Assistance by adaptative damping on a complex bimanual task in laparoscopic surgery.

PURPOSE: Laparoscopic surgery has improved outcomes in abdominal surgery, but presents kinematic restrictions for surgeons. Robotic comanipulation with adaptative damping has been investigated in simple laparoscopic tasks. The present protocol aimed to determine the contribution of adaptive damping in complex bimanual tasks approaching clinical setting. METHODS: Fourteen residents in general surgery performed three exercises, and for each three repetitions without (classic repetitions) and three with robotic assistance (robotic repetitions) in a randomised order. The exercises chosen were trajectory, modified Pea on a Peg and intracorporeal suture. Task performance, gesture performance, workload and impression were measured. Also, a semi-directed interview was performed to collect the participants' feeling about companipulated robots and their potential application in clinical practice. RESULTS: Adaptative damping assistance did not impact task performance, but allowed an economy of movement in the non-dominant hand during suture exercise (distance 916 ± 500 mm in classic vs. 563 ± 261 mm in robotic, p < 0.001). Perceived workload (p = 0.12) and user's impression were not different between classic and robotic repetitions, except novelty (p < 0.001). Participants' interviews revealed their interest for the robotic devices, particularly the gravity compensation, and were ready to use the adaptative damping provided an intermittent use, for example to dissect dangerous areas. CONCLUSION: Adaptative damping applied by comanipulated robots does not influence the performance of the task, but improves the performance of the gesture itself, particularly for the non-dominant hand, and during the realisation of a complex task like suturing. For residents in digestive surgery, this assistance does increase workload, and they would use this help in the operating room under certain conditions.

A new set of reagents and related software used for NGS based classical and non-classical HLA typing showing evidence for a greater HLA haplotype diversity.

To evaluate the HLA typing performance of a new Long-Range PCR NGS set of reagents and its dedicated software, a panel of 41 reference homozygous cell lines from the International Histocompatibility Working Group (IHWG) and a panel of 376 volunteer bone marrow donors were analyzed for classical and non-classical HLA class I and class II genes. All results, except HLA-DPB1, were obtained without any ambiguities at the 3rd field level. Based on the high resolution performance of the reagents, a number of new alleles have been described not only for classical but also for non-classical HLA class I genes, leading to a more accurate haplotype definition. Linkage disequilibrium between HLA-A and HLA-G genes has been defined at 4th field level of resolution. Moreover, for the first time, HLA-DQA2 and DQB2 polymorphisms and their linkage disequilibrium with DQB1 were described.

Perception of haptic motion is enhanced during conditions of increased postural stability.

BACKGROUND: Coupling between postural sway and fingertip displacement has been observed in individuals lightly touching a moving surface. This can be attributed to the central nervous system (CNS) misinterpreting surface motion as self-motion, evoking a compensatory sway response. RESEARCH QUESTION: Does baseline postural state influence the correct perception of haptic object motion? METHODS: Motion perception detection thresholds of index finger displacement at 1 mm s-1 velocity during light touch were determined for three postural conditions: standing with eyes open (EO) and closed (EC), and sitting with eyes closed. For the standing condition with eyes shut, displacement thresholds were measured using three velocities (1, 2 and 4 mm s-1). RESULTS: Postural condition had a large influence on motion perception, with a reduction in displacement threshold from 12 → 6 → 2 mm during the transition from standing EC → standing EO → sitting EC. A systematic decrease in displacement perception threshold was observed with increasing velocity. This tends to suggest that the increase of the touched object velocity may help overcoming the misinterpretation. SIGNIFICANCE: These results suggest that the ability to disambiguate self motion from haptic motion is enhanced during stable postures, and when stimulus velocity is high. Our findings may help to understand the mechanisms underlying the coupling between surface movements and postural sway, reported in the literature.

Evidence for a higher resolution of HLA genotyping by a new NGS-based approach.

With more than 16,000 alleles identified, the human leucocyte antigen (HLA) system is one of the most polymorphic regions of the human genome. Regarding the crucial role of HLA compatibility in transplantation and especially in Hematopoietic Stem Cell Transplantation, identification of HLA polymorphisms at a high-resolution level is of major interest. Recently, NGS technology has been proposed which appears to be simpler and more informative than the classical molecular methods such as SSP, SSOr and SBT. In the present report, a new set of NGS reagents and the appropriate associated software for sequence analysis are described. Through different studies, the performances of the system are illustrated and demonstrate that the method herein described overcomes current limitations in performing high-resolution HLA typing in clinical laboratories.

Characterization of a new human monoclonal antibody directed against the Vel antigen.

BACKGROUND AND OBJECTIVES: The Vel blood group antigen is a poorly characterized high-prevalence antigen. Until now, anti-Vel antibodies have been observed in only alloimmunized Vel-negative individuals. In this study, we aimed to establish a human hybridoma cell line secreting the first anti-Vel monoclonal antibody (mAb), clone SpG213Dc. MATERIALS AND METHODS: Peripheral blood lymphocytes from a French Vel-negative woman with anti-Vel in her plasma were transformed with Epstein-Barr virus and then hybridized with the myeloma cell line Sp2/O-Ag14 using the polyethylene glycol (PEG) method. A specific anti-Vel mAb was successfully produced and was extensively characterized by serological, flow cytometry and Western blot analyses. RESULTS: One human anti-Vel-secreting clone was produced and the secreted anti-Vel mAb (SpG213Dc) was examined. The specificity of the SpG213Dc mAb was assessed by its reactivity against a panel of nine genotyped RBCs including, respectively, three Vel-negative and six Vel-positive (three wild-type homozygous and three heterozygous) samples using flow cytometry method. Vel-positive RBCs were specifically stained and were subsequently used to perform Western blot and immunoprecipitation analysis of the Vel antigen. CONCLUSION: Serological characterization of the new monoclonal anti-Vel SpG213Dc showed a heterogeneous level of expression of the Vel antigen on the different RBCs. Our results suggest that the mAb SpG213Dc can be reliably used as a blood grouping reagent, thus allowing the mass-scale phenotyping of blood donors to strengthen rare blood banks with Vel-negative RBC units.

The von Hippel-Lindau tumour suppressor gene: uncovering the expression of the pVHL172 isoform.

BACKGROUND: The von Hippel-Lindau (VHL) gene encodes two mRNA variants. Variant 1 encodes two protein isoforms, pVHL213 and pVHL160, that have been extensively documented in the literature. Variant 2 is produced by alternative splicing of exon 2 and encodes a pVHL isoform of 172 amino acids with a theoretical molecular weight of 19 kDa (pVHL172), the expression of which has never been demonstrated so far due to the absence of suitable antibodies. METHODS: We have generated an anti-pVHL monoclonal antibody (JD-1956) using pVHL172 recombinant protein. We tested the antibody against exogenous or endogenous expressed proteins in different cell lines. We identified the pVHL172 using a silencing RNA strategy. The epitope of the antibody was mapped using a peptide array. RESULTS: We efficiently detected the three different isoforms of pVHL in cell lines and tumorigenic tissues by western blotting and immunohistochemistry and confirmed for the first time the endogenous expression of pVHL172. CONCLUSIONS: The endogenous expression of the three isoforms and particularly the pVHL172 has never been shown before due to a lack of a highly specific antibody since none of the available commercial antibodies distinguish the three isoforms of pVHL in cells or in both normal and cancerous human tissues. Evidence of pVHL172 expression emphasises the need to further study its implication in renal tumorigenesis and VHL disease.

Use of Chinese hamster ovary cell lines transfected with cloned human thyrotropin receptor for the measurement of thyroid-stimulating antibodies: advantages and difficulties.

We compared the activities of thyroid-stimulating antibodies (TSAb) as measured with two cell lines (JP26 and JP26/26) transfected with cloned human thyrotropin (TSH) receptor and the values for TSAb measured on human thyrocytes cultures. Sera were obtained from patients with Graves' disease, before, during and after therapy with carbimazole (1-methyl-2-thio-3-carbethoxyimidazole). The activities of TSAb performed with the three assays correlated significantly. The TSAb technique using JP26/26 cells was as sensitive as the method performed on human thyrocyte cultures since positive TSAb values were found in 45 out of 47 (95.7%) newly diagnosed patients, in 100% of patients who relapsed after drug withdrawal and in none in remission. When the JP26 cell line was used, sensitivity decreased as the detection rate was only 53.2 and 55.5% before treatment and in case of relapse, respectively. The TSH receptors analysis showed a receptor density two times higher for JP26/26 than for JP26. JP26/26 cells provide similar diagnostic information on human thyrocytes in patients with Graves' disease. Moreover with these cells, the procedure for cell culture is less cumbersome and precision is better. However, rigorous culture conditions are required to maintain TSH receptor expression in transfected cells.

Anti-pancreatic autoimmunity and Graves' disease: study of a cohort of 600 Caucasian patients.

The aim of this study was to investigate the frequencies of clinical diabetes and humoral markers of anti-pancreatic autoimmunity in a homogeneous population of 600 Caucasian patients with recently diagnosed Graves' disease (GD), in order to characterize the specific features of this group of endocrine patients among subjects at risk of diabetes. Ten were already diabetic at GD diagnosis. Among the 590 non-diabetic patients, 29 had islet cell antibodies (ICA), including 15 with low titre ICA and only 1 ICA-positive subject with a familial history of diabetes. Twenty-four patients had insulin autoantibodies, including three in association with ICA. Glutamic acid decarboxylase (GAD)/64 kDa antibodies were found in 16 of the 150 tested sera, including 13 of the 29 ICA-positive sera. Four ICA-positive patients displayed 37/40 kDa antibodies, including three in association with GAD/64 kDa antibodies. During follow-up, one of the ICA-positive patients developed insulin-dependent diabetes, 14 years after the GD diagnosis. To summarize, this anti-pancreatic autoimmunity study was focused on a large but specific and homogeneous group of subjects at risk for diabetes: recently diagnosed GD patients. This population was characterized by a high prevalence of GAD/64 kDa antibodies but also by a low frequency of evolution towards diabetes and the slowness of the process which could be due to the fact that only a minority of subjects possessed a sufficient combination of anti-pancreatic markers at the same time.