4D printing of biodegradable elastomers with tailorable thermal response at physiological temperature.

4D printing has a great potential for the manufacturing of soft robotics and medical devices. The alliance of digital light processing (DLP) 3D printing and novel shape-memory photopolymers allows for the fabrication of smart 4D-printed medical devices in high resolution and with tailorable functionalities. However, most of the reported 4D-printed materials are nondegradable, which limits their clinical applications. On the other hand, 4D printing of biodegradable shape-memory elastomers is highly challenging, especially when transition points close to physiological temperature and shape fixation under ambient conditions are required. Here, we report the 4D printing of biodegradable shape-memory elastomers with tailorable transition points covering physiological temperature, by using poly(D,L-lactide-co-trimethylene carbonate) methacrylates at various monomer feed ratios. After the programming step, the high-resolution DLP printed stents preserved their folded shape at room temperature, and showed efficient shape recovery at 37 °C. The materials were cytocompatible and readily degradable under physiological conditions. Furthermore, drug-loaded devices with tuneable release kinetics were realized by DLP-printing with resins containing polymers and levofloxacin or nintedanib. This study offers a new perspective for the development of next-generation 4D-printed medical devices.

Functional reorganization of the auditory pathways following late callosotomy.

Injuries at various levels of the auditory system have been shown to lead to functional reorganization of the auditory pathways. In particular, it has recently been shown that such reorganization can occur in callosal agenesis. The pattern of cortical activity following callosotomy is however still unknown, but behavioral results suggest that it could be significantly different from that observed in callosal agenesis. We aimed to confirm this hypothesis by investigating fMRI responses to complex sounds presented binaurally and monaurally in a callosotomized patient. In the binaural condition, the callosotomized subject showed patterns of auditory cortical activation that were similar to those of neurologically intact individuals. However, in both monaural conditions, the callosotomized individual showed a significant increase of the asymmetries favoring the contralateral pathways. Such patterns of cortical responses are only partially consistent with the results obtained from callosal agenesis subjects using the exact same procedure. Indeed, the latter show differences compared with normals in both binaural and monaural conditions. These findings provide neurological evidence that callosotomy could lead to distinctive functional reorganization of the human auditory pathways.

Functional reorganization of the human auditory pathways following hemispherectomy: an fMRI demonstration.

The present study investigated the functional reorganization of ipsilateral and contralateral auditory pathways in hemispherectomized subjects. Functional reorganization was assessed using functional Magnetic Resonance Imaging (fMRI) and stimulation with complex sounds presented binaurally and monaurally. For neurologically intact control subjects, results showed that binaural stimulations evoked balanced activity in both hemispheres while monaural stimulations induced strong contralateral activity and weak ipsilateral activity. The results obtained from hemispherectomized subjects were substantially different from those obtained from control subjects. Specifically, activity in the intact hemisphere showed a significant decrease in response to contralateral stimulation but, concomitantly, an increase in response to ipsilateral stimulation. The present findings suggest that a substantial functional reorganization takes place in the auditory pathways following an early hemispherectomy. The exact nature of this functional reorganization remains to be specified.

Legg-Calvé-Perthes disease.

Current knowledge of the causes and risk factors of Legg-Calvé-Perthesdisease (LCPD) does not allow effective preventive strategies. The outcome in adulthood is usually good. Hip osteoarthritis rarely develops before 50 years of age. The risk of osteoarthrosis depends chiefly on the final degree of joint incongruence. Age at onset and the lateral pillar classification are the two main outcome predictors and serve to guide the surgical indications based on the studies by Herring's group. Non-operative treatment is not effective. In contrast, femoral varus osteotomy and Salter's innominate osteotomy provide good outcomes. In severe forms, however, combining these two techniques or performing a triple pelvic osteotomy seem preferable. Surgery is now performed considerably less often than in the past, as it is effective only in patients with lateral pillar group B or B/C disease with onset after eight years of age. In other situations, therapeutic abstention is recommended.

Infantile form of carnitine palmitoyltransferase II deficiency with hepatomuscular symptoms and sudden death. Physiopathological approach to carnitine palmitoyltransferase II deficiencies.

Reported cases of carnitine palmitoyltransferase II (CPT II) deficiency are characterized only by a muscular symptomatology in young adults although the defect is expressed in extra-muscular tissues as well as in skeletal muscle. We describe here a CPT II deficiency associating hypoketotic hypoglycemia, high plasma creatine kinase level, heart beat disorders, and sudden death in a 3-mo-old boy. CPT II defect (-90%) diagnosed in fibroblasts is qualitatively similar to that (-75%) of two "classical" CPT II-deficient patients previously studied: It resulted from a decreased amount of CPT II probably arising from its reduced biosynthesis. Consequences of CPT II deficiency studied in fibroblasts differed in both sets of patients. An impaired oxidation of long-chain fatty acids was found in the proband but not in patients with the "classical" form of the deficiency. The metabolic and clinical consequences of CPT II deficiency might depend, in part, on the magnitude of residual CPT II activity. With 25% residual activity CPT II would become rate limiting in skeletal muscle but not in liver, heart, and fibroblasts. As observed in the patient described herein, CPT II activity ought to be more reduced to induce an impaired oxidation of long-chain fatty acids in these tissues.

Immunity to the G1 globular domain of the cartilage proteoglycan aggrecan can induce inflammatory erosive polyarthritis and spondylitis in BALB/c mice but immunity to G1 is inhibited by covalently bound keratan sulfate in vitro and in vivo.

Earlier work from this laboratory showed that the human proteoglycan aggrecan from fetal cartilages can induce a CD4+ T cell-dependent inflammatory polyarthritis in BALB/c mice when injected after removal of chondroitin sulfate chains. Adult keratan sulfate (KS)-rich aggrecan does not possess this property. We found that two CD4+ T cell hybridomas (TH5 and TH14) isolated from arthritic mice recognize bovine calf aggrecan and the purified G1 domain of this molecule, which also contains a portion of the interglobular domain to which KS is bound. These hybridoma responses to G1 are enhanced by partial removal of KS by the endoglycosidase keratanase or by cyanogen bromide cleavage of core protein. KS removal results in increased cellular uptake by antigen-present cells in vitro. After removal of KS by keratanase, G1 alone can induce a severe erosive polyarthritis and spondylitis in BALB/c mice identifying it as an arthritogenic domain of aggrecan. The presence of KS prevents induction of arthritis presumably as a result of an impaired immune response as observed in vitro. These observations not only identify the arthritogenic properties of G1 but they also point to the importance of glycosylation and proteolysis in determining the arthritogenicity of aggrecan and fragments thereof.

Arthritis induced by proteoglycan aggrecan G1 domain in BALB/c mice. Evidence for t cell involvement and the immunosuppressive influence of keratan sulfate on recognition of t and b cell epitopes.

Our previous work showed that the proteoglycan aggrecan can induce erosive polyarthritis and spondylitis in BALB/c mice, and that the G1 domain of the proteoglycan aggrecan (G1) is the arthritogenic region. In this study, two T cell epitopes residing on G1 within residues 70-84 (peptide G5) and 150-169 (peptide G9) were identified using synthetic peptides and aggrecan-specific T cell lines. Two G1-specific T cell hybridomas exclusively responded to peptide G5. When the G5-specific T cell line was injected intraperitoneally into BALB/c mice, it induced acute inflammatory arthritis in joints, but only in those that had been injected with the epitope recognized by these T cells. Furthermore, we also demonstrate that the keratan sulfate chain(s) (KS) on G1 possess immunosuppressive properties with respect to T and B cell epitope recognition. T cell lines that recognize both G1 and peptide G5 show an increased response to G1 after KS is removed. Antibodies in hyperimmune sera of mice immunized with G1 show increased epitope recognition (quantitative and qualitative) after KS removal before immunization. These studies reveal that a T cell line specific to an epitope on the G1 domain of aggrecan, also recognizing a corresponding mouse G1 epitope, can induce arthritis by adoptive transfer and homing to the intraarticular epitope, thereby implicating T cells in arthritis development caused by immunity to the G1 domain of aggrecan. Moreover, the presence of KS on G1 can inhibit arthritis development by suppressing T and B cell epitope recognition.

[Slipped capital femoral epiphysis]. / Épiphysiolyse fémorale supérieure.

Slipped capital femoral epiphysis (SFCE) is a disorder of the hip, characterized by a displacement of the capital femoral epiphysis from the metaphysic through the femoral growth plate. The epiphysis slips posteriorly and inferiorly. SCFE occurs during puberty and metabolic and epidemiologic risk factors, such as obesity are frequently found. Most chronic slips are diagnosed late. Sagittal hip X-rays show epiphysis slip. In case of untreated SCFE, a slip progression arises with an acute slip risk. Treatment is indicated to prevent slip worsening. The clinical and radiological classification is useful to guide treatment and it is predictive of the prognosis. In situ fixation of stable and moderately displaced SCFE with cannulated screws gives excellent results. Major complications are chondrolysis and osteonecrosis and the major sequelae are femoroacetabular impingement and early arthritis.

Releasable and traceless PEGylation of arginine-rich antimicrobial peptides.

Arginine-rich antimicrobial peptides (AMPs) are emerging therapeutics of interest. However, their applicability is limited by their short circulation half-life, caused in part by their small size and digestion by blood proteases. This study reports a strategy to temporarily mask arginine residues within AMPs with methoxy poly(ethylene glycol). Based on the reagent used, release of AMPs occurred in hours to days in a completely traceless fashion. In vitro, conjugates were insensitive to serum proteases, and released native AMP with full in vitro bioactivity. This strategy is thus highly relevant and should be adaptable to the entire family of arginine-rich AMPs. It may potentially be used to improve AMP-therapies by providing a more steady concentration of AMP in the blood after a single injection, avoiding toxic effects at high AMP doses, and reducing the number of doses required over the treatment duration.

Five-year outcomes of the First Distal Uninstrumented Vertebra after posterior fusion for Adolescent Idiopathic Scoliosis Lenke 1 or 2.

BACKGROUND: Tilt of the First Distal Uninstrumented Vertebra (FDUV) reflects changes in the main curve and compensatory lumbar curve after posterior fusion to treat thoracic Adolescent Idiopathic Scoliosis (AIS). HYPOTHESIS: FDUV tilt 5 years or more post-fusion depends chiefly on reduction of the main curve and on other factors such as selection of the last instrumented vertebra. MATERIAL AND METHOD: A multicenter retrospective cohort of 182 patients with Lenke 1 or 2 AIS treated with posterior instrumentation and followed up for a mean of 8 years and a minimum of 5 years was studied. The patients were divided into two groups based on whether tilt of the upper endplate of the FDUV was ≤5° or >5°at last follow-up. Variables associated with tilt were identified by multiple logistic regression. RESULTS: Six variables were significantly associated with FDUVtilt: percentage of correction at last follow-up, correction loss, lumbar modifier B, number of instrumented vertebrae, inclusion within the instrumentation of the distal neutral vertebra, and inclusion within the instrumentation of the lowest vertebra intersected by the central sacral vertical line. DISCUSSION AND CONCLUSION: The main variables associated with FDUVtilt ≤5° were a final correction percentage ≥60% and absence of correction loss between the postoperative period and last follow-up. Given the stable reduction provided by contemporary instrumentations, we recommend selective thoracic fusion of Lenke 1 or 2 AIS with lumbar modifiers A, B, and C. The lowest instrumented vertebra should be either the neutral vertebra or the vertebra intersected by the central sacral vertical line if it is distal to the neutral vertebra. LEVEL OF EVIDENCE IV: Retrospective multicenter study.

Evaluation of pegylated lipid nanocapsules versus complement system activation and macrophage uptake.

This work consisted in defining the in vitro behavior of pegylated lipid nanocapsules (LNC) toward the immune system. LNC were composed of an oily core surrounded by a shell of lecithin and polyethylene glycol (PEG) known to decrease the recognition of nanoparticles by the immune system. The "stealth" properties were evaluated by measuring complement activation (CH50 technique and crossed-immunoelectrophoresis (C3 cleavage)) and macrophage uptake. These experiments were performed on 20-, 50-, and 100-nm LNC before and after dialysis. A high density of PEG at the surface led to very low complement activation by LNC with a slight effect of size. This size effect, associated to a dialysis effect in macrophage uptake, was due to differences in density and flexibility of PEG chains related to LNC curvature radius. Thanks to a high density, 660-Da PEG provided LNC a steric stabilization and a protective effect versus complement protein opsonization, but this protection decreased with the increase of LNC size, especially versus macrophage uptake.

Impairment of the mitochondrial respiratory chain activity in diethylnitrosamine-induced rat hepatomas: possible involvement of oxygen free radicals.

Alterations in the energy metabolism of cancer cells have been reported for many years. However, the deleterious mechanisms involved in these deficiencies have not yet been clearly proved. The main goal of this study was to decipher the harmful mechanisms responsible for the respiratory chain deficiencies in the course of diethylnitrosamine (DENA)-induced rat hepatocarcinogenesis, where mitochondrial DNA abnormalities had been previously reported. The respiratory activity of freshly isolated hepatoma mitochondria, assessed by oxygen consumption experiments and enzymatic assays, presented a severe complex I deficiency 19 months after DENA treatment, and later on, in addition, a defective complex III activity. Since respiratory complex subunits are encoded by both nuclear and mitochondrial genes, we checked whether the respiratory chain defects were due to impaired synthesis processes. The specific immunodetection of complex I failed to show any alterations in the steady-state levels of both nuclear and mitochondrial encoded subunits in the hepatomas. Moreover, in vitro protein synthesis experiments carried out on freshly isolated hepatoma mitochondria did not bring to light any modifications in the synthesis of the mitochondrial subunits of the respiratory complexes, whatever the degree of tumor progression. Finally, Southern blot analysis of mitochondrial DNA did not show any major mitochondrial DNA rearrangements in DENA-induced hepatomas. Because the synthetic processes of respiratory complexes did not seem to be implicated in the respiratory chain impairment, these deficiencies could be partly ascribed to a direct toxic impact of highly reactive molecules on these complexes, thus impairing their function. The mitochondrial respiratory chain is an important generator of noxious, reactive oxygen free radicals such as superoxide and H2O2, which are normally catabolized by powerful antioxidant scavengers. Nineteen months after DENA treatment, a general collapse of the antioxidant enzymatic system was demonstrated in the hepatomas, as recurrently observed in cancer cells. This oxidant versus antioxidant imbalance was characterized by the establishment of oxidative stress in the course of hepatocarcinogenesis, as partly shown by the important decrease of glutamine synthetase activity, an enzyme whose function is highly sensitive to oxidant reactions. This disequilibrium would result in a net increase of the steady-state concentration of superoxide generated between respiratory complexes I and III in the mitochondria. Once generated, superoxide would likely inactivate complexes I and III via oxidant reactions on their superoxide-sensitive [4Fe, 4S] clusters. The role of mitochondrial respiratory chain impairment in chemical carcinogenesis and/or the persistence of the cancerous state is further discussed.

Surgical treatment using The Unit Rod in children with neuromuscular scoliosis.

The article represents a retrospective clinical and radiological study. Objective. To assess the safety and the stability in time of the Unit Rod instrumentation in the treatment of severe neuromuscular scoliosis in children and adolescents. Summary. The treatment of patients with neuromuscular scoliosis always represents a challenge. The patients are debilitated and usual interventions are very long with great loss of blood. Serious complications can compromise the result of the surgery. The technique we used (the Unit Rod) is worldwide recognized, is simple, and gives excellent stability with a low rate of complications. Methods. We conducted a clinical and radiological retrospective study with a follow-up of at least 4 years in 58 patients with serious neuromuscular conditions, most of them being non-walkers. They were surgically treated by using mostly the Unit Rod technique, in the department of Paediatric Orthopaedics of the Rouen University Hospital, France, between 2000 and 2008. The back fusion was generally from T2 to pelvis. We used the Galveston technique for the patients who needed a pelvic fixation. Results. The mean Cobb angle correction was of 67% immediately after surgery; the correction of the curve decreased in time only in 4% of the cases. Pelvic obliquity was also very well corrected: 73% immediately and 70% at the last radiological follow-up. The mean operative time was of 175 minutes compared to 269 minutes for screws and hooks instrumentation. The most common complication for our technique was the radiolucent halo that appeared around the pelvic inserts. There was no significant degradation in time of the correction obtained. Conclusions. The use of this technique is safe, gives excellent results, achieving significant improvements in the postoperative functional status of the patients. The intra- and postoperative complications were minor. The advantage of using this method is the low cost of the material and technical simplicity, the corrective results being the same as the ones obtained with other techniques.

[Are C2 pedicles always screwable? Calibration and planning with a pedicle-lamina angle]. / Les pédicules de C2 sont-ils toujours vissables ? Calibration et planification selon l'angle pédiculo-lamaire.

INTRODUCTION: Posterior cervical arthrodesis is associated with osteosynthesis. C2 pedicular screwing affords a good bone anchoring but involves neurological and vascular risks. PURPOSE: To determine C2 pedicular screwing feasibility from a large cohort of cervical CT scans. To describe the visible anatomical parameters during a surgical procedure in order to plan and secure it. MATERIALS AND METHODS: Retrospective consecutive series of 100 cervical CT scans was analyzed. Cases with upper cervical fracture were excluded. C2 surgical anatomy was assessed according to maximum length, minimum width and minimum height. Angular parameters were pedicle-transverse angle and sagittal angle. Original pedicle-lamina angle was used as a visible mark during the procedure independent of the patient's position. Pedicular screwing feasibility was evaluated. It was arbitrarily defined by a lower minimum height less than 4mm. RESULTS: Two hundred C2 pedicles were analyzed with 7.5% that were not screwable. Their mean length was 26.2mm, with a mean width of 5.2mm and a mean height of 9.2mm. Mean pedicle-transverse angle was 36.2°, mean sagittal angle was 25.8° and mean pedicle-lamina angle was 81.3°. CONCLUSION: C2 pedicle screwing feasibility is inconstant due to anatomical variability. In fact, 13% of patients have at least one non-screwable pedicle. Preoperative planning is essential to achieve this procedure. A pedicle-lamina angle can be used which remains independent from the patient's position.

Cervical myelopathy involving os odontoideum and retro-odontoid cyst treated with Harms C1-C2 arthrodesis.

An episode of acute decompensation of cervical myelopathy occurred after an injury without fracture of an os odontoideum associated with a compressive retro-odontoid cyst. The 51-year-old female patient presented Fränkel C, Nurick grade 4 neurological status and pyramid syndrome. The initial MRI demonstrated an intramedullary T2 hyperintense signal in the context of spinal cord narrowing. The retro-odontoid cyst demonstrates atlantoaxial instability related to the os odontoideum. Harms C1-C2 arthrodesis without laminectomy was performed and the cyst disappeared completely. Spinal cord decompression was thus obtained on the MRI taken 3 months later. Neurological recovery was complete and continued at 1 year.

UDP-glucuronosyltransferase, epoxide hydrolase and glutathione S-transferase activities in the liver of diabetic mice.

The activities of UDPglucuronosyltransferase, microsomal epoxide hydrolase and cytosolic glutathione S-transferase were measured in the liver of spontaneously (db/db and ob/ob) or streptozotocin-induced diabetic mice. An important (2-3-fold) increase of most phase II activities was observed in streptozotocin-treated animals, whereas slighter changes were detected in spontaneously diabetic animals. The latter also exhibited physico-chemical modifications of the liver microsomal membranes, as shown by the temperature-induced variations of epoxide hydrolase activity.

The metabolic effects of oxalate on intact red blood cells.

The metabolic effects of oxalate on pyruvate kinase were studied in intact human red blood cells and compared to the spontaneous modifications induced by congenital pyruvate kinase deficiency. In normal cells, oxalate (2-3 . 10(-4) M) produces a large increase of the monophosphoglycerates, phosphoenolpyruvate pool and decrease of pyruvate concentrations as a result of pyruvate kinase inhibition; it does not significantly modify 2,3-diphosphoglycerate level, ATP formation or overall glycolytic activity. Those effects of oxalate are not due to Mg2+ chelation. A similar metabolite pattern is observed in vivo in erythrocytes with congenital pyruvate kinase deficiency, in which ATP concentration and glycolytic activity are described. These cells are more sensitive to oxalate than normal ones. Results are discussed with reference to the rate-limiting character of normal or congenitally deficient pyruvate kinase.

The effect of adenosine and chloroadenosine on sex differences in the energy metabolism of rat hepatocytes.

The intensity and regulation of metabolic pathways are different depending on the sex of the source animal for hepatocytes isolated from mature rats. In cells from fed animals incubated without exogenous substrate, ATP level and ketone body production are higher in males (+25% and +100%) and lactate production is higher (+64%) in females; oleate enhances mitochondrial pyruvate oxidation in hepatocytes from fed male rats but not from fed females; in cells from starved animals oleate increases gluconeogenesis in both sexes at saturating levels of gluconeogenic substrates. However, at physiological levels (1 mM lactate and 0.1 mM pyruvate), this activation can only be detected in cells from males. In both sexes, oleate activation is abolished by adenosine which reduces in parallel the mitochondrial oxidation of pyruvate; chloroadenosine, an A2-receptor agonist, increases glycogenolysis strongly in hepatocytes from male animals (+80%) but only very slightly in female cells (+12%).

Purification of a new cytochrome P-450 from human liver microsomes.

Using a classical methodology of purification consisting of three chromatographic steps (Octyl-Sepharose, DEAE-cellulose, CM-cellulose) we have purified a new cytochrome P-450 from human liver microsomes. It was called cytochrome P-450(9). It has been proven to be different from all precedingly purified human liver microsomal cytochrome P-450 isozymes by its immunological and electrophoretical properties. It does not cross-react with any rat liver cytochrome P-450 and anti-cytochrome P-450(9) does not recognize rat liver microsomes; thus this cytochrome P-450(9) is specific to humans. This cytochrome P-450 isozyme exists in low amounts in human liver microsomes and exhibits an important quantitative polymorphism. In reconstituted system, cytochrome P-450(9) is able to hydroxylate all substrates tested but is not specific of any; its exact role in xenobiotic metabolism in man remains to be elucidated.

Influence of oxalate on the rate of the tricarboxylic acid cycle in rat hepatocytes.

In hepatocytes isolated from fed rats, physiological concentrations of oxalate lower the flux through the tricarboxylic acid cycle (-48%) and reduce the steady-state levels of oxaloacetate and other Krebs cycle intermediates. All the metabolic modifications observed are explained by pyruvate carboxylase inhibition, since oxalate hardly modifies the flux through pyruvate dehydrogenase.