmacology in cells derived from human renal proximal tubule cells (hRPTCs) and three human renal cell carcinoma (RCC) cell lines, A498, A704, and Caki-1. Human equilibrative nucleoside transporters 1 and 2 (hENT1 and hENT2) mediated activities and a sodium-independent nucleobase activity were present in hRPTCs. In hRPTCs, uptake of 5'-deoxy-5-fluorouridine (DFUR), a nucleoside metabolite of capecitabine, was pH dependent with highest uptake seen at pH 6.0. In RCC cell lines, hENT1 was the major nucleoside transporter. Nucleobase transport activity was variable among the three RCC cell lines, with Caki-1 showing the highest and A498 showing the lowest activities. Treatment of RCC cell lines with interferon alpha (IFN-α) increased thymidine phosphorylase levels and prior treatment of RCC cell lines with IFN-α followed by 5-FU or DFUR resulted in enhanced sensitivity of all cell lines to 5-FU and two of three cell lines to DFUR. We report for the first time a nucleobase transport activity in hRPTCs and RCC cell lines. In addition, our in vitro cytotoxicity results showed that RCC cell lines differed in their response to 5-FU and DFUR and prior treatment with IFN-α potentiated cytotoxic response to metabolites of capecitabine.

Congenital diaphragmatic hernia (CDH) mortality without surgical repair? A plea to clarify surgical ineligibility.

PURPOSE: Little is known about liveborn CDH patients who die without surgery. We audited a national CDH cohort to determine whether these patients were different from patients who received CDH repair. METHODS: A national CDH database was analyzed (2005-2009). After excluding infants with severe physiologic instability and genetic/congenital malformations, a potential surgical candidate (PSC) subgroup was identified. PSCs were compared to the operative group (OG) and the operative non-survivor (ONS) subgroup. Standard statistical analyses were performed. RESULTS: Of 275 liveborns, 35 (13%) died without surgery. The PSC subgroup (n=11) had a median survival of 10 days (range: 3-18). Ten of 11 PSC infants were treated in ECMO centers, with 4 receiving ECMO. No differences in BW, GA, and rates of minor malformation were observed between PSC and OG patients. While neonatal illness severity (SNAP-II) predicted overall mortality, SNAP-II scores were similar between PSC and ONS groups (34 vs. 29; p=0.431). Furthermore, greater than 80% of infants with SNAP-II scores between 30 and 39 survived in the OG cohort. CONCLUSION: Our analysis demonstrated that PSCs were similar to infants offered surgery based on illness severity and the presence of congenital malformations. We suggest that criteria for surgical ineligibility be developed to standardize the selection of surgical candidates.

Hearing loss in congenital diaphragmatic hernia (CDH) survivors: is it as prevalent as we think?

PURPOSE: The incidence of sensorineural hearing loss (SNHL;>20 dB loss) in CDH survivors is debated. We evaluated long-term audiological outcomes at a single tertiary care center with ECMO capability and an established neonatal follow-up program. METHODS: With REB approval, records of CDH survivors from 2000 to 2010 were retrospectively analyzed. Demographic, postnatal, and audiometric information was gathered. All underwent auditory brainstem response (ABR) or otoacoustic emissions screening before discharge and complete audiological surveillance. Thirty-three patients were evaluated to age 4+ years with others continuing follow-up. RESULTS: Forty-three patient records were reviewed with 1 excluded (transferred to another institution). Median GA and BW were 39 weeks (35-41) and 3.1 kg (2-4), respectively. Median ventilation days were 10 (2-189) with 34 infants ventilated 5+ days. Sixteen (36%) received HFOV, 21 (49%) iNO, and 5 (12%) ECMO. The median time to CDH repair was 3 days (1-23), and 11 (26%) required patch repair. Nine infants (21%) received diuretics and oxygen after discharge. Audiological surveillance identified only one patient with SNHL (received HFO, iNO, and patch repair). CONCLUSION: Neonatal screening identifies CDH survivors at risk for hearing difficulties but must be followed with comprehensive testing until school age. The incidence of SNHL may be less than previously reported in this population.

Infantile myofibromas obstructing opposite ends of the gastrointestinal tract.

Myofibromas are benign congenital tumors of soft tissue that can present at birth or during infancy in solitary or multicentric forms. Visceral myofibromas are rarely reported, but are typically symptomatic due to involvement of vital structures. We present two cases of congenital myofibromas, one obstructing the proximal esophagus and the other obstructing the distal rectum. Lessons learned from the treatment of these two patients are shared and the pertinent literature is reviewed.

Oncolytic viruses and histone deacetylase inhibitors--a multi-pronged strategy to target tumor cells.

Oncolytic viruses (OVs) have shown promise as cancer therapeutics in pre-clinical and clinical testing; however, it is unlikely that OVs will constitute a stand-alone treatment. Histone deacetylase inhibitors (HDIs) represent a class of anticancer agents known to influence epigenetic modifications of chromatin, alter gene expression and manipulate a variety of signaling pathways, in some cases blunting the cellular antiviral response. Recent studies have shown that combining OV therapy with HDI treatment enhances viral replication and synergistically induces the killing of cancer cells in vitro and in vivo, an effect that has now been demonstrated in variety of virus/HDI combinations. This review discusses the results obtained with the different OV/HDI combinations, the rationale supporting these combinations and the advantages for oncolytic virus therapy.