International initiative for a curated SDHB variant database improving the diagnosis of hereditary paraganglioma and pheochromocytoma

Funder: Cancer Research UK Cambridge Cancer CentreBackground: SDHB is one of the major genes predisposing to paraganglioma/pheochromocytoma (PPGL). Identifying pathogenic SDHB variants in patients with PPGL is essential to the management of patients and relatives due to the increased risk of recurrences, metastases and the emergence of non-PPGL tumours. In this context, the ‘NGS and PPGL (NGSnPPGL) Study Group’ initiated an international effort to collect, annotate and classify SDHB variants and to provide an accurate, expert-curated and freely available SDHB variant database. Methods: A total of 223 distinct SDHB variants from 737 patients were collected worldwide. Using multiple criteria, each variant was first classified according to a 5-tier grouping based on American College of Medical Genetics and NGSnPPGL standardised recommendations and was then manually reviewed by a panel of experts in the field. Results: This multistep process resulted in 23 benign/likely benign, 149 pathogenic/likely pathogenic variants and 51 variants of unknown significance (VUS). Expert curation reduced by half the number of variants initially classified as VUS. Variant classifications are publicly accessible via the Leiden Open Variation Database system (https://databases.lovd.nl/shared/genes/SDHB). Conclusion: This international initiative by a panel of experts allowed us to establish a consensus classification for 223 SDHB variants that should be used as a routine tool by geneticists in charge of PPGL laboratory diagnosis. This accurate classification of SDHB genetic variants will help to clarify the diagnosis of hereditary PPGL and to improve the clinical care of patients and relatives with PPGL

Performance of ceramic micro- and ultrafiltration membranes treating limed and partially clarified sugar cane juice

The performance of ceramic membranes with pore sizes of 0.02, 0.05 and 0.10 μm in clarifying limed and partially clarified raw sugar cane juice was investigated under different operating conditions. For the 0.10 μm membrane, the increase in transmembrane pressure (TMP) from 1 to 3 bar increased the initial flux by 15.5% and increased the average flux over a period of 4 h by 11.9%. The initial flux of the 0.10 μm membrane increased dramatically at a TMP of 1 bar when the membrane underwent a chemical cleaning with 1% NaOH and NaOCl equivalent to 3000 ppm free chlorine for 1 h and the average flux over a period of 4 h was also increased. Among the three membranes tested 0.05 μm membrane performed better than the other two membranes and yielded higher initial and average fluxes. Out of the four fouling models used to fit the experimental data, the cake filtration model predicted the initial fluxes of 0.02 and 0.05 μm membrane more accurately. On the other hand, the combination of external and progressive internal fouling model predicted the performance of 0.10 μm membrane better compared to the others. Intermittent air back flushing improved the performance of 0.10 μm but did not have any effect on the performance of the other two membranes. However, all the membranes produced high quality filtered juice

Targeted next-generation sequencing detects rare genetic events in pheochromocytoma and paraganglioma

BACKGROUND: Knowing the genetic status of patients affected by paragangliomas and pheochromocytomas (PPGL) is important for the guidance of their management and their relatives. Our objective was to improve the diagnostic performances of PPGL genetic testing by next-generation sequencing (NGS). METHODS: We developed a custom multigene panel, which includes 17 PPGL genes and is compatible with both germline and tumour DNA screening. The NGS assay was first validated in a retrospective cohort of 201 frozen tumour DNAs and then applied prospectively to 623 DNAs extracted from leucocytes, frozen or paraffin-embedded PPGL tumours. RESULTS: In the retrospective cohort, the sensitivity of the NGS assay was evaluated at 100% for point and indels mutations and 86% for large rearrangements. The mutation rate was re-evaluated from 65% (132/202) to 78% (156/201) after NGS analysis. In the prospective cohort, NGS detected not only germline and somatic mutations but also co-occurring variants and mosaicism. A mutation was identified in 74% of patients for whom both germline and tumour DNA were available. CONCLUSION: The analysis of 824 DNAs from patients with PPGL demonstrated that NGS assay significantly improves the performances of PPGL genetic testing compared with conventional methods, increasing the rate of identified mutations and identifying rare genetic mechanisms

Concentration des peroxydes et temperature dans une flamme froide d'heptane normal stabilisee en ecoulement turbulent ou laminaire

CNRS RP 440 (232) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

A highly virulent variant of HIV-1 circulating in the Netherlands.

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log <sub>10</sub> increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence