A pilot study investigating the feasibility of using a fully automatic software to assess the RENAL and PADUA score.

PURPOSE: Image-based morphometric scoring systems such as the RENAL and PADUA scores are useful to evaluate the complexity of partial nephrectomy for renal cell carcinoma (RCC). The main aim of this study was to develop a new imaging software to enable an automatic detection and a 3D visualization of RCC from CT angiography (CTA) and to address the feasibility to use it to evaluate the features of the RENAL and the PADUA scores. METHODS: A training dataset of 210 patients CTA-scans manually segmented was used to train a deep learning algorithm to develop the automatic detection and 3D-visualization of RCC. A trained operator blindly assessed the RENAL and PADUA scores on a testing dataset of 41 CTA from patients with RCC using a commercialized semi-automatic software (ground truth) and the new automatic software. Concordance between the two methods was evaluated. RESULTS: The median PADUA score was 9 (7-11) and the renal score was 8 (5.5-9). The automatic software enabled to automatically detect the tumoral kidney and provided a 3D-visualization in all cases, with a computational time less than 20 seconds. Concordances for staging the anatomical features of the RENAL scores were respectively: 87.8% for radius, 85.4% for exophytic rate, 82.9% for location to the polar lines and 92.7% for the antero-posterior location. For the PADUA scores, concordances were 90.2% for tumor size, 85.4% for exophytic rate, 87.8% for polar location and 100% for renal rim. CONCLUSION: By enabling an automatic 3D-visualization of tumoral kidney, this software could help to calculate morphometric scores, save time and improve reproducibility for clinicians.

[Single-use versus reusable flexible ureteroscope: Technical and medico-economic aspects]. / Urétéroscope souple à usage unique versus réutilisable : aspects techniques et médico-économiques.

INTRODUCTION: Sate of the art on the indications, methods of implementation and medico-economic considerations of reusable flexible ureteroscopes (URSr) vs single use (URSuu)? METHOD: Review of the literature (Pubmed) on reusable and single-use ureteroscopes, as well as on the expertise of our center. A PubMed search and narrative review of the data was performed in July 2021. Only articles in French or English were selected. RESULTS: The URSr and URSuu have similar technical characteristics and are suitable for the exploration of the upper urinary excretory tract: treatment of stones of the kidney <2cm or of the ureter. The URSr is the most common type of ureteroscope. URSuu are newer and associated with many advantages: no sterilization procedure, immediate availability of equipment in the operating room, reduced waste production at the institutional level. A hybrid use of URSr and URSuu currently seems to be the best compromise from a medico-economic point of view for high volume centers. In the case of a smaller activity or a secondary site, URSuu are more advantageous and the reduction in purchasing costs should accentuate this benefit. CONCLUSION: URSr and URSuu are technically similar and allow identical treatment of upper urinary tract pathologies. Their complementary use optimizes the care of urology patients. The barrier to the exclusive use of URSuu remains their cost.

Management of accessory renal arteries during aneurysm repair in a patient with end-stage renal failure.

The presence of accessory renal artery is a frequent anatomic variation that can challenge abdominal aortic aneurysm (AAA) repair. Here, we show an image of an abdominal aortic aneurysm extended to multiple accessory renal arteries in a patient known for an end-stage renal failure. This case raises the questions of the criteria that should be taken in consideration for an optimal management of accessory renal artery during AAA repair.

Serum sclerostin: the missing link in the bone-vessel cross-talk in hemodialysis patients?

UNLABELLED: We found for the first time that in maintenance hemodialysis patients, higher sclerostin serum level was associated with severe abdominal aortic calcification (AAC). In addition, cortical bone microarchitecture (density and thickness) assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT) at tibia was also independently associated with severe AAC. These results suggest that sclerostin may be involved in the association of mineral and bone disorder with vascular calcification in hemodialysis patients. INTRODUCTION: Severe abdominal aortic calcifications are predictive of high cardiovascular mortality in maintenance hemodialysis (MHD) patients. In patients with end-stage renal disease, a high aortic calcification score was associated with lower bone turnover on bone biopsies. Thus, we hypothesized that sclerostin, a Wnt pathway inhibitor mainly secreted by osteocytes and acting on osteoblasts to reduce bone formation, may be associated with vascular calcifications in MHD patients. METHODS: Fifty-three MHD patients, aged 53 years [35-63] (median [Q1-Q3]) were included. Serum was sampled before the MHD session to assay sclerostin. Framingham score was computed and the abdominal aortic calcification (AAC) score was assessed according to Kauppila method on lateral spine imaging using DEXA. Tibia bone status was evaluated by high-resolution peripheral quantitative computed tomography (HR-pQCT). Patients were distributed into two groups according to their AAC score: patients with mild or without AAC (score below 6) versus patients with severe AAC (score of 6 and above). RESULTS: In multivariate analysis, after adjustment on age, dialysis duration and diabetes, serum sclerostin and cortical thickness were independently associated with severe AAC (odds ratio (OR) = 1.43 for each 0.1 ng/mL increase [95 % confidence interval (CI) 1.10-1.83]; p = 0.006 and 0.16 for 1 SD increase [0.03-0.73]; p = 0.018, respectively). A second cardiovascular model adjusted on Framingham score and the above mentioned confounders showed similar results. CONCLUSIONS: Elevated sclerostin serum level and poorer tibia cortical bone structure by HR-pQCT were positively and independently associated with higher odds of severe AAC in MHD patients. Serum sclerostin may become a biomarker of mineral and bone disorder and vascular risk in MHD patients.

The first simultaneous kidney-adrenal gland-pancreas transplantation: outcome at 1 year.

Adrenal insufficiency is a rare but life-threatening disease. Replacement therapy sometimes fails to prevent an acute adrenal crisis and most often does not lead to restoration of well-being. We report here the 1-year outcome of the first simultaneous kidney-adrenal gland-pancreas transplantation in a 33-year-old patient with type 1 diabetes and concomitant autoimmune adrenal insufficiency. En bloc left adrenal gland and kidney grafts were anastomosed on the left iliac vessels in normal vascular conditions and the pancreas graft was anastomosed on the right iliac vessels. The immunosuppressive regimen was not modified by the addition of the adrenal gland. We observed no additional morbidity due to the adrenal gland transplantation, as there were no surgical complications. One-year kidney and pancreas graft functions were satisfactory (estimated glomerular filtration rate: 55 mL/min/1.73 m(2) and HbA1c: 4.8%). The adrenal graft functioned well at 12 months with a normalization of cortisol and aldosterone baseline levels. Functional imaging at 3 months showed good uptake of [(123) I]-metaiodobenzylguanidine by the adrenal graft. Transplantation of the adrenal gland en bloc with the left kidney appears to be a good therapeutic option in patients with adrenal insufficiency awaiting kidney or kidney-pancreas transplantation.

Osteoid osteoma is an osteocalcinoma affecting glucose metabolism.

Osteocalcin is a hormone secreted by osteoblasts, which regulates energy metabolism by increasing ß-cell proliferation, insulin secretion, insulin sensitivity, and energy expenditure. This has been demonstrated in mice, but to date, the evidence implicating osteocalcin in the regulation of energy metabolism in humans are indirect. To address this question more directly, we asked whether a benign osteoblastic tumor, such as osteoma osteoid in young adults, may secrete osteocalcin. The study was designed to assess the effect of surgical resection of osteoid osteoma on osteocalcin and blood glucose levels in comparison with patients undergoing knee surgery and healthy volunteers. Blood collections were performed the day of surgery and the following morning after overnight fasting. Patients and controls were recruited in the orthopedic surgery department of New York Presbiterian Hospital, NY-USA and Hospices Civils de Lyon, France. Seven young males were included in the study: two had osteoid osteoma, two underwent knee surgery, and three were healthy volunteers. After resection of the osteoid osteomas, we observed a decrease of osteocalcin by 62% and 30% from the initial levels. Simultaneously, blood glucose increased respectively by 32% and 15%. Bone turnover markers were not affected. This case study shows for the first time that osteocalcin in humans affects blood glucose level. This study also suggests that ostoid osteoma may be considered, at least in part, as an osteocalcinoma.

Nucleotide hydrolysis in cytoskeletal assembly.

Two major polymers of the cytoskeleton, actin filaments and microtubules, are assembled with expenditure of energy: the ATP/GTP tightly bound to actin/tubulin is irreversibly hydrolyzed to ADP/GTP during the assembly process, and liberation of Pi in the medium occurs subsequent to the incorporation of subunits in the polymer. Pi release acts as a switch, causing the destabilization of protein-protein interactions in the polymer, therefore regulating the dynamics of these fibres. An understanding of this regulation in vivo requires that progress be made in four areas: the chemistry of the NTPase reaction; the structure of the intermediates in nucleotide hydrolysis and the nature of the conformational switch; the regulation of parameters involved in dynamic instability of microtubules; and the possible involvement of nucleotide hydrolysis in the macroscopic organization of these polymers in highly concentrated solutions, compared with the simple case of a equilibrium polymers. Progress made along these lines will define trends for future investigation.

Control of actin dynamics.

Actin-based motility processes are tightly linked to the rapid turnover of actin filaments. Factors that control the steady state of actin assembly, such as capping proteins and actin-depolymerizing factor/cofilin, directly affect motility. Actin-depolymerizing factor increases the treadmilling of actin filaments in vitro and in vivo. Cellular factors that are involved in linking initiation of barbed end assembly to cell signaling are being identified using Listeria monocytogenes and Saccharomyces cerevisiae as model systems.

The Arp2/3 complex branches filament barbed ends: functional antagonism with capping proteins.

The Arp2/3 complex is an essential regulator of actin polymerization in response to signalling and generates a dendritic array of filaments in lamellipodia. Here we show that the activated Arp2/3 complex interacts with the barbed ends of filaments to initiate barbed-end branching. Barbed-end branching by Arp2/3 quantitatively accounts for polymerization kinetics and for the length correlation of the branches of filaments observed by electron microscopy. Filament branching is visualized at the surface of Listeria in a reconstituted motility assay. The functional antagonism between the Arp2/3 complex and capping proteins is essential in the maintenance of the steady state of actin assembly and actin-based motility.

Actin-based movement of Listeria monocytogenes: actin assembly results from the local maintenance of uncapped filament barbed ends at the bacterium surface.

The thermodynamic basis for actin-based motility of Listeria monocytogenes has been investigated using cytoplasmic extracts of Xenopus eggs, initially developed by Theriot et al. (Theriot, J. A., J. Rosenblatt, D. A. Portnoy, P. J. Goldschmidt-Clermont, and T. J. Mitchison. 1994. Cell. 76:505-517) as an in vitro cell-free system. A large proportion (75%) of actin was found unpolymerized in the extracts. The amount of unassembled actin (12 microM) is accounted for by the sequestering functions of T beta 4Xen (20 microM) and profilin (5 microM), the barbed ends being capped. Movement of Listeria was not abolished by depletion of over 99% of the endogenous profilin. The proline-rich sequences of ActA are unlikely to be the target of profilin. All data support the view that actin assembly at the rear of Listeria results from a local shift in steady state due to a factor, keeping filaments uncapped, bound to the surface of the bacterium, while barbed ends are capped in the bulk cytoplasm. Movement is controlled by the energetic difference (i.e., the difference in critical concentration) between the two ends of the filaments, hence a constant ATP supply and the presence of barbed end capped F-actin in the medium are required to buffer free G-actin at a high concentration. The role of membrane components is demonstrated by the facts that: (a) Listeria movement can be reconstituted in the resuspended pellets of high speed-centrifuged extracts that are enriched in membranes; (b) Actin-based motility of endogenous vesicles, exhibiting the same rocketing movement as Listeria, can be observed in the extracts.

Activation of the CDC42 effector N-WASP by the Shigella flexneri IcsA protein promotes actin nucleation by Arp2/3 complex and bacterial actin-based motility.

To propel itself in infected cells, the pathogen Shigella flexneri subverts the Cdc42-controlled machinery responsible for actin assembly during filopodia formation. Using a combination of bacterial motility assays in platelet extracts with Escherichia coli expressing the Shigella IcsA protein and in vitro analysis of reconstituted systems from purified proteins, we show here that the bacterial protein IcsA binds N-WASP and activates it in a Cdc42-like fashion. Dramatic stimulation of actin assembly is linked to the formation of a ternary IcsA-N-WASP-Arp2/3 complex, which nucleates actin polymerization. The Arp2/3 complex is essential in initiation of actin assembly and Shigella movement, as previously observed for Listeria monocytogenes. Activation of N-WASP by IcsA unmasks two domains acting together in insertional actin polymerization. The isolated COOH-terminal domain of N-WASP containing a verprolin-homology region, a cofilin-homology sequence, and an acidic terminal segment (VCA) interacts with G-actin in a unique profilin-like functional fashion. Hence, when N-WASP is activated, its COOH-terminal domain feeds barbed end growth of filaments and lowers the critical concentration at the bacterial surface. On the other hand, the NH(2)-terminal domain of N-WASP interacts with F-actin, mediating the attachment of the actin tail to the bacterium surface. VASP is not involved in Shigella movement, and the function of profilin does not require its binding to proline-rich regions.

Actin depolymerizing factor (ADF/cofilin) enhances the rate of filament turnover: implication in actin-based motility.

Actin-binding proteins of the actin depolymerizing factor (ADF)/cofilin family are thought to control actin-based motile processes. ADF1 from Arabidopsis thaliana appears to be a good model that is functionally similar to other members of the family. The function of ADF in actin dynamics has been examined using a combination of physical-chemical methods and actin-based motility assays, under physiological ionic conditions and at pH 7.8. ADF binds the ADP-bound forms of G- or F-actin with an affinity two orders of magnitude higher than the ATP- or ADP-Pi-bound forms. A major property of ADF is its ability to enhance the in vitro turnover rate (treadmilling) of actin filaments to a value comparable to that observed in vivo in motile lamellipodia. ADF increases the rate of propulsion of Listeria monocytogenes in highly diluted, ADF-limited platelet extracts and shortens the actin tails. These effects are mediated by the participation of ADF in actin filament assembly, which results in a change in the kinetic parameters at the two ends of the actin filament. The kinetic effects of ADF are end specific and cannot be accounted for by filament severing. The main functionally relevant effect is a 25-fold increase in the rate of actin dissociation from the pointed ends, while the rate of dissociation from the barbed ends is unchanged. This large increase in the rate-limiting step of the monomer-polymer cycle at steady state is responsible for the increase in the rate of actin-based motile processes. In conclusion, the function of ADF is not to sequester G-actin. ADF uses ATP hydrolysis in actin assembly to enhance filament dynamics.

Role of proteins of the Ena/VASP family in actin-based motility of Listeria monocytogenes.

Intracellular propulsion of Listeria monocytogenes is the best understood form of motility dependent on actin polymerization. We have used in vitro motility assays of Listeria in platelet and brain extracts to elucidate the function of the focal adhesion proteins of the Ena (Drosophila Enabled)/VASP (vasodilator-stimulated phosphoprotein) family in actin-based motility. Immunodepletion of VASP from platelet extracts and of Evl (Ena/VASP-like protein) from brain extracts of Mena knockout (-/-) mice combined with add-back of recombinant (bacterial or eukaryotic) VASP and Evl show that VASP, Mena, and Evl play interchangeable roles and are required to transform actin polymerization into active movement and propulsive force. The EVH1 (Ena/VASP homology 1) domain of VASP is in slow association-dissociation equilibrium high-affinity binding to the zyxin-homologous, proline-rich region of ActA. VASP also interacts with F-actin via its COOH-terminal EVH2 domain. Hence VASP/ Ena/Evl link the bacterium to the actin tail, which is required for movement. The affinity of VASP for F-actin is controlled by phosphorylation of serine 157 by cAMP-dependent protein kinase. Phospho-VASP binds with high affinity (0.5 x 10(8) M-1); dephospho-VASP binds 40-fold less tightly. We propose a molecular ratchet model for insertional polymerization of actin, within which frequent attachment-detachment of VASP to F-actin allows its sliding along the growing filament.

Actin polymerization and ATP hydrolysis.

F-actin is the major component of muscle thin filaments and, more generally, of the microfilaments of the dynamic, multifunctional cytoskeletal systems of nonmuscle eukaryotic cells. Polymeric F-actin is formed by reversible noncovalent self-association of monomeric G-actin. To understand the dynamics of microfilament systems in cells, the dynamics of polymerization of pure actin must be understood. The following model has emerged from recent work. During the polymerization process, adenosine 5'-triphosphate (ATP) that is bound to G-actin is hydrolyzed to adenosine 5'-diphosphate (ADP) that is bound to F-actin. The hydrolysis reaction occurs on the F-actin subsequent to the polymerization reaction in two steps: cleavage of ATP followed by the slower release of inorganic phosphate (Pi). As a result, at high rates of filament growth a transient cap of ATP-actin subunits exists at the ends of elongating filaments, and at steady state a stabilizing cap of ADP.Pi-actin subunits exists at the barbed ends of filaments. Cleavage of ATP results in a highly stable filament with bound ADP.Pi, and release of Pi destabilizes the filament. Thus these two steps of the hydrolytic reaction provide potential mechanisms for regulating the monomer-polymer transition.

Mechanism of actin-based motility.

Spatially controlled polymerization of actin is at the origin of cell motility and is responsible for the formation of cellular protrusions like lamellipodia. The pathogens Listeria monocytogenes and Shigella flexneri, which undergo actin-based propulsion, are acknowledged models of the leading edge of lamellipodia. Actin-based motility of the bacteria or of functionalized microspheres can be reconstituted in vitro from only five pure proteins. Movement results from the regulated site-directed treadmilling of actin filaments, consistent with observations of actin dynamics in living motile cells and with the biochemical properties of the components of the synthetic motility medium.

[Consequences for clinical biochemists of the modifications of the creatinine-based evaluation of glomerular filtration rate between 2005 and 2008]. / Evolution des modalités d'évaluation de la fonction rénale basée sur la créatinine entre 2005 et 2008: conséquences pour les biologistes.

Since 2005, international guidelines propose a stadification for chronic renal failure based on the glomerular filtration rate (GFR) value. The performance of the creatinine-based equations allowing the estimation of GFR and the bias of the creatinine measurements is, more than ever, a crucial issue. The consequences for the clinical biologists are of importance. First, the Cockcroft-Gault formula must be replaced by the four variable-MDRD equation. Second, the biologists must chose from the "175" and the "186" versions of the MDRD equation. The first one fits the creatinine methods which are traceable to the reference method (liquid or gas chromatography coupled to mass spectrometry). The second equation must be used for creatinine methods, which are not traceable to the reference method. Today, only some enzymatic methods can prove that they are traceable to the reference method. For the colorimetric methods, future is inclear.

[Neonatal intoxication to vitamin D in premature babies: A series of 16 cases]. / Intoxication néonatale à la vitamine D chez des anciens prématurés : une série de 16 cas.

INTRODUCTION: Preterm neonates are particularly at risk of vitamin D (25-D) deficiency. To prevent rickets and osteopenia in this population, international guidelines vary between 800 and 1000IU per day of vitamin D in Europe and recommend 400IU per day in the USA. Target levels of circulating 25-D are not well identified, with the lower target level 50-75nmol/L and the upper target level probably 120nmol/L. METHODS: Between 2013 and 2015, 16 premature infants (born<35WG) were referred to pediatric nephrology clinics because of symptoms secondary to 25-D overdose during the neonatal period. Clinical and biological data were retrospectively reviewed to better define this population. The results are presented as the median (range). RESULTS: Gestational age was 27 (24-35)WG with a birth weight of 810 (560-2120)g. Nephrocalcinosis was the initial symptom in 37% of cases, hypercalcemia in 44%, and hypercalciuria in 19%. Daily vitamin D doses were 333 (35-676)IU. Age and body weight at initial symptom were 36.6 (27.6-47.6)WG and 2300 (640-3760)g, respectively. The 25-D level at the time of the first dosage was 210 (119-350)nmol/L and the 1-25 vitamin D level was 370 (245-718)pmol/L (local normal values for age<240). During follow-up, 12 patients displayed nephrocalcinosis, ten hypercalciuria, and three hypercalcemia. The 25-D level normalized in ten patients within 10 (3-32)months after vitamin D withdrawal. Nephrocalcinosis improved in ten of 12 patients, within 12 (3-30)months. Vitamin D could be readministered in ten patients. When searched (n=3), no CYP24A1 mutation was identified in two patients, but was identified in the heterozygous state in one. CONCLUSION: A 25-D overdose should be systematically ruled out in the presence of nephrocalcinosis, hypercalcemia, and/or hypercalciuria during infancy in children born preterm. Studies are required to assess the exact frequency of 25-D deficiency and overdose in this population, as well as to evaluate the potential deleterious effects of this imbalance on bone, kidney, and brain development.

The interaction between lipid derivatives of colchicine and tubulin: consequences of the interaction of the alkaloid with lipid membranes.

Colchicine is a potent antimitotic poison which is well known to prevent microtubule assembly by binding tubulin very tightly. Colchicine also possesses anti-inflammatory properties which are not well understood yet. Here we show that colchicine tightly interacts with lipid layers. The physical and biological properties of three different lipid derivatives of colchicine are investigated parallel to those of membrane lipids in the presence of colchicine. Upon insertion in the fatty alkyl chains, colchicine rigidifies the lipid monolayers in a fluid phase and fluidifies rigid monolayers. Similarly X-ray diffraction data show that lecithin-water phases are destabilized by colchicine. In addition, an unexpectedly drastic enhancement of the photoisomerization rate of colchicine into lumicolchicine in the lipid environment is observed and further supports insertion of the alkaloid in membranes. Finally the interaction of colchicine with lipids makes the drug inaccessible to tubulin. The possible in vivo significance of these results is discussed.

Cardiac tamponade early after thrombolysis for acute myocardial infarction: a rare but not reported hemorrhagic complication.

Among 392 consecutive patients admitted for acute myocardial infarction and treated with thrombolytic drugs, 4 patients (1%) developed an early hemorrhagic pericardial effusion (without ventricular wall rupture) evolving within 24 h to cardiogenic shock consequent to cardiac tamponade. They all suffered from a large anterior myocardial infarction treated within 4 h after onset of symptoms with intravenous anisoylated plasminogen streptokinase activator complex (one case), recombinant tissue-type plasminogen activator (rt-PA) (two cases) or streptokinase (one case), anticoagulation with heparin (all cases) and aspirin (three cases). As soon as pericardial effusion was established by echocardiography, emergency percutaneous pericardiocentesis was performed at the bedside 20 +/- 6 h after thrombolytic therapy was started. This corrected immediately the clinical and hemodynamic status of each patient and a catheter was left in the pericardial space for 34 +/- 18 h. Thus, in the presence of unexplained clinical and hemodynamic deterioration occurring during the first 24 h after thrombolytic treatment of a large myocardial infarction, cardiac tamponade should be suspected. Immediate percutaneous pericardiocentesis followed by continuous drainage is a simple and definitive treatment for this complication.

Control of actin dynamics in cell motility.

Actin polymerization plays a major role in cell movement. The controls of actin sequestration/desequestration and of filament turnover are two important features of cell motility. Actin binding proteins use properties derived from the steady-state monomer-polymer cycle of actin in the presence of ATP, to control the F-actin/G-actin ratio and the turnover rate of actin filaments. Capping proteins and profilin regulate the size of the pools of F-actin and unassembled actin by affecting the steady-state concentration of ATP-G-actin. At steady state, the treadmilling cycle of actin filaments is fed by their disassembly from the pointed ends. It is regulated in two different ways by capping proteins and ADF, as follows. Capping proteins, in decreasing the number of growing barbed ends, increase their individual rate of growth and create a "funneled" treadmilling process. ADF/cofilin, in increasing the rate of pointed-end disassembly, increases the rate of filament turnover, hence the rate of barbed-end growth. In conclusion, capping proteins and ADF cooperate to increase the rate of actin assembly up to values that support the rates of actin-based motility processes.