High throughput optical modulation biosensing for highly sensitive and rapid detection of biomarkers

Rapid, highly sensitive, and high-throughput detection of biomarkers at low concentrations is invaluable for early diagnosis of various diseases. In many highly sensitive immunoassays, magnetic beads are used to capture fluorescently labeled target molecules. The target molecules are then quantified by detecting the fluorescent signal from individual beads, which is time consuming and requires a complicated and expensive detection system. Here, we demonstrate a high-throughput optical modulation biosensing (ht-OMB) system, which uses a small permanent magnet to aggregate the beads into a small detection volume and eliminates background noise by steering a laser beam in and out of the cluster of beads. Shortening the aggregation, acquisition, and well-to-well scanning transition times enables reading a 96-well plate within 10 min. Using the ht-OMB system to detect human Interleukin-8, we demonstrated a limit of detection of 0.14 ng/L and a 4-log dynamic range. Testing 94 RNA extracts from 36 confirmed RT-qPCR SARS-CoV-2-positive patients (C_t≤40) and 58 confirmed RT-qPCR SARS-CoV-2-negative individuals resulted in 100% sensitivity and 100% specificity.

Optical modulation biosensing system for rapid detection of biological targets at low concentrations

In many sensitive assays, target molecules are tagged using fluorescently labeled probes and captured using magnetic beads. Here, we introduce an optical modulation biosensing (OMB) system, which aggregates the beads into a small detection area and separates the signal from the background noise by manipulating the laser beam in and out of the cluster of beads. Using the OMB system to detect human interleukin-8, we demonstrated a limit of detection of 0.02 ng/L and a 4-log dynamic range. Using Zika-positive and healthy individuals' serum samples, we show that the OMB-based Zika IgG serological assay has 96% sensitivity and 100% specificity.

Partial volume effect estimation and correction in the aortic vascular wall in PET imaging

We evaluated the impact of partial volume effect (PVE) in the assessment of arterial diseases with (18)FDG PET. An anthropomorphic digital phantom enabling the modeling of aorta related diseases like atherosclerosis and arteritis was used. Based on this phantom, we performed GATE Monte Carlo simulations to produce realistic PET images with a known organ segmentation and ground truth activity values. Images corresponding to 15 different activity-concentration ratios between the aortic wall and the blood and to 7 different wall thicknesses were generated. Using the PET images, we compared the theoretical wall-to-blood activity-concentration ratios (WBRs) with the measured WBRs obtained with five measurement methods: (1) measurement made by a physician (Expert), (2) automated measurement supposed to mimic the physician measurements (Max), (3) simple correction based on a recovery coefficient (Max-RC), (4) measurement based on an ideal VOI segmentation (Mean-VOI) and (5) measurement corrected for PVE using an ideal geometric transfer matrix (GTM) method. We found that Mean-VOI WBRs values were strongly affected by PVE. WBRs obtained by the physician measurement, by the Max method and by the Max-RC method were more accurate than WBRs obtained with the Mean-VOI approach. However Expert, Max and Max-RC WBRs strongly depended on the wall thickness. Only the GTM corrected WBRs did not depend on the wall thickness. Using the GTM method, we obtained more reproducible ratio values that could be compared across wall thickness. Yet, the feasibility of the implementation of a GTM-like method on real data remains to be studied.

Nasal polyposis: is there an inheritance pattern? A single family study

BACKGROUND

Nasal Polyposis (NP) is defined as a chronic inflammatory disease of sinonasal mucosa leading to diffuse formation of benign polyps. Although family histories are frequently suggested in medical literature, no specific study focused on this point has been reported. The purpose of this study is to determine whether a hereditary factor could be implied for NP in a family where several members were affected. We included 99 members of this family.

METHODS

All patients were assessed for conditions known to be associated with the development or presence of NP. Concerning NP, patients were screened with a validated questionnaire and selected patients had a medical examination by an Ear, Nose and Throat practitioner.

RESULTS

Thirteen patients had a personal history of NP without asthma, aspirin intolerance, Churg Strauss syndrome, cystic fibrosis, Young's syndrome, bare lymphocyte syndrome, or primary ciliary dyskinesia. Within this family, 19.7% of those older than 17 years were affected by NP, as compared with the national French prevalence of 2.1%.

CONCLUSIONS

Regarding the pedigree, we discuss different modes of inheritance. The presence of consanguineous unions in this family suggests the possibility of a common ancestor and thus a recessive autosomal mode of inheritance.

[Idiopathic CD4 lymphocytopenia with lethal Salmonella typhimurium sepsis]

In April 1991, a then 43-year-old woman fell ill with a systemic cryptococcal infection which responded well to antimycotic treatment. Four months later she was found to have a T-helper cell deficiency (48/microliters, 15%). Since August 1992 she noted an increased tendency towards infections and had recurrent fever bouts over 4 weeks, which led to her hospitalization in January 1993. Repeated HIV tests were negative. During the first 4 days she was free of infection, but developed a temperature of 39.1 degrees C on the fifth day, and within a few hours a fulminant septicaemia with cardiorespiratory failure developed ending fatally the same day. Blood cultures drawn during fever bouts grew Salmonella typhimurium by the time of her death. Lymphocyte differentiation revealed absolute and relative reduction in the number of CD4-lymphocytes (158/microliters; 18%), retrospectively providing the diagnosis of idiopathic CD4-lymphocytopenia.--In cases such as this there is the need of including opportunistic and masked disease entities in the differential diagnosis, even in the absence of HIV infections, and start early treatment.

[Effect of different media on long-term cultivation of human synovial macrophages]

Cells of rheumatoid synovial tissue were bred in dispersion culture. In order to investigate the influence of three different culture media on the maturation and vitality of synovio-macrophages, Ham F10 (+fetal calf serum) and RPMI 1640 (+pooled AB Rh+ human serum) were compared with the serum- and cytokin-free solution AIM V. Combining light microscopic, transmission electron, and scanning electron microscopic methods (backscatter-mode), the enzyme and antibody features of synoviocytes were detected. The ratio of macrophages were determined in the light microscope by marking with CD 14. The functional maturation was shown by the amboceptor test. This study demonstrates that RPMI 1640 (+AB Rh+ human serum) is favorable for cultivating human synoviomacrophages. Under serum-free conditions AIM V is especially appropriate.