Tibial tubercle avulsion fracture during sport activities in adolescent: a case report

BACKGROUND AND AIM OF WORK: Tibial tubercle avulsion fractures (TTAF) are uncommon condition in children and adolescents. These lesions may be misdiagnosed and consequently not properly treated. Reduction and fixation is indicated if displacement is higher than 2mm or if the extensor apparatus is damaged. Authors present a case of a TTAF associated with a complete lateral patellar retinaculum lesion in a 13-year-old male adolescent non-professional basketball player. METHODS: Surgery consisted of reduction and fixation with 2 half threaded cancellous and washers; TTA was then basted and reinforced with a non absorbable suture according to Krachow technique and finally the patellar lateral retinaculum through a direct repair with absorbable material. RESULTS: Clinical evaluation after 3 years showed bone healing, a complete resolution of pain, complete range of motion, good strength and complete functionality of the operated limb. CONCLUSIONS: Misdiagnosis or delayed treatment of TTAF can often result in nonunion, functional impairment, and persistent pain. For these reasons, authors believe that a stable and quick fixation associated to specialized rehabilitation are crucial for recovery. (www.actabiomedica.it)

Clinical trial of laronidase in Hurler syndrome after hematopoietic cell transplantation.

BackgroundMucopolysaccharidosis I (MPS IH) is a lysosomal storage disease treated with hematopoietic cell transplantation (HCT) because it stabilizes cognitive deterioration, but is insufficient to alleviate all somatic manifestations. Intravenous laronidase improves somatic burden in attenuated MPS I. It is unknown whether laronidase can improve somatic disease following HCT in MPS IH. The objective of this study was to evaluate the effects of laronidase on somatic outcomes of patients with MPS IH previously treated with HCT.MethodsThis 2-year open-label pilot study of laronidase included ten patients (age 5-13 years) who were at least 2 years post-HCT and donor engrafted. Outcomes were assessed semi-annually and compared to historic controls.ResultsThe two youngest participants had a statistically significant improvement in growth compared to controls. Development of persistent high-titer anti-drug antibodies (ADA) was associated with poorer 6-min walk test (6MWT) performance; when patients with high ADA titers were excluded, there was a significant improvement in the 6MWT in the remaining seven patients.ConclusionsLaronidase seemed to improve growth in participants <8 years old, and 6MWT performance in participants without ADA. Given the small number of patients treated in this pilot study, additional study is needed before definitive conclusions can be made

Maintenance of a functional hematopoietic stem cell niche through galactocerebrosidase and other enzymes

Purpose of Review: The maintenance of a functional hematopoietic niche is critical for modulating the fate of hematopoietic stem cells (HSCs). Several enzymes were described as essential for guaranteeing niche functionality. This review summarizes the recent findings about the role of galactocerebrosidase and other enzymes involved in the maintenance of a functional HSC niche. Recent Findings: The essential role of enzymes actively involved in the maintenance of the bone marrow microenvironment, in bone remodeling, in regulating the sympathetic innervation of the niche, and in the production and relative balance of sphingolipids active in the niche has been recently highlighted. Enzymes involved in bone remodeling modify the cell-to-cell interaction between osteoblasts and HSCs. Heparanase, neutrophil elastase, and alpha-iduronidase affect the bioavailability of key cytokines and ligands within the extracellular matrix of the niche. Moreover, galactosyltransferase and galactocerebrosidase affect the function of the sympathetic nervous system and/or the balance of bioactive sphingolipids, thus influencing the SDF-1/CXCR4 axis and the proliferation of HSCs. SUMMARY: Here, we discuss the role of different enzymes directly or indirectly influencing the niche microenvironment, and we provide a comprehensive picture of their cooperative role, together with receptors, soluble factors, and the extracellular matrix, in maintaining a functional hematopoietic niche. \ua9 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Development and maturation of invariant NKT cells in the presence of lysosomal engulfment

A defect in invariant NKT (iNKT) cell selection was hypothesized in lysosomal storage disorders (LSD). Accumulation of glycosphingolipids (GSL) in LSD could influence lipid loading and/or presentation causing entrapment of endogenous ligand(s) within storage bodies or competition of the selecting ligand(s) by stored lipids for CD1d binding. However, when we analyzed the iNKT cell compartment in newly tested LSD animal models that accumulate GSL, glycoaminoglycans or both, we observed a defective iNKT cell selection only in animals affected by multiple sulfatase deficiency, in which a generalized aberrant T-cell development, rather than a pure iNKT defect, was present. Mice with single lysosomal enzyme deficiencies had normal iNKT cell development. Thus, GSL/glycoaminoglycans storage and lysosomal engulfment are not sufficient for affecting iNKT cell development. Rather, lipid ligand(s) or storage compounds, which are affected in those LSD lacking mature iNKT cells, might indeed be relevant for iNKT cell selection. \ua9 2009 Wiley-VCH Verlag GmbH & Co. KGaA

Specific determination of β-galactocerebrosidase activity via competitive inhibition of β-galactosidase

background: The determination of cellular β-galactocerebrosidase activity is an established procedure to diagnose Krabbe disease and monitor the efficacy of gene/stem cell-based therapeutic approaches aimed at restoring defective enzymatic activity in patients or disease models. Current biochemical assays for β-galactocerebrosidase show high specificity but generally require large protein amounts from scanty sources such as hematopoietic or neural stem cells. We developed a novel assay based on the hypothesis that specific measurements of β-galactocerebrosidase activity can be performed following complete inhibition of β-galactosidase activity. methods: We performed the assay using 2-7.5 μg of sample proteins with the artificial fluorogenic substrate 4-methylumbelliferone-β-galactopyranoside (1.5 mmol/L) resuspended in 0.1/0.2 mol/L citrate/phosphate buffer, pH 4.0, and AgNO3. Reactions were incubated for 30 min at 37 °C. Fluorescence of liberated 4-methylumbelliferone was measured on a spectrofluorometer (λex 360 nm, λem 446 nm). results: AgNO 3 was a competitive inhibitor of β- galactosidase [inhibition constant (Ki) = 0.12 μmol/L] and completely inhibited β-galactosidase activity when used at a concentration of 11 μmol/L. Under this condition, the β-galactocerebrosidase activity was preserved and could be specifically and accurately measured. The assay can detect β-galactocerebrosidase activity in as little as 2 μg cell protein extract or 7.5 μg tissue. Assay validation was performed using (a) brain tissues from wild-type and twitcher mice and (b) murine GALC-/- hematopoietic stem cells and neural precursor cells transduced by GALC-lentiviral vectors. conclusions: The procedure is straightforward, rapid, and reproducible. Within a clinical context, our method unequivocally discriminated cells from healthy subjects and Krabbe patients and is therefore suitable for diagnostic applications. © 2008 American Association for Clinical Chemistry

Rapamycin stimulates arginine influx through CAT2 transporters in human endothelial cells

In endothelial cells Tumor Necrosis Factor-α (TNFα) stimulates arginine transport through the increased expression of SLC7A2/CAT2 transcripts. Here we show that also rapamycin, an inhibitor of mTOR kinase, stimulates system y+-mediated arginine uptake in human endothelial cells derived from either saphenous (HSVECs) or umbilical veins (HUVECs). When used together with TNFα, rapamycin produces an additive stimulation of arginine transport in both cell models. These effects are observed also upon incubation with AICAR, a stimulator of Adenosine-Monophosphate-dependent-Protein Kinase (AMPK) that produces a rapamycin-independent inhibition of the mTOR pathway. Rapamycin increases the Vmax of high affinity arginine transport and causes the appearance of a low affinity component that is particularly evident if the treatment is carried out in the presence of TNFα. RT-qPCR studies have demonstrated that these kinetic changes correspond to the induction of both the high affinity transporter CAT2B and the low affinity isoform CAT2A. Western blot and immunocytochemical analyses indicate that, consistently, the expression of CAT2 proteins is also stimulated under the same conditions. These changes are associated with an increase of the intracellular arginine concentration but with a decrease of NO production. Thus, our data suggest that mTOR activity is associated with the repression of CAT2 expression at mRNA and protein level