Patellofemoral Instability in Children: Correlation Between Patellofemoral Incongruence, Mechanism of Injury, and Cartilage Damage.

OBJECTIVE. The objective of our study was to assess correlation between patellofemoral incongruency and injury mechanism, recurrence, bilaterality, and cartilage damage in patients with patellofemoral instability (PFI). MATERIALS AND METHODS. Ninety-four knee MRI examinations (10 bilateral) of 84 patients with PFI (47 female and 37 male patients; mean age ± SD, 15.0 ± 2.5 years) who had patella dislocation and medial patellofemoral ligament reconstruction (MPFLR) and 66 examinations of age- and sex-matched control subjects were reviewed. The PFI group was subclassified on the basis of injury, recurrence, and bilaterality. Patellofemoral congruence was assessed in both groups with the following MRI measurements: lateral femoral trochlear inclination angle, femoral sulcus depth, medial-to-lateral facet ratio, distance between tibial tuberosity (TT) and trochlear groove (TG), and patellar tendon ratio. Patella cartilage damage was assessed in the PFI group using conventional MRI (International Cartilage Repair Society grade 0-4) and T2 relaxation time mapping at three locations. MRI measurements were compared between groups and subgroups (Wilcoxon rank sum test) and were correlated with cartilage damage (Spearman correlation). RESULTS. All MRI measurements were significantly different between the group with PFI and the group without PFI (p < 0.0001). The bilateral PFI group had significantly increased TT-TG distance (mean, 15.9 vs 13.1 mm, p < 0.05) and patellar tendon ratio (mean, 1.6 vs 1.4, p < 0.05) compared with the unilateral PFI group. The TT-TG distance positively correlated with T2 values of medial and lateral patella cartilage. There were no differences between other subgroups and no correlation between other MRI measurements and the severity of cartilage damage. CONCLUSION. In patients with PFI, the severity of patellofemoral incongruence was not associated with injury mechanism or cartilage damage. However, increased lateralization of the patellar tendon (TT-TG distance) and patella alta (patellar tendon ratio) correlated with injury to the contralateral knee requiring bilateral MPFLR.

Neocentromeres Provide Chromosome Segregation Accuracy and Centromere Clustering to Multiple Loci along a Candida albicans Chromosome.

Assembly of kinetochore complexes, involving greater than one hundred proteins, is essential for chromosome segregation and genome stability. Neocentromeres, or new centromeres, occur when kinetochores assemble de novo, at DNA loci not previously associated with kinetochore proteins, and they restore chromosome segregation to chromosomes lacking a functional centromere. Neocentromeres have been observed in a number of diseases and may play an evolutionary role in adaptation or speciation. However, the consequences of neocentromere formation on chromosome missegregation rates, gene expression, and three-dimensional (3D) nuclear structure are not well understood. Here, we used Candida albicans, an organism with small, epigenetically-inherited centromeres, as a model system to study the functions of twenty different neocentromere loci along a single chromosome, chromosome 5. Comparison of neocentromere properties relative to native centromere functions revealed that all twenty neocentromeres mediated chromosome segregation, albeit to different degrees. Some neocentromeres also caused reduced levels of transcription from genes found within the neocentromere region. Furthermore, like native centromeres, neocentromeres clustered in 3D with active/functional centromeres, indicating that formation of a new centromere mediates the reorganization of 3D nuclear architecture. This demonstrates that centromere clustering depends on epigenetically defined function and not on the primary DNA sequence, and that neocentromere function is independent of its distance from the native centromere position. Together, the results show that a neocentromere can form at many loci along a chromosome and can support the assembly of a functional kinetochore that exhibits native centromere functions including chromosome segregation accuracy and centromere clustering within the nucleus.

Pazopanib therapy for desmoid tumors in adolescent and young adult patients.

BACKGROUND: Desmoid tumors/aggressive fibromatosis (DT/AF) lack a reliably effective medical therapy. Surgical resection may be morbid and does not preclude recurrence. Radiation may carry severe late effects, particularly detrimental in young patients. At our institution, we recently observed promising results with pazopanib therapy for DT/AF in adolescent and young adult (AYA) patients. PROCEDURE: Retrospective single-institution chart review. RESULTS: Six DT/AF patients of 3-21 years with previously treated DT/AF received pazopanib; 31 DT/AF patients received established therapies only. In both groups, median age at diagnosis was 16 years, female patients comprised 50%, and most common DT/AF site was extremity. Established therapies showed few objective responses and most patients therefore received multiple therapies. Surgical resection had a 68% recurrence rate. Of eight patients who received vinblastine/methotrexate, only one had a partial response (PR) by RECIST 1.1 and five had stable disease (SD); 62.5% required additional therapy. Of seven patients who received sulindac/tamoxifen, none showed objective improvement. In contrast, pazopanib demonstrated best responses by RECIST of PR in two of seven and SD in six of seven tumors. A PR of 66% was observed in a patient who had failed multiple prior therapies. The mesenteric DT/AF also showed PR. Maximum volumetric decrease by T2-weighted magnetic resonance imaging (MRI) was 97%. Dramatically increased fibrosis was seen on T2-weighted MRI. Patients reported pain relief and improvement in function within 1 month. Except for one case of edema, all other toxicities responded to dose reduction without sacrificing objective treatment response. CONCLUSION: Pazopanib provides a promising, well-tolerated therapy for DT/AF in the AYA population and warrants further study.

Mechanistic Analysis of CCP1 in Generating ΔC2 α-Tubulin in Mammalian Cells and Photoreceptor Neurons.

An important post-translational modification (PTM) of α-tubulin is the removal of amino acids from its C-terminus. Removal of the C-terminal tyrosine residue yields detyrosinated α-tubulin, and subsequent removal of the penultimate glutamate residue produces ΔC2-α-tubulin. These PTMs alter the ability of the α-tubulin C-terminal tail to interact with effector proteins and are thereby thought to change microtubule dynamics, stability, and organization. The peptidase(s) that produces ΔC2-α-tubulin in a physiological context remains unclear. Here, we take advantage of the observation that ΔC2-α-tubulin accumulates to high levels in cells lacking tubulin tyrosine ligase (TTL) to screen for cytosolic carboxypeptidases (CCPs) that generate ΔC2-α-tubulin. We identify CCP1 as the sole peptidase that produces ΔC2-α-tubulin in TTLΔ HeLa cells. Interestingly, we find that the levels of ΔC2-α-tubulin are only modestly reduced in photoreceptors of ccp1-/- mice, indicating that other peptidases act synergistically with CCP1 to produce ΔC2-α-tubulin in post-mitotic cells. Moreover, the production of ΔC2-α-tubulin appears to be under tight spatial control in the photoreceptor cilium: ΔC2-α-tubulin persists in the connecting cilium of ccp1-/- but is depleted in the distal portion of the photoreceptor. This work establishes the groundwork to pinpoint the function of ΔC2-α-tubulin in proliferating and post-mitotic mammalian cells.

Combination treatment of berberine and solid lipid curcumin particles increased cell death and inhibited PI3K/Akt/mTOR pathway of human cultured glioblastoma cells more effectively than did individual treatments.

The treatment of glioblastoma is challenging for the clinician, due to its chemotherapeutic resistance. Recent findings suggest that targeting glioblastoma using anti-cancer natural polyphenols is a promising strategy. In this context, curcumin and berberine have been shown to have potent anti-cancer and anti-inflammatory effects against several malignancies. Due to the poor solubility and limited bioavailability, these compounds have limited efficacy for treating cancer. However, use of a formulation of curcumin with higher bioavailability or combining it with berberine as a co-treatment may be proving to be more efficacious against cancer. Recently, we demonstrated that solid lipid curcumin particles (SLCPs) provided more bioavailability and anti-cancer effects in cultured glioblastoma cells than did natural curcumin. Interestingly, a combination of curcumin and berberine has proven to be more effective in inhibiting growth and proliferation of cancer in the liver, breast, lung, bone and blood. However, the effect of combining these drugs for treating glioblastoma, especially with respect to its effect on activating the PI3K/Akt/mTOR pathways has not been studied. Therefore, we decided to assess the co-treatment effects of these drugs on two different glioblastoma cell lines (U-87MG and U-251MG) and neuroblastoma cell lines (SH-SY5Y) derived from human tissue. In this study, we compared single and combination (1:5) treatment of SLCP (20 µM) and berberine (100 µM) on measures of cell viability, cell death markers, levels of c-Myc and p53, along with biomarkers of the PI3K/Akt/mTOR pathways after 24-48 h of incubation. We found that co-treatment of SLCP and berberine produced more glioblastoma cell death, more DNA fragmentation, and significantly decreased ATP levels and reduced mitochondrial membrane potential than did single treatments in both glioblastoma cells lines. In addition, we observed that co-treatment inhibited the PI3K/Akt/mTOR pathway more efficiently than their single treatments. Our study suggests that combination treatments of SLCP and berberine may be a promising strategy to reduce or prevent glioblastoma growth in comparison to individual treatments using either compound.

Labeling and Imaging of Amyloid Plaques in Brain Tissue Using the Natural Polyphenol Curcumin.

Deposition of amyloid beta protein (Aß) in extra- and intracellular spaces is one of the hallmark pathologies of Alzheimer's disease (AD). Therefore, detection of the presence of Aß in AD brain tissue is a valuable tool for developing new treatments to prevent the progression of AD. Several classical amyloid binding dyes, fluorochrome, imaging probes, and Aß-specific antibodies have been used to detect Aß histochemically in AD brain tissue. Use of these compounds for Aß detection is costly and time consuming. However, because of its intense fluorescent activity, high-affinity, and specificity for Aß, as well as structural similarities with traditional amyloid binding dyes, curcumin (Cur) is a promising candidate for labeling and imaging of Aß plaques in postmortem brain tissue. It is a natural polyphenol from the herb Curcuma longa. In the present study, Cur was used to histochemically label Aß plaques from both a genetic mouse model of 5x familial Alzheimer's disease (5xFAD) and from human AD tissue within a minute. The labeling capability of Cur was compared to conventional amyloid binding dyes, such as thioflavin-S (Thio-S), Congo red (CR), and Fluoro-jade C (FJC), as well as Aß-specific antibodies (6E10 and A11). We observed that Cur is the most inexpensive and quickest way to label and image Aß plaques when compared to these conventional dyes and is comparable to Aß-specific antibodies. In addition, Cur binds with most Aß species, such as oligomers and fibrils. Therefore, Cur could be used as the most cost-effective, simple, and quick fluorochrome detection agent for Aß plaques.