Osteonecrosis in SLE: prevalence, patterns, outcomes and predictors.

Objective Osteonecrosis is a serious comorbidity in patients with systemic lupus erythematosus. The aims of this study were to describe the prevalence of symptomatic osteonecrosis, determine the pattern of joint involvement, identify the outcomes and investigate predictive factors in a large cohort of patients with systemic lupus erythematosus followed prospectively. Methods At the Toronto Lupus Clinic patients have been followed prospectively according to a standard protocol since 1970. Osteonecrosis is recorded if patients are symptomatic and is confirmed by imaging. The site of osteonecrosis is recorded and whether or not surgery was performed. For determination of prevalence, pattern and outcome of osteonecrosis a longitudinal cohort design was performed. For the predictive factors, only patients with incident osteonecrosis were included and were matched for gender, year of entry to clinic (within 5 years), year of birth (within 5 years) and disease duration (within 3 years) with systemic lupus erythematosus patients without osteonecrosis. Results Of 1729 patients with systemic lupus erythematosus registered in the database, 234 (13.5%) developed symptomatic osteonecrosis in 581 sites. Hips and knees were most commonly affected and 47% of the patients had multiple sites involved. More than half of the joints involved at first occurrence of osteonecrosis had surgery. Univariate analysis identified black race, damage, elevated cholesterol and glucocorticosteroids as predictive factors, but glucocorticosteroids remained as the primary predictor for the development of osteonecrosis on multivariable analysis. Conclusion Despite advancements in the assessment and treatment of systemic lupus erythematosus, symptomatic osteonecrosis continues to be a significant comorbidity. Strategies to minimize glucocorticosteroid use are necessary to prevent this serious complication.

Temporal artery biopsies in south-east Scotland: a five year review.

Temporal artery biopsy is the gold standard investigation for the diagnosis of giant cell arteritis. The aim of this retrospective study was to investigate the use of temporal artery biopsy in diagnosing giant cell arteritis in south-east Scotland over a five-year period. We aimed to quantify success rates, and predictive factors for a positive biopsy, as well as compare the different specialities performing the biopsies. The data should enable the development of better criteria for referral for investigation of giant cell arteritis. Methods Patients were identified using a database of temporal artery biopsies generated by the pathology department in NHS Lothian (south east Scotland), for all biopsies examined between January 2010 and December 2015. An electronic patient record was used to retrospectively examine the records of patients in the database. Results A total of 715 biopsies were included in the study, of which 250 (35.0%) showed features of giant cell arteritis. The main predictors for a positive biopsy were age at biopsy, specialty performing biopsy, erythrocyte sedimentation rate, jaw claudication/pain, and ophthalmic symptoms. The most important predictor of a positive biopsy was erythrocyte sedimentation rate. The length of biopsy was not found to be a predictor of positive biopsy; however, diameter of biopsy was predictive. Conclusions We have shown that many temporal artery biopsies are negative, and finding ways to reduce the number of patients unnecessarily undergoing biopsy will be essential in reducing workload and streamlining services. This study demonstrates some key predictive factors for patients with positive biopsies. The study also shows that a large proportion of biopsies taking place do not result in the recommended length of specimen, but this does not necessarily reduce the likelihood of a positive biopsy.

Characteristics and Evaluation of Geographically Distant vs Geographically Nearby Living Kidney Donors.

BACKGROUND: Living donor kidney transplant (LDKT) can be impeded by multiple barriers. One possible barrier to LDKT is a large physical distance between the living donor's home residence and the procuring transplant center. METHODS: We performed a retrospective, single-center study of living kidney donors in the United States who were geographically distant (residing ≥150 miles) from our transplant center. Each distant donor was matched to 4 geographically nearby donors (<150 miles from our center) as controls. RESULTS: From 2007 to 2010, of 429 live kidney donors, 55 (12.8%) were geographically distant. Black donors composed a higher proportion of geographically distant vs nearby donors (34.6% vs 15.5%), whereas Hispanic and Asian donors composed a lower proportion (P = .001). Distant vs nearby donors had similar median times from donor referral to actual donation (165 vs 161 days, P = .81). The geographically distant donors lived a median of 703 miles (25% to 75% range, 244 to 1072) from our center and 21.2 miles (25% to 75% range, 9.8 to 49.7) from the nearest kidney transplant center. The proportion of geographically distant donors who had their physician evaluation (21.6%), psychosocial evaluation (21.6%), or computed tomography angiogram (29.4%) performed close to home, rather than at our center, was low. CONCLUSIONS: Many geographically distant donors live close to transplant centers other than the procuring transplant center, but few of these donors perform parts of their donor evaluation at these closer centers. Black donors comprise a large proportion of geographically distant donors. The evaluation of geographically distant donors, especially among minorities, warrants further study.

Natural history of retinopathy in children and young people with type 1 diabetes.

PurposeTo describe the prevalence and natural history of retinopathy in a cohort of children and young people with type 1 diabetes attending a tertiary hospital diabetes clinic.MethodsWe analysed retinopathy screening data from 2008 to 2010 on all eligible children using the 'Twinkle' diabetes database and the regional retinal screening database.ResultsA total of 88% (149/169) of eligible children were screened in 2008, median age 14 years, 52% male. The prevalence of retinopathy was 19.5% (30/149). All children had background retinopathy grade R1. There was significant difference in median (range) duration of diabetes, 7.7 years (0.6-13.7) vs 5 years (0.2-12.5) (P<0.001) and median (range) HbA1C, 9.1% (7.2-14) vs 8.6% (5.6-13.1) (P=0.02), between the groups with and without retinopathy. At 2- years follow-up, 12/30 (40%) had unchanged retinopathy grade R1, 10/30 (33.3%) showed resolution of changes (R0), 1/30 progressed to maculopathy, and 7/30 had no follow-up data. Median (range) HbA1C in 2008 and 2010 for the groups with stable vs resolved changes was similar, 9.1% (7.2-14.0) and 9.2% (7-14.0) vs 9.5% (7.8-14.0) and 9.2% (8.7-14.0). Of the 119 without retinopathy in 2008, 27 (22.5%) had developed retinopathy within 2 years, including 1 with pre-proliferative retinopathy and 1 with maculopathy. There was no significant difference in HbA1c between those who progressed to retinopathy (8.7% (7.1-13.1)) (8.7% (7.1-13.1)), and those who did not (8.6% (6.3-12.2)).ConclusionsPrevalence of background retinopathy in our cohort was comparable to the previously published reports, with higher HbA1c and longer duration of diabetes being significant risk factors. On short-term follow-up, Grade 1 retinopathy is likely to resolve in a third of patients and remain unchanged in just over a third.

Fractures and Fanconi syndrome due to prolonged sodium valproate use.

BACKGROUND: Sodium valproate (VPA) is commonly used to treat epilepsy in children. Renal dysfunction is a rare side eff ect but can present as tubulopathy such as Fanconi syndrome. CASE REPORT: We report on an 8-year-old disabled girl with myoclonic epilepsy who was referred for investigation of recurrent low impact fractures of the distal femur which were initially thought to be caused by her severe immobility. However, she was subsequently found to have hypophosphataemia secondary to Fanconi syndrome due to prolonged VPA use. After VPA withdrawal renal function and serum phosphate levels normalised and X-rays improved dramatically. CONCLUSION: The possibility of drug-induced osteoporosis and fractures should always be considered in disabled children, even in the presence of severe immobility.

Teaching fearlessness: a manifesto.

CONTEXT: Negative role modeling is a plague medical educators fight once students enter the clinical arena. The literature is replete on the fact that students routinely encounter faculty who display attitudes and behaviors inconsistent with the values taught throughout the medical curriculum, particularly in the preclinical years. APPROACH: Using a back and forth between the text of a third-year student's reflective essay and two of her faculty's observations on her negative encounters with several clinical faculty, the authors propose 'teaching for fearlessness.' DISCUSSION: Using Papadimos and Murray's use of 'fearless speech' derived from Foucault's thinking on parrhesia, the authors build a case that students should be encouraged to expose and challenge inequities on behalf of their patients, themselves and the profession at large. CONCLUSIONS: Medical educators should model and provide students with opportunities to develop and use 'fearless speech' as a way to reshape the culture of medical education and patient care.

Immune reconstitution following rabbit antithymocyte globulin.

Depletional induction therapies are routinely used to prevent acute rejection and improve transplant outcome. The effects of depleting agents on T-cell subsets and subsequent T-cell reconstitution are incompletely defined. We used flow cytometry to examine the effects of rabbit antithymocyte globulin (rATG) on the peripheral T-cell repertoire of pediatric and adult renal transplant recipients. We found that while rATG effectively depleted CD45RA+CD27+ naïve and CD45RO+CD27+ central memory CD4+ T cells, it had little effect on CD45RO+CD27- CD4+ effector memory or CD45RA+CD31-, CD45RO+CD27+ and CD45RO+CD27- CD8+ T cell subsets. When we performed a kinetic analysis of CD31+ recent thymic emigrants and CD45RA+/RO+ T cells, we found evidence for both thymopoiesis and homeostatic proliferation contributing to immune reconstitution. We additionally examined the impact of rATG on peripheral CD4+Foxp3+ T cells. We found that in adults, administration of rATG-induced peripheral expansion and new thymic emigration of T cells with a Treg phenotype, while CD4+Foxp3+ T cells of thymic origin predominated in children, providing the first evidence that rATG induces Treg in vivo. Collectively our data indicate that rATG alters the balance of regulatory to memory effector T cells posttransplant, providing an explanation for how it positively impacts transplant outcome.

RACK1 inhibits colonic cell growth by regulating Src activity at cell cycle checkpoints.

Previously, we showed that Src tyrosine kinases are activated early in the development of human colon cancer and are suppressed as intestinal cells differentiate. We identified RACK1 as an endogenous substrate, binding partner and inhibitor of Src. Here we show (by overexpressing RACK1, depleting Src or RACK1 and utilizing cell-permeable peptides that perturb RACK1's interaction with Src) that RACK1 regulates growth of colon cells by suppressing Src activity at G(1) and mitotic checkpoints, and consequently delaying cell cycle progression. Activated Src rescues RACK1-inhibited growth of HT-29 cells. Conversely, inhibiting Src abolishes growth promoted by RACK1 depletion in normal cells. Two potential mechanisms whereby RACK1 regulates mitotic exit are identified: suppression of Src-mediated Sam68 phosphorylation and maintenance of the cyclin-dependent kinase (CDK) 1-cyclin B complex in an active state. Our results reveal novel mechanisms of cell cycle control in G(1) and mitosis of colon cells. The significance of this work lies in the discovery of a mechanism by which the growth of colon cancer cells can be slowed, by RACK1 suppression of an oncogenic kinase at critical cell cycle checkpoints. Small molecules that mimic RACK1 function may provide a powerful new approach to the treatment of colon cancer.

Cyclin E overexpression enhances cytokine-mediated apoptosis in MCF7 breast cancer cells.

Cyclin E, the regulatory component of the cyclin E/cyclin-dependent kinase (CDK) complex, is required for proliferation and overexpression of this cyclin is associated with many types of human tumors. To elucidate the mechanism by which cyclin E overexpression promotes tumorigenesis, cyclin E was overexpressed in two breast cancer lines: MCF7 and T47D. Cells overexpressing cyclin E display a marked decrease in the expression of Bcl-2, an antiapoptotic protein, and increased levels of the proapoptotic proteins Bad and Bax. The levels of Bcl-X(L) and Mcl-1 remain unchanged. Since the homeostasis of pro- and antiapoptotic proteins was altered, we asked if cyclin E overexpression modifies responses to cytokines. MCF7 cyclin E overexpressing cells have an enhanced sensitivity to Fas, TRAIL, and TNF-alpha-induced apoptosis. T47D cells overexpressing cyclin E have a significant increase in TNF-alpha and TRAIL-induced apoptosis. In conclusion, our results provide a link between expression of cyclin E, deregulation of Bcl-2, and an altered response to cytokine-mediated apoptosis.

Influence of W-7, a calmodulin antagonist on phospholipid biosynthesis in Candida albicans.

AIM: This study was undertaken to investigate the role of calmodulin in phospholipid biosynthesis in Candida albicans using W-7, a calmodulin antagonist. METHODS: Cells were grown as shake cultures in the absence and presence of W-7 at different concentrations. Changes in cell mass, phospholipid content and incorporation of labelled precursor into phospholipid and activities of respective enzymes have been studied. RESULTS: Decreased incorporation of labelled acetate into total lipids and phospholipids was observed in the presence of 40 microm of W-7 which was not as a consequence of altered growth of Candida in the presence of calmodulin antagonist. Further, a significant decrease in the levels of calmodulin and CaM dependent protein kinase activity was observed in cells grown with different concentrations of W-7. This was accompanied by decreased/increased activity of phosphatidic acid phosphatase and phospholipase A, respectively in W-7 grown cells as compared to controls. CONCLUSIONS: These findings suggest definite involvement of calmodulin in the regulation of phospholipid metabolism in Candida albicans.

The internal mechanics of the intervertebral disc under cyclic loading.

The mechanics of the intervertebral disc (IVD) under cyclic loading are investigated via a one-dimensional poroelastic model and experiment. The poroelastic model, based on that of Biot (J. Appl. Phys. 12 (1941) 155; J. Appl. Mech. 23 (1956) 91), includes a power-law relation between porosity and permeability, and a linear relation between the osmotic potential and solidity. The model was fitted to experimental data of the unconfined IVD undergoing 5 cyclic loads of 20 min compression by an applied stress of 1MPa, followed by 40 min expansion. To obtain a good agreement between experiment and theory, the initial elastic deformation of the IVD, possibly associated with the bulging of the IVD into the vertebral bodies or laterally, was removed from the experimental data. Many combinations of the permeability-porosity relationship with the initial osmotic potential (pi(i)) were investigated, and the best-fit parameters for the aggregate modulus (H(A)) and initial permeability (k(i)) were determined. The values of H(A) and k(i) were compared to literature values, and agreed well especially in the context of the adopted high-stress testing regime, and the strain related permeability in the model.

Sir2p exists in two nucleosome-binding complexes with distinct deacetylase activities.

The absolute requirement for the histone deacetylase activity of Sir2p in silencing coupled with the conservation of Sir2p-like proteins in larger eukaryotes suggests that this molecule plays an important role in gene regulation in all organisms. Here we report the purification and characterization of two Sir2p-containing protein complexes; one of which contains Sir4p and the other Net1p. The Sir4p-containing complex has an NAD-dependent histone deacetylase activity, while the Net1p-containing complex possesses deacetylase activity but only weak NAD-dependent histone deacetylase activity. Finally, we demonstrate that the Sir2p-containing complexes bind nucleosomes efficiently and partially restrict accessibility of the linker DNA to enzymatic probes.

Effect of frozen storage on the creep behavior of human intervertebral discs.

STUDY DESIGN: A biomechanical study of the compressive creep behavior of the human intervertebral disc before and after frozen storage. OBJECTIVES: To determine whether frozen storage alters the time-dependent response of the intact human intervertebral disc. SUMMARY OF BACKGROUND DATA: The biomechanical properties of the intervertebral disc are generally determined using specimens that have been previously frozen. Although it is well established that freezing does not alter the elastic response of the disc, recent data demonstrate that freezing permanently alters the time-dependent mechanical behavior of porcine discs. METHODS: Twenty lumbar motion segments from 10 human spines were harvested between 12 and 36 hours postmortem. The specimens were randomly assigned to one of two groups: Group 1 was tested promptly, stored frozen for 3 weeks, then thawed, and tested a second time; Group 2 was stored frozen for 3 weeks, thawed, and then tested. Each specimen was subjected to 5 cycles of compressive creep under 1 MPa for 20 minutes, followed by a 40-minute recovery under no load. After testing each specimen was graded on a degeneration scale. A fluid transport model was used to parameterize the creep data. RESULTS: There was no statistically significant effect of freezing on the elastic or creep response of the discs. The degree of pre-existing degeneration had a significant effect on the creep response, with the more degenerated discs appearing more permeable. CONCLUSIONS: Frozen storage for a reasonable time with a typical method does not significantly alter the creep response of human lumbar discs. Freezing may produce subtle effects, but these potential artifacts do not appear to alter the discs' time-dependent behavior in any consequential way. These results may not apply to tissue kept frozen for long durations and with poor packaging.

A histone variant, Htz1p, and a Sir1p-like protein, Esc2p, mediate silencing at HMR.

Silencing at HMR requires silencers, and one of the roles of the silencer is to recruit Sir proteins. This work focuses on the function of Sir1p once it is recruited to the silencer. We have generated mutants of Sir1p that are recruited to the silencer but are unable to silence, and we have utilized these mutants to identify four proteins, Sir3p, Sir4p, Esc2p, and Htz1p, that when overexpressed, restored silencing. The isolation of Sir3p and Sir4p validated this screen. Molecular analysis suggested that Esc2p contributed to silencing in a manner similar to Sir1p and probably helped recruit or stabilize the other Sir proteins, while Htz1p present at HMR assembled a specialized chromatin structure necessary for silencing.

Analysis of eryBI, eryBIII and eryBVII from the erythromycin biosynthetic gene cluster in Saccharopolyspora erythraea.

The gene cluster (ery) governing the biosynthesis of the macrolide antibiotic erythromycin A by Saccharopolyspora erythraea contains, in addition to the eryA genes encoding the polyketide synthase, two regions containing genes for later steps in the pathway. The region 5' of eryA that lies between the known genes ermE (encoding the erythromycin resistance methyltransferase) and eryBIII (encoding a putative S-adenosylmethionine-dependent methyltransferase), and that contains the gene eryBI (orf2), has now been sequenced. The inferred product of the eryBI gene shows striking sequence similarity to authentic beta-glucosidases. Specific mutants were created in eryBI, and the resulting strains were found to synthesise erythromycin A, showing that this gene, despite its position in the biosynthetic gene cluster, is not essential for erythromycin biosynthesis. A mutant in eryBIII and a double mutant in eryBI and eryBIII were obtained and the analysis of novel erythromycins produced by these strains confirmed the proposed function of EryBIII as a C-methyltransferase. Also, a chromosomal mutant was constructed for the previously sequenced ORF19 and shown to accumulate erythronolide B, as expected for an eryB mutant and consistent with its proposed role as an epimerase in dTDP-mycarose biosynthesis.

Ste5 RING-H2 domain: role in Ste4-promoted oligomerization for yeast pheromone signaling.

Ste5 is a scaffold for the mitogen-activated protein kinase (MAPK) cascade components in a yeast pheromone response pathway. Ste5 also associates with Ste4, the beta subunit of a heterotrimeric guanine nucleotide-binding protein, potentially linking receptor activation to stimulation of the MAPK cascade. A RING-H2 motif at the Ste5 amino terminus is apparently essential for function because Ste5(C177S) and Ste5(C177A C180A) mutants did not rescue the mating defect of a ste5Delta cell. In vitro Ste5(C177A C180A) bound each component of the MAPK cascade, but not Ste4. Unlike wild-type Ste5, the mutant did not appear to oligomerize; however, when fused to a heterologous dimerization domain (glutathione S-transferase), the chimeric protein restored mating in an ste5Delta cell and an ste4Delta ste5Delta double mutant. Thus, the RING-H2 domain mediates Ste4-Ste5 interaction, which is a prerequisite for Ste5-Ste5 self-association and signaling.