TAMI-48. THE KETOGENIC DIET IS INEFFECTIVE IN PRECLINICAL MODELS OF IDH1 WILD-TYPE AND IDH1 MUTANT GLIOMA

Despite decades of intensive research, infiltrative gliomas are still usually lethal and challenging to treat. A subset of gliomas contains mutations in isocitrate dehydrogenase 1 (IDH1mut), which disrupts cellular biochemistry; such gliomas are generally less aggressive than their IDH1 wild-type (IDH1wt) counterparts. Some preclinical studies have suggested that a ketogenic diet (KD), characterized by low-carbohydrate and high-fat content, may be beneficial against a variety of cancers, including gliomas. However, not all studies have shown promising results, and to date, no study has addressed the sensitivity of glioma cells to KD in the specific context of the endogenous IDH1mut metabolic landscape. The aim of the current study was to compare the effects of KD in preclinical models to IDH1wt versus IDH1mut gliomas. In vitro treatment of patient-derived IDH1wt and IDH1mut glioma cells with the ketone body β-hydroxybutyrate showed no significant effect on cell proliferation in a low glucose culture environment. Likewise, the in vivo flank growth rates of these patient-derived IDH1wt and IDH1mut glioma xenografts showed no significant difference when mice were fed KD versus regular diet (GBM12 p=0.98, GBM164 p=0.4, GBM196 p=0.11). Finally, KD had no effect on the survival of mice engrafted with isogenic Sleeping-Beauty transposase-engineered IDH1wt (median control survival 22 days versus treatment 23 days, p=0.23) or IDH1mut glioma cells (median control survival 26.5 days versus treatment 26 days, p=0.81). These data suggest that IDH1mut gliomas are not more responsive than IDH1wt gliomas to KD, and that clinical trials further exploring KD in this subset of glioma patients are probably not warranted.

Heat-induced triploids in Brycon amazonicus: a strategic fish species for aquaculture and conservation

Summary Triploidization plays an important role in aquaculture and surrogate technologies. In this study, we induced triploidy in the matrinxã fish (Brycon amazonicus) using a heat-shock technique. Embryos at 2 min post fertilization (mpf) were heat shocked at 38°C, 40°C, or 42°C for 2 min. Untreated, intact embryos were used as a control. Survival rates during early development were monitored and ploidy status was confirmed using flow cytometry and nuclear diameter analysis of erythrocytes. The hatching rate reduced with heat-shock treatment, and heat-shock treatments at 42°C resulted in no hatching events. Optimal results were obtained at 40°C with 95% of larvae exhibiting triploidy. Therefore, we report that heat-shock treatments of embryos (2 mpf) at 40°C for 2 min is an effective way to induce triploid individuals in B. amazonicus.

Influence of Feeding and Organism Age on the Acute Toxicity of Sodium Bromide to Artemia salina

Bromide is a common ion found in freshwater and marine systems. Although normally at relatively low concentrations, higher levels may occur in point-released wastewaters as well as nonpoint runoff from agricultural or industrial locations where bromide compounds are used as biocides and disinfectants. In this study, the potential toxicity of NaBr in a saltwater environment was studied using the brine shrimp, Artemia salina. The confounding factors of organism age at test initiation and pre-test feeding were included in the test design. Survival of brine shrimp nauplii in several NaBr treatments up to 11,000 mg Br−/L (measured) was assessed after 24 h in both fed- and unfed-tests. In tests with unfed organisms, only the youngest (< 24 h old) nauplii had acceptable control survival (≥90%), while control survival for all of the tests with fed organisms (< 24 h old, < 48 h old, < 72 h old) was acceptable. There was also greater and more erratic mortality in the unfed tests. These data indicate feeding A. salina prior to initiating a short-term acute test improved performance. Not feeding the test organisms, especially in longer tests or when using > 24 h old organisms, may result in excessive control mortality and an invalid test. These studies show that, when healthy organisms are used in the toxicity tests, 11,000 mg/L of Br− (~ 14,200 mg/L NaBr) is not acutely toxic to Artemia salina.

Effects of the microbiome manipulation on survival and GI tract development of larval zebrafish (Danio rerio)

Microbial diversity within an aquatic community can be used to increase the growth and development of organisms. In this study, Zebrafish larvae were reared in three treatments 1) a probiotic containing 17 strains of Lactobacillus spp., 2) an amoxicillin solution, 3) water from the broodstock culture tank as the control. Survival of the larvae throughout 10 dpf was recorded. To determine the development of the gastrointestinal tract DASPEI stain was used for larvae at the age of 3 dpf to 6dpf. The intensity of the fluorescence in each larva was observed through the automated digital microscope. According to the experiment results, a significant difference (P<0.0001) in the survival rates among all treatments was recorded. The probiotic-treated larvae (PTL) had a higher survival rate. This could be due to the presence of lactic acid bacteria in the probiotic treatment, which helps in enhancing immunity. In DASPEI staining, also PTL exhibits more fluorescence in the GI tract at 24 hours to 48 hours post-hatch than the other two treatments. The main possible reason behind this could also be the presence of Lactobacillus spp. Which directly influences the higher activity of the digestive system.

Early Determinants of Length of Hospital Stay: A Case Control Survival Analysis among COVID-19 Patients admitted in a Tertiary Healthcare Facility of East India

Background: Length of hospital stay (LOS) for a disease is a vital estimate for healthcare logistics planning. The study aimed to illustrate the effect of factors elicited on arrival on LOS of the COVID-19 patients. Materials and Methods: It was a retrospective, record based, unmatched, case control study using hospital records of 334 COVID-19 patients admitted in an East Indian tertiary healthcare facility during May to October 2020. Discharge from the hospital (cases/survivors) was considered as an event while death (control/non-survivors) as right censoring in the case-control survival analysis using cox proportional hazard model. Results: Overall, we found the median LOS for the survivors to be 8 days [interquartile range (IQR): 7-10 days] while the same for the non-survivors was 6 days [IQR: 2-11 days]. In the multivariable cox-proportional hazard model; travel distance (>16 km) [adjusted hazard ratio (aHR): 0.69, 95% CI: (0.50-0.95)], mode of transport to the hospital (ambulance) [aHR: 0.62, 95% CI: (0.45-0.85)], breathlessness (yes) [aHR: 0.56, 95% CI: (0.40-0.77)], number of co-morbidities (1-2) [aHR: 0.66, 95% CI: (0.47-0.93)] (≥3) [aHR: 0.16, 95% CI: (0.04-0.65)], COPD/asthma (yes) [ [aHR: 0.11, 95% CI: (0.01-0.79)], DBP (<60/≥90) [aHR: 0.55, 95% CI: (0.35-0.86)] and qSOFA score (≥2) [aHR: 0.33, 95% CI: (0.12-0.92)] were the significant attributes affecting LOS of the COVID-19 patients. Conclusion: Factors elicited on arrival were found to be significantly associated with LOS. A scoring system inculcating these factors may be developed to predict LOS of the COVID-19 patients.

Effects of Temperature on Growth and Development of the Brown Planthopper, Nilaparvata lugens (Homoptera: Delphacidae)

The brown planthopper, Nilaparvata lugens (Stål), is one of the most serious and destructive pests of rice in Asia. Climate warming in tropical regions and extreme-high- or low-temperature events may become limiting factors affecting the survival and distribution of N. lugens. The effects of continuous high temperature (CHT), discontinuous high temperature (DHT), and abnormal low temperature in summer (ALT) on the growth and development of N. lugens were studied under lab conditions. High temperatures and ALT decreased the survival rate of nymphs (in fourth-instar nymphs, CHT, DHT, ALT, and control survival was 46.67% ± 1.67, 31.67% ± 1.67, 48.33% ± 4.41, and 60.00% ± 2.89, respectively, P &lt; 0.05). ALT also prolonged the development of N. lugens nymphs (in fourth-instar nymphs, ALT and control survival was 6.09 ± 0.193 d and 5.39 ± 0.082 d, respectively, P &lt; 0.05). In fifth-instar nymphs, CHT (2.36 ± 0.064 d, P &lt; 0.05) and DHT (2.34 ± 0.048 d, P &lt; 0.05) had little influence on nymphal development compared with the control (2.25 ± 0.012 d, P &lt; 0.05). The three temperature treatments (CHT, DHT, and ALT) decreased the number of eggs produced (61.33 ± 0.067, 62.67 ± 0.882, and 34.00 ± 0.577, respectively, P &lt; 0.05) compared with the control (68.00 ± 1.000, P &lt; 0.05). The female sex ratio decreased after nymphs were subjected to CHT (65.82% ± 0.771, P &lt; 0.05, in fifth-instar nymphs) and ALT (76.01% ± 1.362, P &lt; 0.05) compared with the control (81.63% ± 1.007, P &lt; 0.05). Adults in CHT (25.30 ± 0.182, P &lt; 0.05) and DHT (14.64 ± 0.238, P &lt; 0.05) consumed significantly more food than the control (11.54 ± 0.181, P &lt; 0.05), but adults in ALT (6.54 ± 0.196, P &lt; 0.05) fed significantly less than the control (11.54 ± 0.181, P &lt; 0.05). Hatching rates of eggs under the three temperature treatments (CHT, DHT, and ALT were 69.57% ± 0.215, 71.29% ± 0.529, and 43.13% ± 0.508, respectively, and were significantly lower (P &lt; 0.05) than the control (78.95% ± 1.000, P &lt; 0.05). These experiments revealed that extreme temperatures can influence the growth and development of N. lugens and may affect its distribution. As such, N. lugens remains a serious pest of rice.

The efficacy and safety of hybrid ablations for atrial fibrillation, assessed using implantable ECG recorders and sequential magnetic resonance imaging

Background Treatment strategies for patients with non-paroxysmal atrial fibrillation (AF) still do not provide satisfactory results. In pursuit of better results, other approaches, such as the hybrid ablation (i.e., thoracoscopic epicardial ablation followed by catheter ablation), have been used. The accurate data regarding the efficacy and safety of the procedure are still limited. Purpose To determine the procedural safety, and the mid-term efficacy of hybrid ablation. Methods Patients with non-paroxysmal AF were included. They underwent thoracoscopic, off-pump ablation using the COBRA Fusion radiofrequency system, followed by a percutaneous catheter ablation (2.6±1.0 mo after surgery). Sequential cerebral magnetic resonance imaging (MRI) was done (1 day before and 3–5 days after surgery) to look for new ischemic lesions in the brain. Implantable loop recorders (ILR) were implanted 1–3 days after the thoracoscopic procedure. Rhythm outcomes were defined as (1) AF-free OFF survival (i.e., no single episode of AF or atrial tachycardia (AT) lasting &gt;30 sec as assessed using ILR, remaining OFF anti-arrhythmic drugs (AADs) and without a redo ablation or cardioversion), (2) AF-free ON survival (i.e., recurrence of AF or AT, however, AF freedom with no more AF/AT episodes &gt;30 sec was achieved through re-initiation AADs, re-ablation, or cardioversion), and (3) rhythm control survival (repeated self-terminated paroxysms of AF/AT despite AADs, re-ablation, or cardioversion). Rate control strategy (i.e. the presence of AF with no more attempts for SR reinitiation) was considered as failure of the procedure. Results Sixty patients were enrolled, 37 (62%) were men, the mean age was 62.6±10.5 years, 29 (48%) with long-standing persistent AF. Thoracoscopic ablation was successfully performed in 56 (93.3%) patients, and significant complications occurred in 7 (11.8%) patients. Fifty-three patients (88.3%) underwent a pre- and 47 underwent a control postoperative cerebral MRI. Chronic ischemic brain lesions were present in 36 (68%) patients on the pre-operative MRI. New ischemic brain lesions on the post-operative MRI were seen in 19 (40%) patients, 18 of whom were without neurological symptoms, 1 patient had a manifest stroke. Catheter ablations were carried out in all 60 patients without complications. The mean follow-up was 22.9±10.3 months. AF-free OFF survival was present in 53.4% at 1 and in 41.5% at 2 years. AF-free ON survival was present in 72% at 1 year and 62% at 2 years. Rhythm control survival was present in 91% at 1 year and 89% at 2 years. Only 9%, or 11% of patients were on rate control at 1 and 2 years, resp. Conclusions Hybrid ablation presents an effective treatment strategy for patients with non-paroxysmal AF. The thoracoscopic part of the hybrid ablation procedure is accompanied by a high risk of silent cerebral ischemia, which should be considered in patients referred to this procedure. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Research grant of the Ministry of Health of the Czech Republic, Nr. 16-32478A