Long-Term Results of Alumina Ceramic-On-Ceramic Bearings in Cementless Total Hip Arthroplasty: A 20-Year Minimum Follow-Up.

BACKGROUND: Alumina ceramic-on-ceramic bearings are used in total hip arthroplasty (THA) because of their wear-resistant and inert properties. In this study, we assessed the clinical and radiographic outcomes of patients undergoing primary cementless ceramic-on-ceramic THA at a minimum follow-up of 20 years. METHODS: A series of 301 consecutive primary THAs in 283 patients were assessed. Clinically, patients were assessed with the modified Harris Hip Score (HHS) and pain questionnaires. Anteroposterior radiographs of the pelvis and lateral radiographs of the hip were used to radiologically assess the implant. Patients were classified as lost to follow-up if they could not be contacted on multiple occasions or did not wish to participate further in this study. RESULTS: At twenty years after operation, 60 patients had died of a cause unrelated to surgery, 16 had experienced complications requiring reoperation, and 100 hips had both clinical assessments and radiographs at a minimum of 20 years of follow-up. The average HHS improved from 56.1 (range: 17-89) before THA to 92.5 (range: 63-100) at the latest follow-up. The classification of the HHS was good or excellent in 96.4% of patients. Only 1.8% of patients still had moderate residual pain at the thigh or groin. Radiographically, all patients demonstrated bony ingrowth but no clinical symptoms of loosening. The overall survival rate of the implants was 94.2% at 20 years with revision for any reason as the end point. CONCLUSION: Long-Term follow-up in our series showed excellent implant survival, excellent functional outcomes, and minimal late complications. There was no significant radiographic evidence of failure at a minimum of 20 years after THA. LEVEL OF EVIDENCE: Therapeutic Level IV.

First-in-human, phase I/IIa dose-escalation and safety study of balugrastim in breast cancer patients receiving myelosuppressive chemotherapy.

PURPOSE: To evaluate safety of balugrastim, a recombinant human serum albumin and granulocyte colony-stimulating factor (G-CSF), administered over a range of therapeutic doses in women with breast cancer receiving doxorubicin plus docetaxel chemotherapy. METHODS: The phase I, sequential dose-escalation first segment compared subcutaneous balugrastim 50, 150, 300, and 450 µg/kg during chemotherapy cycles 0-2. The randomized (2:2:1), open-label, phase IIa second segment compared balugrastim 300 or 450 µg/kg with pegfilgrastim 6 mg during chemotherapy cycles 1 and 2. RESULTS: In the phase I segment, balugrastim was escalated to 450 µg/kg in 13 patients without dose-limiting toxicity. Three (9.7 %) of the 31 adverse events (AEs) reported in nine patients were grade 3 (agranulocytosis, vomiting, hypertension); none was grade 4. In the open-label phase IIa segment (N = 51), the majority of the 64 AEs reported in 31 (75.6 %) balugrastim-treated patients were grade 1 (59.4 %), with 39.1 % grade 2, 1.6 % grade 3 (one AE of vomiting), and none grade 4. Of the 16 AEs reported in seven (70.0 %) pegfilgrastim-treated patients, 87.5 % were grade 1, 6.3 % were grade 2, 6.3 % were grade 3 (one AE of thrombocytopenia), and none were grade 4. Overall, there were six bone pain AEs reported, one in the balugrastim 300 µg/kg group and five in the balugrastim 450 µg/kg group. No AEs in either study necessitated treatment interruption/discontinuation. The incidence and duration of grade 3-4 neutropenia were similar between balugrastim- and pegfilgrastim-treated patients. CONCLUSIONS: Balugrastim was well tolerated in this small population of breast cancer patients.

Structures of lactate dehydrogenase A (LDHA) in apo, ternary and inhibitor-bound forms.

Lactate dehydrogenase (LDH) is an essential metabolic enzyme that catalyzes the interconversion of pyruvate and lactate using NADH/NAD(+) as a co-substrate. Many cancer cells exhibit a glycolytic phenotype known as the Warburg effect, in which elevated LDH levels enhance the conversion of glucose to lactate, making LDH an attractive therapeutic target for oncology. Two known inhibitors of the human muscle LDH isoform, LDHA, designated 1 and 2, were selected, and their IC50 values were determined to be 14.4 ± 3.77 and 2.20 ± 0.15 µM, respectively. The X-ray crystal structures of LDHA in complex with each inhibitor were determined; both inhibitors bind to a site overlapping with the NADH-binding site. Further, an apo LDHA crystal structure solved in a new space group is reported, as well as a complex with both NADH and the substrate analogue oxalate bound in seven of the eight molecules and an oxalate only bound in the eighth molecule in the asymmetric unit. In this latter structure, a kanamycin molecule is located in the inhibitor-binding site, thereby blocking NADH binding. These structures provide insights into LDHA enzyme mechanism and inhibition and a framework for structure-assisted drug design that may contribute to new cancer therapies.

Insights into O-linked N-acetylglucosamine ([0-9]O-GlcNAc) processing and dynamics through kinetic analysis of O-GlcNAc transferase and O-GlcNAcase activity on protein substrates.

Cellular O-linked N-acetylglucosamine (O-GlcNAc) levels are modulated by two enzymes: uridine diphosphate-N-acetyl-D-glucosamine:polypeptidyltransferase (OGT) and O-GlcNAcase (OGA). To quantitatively address the activity of these enzymes on protein substrates, we generated five structurally diverse proteins in both unmodified and O-GlcNAc-modified states. We found a remarkably invariant upper limit for k(cat)/K(m) values for human OGA (hOGA)-catalyzed processing of these modified proteins, which suggests that hOGA processing is driven by the GlcNAc moiety and is independent of the protein. Human OGT (hOGT) activity ranged more widely, by up to 15-fold, suggesting that hOGT is the senior partner in fine tuning protein O-GlcNAc levels. This was supported by the observation that K(m,app) values for UDP-GlcNAc varied considerably (from 1 µM to over 20 µM), depending on the protein substrate, suggesting that some OGT substrates will be nutrient-responsive, whereas others are constitutively modified. The ratios of k(cat)/K(m) values obtained from hOGT and hOGA kinetic studies enable a prediction of the dynamic equilibrium position of O-GlcNAc levels that can be recapitulated in vitro and suggest the relative O-GlcNAc stoichiometries of target proteins in the absence of other factors. We show that changes in the specific activities of hOGT and hOGA measured in vitro on calcium/calmodulin-dependent kinase IV (CaMKIV) and its pseudophosphorylated form can account for previously reported changes in CaMKIV O-GlcNAc levels observed in cells. These studies provide kinetic evidence for the interplay between O-GlcNAc and phosphorylation on proteins and indicate that these effects can be mediated by changes in hOGT and hOGA kinetic activity.

Discrimination analysis of mass spectrometry proteomics for ovarian cancer detection.

AIM: A discrimination analysis has been explored for the probabilistic classification of healthy versus ovarian cancer serum samples using proteomics data from mass spectrometry (MS). METHODS: The method employs data normalization, clustering, and a linear discriminant analysis on surface-enhanced laser desorption ionization (SELDI) time-of-flight MS data. The probabilistic classification method computes the optimal linear discriminant using the complex human blood serum SELDI spectra. Cross-validation and training/testing data-split experiments are conducted to verify the optimal discriminant and demonstrate the accuracy and robustness of the method. RESULTS: The cluster discrimination method achieves excellent performance. The sensitivity, specificity, and positive predictive values are above 97% on ovarian cancer. The protein fraction peaks, which significantly contribute to the classification, can be available from the analysis process. CONCLUSION: The discrimination analysis helps the molecular identities of differentially expressed proteins and peptides between the healthy and ovarian patients.

Structure of an O-GlcNAc transferase homolog provides insight into intracellular glycosylation.

N-Acetylglucosamine (O-GlcNAc) modification of proteins provides a mechanism for the control of diverse cellular processes through a dynamic interplay with phosphorylation. UDP-GlcNAc:polypeptidyl transferase (OGT) catalyzes O-GlcNAc addition. The structure of an intact OGT homolog and kinetic analysis of human OGT variants reveal a contiguous superhelical groove that directs substrates to the active site.

Protein kinase Cdelta regulates antigen receptor-induced lytic granule polarization in mouse CD8+ CTL.

Lytic granule exocytosis is the major pathway used by CD8+ CTL to kill virally infected and tumor cells. Despite the obvious importance of this pathway in adaptive T cell immunity, the molecular identity of enzymes involved in the regulation of this process is poorly characterized. One signal known to be critical for the regulation of granule exocytosis-mediated cytotoxicity in CD8+ T cells is Ag receptor-induced activation of protein kinase C (PKC). However, it is not known which step of the process is regulated by PKC. In addition, it has not been determined to date which of the PKC family members is required for the regulation of lytic granule exocytosis. By combination of pharmacological inhibitors and use of mice with targeted gene deletions, we show that PKCdelta is required for granule exocytosis-mediated lytic function in mouse CD8+ T cells. Our studies demonstrate that PKCdelta is required for lytic granule exocytosis, but is dispensable for activation, cytokine production, and expression of cytolytic molecules in response to TCR stimulation. Importantly, defective lytic function in PKCdelta-deficient cytotoxic lymphocytes is reversed by ectopic expression of PKCdelta. Finally, we show that PKCdelta is not involved in target cell-induced reorientation of the microtubule-organizing center, but is required for the subsequent exocytosis step, i.e., lytic granule polarization. Thus, our studies identify PKCdelta as a novel and selective regulator of Ag receptor-induced lytic granule polarization in mouse CD8+ T cells.

Heterogeneous patterns of lymphatic drainage to sentinel lymph nodes by primary melanoma from different anatomic sites.

UNLABELLED: We want to define the patterns of lymphatic drainage for primary melanoma to sentinel lymph nodes (SLNs) based on a large lymphoscintigraphic database. Preoperative lymphoscintigraphy was used to identify and classify SLN drainage basins and patterns of drainage. METHODS: Lymphoscintigraphy using intradermally administered technetium-99m labeled sulfur colloid was performed on 400 consecutive patients with malignant melanoma to define lymphatic drainage channels and draining SLN basins before surgery. Primary tumor sites consisted of head and neck, upper extremity, trunk, and lower extremity. Different types of drainage patterns were classified and correlated with different anatomic sites. RESULTS: SLN(s) were identified in over 98% of the patients, whereas lymphatic drainage channels were successfully identified in 90% of the patients. Drainage from the primary site to a single SLN through a single lymphatic channel (type IA) was seen in 186 of 400 patients (47%) as the most common type. In patients with a single SLN within a single basin (type I-V), the percentage of patients with primary lesions in the head and neck, upper extremity, trunk, and lower extremity regions were 61%, 79%, 55%, and 78%, respectively. In cases of multiple lymphatic channels (type VI-VII), the percentages of patients with primary lesions in the head and neck, upper extremity, trunk, and lower extremity regions were 24%, 8%, 36%, and 19%, respectively. CONCLUSION: Various drainage patterns were noted from primary melanomas in different anatomic sites. Preoperative lymphoscintigraphy is important in establishing the SLN basins for harvesting the SLN(s).