In-cell DNP NMR reveals multiple targeting effect of antimicrobial peptide.

Dynamic nuclear polarization NMR spectroscopy was used to investigate the effect of the antimicrobial peptide (AMP) maculatin 1.1 on E. coli cells. The enhanced 15N NMR signals from nucleic acids, proteins and lipids identified a number of unanticipated physiological responses to peptide stress, revealing that membrane-active AMPs can have a multi-target impact on E. coli cells. DNP-enhanced 15N-observed 31P-dephased REDOR NMR allowed monitoring how Mac1 induced DNA condensation and prevented intermolecular salt bridges between the main E. coli lipid phosphatidylethanolamine (PE) molecules. The latter was supported by similar results obtained using E. coli PE lipid systems. Overall, the ability to monitor the action of antimicrobial peptides in situ will provide greater insight into their mode of action.

A novel method for the quantification of tire and polymer-modified bitumen particles in environmental samples by pyrolysis gas chromatography mass spectroscopy.

Tire and road wear particles may constitute the largest source of microplastic particles into the environment. Quantification of these particles are associated with large uncertainties which are in part due to inadequate analytical methods. New methodology is presented in this work to improve the analysis of tire and road wear particles using pyrolysis gas chromatography mass spectrometry. Pyrolysis gas chromatography mass spectrometry of styrene butadiene styrene, a component of polymer-modified bitumen used on road asphalt, produces pyrolysis products identical to those of styrene butadiene rubber and butadiene rubber, which are used in tires. The proposed method uses multiple marker compounds to measure the combined mass of these rubbers in samples and includes an improved step of calculating the amount of tire and road based on the measured rubber content and site-specific traffic data. The method provides good recoveries of 83-92% for a simple matrix (tire) and 88-104% for a complex matrix (road sediment). The validated method was applied to urban snow, road-side soil and gully-pot sediment samples. Concentrations of tire particles in these samples ranged from 0.1 to 17.7 mg/mL (snow) to 0.6-68.3 mg/g (soil/sediment). The concentration of polymer-modified bitumen ranged from 0.03 to 0.42 mg/mL (snow) to 1.3-18.1 mg/g (soil/sediment).

Regulation of Opioid Receptors by Their Endogenous Opioid Peptides.

Activation of µ, δ, and κ opioid receptors by endogenous opioid peptides leads to the regulation of many emotional and physiological responses. The three major endogenous opioid peptides, ß-endorphin, enkephalins, and dynorphins result from the processing of three main precursors: proopiomelanocortin, proenkephalin, and prodynorphin. Using a knockout approach, we sought to determine whether the absence of endogenous opioid peptides would affect the expression or activity of opioid receptors in mice lacking either proenkephalin, ß-endorphin, or both. Since gene knockout can lead to changes in the levels of peptides generated from related precursors by compensatory mechanisms, we directly measured the levels of Leu-enkephalin and dynorphin-derived peptides in the brain of animals lacking proenkephalin, ß-endorphin, or both. We find that whereas the levels of dynorphin-derived peptides were relatively unaltered, the levels of Leu-enkephalin were substantially decreased compared to wild-type mice suggesting that preproenkephalin is the major source of Leu-enkephalin. This data also suggests that the lack of ß-endorphin and/or proenkephalin does not lead to a compensatory change in prodynorphin processing. Next, we examined the effect of loss of the endogenous peptides on the regulation of opioid receptor levels and activity in specific regions of the brain. We also compared the receptor levels and activity in males and females and show that the lack of ß-endorphin and/or proenkephalin leads to differential modulation of the three opioid receptors in a region- and gender-specific manner. These results suggest that endogenous opioid peptides are important modulators of the expression and activity of opioid receptors in the brain.

Differential protein expression and post-translational modifications in metronidazole-resistant Giardia duodenalis.

Background: Metronidazole (Mtz) is the frontline drug treatment for multiple anaerobic pathogens, including the gastrointestinal protist, Giardia duodenalis. However, treatment failure is common and linked to in vivo drug resistance. In Giardia, in vitro drug-resistant lines allow controlled experimental interrogation of resistance mechanisms in isogenic cultures. However, resistance-associated changes are inconsistent between lines, phenotypic data are incomplete, and resistance is rarely genetically fixed, highlighted by reversion to sensitivity after drug selection ceases or via passage through the life cycle. Comprehensive quantitative approaches are required to resolve isolate variability, fully define Mtz resistance phenotypes, and explore the role of post-translational modifications therein. Findings: We performed quantitative proteomics to describe differentially expressed proteins in 3 seminal Mtz-resistant lines compared to their isogenic, Mtz-susceptible, parental line. We also probed changes in post-translational modifications including protein acetylation, methylation, ubiquitination, and phosphorylation via immunoblotting. We quantified more than 1,000 proteins in each genotype, recording substantial genotypic variation in differentially expressed proteins between isotypes. Our data confirm substantial changes in the antioxidant network, glycolysis, and electron transport and indicate links between protein acetylation and Mtz resistance, including cross-resistance to deacetylase inhibitor trichostatin A in Mtz-resistant lines. Finally, we performed the first controlled, longitudinal study of Mtz resistance stability, monitoring lines after cessation of drug selection, revealing isolate-dependent phenotypic plasticity. Conclusions: Our data demonstrate understanding that Mtz resistance must be broadened to post-transcriptional and post-translational responses and that Mtz resistance is polygenic, driven by isolate-dependent variation, and is correlated with changes in protein acetylation networks.

Benefit of Adjuvant Chemotherapy and Pelvic Lymph Node Dissection in pT3 and Node Positive Bladder Cancer Patients Treated with Radical Cystectomy.

Background: Benefits of adjuvant chemotherapy (AC) and extent of pelvic lymph node dissection (PLND) in radical cystectomy (RC) are debated. Results from randomized trials are still expected. Objective: To analyze the effects of AC and PLND in two academic centers with opposite policies regarding their use. Methods: 581 bladder cancer patients who underwent RC without neoadjuvant chemotherapy, from Toronto (University Health Network), Canada, and Turku University Hospital, Finland were included. Disease specific survival (DSS) and failure patterns were assessed. Results: Centers differed in PLND rate (93% and 36% in Toronto and Turku respectively, p <  0.001), PLND extent (≥10 removed nodes, 58% vs. 8%, p <  0.001) and AC rate (21% vs. 2%, p <  0.001). Survival between centers among pT≤1 or pT4 patients was similar. pT3 patients in Toronto had an improved 10 year DSS (43% vs. 22%, p = 0.025). Distant failures were less common after AC (HR 0.56, 95%  CI 0.33-0.98, p <  0.042). In node positive (N+) patients, mortality was significantly higher in Turku (HR 2.19, 95%  CI 1.44-3.34, p <  0.001) and lower in patients receiving AC (HR 0.60, 95%  CI 0.37-0.99, p = 0.044). 41% DSS at 10 years was observed in N+ Toronto patients. Limitations included the non-randomized retrospective design and absence of propensity score analysis. Conclusion: Combining AC and PLND to RC is associated with improved survival in pT3 and N+ patients. PLND did not affect survival independently but helps in selecting patients for AC. Our data adds to the growing body of evidence supporting the usefulness of AC in addition to PLND in high risk patients operated by cystectomy.

Overexpression of Striated Muscle Activator of Rho Signaling (STARS) Increases C2C12 Skeletal Muscle Cell Differentiation.

BACKGROUND: Skeletal muscle growth and regeneration depend on the activation of satellite cells, which leads to myocyte proliferation, differentiation and fusion with existing muscle fibers. Skeletal muscle cell proliferation and differentiation are tightly coordinated by a continuum of molecular signaling pathways. The striated muscle activator of Rho signaling (STARS) is an actin binding protein that regulates the transcription of genes involved in muscle cell growth, structure and function via the stimulation of actin polymerization and activation of serum-response factor (SRF) signaling. STARS mediates cell proliferation in smooth and cardiac muscle models; however, whether STARS overexpression enhances cell proliferation and differentiation has not been investigated in skeletal muscle cells. RESULTS: We demonstrate for the first time that STARS overexpression enhances differentiation but not proliferation in C2C12 mouse skeletal muscle cells. Increased differentiation was associated with an increase in the gene levels of the myogenic differentiation markers Ckm, Ckmt2 and Myh4, the differentiation factor Igf2 and the myogenic regulatory factors (MRFs) Myf5 and Myf6. Exposing C2C12 cells to CCG-1423, a pharmacological inhibitor of SRF preventing the nuclear translocation of its co-factor MRTF-A, had no effect on myotube differentiation rate, suggesting that STARS regulates differentiation via a MRTF-A independent mechanism. CONCLUSION: These findings position STARS as an important regulator of skeletal muscle growth and regeneration.

Patterns of relapse in patients with clinical stage I testicular cancer managed with active surveillance.

PURPOSE: To evaluate the performance of active surveillance as a management strategy in broad populations and to inform the development of surveillance schedules by individual patient data regarding timing and type of relapse. METHODS: Retrospective study including data from 2,483 clinical stage I (CSI) patients, 1,139 CSI nonseminoma and 1,344 CSI seminoma managed with active surveillance, with the majority treated between 1998 and 2010. Clinical outcomes including relapse and death, time distribution, extent of relapse and method of relapse detection observed on active surveillance were recorded. RESULTS: Relapse occurred in 221 (19%) CSI-nonseminoma and 173 (13%) CSI-seminoma patients. Median time to relapse was 4 months (range, 2-61 months), 8 months (range, 2-77 months) and 14 months (range, 2-84 months) for lymphovascular invasion-positive CSI nonseminoma, lymphovascular invasion-negative CSI nonseminoma and CSI seminoma. Most relapses were observed within the first 2 years/3 years after orchiectomy for CSI nonseminoma (90%)/CSI seminoma (92%). Relapses were detected by computed tomography scan/tumor-markers in 87%/3% of seminoma recurrences, in 48%/38% of lymphovascular invasion-negative and 41%/61% of lymphovascular invasion-positive patients, respectively. 90% of CSI-nonseminoma and 99% of CSI-seminoma relapses exhibited International Germ Cell Collaborative Group good-risk features. Three patients with CSI nonseminoma died of disease (0.3%). One patient with CSI seminoma and two patients with CSI nonseminoma died because of treatment-related events. Overall, advanced disease was seen in both early- and late-relapse patients. All late recurrences were cured with standard therapy. Five-year disease-specific survival was 99.7% (95% CI, 99.24% to 99.93%). CONCLUSION: Active surveillance for CSI testis cancer leads to excellent outcomes. The vast majority of relapses occur within 2 years of orchiectomy for CSI nonseminoma and within 3 years for CSI seminoma. Late and advanced stage relapse are rarely seen. These data may inform further refinement of rationally designed surveillance schedules.

Dynamic assessment of the changing geometry of the mitral apparatus in 3D could stratify abnormalities in functional mitral regurgitation and potentially guide therapy.

INTRODUCTION: In functional mitral regurgitation (FMR), effective regurgitant orifice area (EROA) displays a dynamic pattern. The impact of dynamic changes of annulus dysfunction and leaflets tenting on phasic EROA was explored with real-time three-dimensional transesophageal echocardiography (RT3D-TEE). METHODS: RT3D-TEE was performed in 52 FMR patients and 30 controls. Mitral annulus dimensions and leaflets tenting were measured throughout systole (TomTec, Germany). Phasic EROA was measured by proximal isovelocity surface area (PISA) method. RESULTS: Mitral annulus had the minimal area and an oval shape with saddle configuration during early systole in controls, which enlarged and became round and flattened towards mid and late systole (P<0.05). In contrast, annulus in FMR was significantly larger, rounder and flatter (P<0.001), which further dilated and became more flattened at late systole (P<0.05 vs control). Leaflet tenting height in FMR decreased in mid systole and remains unchanged towards late systole. The leaflet tenting volume peaked at early and late systole with a mid-systolic trough in both FMR and controls. But tenting volume of patients with FMR was significantly larger than that of controls (all P<0.001 vs control in whole systole). Further analysis demonstrated that early tenting volume (ß value=0.053, P<0.05) was a predictor of early EROA, whereas late tenting volume (ß value=0.031, P<0.05) and late annular displacement velocity were predictors of late EROA. CONCLUSIONS: The early and late peak EROAs of FMR was primarily contributed by tenting volume at early systole and late systole respectively. These findings would be of value to consider in interventions aimed at reducing the severity of FMR.

Aflibercept in the treatment of patients with metastatic colorectal cancer: latest findings and interpretations.

Inhibition of angiogenesis is an established adjunct in the treatment of metastatic colorectal cancer. Bevacizumab, a monoclonal antibody that binds to vascular endothelial growth factor (VEGF) A, improves clinical outcomes when added to standard chemotherapy for metastatic colorectal cancer. Unfortunately, the development of resistance is inevitable, and novel therapeutic strategies are needed. Aflibercept is an intravenously administered fusion protein of the human vascular endothelial growth factor receptor 1 (VEGFR1) and VEGFR2 extracellular domains. This antiangiogenic agent binds to VEGF A, VEGF B, and placental growth factor 1 (PlGF1) and PlGF2 with high affinity and inhibits downstream signaling. Common side effects of single agent aflibercept are similar to other antiangiogenic drugs and include hypertension, proteinuria, fatigue, and headache. Recent clinical data regarding the efficacy of aflibercept with standard chemotherapy for metastatic colorectal cancer, associated adverse events, and future areas of research are reviewed.

Childhood sexual victimization, pedophilic interest, and sexual recidivism.

OBJECTIVE: The goal of the current study was to examine the extent to which child sexual abuse (CSA) and particular characteristics of CSA are associated with pedophilic interest and sexual recidivism. METHODS: Subjects were 462 adult male sexual offenders who had been incarcerated in Canadian federal prisons. RESULTS: Compared to sexual offenders who had not been sexually abused, those who had been sexually abused before age 16 sexually offended against significantly younger victims and had significantly more indicators of pedophilic interest. This was the case whether we examined self-reported or officially documented CSA. Offenders who had been sexually abused exclusively by a male had significantly more indicators of pedophilic interest than those who had been sexually abused exclusively by a female. These findings are consistent with past research and theory suggesting that CSA may play a role in pedophilia and sexual offending against children. CSA exclusively by a female abuser predicted higher rates of sexual recidivism than abuse by a male or both a male and female abuser. Among offenders with victims 15 years old or younger, a closer relationship between offender and abuser predicted higher rates of sexual recidivism. The relationship between CSA and sexual recidivism was significantly moderated by actuarial risk. More specifically, CSA predicted higher rates of sexual recidivism among higher risk offenders, but CSA did not predict sexual recidivism among lower risk offenders. This novel finding raises the possibility that CSA may play a role in sexual recidivism for some offenders. CONCLUSION: If future research replicates this CSA by risk interaction and identifies the constructs and processes involved, CSA may be worth considering in risk assessment and treatment.

PYRABACTIN RESISTANCE1-LIKE8 plays an important role for the regulation of abscisic acid signaling in root.

Abscisic acid (ABA) signaling plays a critical role in regulating root growth and root system architecture. ABA-mediated growth promotion and root tropic response under water stress are key responses for plant survival under limiting water conditions. In this work, we have explored the role of Arabidopsis (Arabidopsis thaliana) PYRABACTIN RESISTANCE1 (PYR1)/PYR1-LIKE (PYL)/REGULATORY COMPONENTS OF ABA RECEPTORS for root ABA signaling. As a result, we discovered that PYL8 plays a nonredundant role for the regulation of root ABA sensitivity. Unexpectedly, given the multigenic nature and partial functional redundancy observed in the PYR/PYL family, the single pyl8 mutant showed reduced sensitivity to ABA-mediated root growth inhibition. This effect was due to the lack of PYL8-mediated inhibition of several clade A phosphatases type 2C (PP2Cs), since PYL8 interacted in vivo with at least five PP2Cs, namely HYPERSENSITIVE TO ABA1 (HAB1), HAB2, ABA-INSENSITIVE1 (ABI1), ABI2, and PP2CA/ABA-HYPERSENSITIVE GERMINATION3 as revealed by tandem affinity purification and mass spectrometry proteomic approaches. We also discovered that PYR/PYL receptors and clade A PP2Cs are crucial for the hydrotropic response that takes place to guide root growth far from regions with low water potential. Thus, an ABA-hypersensitive pp2c quadruple mutant showed enhanced hydrotropism, whereas an ABA-insensitive sextuple pyr/pyl mutant showed reduced hydrotropic response, indicating that ABA-dependent inhibition of PP2Cs by PYR/PYLs is required for the proper perception of a moisture gradient.

Pre-death grief in Parkinson's caregivers: a pilot survey-based study.

OBJECTIVE: To evaluate the evidence for pre-death grief in caregivers (CGs) of persons with Parkinson's disease (PD) and to compare non-motor PD symptoms (cognitive decline, depression, hallucinations) versus motor symptoms (fluctuations of mobility) for associations with CG grief reactions. BACKGROUND: Prolonged grief in response to loss has been associated with negative outcomes and decreased well-being in caregivers (i.e. spouse or adult child) of relatives with dementia. In Parkinson's disease (PD) the negative impact of providing care has been referred to as caregiver strain. Grief has not been explored in PD caregivers, and understanding grief may offer new insights for future intervention. METHODS: Volunteer caregivers (n = 74) filled out the Marwit and Meuser Caregiver Grief Inventory (MM-CGI-SF) which measures 3 types (i.e. subscales) of grief: Personal Sacrifice and Burden, Heartfelt Sadness and Longing, Worry and Felt Isolation. This scale also provided a total grief score. Volunteer caregivers also responded to self-reported UPDRS questions about the motor and non-motor symptoms of their PD relative (i.e. spouse or parent). T-tests were used to correlate CG subscales of grief with patient variables. A hierarchical regression analysis was used to determine the predictive contribution of motor and nonmotor symptoms to grief. RESULTS: Grief based on the total score was found in 17% of CGs. Grief was significantly higher in CG's whose relative had more severe symptoms. The type of grief experienced was similar across all three subscales. Hierarchical regression analysis revealed that nonmotor symptoms explained slightly more of the variance (14-23%) than motor symptoms (11-17%). CONCLUSIONS: This study revealed that pre-death grief is a significant finding in PD caregivers. The severity of symptoms and the presence of nonmotor symptoms, especially cognitive decline, predict caregivers who are at greatest risk of prolonged grief; however it should be kept in mind that motor symptoms also contribute.

High-resolution functional magnetic resonance imaging mapping of noxious heat and tactile activations along the central sulcus in New World monkeys.

This study mapped the fine-scale functional representation of tactile and noxious heat stimuli in cortical areas around the central sulcus of anesthetized squirrel monkeys by using high-resolution blood oxygen level-dependent (BOLD) fMRI at 9.4T. Noxious heat (47.5°C) stimulation of digits evoked multiple spatially distinct and focal BOLD activations. Consistent activations were observed in areas 3a, 3b, 1, and 2, whereas less frequent activation was present in M1. Compared with tactile activations, thermal nociceptive activations covered more area and formed multiple foci within each functional area. In general, noxious heat activations in area 3b did not colocalize with tactile responses. The spatial relationships of heat and tactile activations in areas 3a and 1/2 varied across animals. Subsequent electrophysiological mapping confirmed that the evoked heat and tactile BOLD signals were somatotopically appropriate. The magnitude and temporal profiles of the BOLD signals to noxious heat stimuli differed across cortical areas. Comparatively late-peaking but stronger signals were observed in areas 3b and 2, whereas earlier-peaking but weaker signals were observed in areas 3a, 1, and M1. In sum, this study not only confirmed the involvement of somatosensory areas of 3a, 3b, and 1, but also identified the engagements of area 2 and M1 in the processing of heat nociceptive inputs. Differential BOLD response profiles of the individual cortical areas along the central sulcus suggest that these areas play different roles in the encoding of nociceptive inputs. Thermal nociceptive and tactile inputs may be processed by different clusters of neurons in different areas. To critically bridge animal and human pain studies, human fMRI was related to primate fMRI and electrophysiology of nociceptive processing, examining the functional role of the primary somatosensory cortex in heat nociception and demonstrating that subregion areas 3a, 3b, 1, 2, and M1 are responsive to noxious heat stimuli.

Co-registration of high resolution MRI scans with partial brain coverage in non-human primates.

Dynamic structural and functional remodeling of the Central Nervous System occurs throughout the lifespan of the organism from the molecular to the systems level. MRI offers several advantages to observe this phenomenon: it is non-invasive and non-destructive, the contrast can be tuned to interrogate different tissue properties and imaging resolution can range from cortical columns to whole brain networks in the same session. To measure these changes reliably, functional maps generated over time with high resolution fMRI need to be registered accurately. This article presents a new method for the automatic registration of thin cortical MR volumes that are aligned with the functional maps. These acquisitions focus on the primary somato-sensory cortex, a region in the anterior parietal part of the brain, responsible for fine touch and proprioception. Currently, these slabs are acquired in approximately the same orientation from acquisition to acquisition and then registered by hand. Because they only cover a small portion of the cortex, their direct automatic registration is difficult. To address this issue, we propose a method relying on an intermediate image, acquired with a surface coil that covers a larger portion of the head to which the slabs can be registered. Because images acquired with surface coils suffer from severe intensity attenuation artifact, we also propose a method to register these. The results from data sets obtained with 3 squirrel monkeys show a registration accuracy of 30 micrometers.).

Canadian Cardiovascular Society Consensus Conference guidelines on heart failure--2008 update: best practices for the transition of care of heart failure patients, and the recognition, investigation and treatment of cardiomyopathies.

Heart failure is a clinical syndrome that normally requires health care to be provided by both specialists and nonspecialists. This is advantageous because patients benefit from complementary skill sets and experience, but can present challenges in the development of a common, shared treatment plan. The Canadian Cardiovascular Society published a comprehensive set of recommendations on the diagnosis and management of heart failure in January 2006, and on the prevention, management during intercurrent illness or acute decompensation, and use of biomarkers in January 2007. The present update builds on those core recommendations. Based on feedback obtained through a national program of heart failure workshops during 2006 and 2007, several topics were identified as priorities because of the challenges they pose to health care professionals. New evidence-based recommendations were developed using the structured approach for the review and assessment of evidence that was adopted and previously described by the Society. Specific recommendations and practical tips were written for best practices during the transition of care of heart failure patients, and the recognition, investigation and treatment of some specific cardiomyopathies. Specific clinical questions that are addressed include: What information should a referring physician provide for a specialist consultation? What instructions should a consultant provide to the referring physician? What processes should be in place to ensure that the expectations and needs of each physician are met? When a cardiomyopathy is suspected, how can it be recognized, how should it be investigated and diagnosed, how should it be treated, when should the patient be referred, and what special tests are available to assist in the diagnosis and treatment? The goals of the present update are to translate best evidence into practice, apply clinical wisdom where evidence for specific strategies is weaker, and aid physicians and other health care providers to optimally treat heart failure patients, resulting in a measurable impact on patient health and clinical outcomes in Canada.

Silicon substitution in the calcium phosphate bioceramics.

Silicon (Si) substitution in the crystal structures of calcium phosphate (CaP) ceramics such as hydroxyapatite (HA) and tricalcium phosphate (TCP) generates materials with superior biological performance to stoichiometric counterparts. Si, an essential trace element required for healthy bone and connective tissues, influences the biological activity of CaP materials by modifying material properties and by direct effects on the physiological processes in skeletal tissue. The synthesis of Si substituted HA (Si-HA), Si substituted alpha-TCP (Si-alpha-TCP), and multiphase systems are reviewed. The biological performance of these Si substituted CaP materials in comparison to stoichiometric counterparts is discussed. Si substitution promotes biological activity by the transformation of the material surface to a biologically equivalent apatite by increasing the solubility of the material, by generating a more electronegative surface and by creating a finer microstructure. When Si is included in the TCP structure, recrystallization to a carbonated HA is mediated by serum proteins and osteoblast-like cells. Release of Si complexes to the extracellular media and the presence of Si at the material surface may induce additional dose-dependent stimulatory effects on cells of the bone and cartilage tissue systems.

Partial hemi-resurfacing of the hip joint--a new approach to treat local osteochondral defects?

There is currently renewed interest in articular resurfacing for the treatment of damaged hip-joint cartilage. In contrast to these implants, which involve endoprosthetic replacement of both articulating surfaces, we present a new joint-preserving technique that allows treatment of local osteochondral defects of the femoral head by partial hemi-resurfacing. In this study we describe the operative and technical aspects and problems for partial hemi-resurfacing of the hip joint and critically discuss indications for this procedure in one case. To guarantee an adequate view of the situs, we recommend a surgical approach involving trochanter flip osteotomy, followed by surgical dislocation of the hip joint. Besides partial hemi-resurfacing of the osteochondral defect, this approach allows treatment of associated labral tears and cartilage defects of the hip joint at the same time. For adequate implant fixation, good bone quality is required. Furthermore, osteochondral defects of limited extent and excellent patient compliance are essential for clinical success. In particular, prominence of the implant has to be avoided, which can lead to an irregular joint surface and may induce further cartilage destruction. Long-term studies on statistical populations will show if partial articular hemi-resurfacing is a bone-preserving and useful therapeutic alternative to hemi-resurfacing caps in the treatment of osteochondral hip-joint defects, especially in young patients.

Application of surface-enhanced laser desorption/ionization technology to the detection and identification of urinary parvalbumin-alpha: a biomarker of compound-induced skeletal muscle toxicity in the rat.

In toxicity studies, compound-induced changes are typically evaluated using a combination of endpoints and there are often a number of potential markers in biological fluids which can indicate toxic change in tissues and organs. However, some biomarkers are not specific to the organ of injury and therefore there is a continuing search for more sensitive and specific indicators of target organ toxicity. In experiments to assess the potential diagnostic usefulness of surface-enhanced laser desorption/ionization (SELDI) ProteinChip technology, skeletal muscle toxicity was induced in Wistar Han rats by administering 2,3,5,6-tetramethyl-p-phenylenediamine (TMPD). The skeletal muscle toxicity was monitored using established endpoints such as increase in serum aldolase (Aldol), aspartate aminotransferase (AST) and histopathology, and also using SELDI retentate chromatography mass spectrometry of urine samples. Clear differences in urinary protein patterns between control and TMPD-treated animals were observed on the ProteinChip surfaces. Additionally a specific urine marker protein of 11.8 kDa was identified in TMPD-dosed rats, and the detection of the marker was related to the degree of skeletal muscle toxicity assessed by recognized clinical pathology endpoints. The 11.8 kDa protein was identified as parvalbumin-alpha. These experiments demonstrated the potential of urinary parvalbumin-alpha as a specific, noninvasive, and easily detectable biomarker for skeletal muscle toxicity in the rat and the potential of SELDI technology for biomarker detection and identification in toxicology studies.