Identifying SARS-COV-2 infected patients through canine olfactive detection on axillary sweat samples; study of observed sensitivities and specificities within a group of trained dogs.

There is an increasing need for rapid, reliable, non-invasive, and inexpensive mass testing methods as the global COVID-19 pandemic continues. Detection dogs could be a possible solution to identify individuals infected with SARS-CoV-2. Previous studies have shown that dogs can detect SARS-CoV-2 on sweat samples. This study aims to establish the dogs' sensitivity (true positive rate) which measures the proportion of people with COVID-19 that are correctly identified, and specificity (true negative rate) which measures the proportion of people without COVID-19 that are correctly identified. Seven search and rescue dogs were tested using a total of 218 axillary sweat samples (62 positive and 156 negative) in olfaction cones following a randomised and double-blind protocol. Sensitivity ranged from 87% to 94%, and specificity ranged from 78% to 92%, with four dogs over 90%. These results were used to calculate the positive predictive value and negative predictive value for each dog for different infection probabilities (how likely it is for an individual to be SARS-CoV-2 positive), ranging from 10-50%. These results were compared with a reference diagnostic tool which has 95% specificity and sensitivity. Negative predictive values for six dogs ranged from ≥98% at 10% infection probability to ≥88% at 50% infection probability compared with the reference tool which ranged from 99% to 95%. Positive predictive values ranged from ≥40% at 10% infection probability to ≥80% at 50% infection probability compared with the reference tool which ranged from 68% to 95%. This study confirms previous results, suggesting that dogs could play an important role in mass-testing situations. Future challenges include optimal training methods and standardisation for large numbers of detection dogs and infrastructure supporting their deployment.

New method of screening for COVID-19 disease using sniffer dogs and scents from axillary sweat samples.

BACKGROUND: Early screening for COVID-19 is needed to limit the spread of the virus. The aim of this study is to test if the sniffer dogs can be successfully trained to identify subjects with COVID-19 for 'proof of concept' and 'non-inferiority' against PCR. We are calling this method, Dognosis (DN). METHODS: Four hundred and fifty-nine subjects were included, 256 (Group 'P') were known cases of COVID-19 (PCR positive, some with and some without symptoms) and 203 (Group 'C') were PCR negative and asymptomatic (control). Samples were obtained from the axillary sweat of each subject in a masked fashion. Two dogs trained to detect specific Volatile Organic Compounds for COVID-19 detection were used to test each sample. RESULTS: [DN] turned out positive (+) in all the cases that were PCR positive (100% sensitivity). On the other hand, [DN] turned positive (+) in an average of 12.5 cases (6.2%) that were initially PCR negative (apparent specificity of 93.8%). When the PCR was repeated, true specificity was 97.2%. These parameters varied in subgroups from 100% sensitivity and 99% specificity in symptomatic patients to 100% sensitivity and 93% specificity in asymptomatic patients. CONCLUSION: DN method shows high sensitivity and specificity in screening COVID-19 patients.

Can the detection dog alert on COVID-19 positive persons by sniffing axillary sweat samples? A proof-of-concept study.

The aim of this proof-of-concept study was to evaluate if trained dogs could discriminate between sweat samples from symptomatic COVID-19 positive individuals (SARS-CoV-2 PCR positive) and those from asymptomatic COVID-19 negative individuals. The study was conducted at 2 sites (Paris, France, and Beirut, Lebanon), followed the same training and testing protocols, and involved six detection dogs (three explosive detection dogs, one search and rescue dog, and two colon cancer detection dogs). A total of 177 individuals were recruited for the study (95 symptomatic COVID-19 positive and 82 asymptomatic COVID-19 negative individuals) from five hospitals, and one underarm sweat sample per individual was collected. The dog training sessions lasted between one and three weeks. Once trained, the dog had to mark the COVID-19 positive sample randomly placed behind one of three or four olfactory cones (the other cones contained at least one COVID-19 negative sample and between zero and two mocks). During the testing session, a COVID-19 positive sample could be used up to a maximum of three times for one dog. The dog and its handler were both blinded to the COVID-positive sample location. The success rate per dog (i.e., the number of correct indications divided by the number of trials) ranged from 76% to 100%. The lower bound of the 95% confidence interval of the estimated success rate was most of the time higher than the success rate obtained by chance after removing the number of mocks from calculations. These results provide some evidence that detection dogs may be able to discriminate between sweat samples from symptomatic COVID-19 individuals and those from asymptomatic COVID-19 negative individuals. However, due to the limitations of this proof-of-concept study (including using some COVID-19 samples more than once and potential confounding biases), these results must be confirmed in validation studies.

Peritoneal Carcinomatosis of Colorectal Origin in Cyclosporine Immunosuppressed Rats.

OBJECTIVE: We evaluate the seeding step of peritoneal carcinomatosis cancer as a surrogate for the role of the omentum in colorectal tumors. METHODS: The study included 5 groups of adult male Sprague Dawley rats: immunocompetent rats (group 1), immunosuppressed rats without omentectomy (group 2), immunosuppressed rats with omentectomy (group 3), immunosuppressed rats with omentectomy receiving NSAID (group 4), and immunosuppressed rats without omentectomy receiving NSAID (group 5). Except for group 1, the rats were immunosuppressed using cyclosporine orally at a dose of 25 mg/kg/day that was started 48 hours before tumor cell infiltration in the peritoneum. All the rats received an intraperitoneal suspension of 10 million Caco-2 cancer cells. Rats in groups 1, 2, and 3 were followed up without further interventions and rats in groups 4 and 5 received naproxen 180mg/kg until rat sacrifice. Cyclosporine and naproxen were continued in the corresponding groups until the killing after 21 days of tumor cell infiltration. RESULTS: Fourteen rats survived the experiment during the observation period and remained in good clinical condition except for one rat (from group 4) that deceased at week 2. At day 21 before sacrifice, mean weight variations showed a +4% in group 0, -9% in group 1, -18% in group 2, -31% in group 3 and -36% in group 4. Light microscopy did not identify any tumor cells in the abdominal cavity or thorax solid organs but showed a granulomatous reaction that involved the majority of the organs. CONCLUSION: The conclusions of this study are limited by the small number of rats as it is a pilot study to design an animal model with peritoneal carcinomatosis. Further steps in this study will include more aggressive cancer cell lines such as HT29 and more aggressive immunosuppression in a larger number of rats.

Glucose restriction reverses the Warburg effect and modulates PKM2 and mTOR expression in breast cancer cell lines.

Aerobic glycolysis, known as the "Warburg effect", is one of several hallmarks of cancer cells. The conversion of phosphoenolpyruvate (PEP) to pyruvate can be down regulated by the re-expression of the embryonic isoform 2 of pyruvate kinase (PKM2). This mechanism allows the accumulation of glycolytic intermediates for the biosynthesis of macromolecules, such as proteins, lipids and nucleic acids. PKM2 is favored by the well-known PI3K/Akt/mTOR proliferative pathway. This pathway is induced by high glucose levels, and the mTOR kinase is the central activator of the Warburg effect. In this study, we investigated the role of glucose restriction (GR) and mTOR inhibition  in reversing the Warburg effect in MDA-MB 231 and MCF-7 breast cancer cell lines. PKM2 expression was measured by western blot. Lactate production by cells was determined by a colorimetric assay. The concentration of glucose in the supernatant of cells was measured using the Trinder method. ATP level  was evaluated by using a Colorimetric/Fluorometric ATP Assay Kit. Our results showed that MDA-MB 231 cells increased glucose consumption when the glucose concentration was 0 g/L (P <0.01). In MCF-7 cells, glucose deprivation reduced lactate secretion by 80% (P =0.0001) but tripled glucose consumption (P = 0.0041). ATP concentration increased approximately when MCF-7 cells were deprived of glucose (P = 0.02). GSK1059615 does not significantly modulate lactate secretion and glucose uptake in both cell lines. Glucose restriction contribute to the reduction of the Warburg effect through mTOR inhibition and regulation of PKM2 kinases.

Total or Subtotal Colectomy with Primary Anastomosis for Occlusive Left Colon Cancer: A Safe, Acceptable and Applicable Procedure.

INTRODUCTION: Occlusive left colon cancer is a major emergency setting in colon cancer with high morbidity and mortality rates. Different surgical treatment exist since there is no clear guidelines for the best treatment. We have conducted this retrospective study in order to evaluate the safety, morbidity, and bowel movement status of the operated patients. METHODS: One-hundred and one left occlusive colon cancer patients were operated of total or subtotal colon resection with primary anastomosis from March 2000 till March 2017 in Hotel Dieu de France hospital. We analyzed the sex ratio, age, caecum condition, tumor localization, number of synchronous adenoma and adenocarcinoma, Dukes stage, major complications and the number of stools per day at 3 and 12 months after surgery. RESULTS: Mean hospital stay was 7.8 days. Thirteen complications were observed in 11 (10.9%) patients, in which one (1%) patient had splenectomy for severe hemorrhage. Six synchronous adenocarcinoma and 40 adenoma with dysplasia were diagnosed on pathology specimens proximal to occlusion site. Caecum laceration was found in 33 (32.6%) of cases. No patient had anastomotic leak. After 12 months of surgery, the average bowel movement was 2 stools per day. CONCLUSION: Our study showed that treating occlusive left colon cancer with total or subtotal colectomy with primary anastomosis is a safe procedure, with a good bowel movement status and presents the advantage to resect an important number of synchronous tumors and adenomas proximal to the occlusion site.

Pilot Study of a New Model of Bariatric Surgery: Laparoscopic Intestinal Bipartition-Safety and Efficacy Against Metabolic Disorders.

BACKGROUND: Despite the availability of many gastric surgery techniques to reduce obesity and its associated comorbidities, most of these procedures can result in life-threatening conditions including lifetime chronic illnesses and death. Vertical sleeve gastrectomy and Roux-en-Y gastric bypass have been reported to improve obesity-related comorbidities such as T2DM, but the long-term efficacy of these two procedures is unknown, and their significant impact on long-term weight loss was diminished by complications as reported in previous studies. Recently, laparoscopic biliopancreatic diversion with duodenal switch (BPD/DS) was developed to achieve sustained weight loss (Buchwald et al. Am J Med. 122:248-56, 2009; Sjöström et al. N Engl J Med. 351:2683-93, 2004) as well as an improvement in comorbid conditions, such as T2DM and hypertension (Buchwald et al. in Am J Med. 122:248-56, 2009; Dorman et al. Surgery. 152:758-65, 2012). The malabsorptive strategy of bypassing portions of the small intestine and delivering nutrients directly to the ileum may promote weight loss by enhanced activation of a negative feedback mechanism known as the "ileal brake" (Näslund et al. J Gastrointest Surg. 5:556-67, 2001). The purpose of this pilot study was to evaluate the safety, reproducibility, and efficiency of a new surgical bariatric model of laparoscopic intestinal bipartition (LIB) in patients with a BMI between 35 and 40 kg/m2. The setting was in university hospitals. METHODS: Between January 2011 and September 2012, seven patients were enrolled in the study and underwent the LIB procedure. One patient was operated by LIB for morbid obesity with comorbidities, especially T2DM, without any previous bariatric or gastric surgery. Six patients underwent the surgery after a sleeve gastrectomy for ≥ 4 years with a recurrence of obesity and diabetes. RESULTS: The comorbidity factors decreased to the normal values in all patients at 6 months, 1 year, and 5 years postoperatively. The percentage of total weight loss was 21.1% at 6 months, 22.6% at 1 year, and 15.6% at 5 years. Weight excess was significantly lower at 6-month, 1-year, and 5-year postoperatively compared with baseline (p < 0.001). Comparison of comorbidity values at 6 months, 1 year, and 5 years did not show any significant differences. CONCLUSION: Laparoscopic intestinal bipartition produced a total recovery from obesity-related comorbidities, especially T2DM and EWL without any signs of nutritional deficiency, although the 5-year follow-up is ongoing in order to demonstrate the efficacy and long-term durability of this procedure.

The role of smartphone game applications in improving laparoscopic skills.

BACKGROUND: Virtual games (VGs) have a positive impact on laparoscopic skills. Time spent playing, the console and the type of game used correlate with the speed of acquisition of laparoscopic skills and their preservation. METHODS: A total of 45 university medical students with no previous surgical experience were divided into three groups: gamers (n=20), control (n=10) and intervention (n=15). They passed the laparoscopic skills testing and training model, developed by the European Academy of Gynecological Surgery, over two sessions. Every 5 intervention participants were asked to play a different smartphone application game daily for 2 months between the two sessions. Scores were calculated at both sessions and used to calculate the evolution ratio between sessions. RESULTS: Significant advantage was found at session 1 of gamers over non-gamers (p=0.002). No significant difference existed between the two non-gamer groups (p=0.96), or between the three intervention sub-groups (p>0.05). All participants' performances improved between sessions. No significant difference existed in evolution between control and gamers (p=0.121), nor between intervention and gamers (p=0.189). Significant advantage was found in evolutions of the intervention group over control group (p=0.035). CONCLUSION: Previous VG experience is a significant factor in showing better laparoscopic skills when virtual reality simulator is used for the first time. Recent and regular smartphone gaming practice significantly improves laparoscopic skills in non-gamers independently of the type of game practiced. Smartphone gaming practice appears to influence positively some specific laparoscopic skills more than others.

Gastrointestinal cancer cells treatment with bevacizumab activates a VEGF autoregulatory mechanism involving telomerase catalytic subunit hTERT via PI3K-AKT, HIF-1α and VEGF receptors.

BACKGROUND: Targeting angiogenesis has been considered a promising treatment of choice for a large number of malignancies, including gastrointestinal cancers. Bevacizumab is an anti-vascular endothelial growth factor (anti-VEGF) being used for this purpose. However, treatment efficacy is largely questioned. Telomerase activity, responsible for cancer cell immortality, is detected in 85-95% of human cancers and is considered a potential regulator of VEGF. The aim of our study was to investigate the interrelationship between VEGF and hTERT in gastrointestinal cancers and to explore cell response to a combined inhibition of telomerase and VEGF. METHODS: AGS (gastric cancer), Caco-2 (colorectal cancer) and HepG2/C3A (hepatocellular carcinoma), were treated with telomerase inhibitors BIBR-1232 (10µM) and costunolide (10µM), with bevacizumab (Avastin® at 5 ng/ml or 100µg/ml) or with a combination of both types of inhibitors. VEGF and hTERT mRNA levels, and telomerase activity were detected by RT-PCR. VEGF levels were quantified by ELISA. Telomerase was knocked down using hTERT siRNA and hTERT was overexpressed in the telomerase negative cell line, Saos-2 (osteosarcoma), using constructs expressing either wild type hTERT (hTERT-WT) or dominant negative hTERT (hTERT-DN). Tube formation by HUVECs was assessed using ECMatrix™ (EMD Millipore). RESULTS: Our results showed that telomerase regulates VEGF expression and secretion through its catalytic subunit hTERT in AGS, Caco2, and HepG2/C3A, independent of its catalytic activity. Interestingly, VEGF inhibition with bevacizumab (100µg/ml) increased hTERT expression 42.3% in AGS, 94.1% in Caco2, and 52.5% in HepG2/C3A, and increased telomerase activity 30-fold in AGS, 10.3-fold in Caco2 and 8-fold in HepG2/C3A. A further investigation showed that VEGF upregulates hTERT expression in a mechanism that implicates the PI3K/AKT/mTOR pathway and HIF-1α. Moreover, bevacizumab treatment increased VEGFR1 and VEGFR2 expression in cancer cells and human umbilical vein endothelial cells (HUVECs) through hTERT. Thus, the combination of bevacizumab with telomerase inhibitors decreased VEGF expression and secretion by cancer cells, inhibited VEGFR1 and VEGFR2 upregulation, and reduced tube formation by HUVECs. CONCLUSIONS: Taken together, our results suggest that bevacizumab treatment activates a VEGF autoregulatory mechanism involving hTERT and VEGF receptors and that an inhibition of this pathway could improve tumor cell response to anti-VEGF treatment.

Validation Study of a Portable Home Trainer Using a Pad for Laparoscopic Practice.

The aim of this study was to describe and validate a homemade laparoscopic trainer. The abdominal cavity is simulated within a 3-mm-thick stainless steel model. Thirty-four participants were evaluated in a pilot study to validate our model. Participants were divided into experts (n = 19) and novices (n = 15) to perform basic and complex laparoscopic skills. The comparison between the homemade trainer (HT) and the standard laparoscopic trainer showed no significant differences for the 2 tasks performed for each group ( P > .05). The experts' performance of the 2 tasks was statistically different from the novices ( P < .05) on both trainers. Both experts (84%) and novices (87%) approved the HT as an effective home trainer. Our HT seems to fulfill the conditions of performing the basic and complex laparoscopic psychomotor skills at a low cost and similar efficiency.