Accuracy of preoperative automatic measurement of the liver volume by CT-scan combined to a 3D virtual surgical planning software (3DVSP)

Background

Liver volumetry is a critical component of safe hepatic surgery, in order to minimize the risk of postoperative liver failure. Liver volumes can be calculated routinely using the time-consuming gold standard method of manual volumetry. The current work sought to evaluate an alternative automatic technique based on a novel 3D virtual planning software, and to compare it to the manual technique.

Methods

A prospective study of patients undergoing liver resection was conducted. Every patient had a pre and 2-day postoperative CT-scan. For each patient, total, remnant and resected volumes were calculated manually and automatically. Planes of resection were verified by a hepatobiliary surgeon and compared with postoperative volumes. Paired t-tests and correlation coefficients were calculated.

Results

A major hepatectomy was carried out in 36/43 patients. The automatic TLV (1,759 mL) and the manual TLV (1,832 mL) were significantly different (p < 0.001), but extremely highly correlated (r = 0.989). The percentages of preoperative RLV (manual 58.5 %, automatic 58.9 %) were similar, with an excellent correlation of 0.917. The preoperative RLV were matched with the 2-day postoperative RLV showing a significant difference (p = 0.0301). The resected volumes using both techniques (871 and 832 mL) were compared with the resected specimen volume (670 mL), showing a significant difference (p < 0.001) but a high degree of correlation (r = 0.874).

Conclusion

The 3D virtual surgical planning software is accurate and reliable in determining the total liver and future remnant liver volumes. This technique demonstrates a good correlation with the manual technique. Future work will be required to confirm these findings and to evaluate the clinical value of the three-dimensional planning platform.     

Monitoring glycosidase activity for clustered sugar substrates,a study on β-glucuronidase

Determination of glycosidase hydrolysis kinetics for a monovalent sugar substrate is relatively straightforward and classically achieved by monitoring the fluorescence signal released from the sugar-conjugated probe after enzymatic hydrolysis. Naturally occuring sugar epitopes are, however, often clustered on biopolymers or at biological surfaces, and previous reports have shown that glycosidase hydrolytic rates can differ greatly with multivalent presentation of the sugar epitopes. New probes are needed to make it easier to interpret the importance of substrate clustering towards a specific enzyme activity. In this work, we developed multivalent glucuronide substrates attached to fluorescent amino-coumarines through self-immolative linkers to enable real time-monitoring of the hydrolysing activity of E.coli β-glucuronidases (GUS) towards clustered substrates. GUS are exoglycosidases of considerable therapeutic interest cleaving β-d-glucuronides and are found in the lysosomes, in the tumoral microenvironment, and are expressed by gut microbiota. GUS showed a much lower catalytic efficiency in hydrolysing clustered glucuronides due to a significantly lower enzymatic velocity and affinity for the substrates. GUS was 52-fold less efficient in hydrolysing GlcA substrates presented on an octameric silsequioxane (COSS) compared with a monovalent GlcA of similar chemical structure. Thus, kinetic and thermodynamic data of GUS hydrolysis towards multivalent glucuronides were easily obtained with these new types of enzymatically-triggered probes. More generally, adapting the substrate nature and valency of these new probes, should improve understanding of the impact of multivalency for a specific enzyme.

Enzymatically-triggered probes to determine glucuronidase hydrolysis kinetics for clustered substrates.     

Prostatic cell lineage markers: Emergence of BCL2+ cells of human prostate cancer xenograft LuCaP 23 following castration

A model of prostate cancer progression based on the expression pattern of informative genes in the human prostate cancer xenograft LuCaP 23.1 is presented. Apparently, there are at least 2 tumor cell populations of LuCaP 23.1, representing 2 different phenotypes. One is NSE (neuron-specific enolase)-positive and the other NSE-negative. NSE-positive tumors were recovered after hormone-independent growth in castrated mice. These hormone-independent tumors also expressed BCL2, a gene product shown to inhibit apoptosis. With NSE, BCL2 and PSA (prostate-specific antigen) as identifying markers, the model specifies a putative progression sequence of the prostate cancer cell types. We also show a proposed lineage relationship among the 3 principal normal cell types found in the prostatic epithelium. © 1996 Wiley-Liss, Inc.     

Effect of Sodium Hypochlorite Concentration on Electronic Apex Locator Reliability

This ex vivo study aimed to measure the performance of an electronic apex locator (EAL) in the presence of sodium hypochlorite irrigants with different concentrations. Two EALs (Root ZX Mini and Locapex 6) were used to locate the apical foramen in 10 extracted single-rooted teeth in the presence of 0.5%, 2.5% and 5% sodium hypochlorite. Visual working lengths were also determined using #10 K-file under a microscope before the electronic measurements were made. The performance of both EALs was compared for the electronic working lengths determined under the different concentrations of sodium hypochlorite. A multiple-way ANOVA and PLSD Fisher’s test with an α risk fixed at 5% were conducted. There were no statistical differences in the working lengths determined by both EALs between the three groups with different concentrations of sodium hypochlorite and their visual control measurements. When a ± 0.5 mm margin was applied, the Root ZX Mini and the Locapex 6 presented 88% and 83% accuracy, respectively. Sodium hypochlorite concentration in irrigants does not affect the accuracy and reliability of either the Root ZX Mini or the Locapex 6. Electronic apex locators are reliable with any concentration of sodium hypochlorite irrigants.     

New biomaterials for Ni biosorption turned into catalysts for Suzuki–Miyaura cross coupling of aryl iodides in green conditions

In parallel with increasing Ni production and utilisation, Ni pollution in the soil–water continuum has become an alarming and global problem. Solutions for removing Ni from industrial effluents have been widely investigated and biosorption has emerged as an efficient, cost-effective, scalable and sustainable alternative for water treatment. However, the biosorption capacity is limited by the chemical composition of the biomaterial and the Ni-enriched biomaterials are rarely valorised. In this work, the biosorption capacity of three abundant biomaterials with different chemical properties – water hyacinth, coffee grounds and pinecones – was studied before and after functionalization, and reached a maximum biosorption capacity of 51 mg g⁻¹ of Ni(ii). A bioinspired functionalization approach was investigated introducing carboxylate moieties and was conducted in green conditions. The Ni-enriched biomaterials were valorised by transformation into catalysts, which were characterised by MP-AES and XRPD. Their characterisation revealed a structure similar to nickel formate, and hence the Eco-Ni(HCOO)₂ catalysts were tested in Suzuki–Miyaura reactions. Several aryl iodides were successfully cross-coupled to phenylboronic acids using Eco-Ni(HCOO)₂ without any ligand, a mild and green base in a mixture of green solvents.

New biomaterials were functionalised for biosorption of Ni from aqueous solutions and valorised as ecocatalysts in Suzuki–Miyaura green reactions.     

Early chains of transmission of COVID-19 in France,January to March 2020

IntroductionSARS-CoV-2, the virus that causes COVID-19, has spread rapidly worldwide. In January 2020, a surveillance system was implemented in France for early detection of cases and their contacts to help limit secondary transmissions.AimTo use contact-tracing data collected during the initial phase of the COVID-19 pandemic to better characterise SARS-CoV-2 transmission.MethodsWe analysed data collected during contact tracing and retrospective epidemiological investigations in France from 24 January to 30 March 2020. We assessed the secondary clinical attack rate and characterised the risk of a contact becoming a case. We described chains of transmission and estimated key parameters of spread.ResultsDuring the study period, 6,082 contacts of 735 confirmed cases were traced. The overall secondary clinical attack rate was 4.1% (95% confidence interval (CI): 3.6–4.6), increasing with age of index case and contact. Compared with co-workers/friends, family contacts were at higher risk of becoming cases (adjusted odds ratio (AOR): 2.1, 95% CI: 1.4–3.0) and nosocomial contacts were at lower risk (AOR: 0.3, 95% CI: 0.1–0.7). Of 328 infector/infectee pairs, 49% were family members. The distribution of secondary cases was highly over-dispersed: 80% of secondary cases were caused by 10% of cases. The mean serial interval was 5.1 days (interquartile range (IQR): 2–8 days) in contact tracing pairs, where late transmission events may be censored, and 6.8 (3–8) days in pairs investigated retrospectively.ConclusionThis study increases knowledge of SARS-CoV-2 transmission, including the importance of superspreading events during the onset of the pandemic.