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Osteoarthritis (OA) is the most common joint disorder and a leading cause of disability. Due to an aging population and increasing obesity, the incidence of OA is rising. The etiology of OA is multifactorial and complex; thus prevention of OA remains challenging. Risk factors can be divided into person-level factors such as age, sex, obesity, genetics, race/ethnicity, and diet, and joint-level factors including injury, malalignment, and abnormal loading of the joints. This review provides a brief overview of the person-level risk factors and a more in-depth analysis of those at the joint level. It is only through an improved understanding of risk factors for the disease that we may be able to intervene meaningfully and prevent its occurrence. [ABSTRACT FROM AUTHOR]

The current study investigated whether a 5-month, adult mentoring intervention delivered by school personnel could enhance the school engagement of ninth grade urban minority adolescents. Compared to 20 at-risk students who did not receive an intervention, 20 at-risk students who were randomly assigned to mentoring exhibited significantly less decline during the first year of high school in perceived teacher support and decision making and were less likely to enter the discipline system. The effects were stronger and included sense of school belonging for participants who were 'mentored as intended.' Moreover, mentee and mentor reports of relationship quality were associated with changes in mentored participants' school-related cognitions and behaviors. The findings indicate that adult mentoring may help to prevent normative declines in urban minority youths' school engagement. [ABSTRACT FROM AUTHOR]

Perinatal nurses are named in patient lawsuits more than most nurses might imagine, and perinatal nurses are especially vulnerable. In 2005, 15% of all payments in nursing cases involved perinatal nurses. This article describes what some nurses have felt when faced with litigation, and offers consideration for how nursing as a profession, and perinatal nursing as a specialty, should change its approach toward more support of nurses who find themselves in this circumstance. [ABSTRACT FROM AUTHOR]

Cardiac amyloidosis is an infiltrative cardiomyopathy characterized by the extracellular deposition of amyloid fibrils within the myocardium. Beyond heart failure, patients with cardiac amyloidosis commonly present with arrhythmias and conduction system disorders. Atrial fibrillation is observed in up to 80% of patients at the time of diagnosis, with patients typically maintaining normal heart rates due to concurrent atrioventricular nodal disease. The thromboembolic risk is particularly high in patients with cardiac amyloidosis, and left atrial thrombi have been observed even in the absence of atrial fibrillation. Conduction system diseases are also highly prevalent, often necessitating permanent pacemaker implantation. The use of implantable defibrillators in this population remains controversial. This overview of published data and therapeutic strategies related to arrhythmias and conduction system disorders aims to assist readers in decision-making in complex clinical scenarios., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Despite several investigations on the atmospheric fate of cyclic volatile methyl siloxanes (VMS), the oxidation chemistry of these purely anthropogenic, high production volume compounds is poorly understood. This led to uncertainties in the environmental impact and fate of the oxidation products. According to laboratory measurements, the main VMS oxidation product is the siloxanol (a -CH 3 replaced with an -OH); however, none of the mechanisms proposed to date satisfactorily explain its formation. Motivated by our previous experimental observations of VMS oxidation products, we use theoretical quantum chemical calculations to (1) explore a previously unconsidered reaction pathway to form the siloxanol from a reaction of a siloxy radical with gas-phase water, (2) investigate differences in reaction rates of radical intermediates in hexamethylcyclotrisiloxane (D3) and octamethylcyclotetrasiloxane (D4) oxidation, and (3) attempt to explain the experimentally observed products. Our results suggest that while the proposed reaction of the siloxy radical with water to form the siloxanol can occur, it is too slow to compete with other unimolecular reactions and thus cannot explain the observed siloxanol formation. We also find that the reaction between the initial D3 peroxy radical (RO 2 • ) with HO 2 • is slower than previously anticipated (calculated as 3 × 10 -13 cm 3 molecule -1 s -1 for D3 and 2 × 10 -11 cm 3 molecule -1 s -1 for D4 compared to the general rate of ∼1 × 10 -11 cm 3 molecule -1 s -1 ). Finally, we compare the anticipated fates of the RO 2 • under a variety of conditions and find that a reaction with NO (assuming a general RO 2 • + NO bimolecular rate constant of 9 × 10 -12 cm 3 molecule -1 s -1 ) will likely be the dominant fate in urban conditions, while isomerization can be important in cleaner environments.

Valvular heart disease (VHD) is common and poses important challenges from the standpoints of diagnosis and therapeutic management. Clinical practice guidelines have been developed to help health care professionals to overcome these challenges and provide optimal management to patients with VHD. The American College of Cardiology, in collaboration with the American Heart Association, and the European Society of Cardiology, in collaboration with the European Association for Cardio-Thoracic Surgery, recently updated their guidelines on the management of VHD. Although these 2 sets of guidelines are generally concordant, there are some substantial differences between these guidelines, which may have significant implications for clinical practice. This review prepared on behalf of the EuroValve Consortium describes the consistencies and discrepancies between the guidelines and highlights the gaps in these guidelines and the future research perspectives to fill these gaps., Competing Interests: Funding Support and Author Disclosures Dr Garbi was The NICE Topic Adviser for the NICE Guidelines on heart valve disease presenting in adults: investigation and management. Dr Dahl has received speaker fees from Edwards. Dr Barbanti has served as a consultant for Edwards Lifesciences, Medtronic, and Boston Scientific. Dr Vannan has received research grants and a speaker honorarium (to Piedmont Heart Institute, not to self) from Abbott, Medtronic, and Edwards Lifesciences. Dr Vassiliou served as an advisor for the NICE Guidelines on valvular heart disease (NG208) referred to in this paper; and has received grants for investigator-initiated research by Medtronic and B Braun Ltd. Dr de Paulis has received royalties from Edwards for a mitral ring; and has received speaker fees from Edwards and Medtronic. Dr Pibarot has received institutional research grants from Edwards Lifesciences, Medtronic, Pi-Cardia, Cardiac Success, and Roche Diagnostics. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Purpose: Long-term needs of stroke survivors (especially psychosocial needs and stroke prevention) are not adequately addressed. Self-management programmes exist but the optimal content and delivery approach is unclear. We aim to describe the process undertook to develop a structured self-management programme to address these unmet needs., Materials and Methods: Based on the Medical Research Council framework for complex interventions, the development involved three phases: "Exploring the idea": Evidence synthesis and patient and public involvement (PPI) with stroke survivors, carers and healthcare professionals. "The iterative phase": Development and iterative refinement of the format, content, underpinning theories and philosophy of the self-management programme My Life After Stroke (MLAS), with PPI. MLAS consists of two individual appointments and four group sessions over nine weeks, delivered interactively by two trained facilitators. It aims to build independence, confidence and hope and focusses on stroke prevention, maximising physical potential, social support and managing emotional responses. MLAS is grounded in the narrative approach and social learning theory. "Ready for research": The refinement of a facilitator curriculum and participant resources to support programme delivery., Results: Through a systematic process, we developed an evidence- and theory-based self-management programme for stroke survivors., Conclusions: MLAS warrants evaluation in a feasibility study.Implications for rehabilitationMy Life After Stroke(MLAS) has been developed using a systematic process, to address the unmet needs of stroke survivors.This systematic process, involved utilising evidence, theories, patient and public involvement, expertise and guidelines from other long-term conditions. This may further help the development of similar self-management programme within the field of stroke.MLAS warrants further evaluation within a feasibility study.

Purpose: An evidence-based, theory-driven self-management programme "My Life After Stroke" (MLAS) was developed to address the longer-term unmet needs of stroke survivors.This study's aim was to test the acceptability and feasibility of MLAS as well as exploring what outcomes measures to include as part of further testing., Methods: Stroke registers in four GP practices across Leicester and Cambridge were screened, invite letters sent to eligible stroke survivors and written, informed consent gained. Questionnaires including Southampton Stroke Self-Management Questionnaire (SSSMQ) were completed before and after MLAS.Participants (and carers) attended MLAS (consisting of two individual appointments and four group sessions) over nine weeks, delivered by two trained facilitators. Feedback was gained from participants (after the final group session and final individual appointment) and facilitators., Results: Seventeen of 36 interested stroke survivors participated alongside seven associated carers. 15/17 completed the programme and attendance ranged from 13-17 per session. A positive change of 3.5 of the SSSMQ was observed. Positive feedback was gained from facilitators and 14/15 participants recommended MLAS (one did not respond)., Conclusions: MLAS was a feasible self-management programme for stroke survivors and warrants further testing as part of the Improving Primary Care After Stroke (IPCAS) cluster randomised controlled trial.IMPLICATIONS FOR REHABILITATIONMy Life After Stroke is a self-management programme developed for stroke survivors living in the community.MLAS is feasible and acceptable to stroke survivors.MLAS could be considered to help address the unmet educational and psychological needs of stroke survivors.

Objective: To test the effectiveness of a 32-week, stepped-care intervention on disease remission rates in overweight and obese patients with medial tibiofemoral osteoarthritis (OA) compared to controls., Methods: In this randomized controlled trial, eligible participants were ≥50 years of age with a body mass index of ≥28 kg/m 2 and radiographic evidence of medial tibiofemoral OA. Participants were randomized to stepped-care (n = 87) or control group (n = 84). The stepped-care group received a 2-step intervention. The first step consisted of an 18-week diet and exercise program. The second step consisted of 4 treatment subgroups: 1) diet and exercise maintenance; 2) cognitive-behavioral therapy; 3) unloader knee brace; and 4) muscle strengthening exercises. Allocation into subgroups was based on disease remission state and clinical characteristics. The primary end point was the disease remission rate (yes/no) at 32 weeks, which was reached when participants achieved the Patient Acceptable Symptom State cutoff value for pain and for the patient global assessment of disease activity and/or functional impairment., Results: Disease remission at 32 weeks was achieved by 18 of 68 (26%) in the control group and 32 of 82 (39%) in the stepped-care group (difference 12.6% [95% confidence interval -2.3, 27.4], P = 0.10). The stepped-care group showed an improvement in pain and function between baseline and 20 weeks. While functional improvement was maintained at 32 weeks, pain levels tended to get worse between weeks 20 and 32., Conclusion: The proposed intervention did not promote a significant difference in the rate of disease remission in comparison to the control group for overweight or obese patients with medial tibiofemoral OA., (© 2020, American College of Rheumatology.)

Intercalation offers a promising way to alter the physical properties of two-dimensional (2D) layered materials. Here, we investigate the electronic and vibrational properties of 2D layered MoSe 2 intercalated with atomic manganese at ambient and high pressure up to 7 GPa by Raman scattering and electronic structure calculations. The behavior of optical phonons is studied experimentally with a diamond anvil cell and computationally through density functional theory calculations. Experiment and theory show excellent agreement in optical phonon behavior. The previously Raman inactive A 2u mode is activated and enhanced with intercalation and pressure, and a new Raman mode appears upon decompression, indicating a possible onset of a localized structural transition, involving the bonding or trapping of the intercalant in 2D layered materials. Density functional theory calculations reveal a shift of the Fermi level into the conduction band and spin polarization in Mn x MoSe 2 that increases at low Mn concentrations and low pressure. Our results suggest that intercalation and pressurization of van der Waals materials may allow one to obtain dilute magnetic semiconductors with controllable properties, providing a viable route for the development of new materials for spintronic applications.

Background: Glutamate is an excitatory neurotransmitter binding to 3 classes of receptors, including the N-methyl, D-aspartate (NMDA) receptor. NMDA receptor binding is lower in major depression disorder and suicide. NMDA receptor blocking with ketamine can have antidepressant and anti-suicide effects. Early-life adversity (ELA) may cause glutamate-mediated excitotoxicity and is more common with major depression disorder and in suicide decedents. We sought to determine whether NMDA-receptor binding is altered with suicide and ELA., Methods: A total 52 postmortem cases were organized as 13 quadruplets of suicide and non-suicide decedents matched for age, sex, and postmortem interval, with or without reported ELA (≤16 years). Tissue blocks containing dorsal prefrontal (BA8), dorsolateral prefrontal (BA9), or anterior cingulate (BA24) cortex were collected at autopsy. Psychiatrically healthy controls and suicide decedents underwent psychological autopsy to determine psychiatric diagnoses and details of childhood adversity. NMDA receptor binding was determined by quantitative autoradiography of [3H]MK-801 binding (displaced by unlabeled MK-801) in 20-µm-thick sections., Results: [3H]MK-801 binding was not associated with suicide in BA8, BA9, or BA24. However, [3H]MK-801 binding with ELA was less in BA8, BA9, and BA24 independent of suicide (P < .05). [3H]MK-801 binding was not associated with age or postmortem interval in any brain region or group., Conclusions: Less NMDA receptor binding with ELA is consistent with the hypothesis that stress can cause excitotoxicity via excessive glutamate, causing either NMDA receptor downregulation or less receptor binding due to neuron loss consequent to the excitotoxicity., (© The Author(s) 2020. Published by Oxford University Press on behalf of CINP.)

Introduction: Symptomatic osteoarthritis (OA) in the knee is defined as the presence of OA radiographic features in combination with knee symptoms. Pain has not been shown to correlate meaningfully to radiographic severity. We aimed to determine the relationship between a tear of the anterior cruciate ligament (ACL) with knee symptoms and radiographic OA., Methods: A within-person, between-knee cross-sectional study of 37 participants from the Osteoarthritis Initiative (OAI) with a complete or partial ACL tear detected on magnetic resonance imaging in 1 knee (index knee) were included. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS) and radiographs of both knees, 1 with an ACL tear and one without (control knee) were scored for OA severity (Kellgren-Lawrence Grading) and symptoms. A generalized estimating equation with linear regression was used to compare symptom scores within individuals as well as to radiographic severity., Results: Thirty-seven individuals (40% female, average age = 60.7years, body mass index = 31.0 kg/m 2 ) reported no difference in knee symptoms (WOMAC pain odds ratio [OR] =1.92, 95%CI 0.699-5.248, P = .21; KOOS symptoms OR = 2.12, 95%CI 0.740-6.065, P = .09), stiffness (OR = 1.67, 95%CI 0.653-5.583, P = .35) or functional disability (OR = 1 0.97, 95%CI 0.515-7.508, P = .32) in the knee that exhibited an ACL tear compared to the control knee. Only knee function and disability (WOMAC Disability OR = 1.12, 95%CI 1.003-1.249, P = .04) were associated with radiographic severity between index and control knees., Conclusion: Individuals did not report an increase in knee pain, stiffness or disability in their ACL-deficient knee. Only disability was associated with worsening severity of radiographic OA in ACL-deficient knees., (© 2020 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.)

Introduction: Current guidelines recommend tailored interventions to optimise knee osteoarthritis (OA) management. However, models of care still have a 'one size fits all' approach, which is suboptimal as it ignores patient heterogeneity. This study aims to compare a stepped care strategy with standard care for overweight and obese persons with medial tibiofemoral OA., Methods and Analysis: Participants will be randomised into two groups (85 each). The intervention will receive a diet and exercise programme for 18 weeks in the first step of the study. Disease remission will then be assessed using the Patient Acceptable Symptom State (PASS). PASS is defined as the highest level of symptom beyond which patients consider themselves well and takes into account pain intensity, patient's global assessment of disease activity and degree of functional impairment. In the second step, participants in remission will continue with diet and exercise. If remission is not achieved, participants will be assigned in a hierarchical order to cognitive behavioural therapy, knee brace or muscle strengthening for 12 weeks. The intervention will be decided based on their clinical presentation for symptoms of depression and varus malalignment. Participants without depression or varus malalignment will undertake a muscle strengthening programme. The control group will receive educational material related to OA management. Main inclusion criteria are age ≥50 years, radiographic medial tibiofemoral OA, body mass index (BMI) ≥28 kg/m 2 , knee pain ≥40 (Visual Analogue Scale, 0-100), PASS (0-100) >32 for pain and global assessment, and 31 for functional impairment. Outcomes will be measured at 20-week and 32-week visits. The primary outcome is disease remission at 32 weeks. Other outcomes include functional mobility; patient-reported outcomes; BMI; waist-hip ratio; quadriceps strength; symptoms of depression, anxiety and stress; and knee range of motion. The analysis will be performed according to the intention-to-treat principle., Ethics and Dissemination: The local ethics committee approved this protocol (HREC/14/HAWKE/381). Dissemination will occur through presentations at international conferences and publication in peer-reviewed journals., Trial Registration Number: ACTRN12615000227594., Competing Interests: Competing interests: DJH reports grants from National Health and Medical Research Council, non-financial support from Prima Health, non-financial support from Össur, personal fees from Merck Serono, personal fees from National Health and Medical Research Council, during the conduct of the study; personal fees from Flexion, personal fees from Tissuegene, personal fees from Nestle, personal fees from Merck Serono, outside the submitted work. The remaining authors report grant from the National Health and Medical Research Council, non-financial support from Prima Health and non-financial support from Össur, during the conduct of the study., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

In 2013 more than 150,000 Americans died from all types of lung cancer. Small cell lung cancer (SCLC) represents about 13% of all lung cancers and is notoriously associated with paraneoplastic syndromes (PNS). Here we present an interesting case of psychosis associated with one such PNS-- ectopic Cushing syndrome of SCLC. A 56 year old African-American male with no prior psychiatric history who was diagnosed with SCLC two months prior, presented to the ER for treatment of a right arm laceration he sustained while fighting off attackers, with high concern these individuals may have been part of hallucinatory experiences and well-systematized persecutory delusions regarding his wife. Physical assessment was notable for Cushingoid symptoms. Initial results of serum ACTH and cortisol were 221pg/ml (10-50pg/ml) and 37.1 mcg/dl (10-20mcg/dl) respectively. For psychosis, patient was started on Olanzapine which was titrated from 5 to final dose of 10mg nightly. Since patient was not a surgical candidate, he was treated with metyrapone 250 mg BID and radiation therapy was continued throughout hospitalization. Serum Cortisol level decreased steadily after initiation of metyrapone and psychotic symptoms dramatically reduced on olanzapine, metyrapone, and radiation therapy with apparently resolved persecutory delusions at discharge. This case broadens the available literature and provides data on successful symptomatic treatment with olanzapine while biological treatments of the underlying condition were beginning to take effect. As SCLC remains an important cause of morbidity and mortality in the US, it is imperative that physicians be aware of paraneoplastic syndromes and their psychiatric sequelae.

Aim: The aim of this study was to examine the difference in the pattern of articular damage in persons with either a partial anterior cruciate ligament (ACL) tear; a complete ACL tear or no ACL tear., Methods: Our study included 600 individuals (of the 600 individuals, 25 with a partial, 12 with a complete ACL tear and 563 with no ACL tear) from the progression sub-cohort of the Osteoarthritis Initiative. Individuals had a mean age of 61.8 years (range 45-79 years). Chi-square tests were used to compare the location of meniscal pathology, bone marrow lesions (BMLs) and regional cartilage morphology between individuals with a partial or complete ACL tear, as seen on magnetic resonance imaging, as well as to a control group of 563 knees., Results: Individuals with either a complete or partial ACL tear displayed predominantly medial tibiofemoral damage. Individuals with complete ACL tears were more likely to have cartilage lesions in the lateral posterior tibia (P = 0.03) and the medial anterior femur (P = 0.008) as well as BMLs in the medial posterior tibia (P = 0.007). However, no significant difference in meniscal morphology was found in either compartment. Individuals with no history of knee trauma or ACL injury displayed predominantly medial tibiofemoral compartment damage., Conclusion: Individuals with prevalent ACL disruptions exhibited concomitant osteoarthritic changes in the medial tibiofemoral compartment, as seen on MRI. As the changes in joint tissues were predominantly located in the medial compartment, it is thought that these ACL tears may represent a manifestation of the overall disease process rather than the precipitant for osteoarthritis incidence., (© 2016 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.)

Background: The development of radiographic knee osteoarthritis (OA) after an anterior cruciate ligament (ACL) rupture has long been studied and proven in the adolescent population. However, similar exhaustive investigations have not been conducted in mature-aged athletes or in older populations., Purpose: To identify whether an older adult population had an increased risk of incident radiographic knee OA after a traumatic knee injury compared with a young adult population., Study Design: Cohort study; Level of evidence, 3., Methods: Patients with ACL ruptures who underwent primary reconstruction were enrolled in a prospective, longitudinal single-center study over 15 years. The adult cohort was defined as participants aged ≥35 years who had a knee injury resulting in an ACL tear, the adolescent-young cohort suffered similar knee injuries and were aged ≤25 years, and a third cohort of participants aged 26 to 34 years who suffered a knee injury was included to identify the existence of any age-related dose-response relationship for the onset of radiographic knee OA. A Kaplan-Meier survival analysis was employed to determine the occurrence of incident radiographic OA across the study populations at 2, 5, 10, and 15 years after reconstruction. Significance at each time point was analyzed using chi-square tests., Results: A total of 215 patients, including 112 adolescents (mean age, 20.4 years; 50.9% female), 71 patients aged 26 to 34 years (mean age, 29.2 years; 42.3% female), and 32 adults (mean age, 40.2 years; 59.4% female), were assessed for International Knee Documentation Committee (IKDC) grading on knee radiographs. It was found that 53.0% and 77.8% of adults at a respective 10 and 15 years after reconstruction had an IKDC grade of B or greater compared with 17.7% and 61.6% of the adolescent-young cohort. Chi-square testing found that adults developed OA earlier than adolescents at 5 and 10 years after reconstruction (P = .017 and P < .0001, respectively). However, survival analysis did not demonstrate that adults were more likely to develop radiographic knee OA at 15 years after reconstruction compared with the adolescent-young cohort (P = .4)., Conclusion: The age at which an ACL injury is sustained does not appear to influence the rate of incident radiographic knee OA, although mature-aged athletes are likely to arrive at the OA endpoint sooner., (© 2016 The Author(s).)

Background: Vitamin D plays an important role in the mineral and bone disorder seen in chronic kidney disease (CKD). Deficiency of 25-hydroxyvitamin D (25OHD) is highly prevalent in the adult CKD population., Methods: The prevalence and determinants of 25OHD deficiency (defined as a level <20 ng/ml) were examined longitudinally in 506 children in the CKiD cohort. Predictors of secondary hyperparathyroidism and the determinants of 1,25-dihydroxyvitamin D (1,25(OH)2D) levels were also evaluated., Results: Deficiency of 25OHD was observed in 28 % of the cohort at enrollment. Significant predictors of 25OHD deficiency were older age, non-white race, higher body mass index, assessment during winter, less often than daily milk intake, non-use of nutritional vitamin D supplement and proteinuria. Lower values of glomerular filtration rate (GFR), serum 25OHD, calcium and higher levels of FGF23 were significant determinants of secondary hyperparathyroidism. Lower GFR, low serum 25OHD, nephrotic-range proteinuria, and high FGF23 levels were significant determinants of serum 1,25(OH)2 D levels., Conclusions: Deficiency of 25OHD is prevalent in children with CKD and is associated with potentially modifiable risk factors such as milk intake, nutritional vitamin D supplement use, and proteinuria. 25OHD deficiency is a risk factor for secondary hyperparathyroidism and decreased serum 1,25(OH)2D in children with CKD.

Introduction: The aim of this study was to determine whether loss of ACL integrity in an older cohort precedes the onset of radiographic OA (ROA)., Methods: Participants in this nested case-control study were selected from the Osteoarthritis Initiative (OAI) study who had risk factors for OA development but did not have ROA (Kellgren-Lawrence grading (KLG) of 0 or 1) in both knees at baseline. The MRIs were assessed for the presence of ACL tears. Case knees were defined by the development of ROA on knee radiographs between the 12 and 48 month visits. Their radiographs were assessed at P0 (time of onset of radiographic knee OA), 1 year prior to P0 (P-1) and at baseline. Controls were selected from amongst those who did not develop incident ROA and were matched to cases., Results: 355 persons who developed ROA were matched to 355 controls. No relationship between loss of ACL integrity and incident ROA was found at any assessment time point. Odds ratios (OR) for baseline, 1 year prior to incident ROA (P1) and at point of occurrence of incident ROA (P0) were 2.00 (0.66-6.06), 2.5 (0.76-8.24) and 2.75 (0.85-8.88) respectively. A significant risk of incident ROA was found in participants who had a history of knee injury with an OR of 1.51 (1.05-2.16)., Conclusion: Loss of ACL integrity does not confer a significantly increased risk of incident ROA in an older adult cohort. In contrast, a history of knee injury was associated with an increased risk of incident ROA., (Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Osteoarthritis (OA) is a leading cause of disability and its incidence is rising due to increasing obesity and an ageing population. Risk factors can be divided into person-level factors, such as age, sex, obesity, genetics, race/ethnicity and diet, and joint-level factors including injury, malalignment and abnormal loading of the joints. The interaction of these risk factors is complex and provides a challenge to the managing physician. The purpose of this review is to illustrate how each of these factors interact together to instigate incident OA as well as to outline the need for ongoing epidemiologic studies for the future prevention of both incident and progressive OA. It is only by understanding the impact of this disease and the modifiable risk factors that we will be able to truly target public health prevention interventions appropriately., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The present study investigated the impact of a manualized high school transition program, the Peer Group Connection (PGC) program, on the graduation rate at a low-income, Mid-Atlantic high school. The program utilized twelfth grade student peer leaders to create a supportive environment for incoming ninth grade students. Results of a randomized control trial demonstrated that male students who participated in the program during ninth grade were significantly more likely to graduate from high school within four years than male students in the control group (81% versus 63%). Findings suggest that peers can be effective in delivering a school-based, social emotional learning intervention and that it is possible to intervene in the ninth grade to influence the probability of high school graduation.

Background: Focal segmental glomerulosclerosis (FSGS) recurs in 20-40 % of allografts. Plasmapheresis (TPE) has been one of the mainstays of treatment with variable results. Rituximab (RTX), a monoclonal antibody to the protein CD20, is being used for treatment of recurrent FSGS (recFSGS) but pediatric experience is limited., Methods: We conducted a retrospective review of eight patients with recFSGS, treated with RTX (1-4 doses) after having minimal response to TPE. Complete response was defined as a decrease in urine protein creatinine ratio (Up/c) to less than 0.2 and partial response was a decrease in Up/c ratio by 50 % of baseline and in the sub-nephrotic range (U p/c <2)., Results: Complete response was seen in two of eight patients, and partial response was seen in four of eight patients. Two patients had no response. At last follow-up, all the partial responders had sub-nephrotic range proteinuria (Up/c ratios ranging from 0.29 to 1.6). Delayed response, up to 9 months post-RTX, was also seen in some of the patients. Significant complications such as rituximab-associated lung injury (RALI), acute tubular necrosis, and central nervous system(CNS) malignancy were also observed in our case series., Conclusions: Rituximab can be used with caution as a treatment for recFSGS. Efficacy is variable from none to complete response. Even partial reduction in proteinuria is of benefit in prolonging the life of the allograft. Long-term, multicenter studies are needed to prove its sustained efficacy in those who respond and to monitor for serious adverse effects.

Little is known about the effects of thalassaemia on the kidney. Characterization of underlying renal function abnormalities in thalassaemia is timely because the newer iron chelator, deferasirox, can be nephrotoxic. We aimed to determine the prevalence and correlates of renal abnormalities in thalassaemia patients, treated before deferasirox was widely available, using 24-h collections of urine. We calculated creatinine clearance and urine calcium-to-creatinine ratio and measured urinary β(2) -microglobulin, albumin, and protein. We used multivariate modelling to identify clinical, therapeutic, and laboratory predictors of renal dysfunction. One-third of thalassaemia patients who were not regularly transfused had abnormally high creatinine clearance. Regular transfusions were associated with a decrease in clearance (P = 0·004). Almost one-third of patients with thalassaemia had hypercalciuria, and regular transfusions were associated with an increase in the frequency and degree of hypercalciuria (P < 0·0001). Albuminuria was found in over half of patients, but was not consistently associated with transfusion therapy. In summary, renal hyperfiltration, hypercalciuria, and albuminuria are common in thalassaemia. Higher transfusion intensity is associated with lower creatinine clearance but more frequent hypercalciuria. The transfusion effect needs to be better understood. Awareness of underlying renal dysfunction in thalassaemia can inform decisions now about the use and monitoring of iron chelation., (© 2011 Blackwell Publishing Ltd.)

Limited information is available to support the validity of using surface electrodes to record activity from infraspinatus. The aims of this study were to compare infraspinatus activity recorded using surface and intramuscular electrodes during several shoulder isometric and dynamic tasks and to establish if infraspinatus activity recorded using intramuscular electrodes is representative of whole muscle activity. Surface and intramuscular electrodes were placed over infraspinatus in nine subjects without shoulder pain. Isometric shoulder external rotation, at 0° and 90° abduction, and extension were performed at six loads. Dynamic shoulder flexion and abduction were performed at 70% maximum load. Results indicated that while surface and intramuscular electrodes record similar activation patterns when infraspinatus is moderately to highly activated (r and slope ∼ 1), only intramuscular electrodes accurately reflected low (<10%MVC) infraspinatus activity (r=0.95 ± 0.04, slope=15.6 ± 16.3). The linear relationship between the activity recorded with surface and intramuscular electrodes when infraspinatus is moderately to highly active also indicated that intramuscular recordings from infraspinatus are representative of activity in the whole muscle. To ensure validity in reporting infraspinatus activation patterns when studying functional shoulder tasks in which infraspinatus may be relatively active and inactive at different phases of these tasks, intramuscular electrodes should be used to record infraspinatus activity., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

This article serves as an introduction to the special issue entitled, "Lesbians of African Descent: Contemporary Perspectives." We briefly discuss our framing of this collection as a contemporary contribution to the canon of Black lesbian writing and art, and identify themes that appear to transcend both earlier and current works of lesbians of African descent.

To explore what mediates relationships between coping styles and substance use, different types of coping, proximal precursors of substance use, and reported substance use/intentions to use were examined in a study of low income, urban, high school freshmen from American ethnic minority groups. Regression analyses showed evidence for two mediators. The relationship between a tendency to depend upon parents to cope with problems and increased substance use was mediated by lowered perceptions of harm from use. The relationship between a tendency to use substances to cope with problems and increased substance use was mediated by increased tolerance for and use by friends.

Water quality data at 12 sites within an urban, a suburban, and a rural stream were collected contemporaneously during four wet and eight dry periods. The urban stream yielded the highest biochemical oxygen demand (BOD), orthophosphate, total suspended sediment (TSS), and surfactant concentrations, while the most rural stream yielded the highest total organic carbon concentrations. Percent watershed development and percent impervious surface coverage were strongly correlated with BOD (biochemical oxygen demand), orthophosphate, and surfactant concentrations but negatively with total organic carbon. Excessive fecal coliform abundance most frequently occurred in the most urbanized catchments. Fecal coliform bacteria, TSS, turbidity, orthophosphate, total phosphorus, and BOD were significantly higher during rain events compared to nonrain periods. Total rainfall preceding sampling was positively correlated with turbidity, TSS, BOD, total phosphorus, and fecal coliform bacteria concentrations. Turbidity and TSS were positively correlated with phosphorus, fecal coliform bacteria, BOD, and chlorophyll a, which argues for better sedimentation controls under all landscape types.

The spindle checkpoint maintains genome stability by inhibiting Cdc20-mediated activation of the anaphase promoting complex/cyclosome (APC/C) until all the chromosomes correctly align on the microtubule spindle apparatus via their kinetochores. BubR1, an essential component of this checkpoint, localises to kinetochores and its kinase activity is regulated by the kinesin-related motor protein Cenp-E. BubR1 also inhibits APC/C(Cdc20) in vitro, thus providing a molecular link between kinetochore-microtubule interactions and the proteolytic machinery that regulates mitotic progression. Several other protein kinases, including Bub1 and members of the Ipl1/aurora family, also regulate anaphase onset. However, in human somatic cells Bub1 and aurora B kinase activity do not appear to be essential for spindle checkpoint function. Specifically, when Bub1 is inhibited by RNA interference, or aurora kinase activity is inhibited with the small molecule ZM447439, cells arrest transiently in mitosis following exposure to spindle toxins that prevent microtubule polymerisation. Here, we show that mitotic arrest of Bub1-deficient cells is dependent on aurora kinase activity, and vice versa. We suggest therefore that the checkpoint is composed of two arms, one dependent on Bub1, the other on aurora B. Analysis of BubR1 complexes suggests that both of these arms converge on the mitotic checkpoint complex (MCC), which includes BubR1, Bub3, Mad2 and Cdc20. Although it is known that MCC components can bind and inhibit the APC/C, we show here for the first time that the binding of the MCC to the APC/C is dependent on an active checkpoint signal. Furthermore, we show that both Bub1 and aurora kinase activity are required to promote binding of the MCC to the APC/C. These observations provide a simple explanation of why BubR1 and Mad2 are essential for checkpoint function following spindle destruction, yet Bub1 and aurora B kinase activity are not. Taken together with other observations, we suggest that these two arms respond to different spindle cues: whereas the Bub1 arm monitors kinetochore-microtubule attachment, the aurora B arm monitors biorientation. This bifurcation in the signalling mechanism may help explain why many tumour cells mount a robust checkpoint response following spindle damage, despite exhibiting chromosome instability.

Whereas a recent study reported an increased risk of colorectal cancer associated with any HFE germ line mutation (C282Y or H63D), other investigators have concluded there is no increased risk, or that any increase is dependent on polymorphisms in HFE-interacting genes such as the transferrin receptor (TFR). We have established the frequency of HFE mutations in colorectal cancer patients (n = 327) with a family history of the disease and randomly selected controls (n = 322); this design increases greatly the study's power. Genotyping for the TRF S142G polymorphism was also conducted on a large proportion of the study group. Using PCR, restriction enzyme mapping, sequencing followed by data analysis with Fisher's exact test and logistic regression, we show that the presence of any HFE mutation (Y282 or D63) was not associated with colorectal cancer risk (P = 0.57). In contrast, individuals compound heterozygous for both mutations (15 cases versus 5 controls) had thrice the odds of developing colorectal cancer (odds ratio, 3.03; 95% confidence interval, 1.06-8.61) compared with those with a single mutation. This finding did not quite reach statistical significance after allowing for multiple post hoc testing (P(observed) = 0.038 versus P = 0.025, with Bonferonni correction). Overall, our data indicate that individuals with a single HFE mutation, C282Y or H63D, are unlikely predisposed to develop colorectal cancer. However, risk of colorectal cancer might be increased by compound heterozygosity for the HFE mutations in the small number of subjects studied. TFR gene polymorphism was not an independent risk factor and did not modify the disease risk associated with HFE mutation.

The majority of human tumour cells are aneuploid owing to an underlying chromosome instability phenotype. While the genetic lesions that cause chromosome instability remain undefined, mouse ES cells harbouring homozygous adenomatous polyposis coli (APC) mutations are frequently tetraploid. In addition, colon cancer cells with APC mutations have weakened kinetochore-microtubule interactions. Furthermore, mitotic spindles assembled in APC-depleted Xenopus egg extracts are aberrant. Therefore, to determine whether APC mutations can initiate chromosome instability in human cells, we expressed N-terminal APC fragments in HCT-116 cells, a near diploid colon cancer cell line with two wild-type APC alleles. We show that cells expressing N-APC mutants exit mitosis prematurely in the presence of spindle toxins, consistent with a spindle checkpoint defect. In addition, N-APC cells show enhanced survival following prolonged spindle damage. In contrast to controls, the N-APC survivors frequently contain dicentric chromosomes and then go on to become highly aneuploid. These observations suggest that truncating APC mutations can exert dominant effects which in turn can initiate chromosome instability. As such, APC mutation not only compromises tumour suppressor function but may also have oncogenic properties. We suggest therefore that the initial APC mutation acts as a 'double whammy', destabilising the genome and setting the stage for deregulated proliferation upon loss of the second APC allele.

During mitosis, the recruitment of spindle-checkpoint-associated proteins to the kinetochore occurs in a defined order. The protein kinase Bub1 localizes to the kinetochore very early during mitosis, followed by Cenp-F, BubR1, Cenp-E and finally Mad2. Using RNA interference, we have investigated whether this order of binding reflects a level of dependency in human somatic cells. Specifically, we show that Bub1 plays a key role in the assembly of checkpoint proteins at the kinetochore, being required for the subsequent localization of Cenp-F, BubR1, Cenp-E and Mad2. In contrast to studies in Xenopus, we also show that BubR1 is not required for kinetochore localization of Bub1. Repression of Bub1 increases the number of cells with lagging chromosomes at metaphase, suggesting that Bub1 plays a role in chromosome congression. However, repression of Bub1 does not appear to compromise spindle checkpoint function either during normal mitosis or in response to spindle damage. This raises the possibility that, in the absence of Bub1, other mechanisms contribute to spindle checkpoint function.

The role of apoptosis in acetaminophen (AAP)-induced hepatic injury was investigated. Six hours after AAP administration to BALB/c mice, a significant loss of hepatic mitochondrial cytochrome c was observed that was similar in extent to the loss observed after in vivo activation of CD95 by antibody treatment. AAP-induced loss of mitochondrial cytochrome c coincided with the appearance in the cytosol of a fragment corresponding to truncated Bid (tBid). At the same time, tBid became detectable in the mitochondrial fraction, and concomitantly, Bax was found translocated to mitochondria. However, AAP failed to activate the execution caspases 3 and 7 as evidenced by a lack of procaspase processing and the absence of an increase in caspase-3-like activity. In contrast, the administration of the pan-inhibitor of caspases, benzyloxycarbonyl-Val-Ala-DL-Asp-fluoromethylketone (but not its analogue benzyloxycarbonyl-Phe-Ala-fluoromethylketone) prevented the development of liver injury by AAP and the appearance of apoptotic parenchymal cells. This correlated with the inhibition of the processing of Bid to tBid. The caspase inhibitor failed to prevent both the redistribution of Bax to the mitochondria and the loss of cytochrome c. In conclusion, apoptosis is an important causal event in the initiation of the hepatic injury inflicted by AAP. However, as suggested by the lack of activation of the main execution caspases, apoptosis is not properly executed and degenerates into necrosis.

The Aurora/Ipl1 family of protein kinases plays multiple roles in mitosis and cytokinesis. Here, we describe ZM447439, a novel selective Aurora kinase inhibitor. Cells treated with ZM447439 progress through interphase, enter mitosis normally, and assemble bipolar spindles. However, chromosome alignment, segregation, and cytokinesis all fail. Despite the presence of maloriented chromosomes, ZM447439-treated cells exit mitosis with normal kinetics, indicating that the spindle checkpoint is compromised. Indeed, ZM447439 prevents mitotic arrest after exposure to paclitaxel. RNA interference experiments suggest that these phenotypes are due to inhibition of Aurora B, not Aurora A or some other kinase. In the absence of Aurora B function, kinetochore localization of the spindle checkpoint components BubR1, Mad2, and Cenp-E is diminished. Furthermore, inhibition of Aurora B kinase activity prevents the rebinding of BubR1 to metaphase kinetochores after a reduction in centromeric tension. Aurora B kinase activity is also required for phosphorylation of BubR1 on entry into mitosis. Finally, we show that BubR1 is not only required for spindle checkpoint function, but is also required for chromosome alignment. Together, these results suggest that by targeting checkpoint proteins to kinetochores, Aurora B couples chromosome alignment with anaphase onset.

Pregnant CD-1 mice were administered a commercial 2,4-dichlorophenoxyacetic acid (2,4-D) formulation on days 6-16 days of gestation, in drinking water at concentrations ranging from 0 to 1.0% of the formulated product, equivalent to approximately 0-650 mg/kg per day expressed as the amine derivative. The effect of 2,4-D on immune function was evaluated in offspring 7 weeks after birth. The dams tolerated repeated 2,4-D exposure in drinking water without difficulty. The offspring exhibited decreased body weight with minor reductions in the kidney weights in the 0.1 and 1.0% 2,4-D treatment groups. A generalized suppression of lymphocyte stimulation by concanavalin A (Con A) was observed at high dose of commercial 2,4-D formulation (1.0%). Cytometric studies of the lymphocyte subpopulations demonstrated an increased relative count of B cells and reduced T cytotoxic or suppressor cells in the 1.0% formulation. The humoral immune response, antibody production against sheep red blood cells and peritoneal macrophage phagocytic function, were not altered by 2,4-D. Since the immune alterations in the offspring were observed many weeks after exposure, it appears as though 2,4-D exposure during gestation causes permanent changes in cell types associated with immune function. Since 2,4-D is not considered a persistent chemical, it is unlikely that 2,4-D residues are contributing significantly to the observed immune alterations. The immune alterations were observed only in the higher treatment groups. Therefore, the impact on human and animal health from an immune perspective, which would be encountered following normal application in the environment, would be minimal.

Colon cancer cells frequently display minisatellite instability (MIN) or chromosome instability (CIN). While MIN is caused by mismatch repair defects, the lesions responsible for CIN are unknown. The observation that CIN cells fail to undergo mitotic arrest following spindle damage suggested that mutations in spindle checkpoint genes may account for CIN. However, here we show that CIN cells do undergo mitotic arrest in response to spindle damage. Although the maximum mitotic index achieved by CIN lines is diminished relative to MIN lines, CIN cells clearly have a robust spindle checkpoint. Consistently, mutations in spindle checkpoint genes are rare in human tumours. In contrast, the adenomatous polyposis coli (APC) gene is frequently mutated in CIN cells. Significantly, we show here that expression of an APC mutant in MIN cells reduces the mitotic index following spindle damage to a level observed in CIN cells, suggesting that APC dysfunction may contribute to CIN.

When T cells are activated, the expression of the CD95 ligand is elevated, with the purpose of inducing apoptosis in target cells and to later eliminate the activated T cells. We have shown previously that mitogen-activated protein kinase (MAPK or ERK) signaling suppresses CD95-mediated apoptosis in different cellular systems. In this study we examined whether MAPK signaling controls the persistence and CD95-mediated termination of an immune response in activated T cells. Our results show that activation of Jurkat T cells through the T cell receptor immediately suppresses CD95-mediated apoptosis, and that this suppression is mediated by MAPK activation. During the phase of elevated MAPK activity, the activation of caspase-8 and Bid is inhibited, whereas the assembly of a functional death-inducing signaling complex (DISC) is not affected. These results explain the resistance to CD95 responses observed during the early phase of T cell activation and suggest that MAPK-activation deflects DISC signaling from activating caspase-8 and Bid. The physiological relevance of the results was confirmed in activated primary peripheral T cells, in which inhibition of MAPK signaling markedly sensitized the cells to CD95-mediated apoptosis.

Nuclear morphological changes during apoptosis are very distinct and effector caspases have been implicated to play a central role in these processes. To investigate this in greater detail we examined the effect of blocking caspase activity and its activation on the nuclear morphological change in Jurkat T cells undergoing apoptosis after staurosporine treatment. In the presence of caspase inhibitors, like benzyloxycarbonyl-Val-Ala-Asp fluoro-methylketone (z-VAD-FMK), N-acetyl Tyr-Val-Ala-Asp chloromethylketone (Ac-YVAD-CMK) and benzyloxy-carbonyl-Asp-Glu-Val-Asp (OMe) fluoromethylketone (z-DEVD-FMK), staurosporine-treated Jurkat cells displayed a nuclear morphological change distinct from that of normal and apoptotic cells. This nuclear morphological change is an early event, characterised by convoluted nuclei with cavitations, and clumps of chromatin abutting to inner regions of the nuclear envelope between the nuclear pores. Both the nuclear envelope and endoplasmic reticulum were grossly dilated. This pre-apoptotic nuclear change precedes the externalisation of phosphatidylserine, chromatin condensation and DNA laddering, and can be dissociated from the formation of high molecular weight DNA fragments and cell shrinkage. Although cytochrome c efflux from the mitochondria and the processing of caspase-3 were observed in Jurkat cells with pre-apoptotic nuclear morphology, caspase-2, -6, -7 and -8 were not activated. In the presence of z-DEVD-FMK or Ac-YVAD-CMK, caspase-3 was processed to both the p17 and p20 fragments in staurosporine-treated cells, but only to p20 fragment in the presence of z-VAD-FMK. However, the caspase-3 substrate, poly(ADP ribose) polymerase was not cleaved in the presence of z-VAD-FMK, despite >70% of the cells have pre-apoptotic nuclei. In addition, caspase-3 null MCF-7 cells also undergo pre-apoptotic nuclear change when treated with staurosporine in the presence of caspase inhibitors, indicating that caspase-3 is not required for the early nuclear morphological change in cells undergoing apoptosis. Although cell death in staurosporine-treated Jurkat cells was markedly delayed, they eventually die without discernible downstream apoptotic features. Other apoptotic stimuli like etoposide and the heavy metal chelator, N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine also induced this nuclear morphological change in Jurkat cells in the presence of z-VAD-FMK. In summary, the effector caspases are not involved in early nuclear morphological change, which precedes the conventional hallmark morphological changes associated with chemical-induced apoptosis.

Body composition is altered in children with chronic renal failure (CRF) and contributes to the significant growth failure seen in these children. Recombinant human growth hormone (rhGH) has been used in the past several years to improve the somatic growth of children with CRF. To determine if the growth achieved in these children occurs concomitantly with body compositional changes, seven prepubertal (n=6) and pubertal (n=1) children with chronic renal insufficiency (n=4) and end-stage renal disease (n=3) underwent measurements of total body fat (FM), fat free mass (FFM), bone mineral density (BMD), total bone mineral mass (TBBM), total body water (TBW), and total body potassium (TBK) before and 6 months after initiation of subcutaneous recombinant human growth hormone (rhGH) at 0.35 mg/kg per week. The techniques used included dual-energy X-ray absorptiometry (for measurement of FM, BMD, and TBBM), total body potassium counting (for measurement of TBK), and deuterated water for assessment of TBW. Significant increases in both height and weight were seen following 6 months of rhGH therapy. These increases were accompanied by significant reductions in FM (4.4+/-1.4 kg vs. 3.6+/-1.2 kg, P=0.002) and percentage fat (18.6+/-3.9% vs. 14.5+/-3.4%, P=0.04), while FFM (17.9+/-3.0 kg vs. 20.7+/-3.6 kg, P=0.04) increased significantly as did TBBM (776+/-171 g vs. 844+/-177 g, P=0.001). Increases in TBK, a measure of body cell mass, were also seen. No difference in total BMD was observed. Thus, growth in CRF is occurring with repletion of the FFM and TBBM compartments. Despite these improvements, no change was observed in the body mass index (BMI). Measurement of BMI alone does not define the compartmental catabolic losses in FFM.

The caspases are known to play a pivotal role in the triggering and execution of apoptosis in virtually all cell types. Because inappropriate apoptosis is a prominent feature of many human diseases, the caspases are attractive targets for therapeutic intervention. In the present study we investigated whether Jurkat T lymphocytes rescued from Fas-induced cell death through the inhibition of caspases are functional. Here we show that the pan-caspase, tripeptide inhibitor, benzyloxycarbonyl-Val-Ala-Asp (Ome) fluoromethylketone (z-VAD-FMK), inhibited the activation of caspase-2, -3, -7, and -8, and subsequently apoptosis in Jurkat T lymphocytes induced by agonistic anti-Fas. The apoptotic signals induced by the cross-linking of the Fas antigen have a relatively long half-life, as z-VAD-FMK had to be continuously present in the culture medium for 72 h after Fas stimulation in order to maintain cell survival. After 72 h, the z-VAD-FMK-rescued cells proliferate normally and responded to activation induced cell death after phytohaemaglutinin treatment, and readily undergo apoptosis when restimulated with agonistic Fas antibodies. Taken together, our results demonstrate that Jurkat T cells rescued from Fas-mediated cell death through the inhibition of caspases are functional., (Copyright 2000 Academic Press.)

The Fas receptor (FasR) is an important physiological mediator of apoptosis in various tissues and cells. However, there are also many FasR-expressing cell types that are normally resistant to apoptotic signaling through this receptor. The mitogen-activated protein kinase (MAPK) signaling cascade has, apart from being a growth-stimulating factor, lately received attention as an inhibitory factor in apoptosis. In this study, we examined whether MAPK signaling could be involved in protecting FasR-insensitive cells. To this end, we used different approaches to inhibit MAPK signaling in HeLa cells, including treatment with the MAPK kinase inhibitor PD 98059, serum withdrawal, and expression of dominant-interfering MAPK kinase mutant protein. All of these treatments were effective in sensitizing the cells to FasR-induced apoptosis, demonstrating that MAPK indeed is involved in the control of FasR responses. The MAPK-mediated control seemed to occur at or upstream of caspase 8, the initiator caspase in apoptotic FasR responses. Transfection with the constitutively active MAPK kinase abrogated FasR-induced apoptosis also in the presence of cycloheximide, indicating that the MAPK-generated suppression of FasR-mediated apoptotic signaling is protein synthesis independent. In cells insensitive to FasR-induced apoptosis, stimulation of the FasR with an agonistic antibody resulted in significant MAPK activation, which was inhibited by PD 98059. When different cell types were compared, the FasR-mediated MAPK activation seemed proportional to the degree of FasR insensitivity. These results suggest that the FasR insensitivity is likely to be a consequence of FasR-induced MAPK activation, which in turn interferes with caspase activation.

The effects of Bcl-2 overexpression on several of its multifunctional characteristics, which include anti-apoptotic properties, impeding of cell proliferation, and telomerase activity, were examined in four Jurkat T cell clones overexpressing different levels of Bcl-2. When treated with anti-Fas or staurosporine, only three of the four clones showed resistance to apoptosis that correlated with the level of Bcl-2 expression. Surprisingly, the clone having no anti-apoptotic characteristic expressed the highest level of Bcl-2. When all the clones were treated with anti-Fas the processing of caspase-2, -3, and -7 but not -8 was inhibited in the resistant clones to a similar extent by the differential overexpression of Bcl-2. However, with staurosporine treatment the processing of all the caspases examined was inhibited to a similar degree by the different levels of Bcl-2 expression in the resistant clones. These results suggest that Bcl-2 blocked Fas-mediated cell death by acting downstream of caspase-8, which is in contrast to staurosporine-induced apoptosis where Bcl-2 is acting upstream of caspase-8. When the anti-proliferative effect of Bcl-2 was examined, a direct correlation between a decrease in cell proliferation and the level of Bcl-2 overexpressed in the clones was observed. The clone overexpressing the greatest amount of Bcl-2 protein, which had no resistance to apoptosis, had the slowest proliferative rate. This suggests that the anti-apoptotic effect of Bcl-2 can be separated from its anti-proliferative effect. The possible effect of overexpression of Bcl-2 on telomerase activity, which is known to control the proliferative capacity of normal cells and cellular senescence, was also determined. Our results suggest that Bcl-2 had no effect on telomerase activity or telomere length in the clones. In summary, our results further suggest that some properties of Bcl-2, such as anti-apoptotic and inhibition of cell proliferation, are individual features of a multifaceted protein., (Copyright 1999 Academic Press.)

In hepatocytes the DNA repair enzyme poly(ADP-ribose)polymerase (PARP) is not proteolytically cleaved during apoptosis. The reason for this was investigated using a cell-free system that consisted of isolated nuclei from hepatocytes or thymocytes and cytosolic extracts from hepatocytes or thymocytes undergoing apoptosis. It was found that liver PARP is resistant to proteolytic cleavage by the caspases present in the cytosolic extracts. Furthermore, liver PARP was not cleaved by recombinant human caspase-3. It is concluded that PARP proteolysis cannot be used as a marker for hepatocyte apoptosis., (Copyright 1999 Academic Press.)

The mechanism of Fas antigen-induced hepatocyte apoptosis was investigated. Using a monoclonal antibody directed against the Fas antigen, apoptosis was induced in freshly isolated murine hepatocytes within 90 minutes of antibody addition as assessed by plasma membrane bleb formation, chromatin condensation, and DNA fragmentation. Pretreatment of the cells with the caspase inhibitors, N-acetyl-Asp-Glu-Val-Asp aldehyde (Ac-DEVD-CHO), benzyloxycarbonyl-Val-Ala-DL-Asp-fluoromethylketone (Z-VAD-FMK), or Z-Asp-2,6-dichlorobenzoyloxymethylketone inhibited anti-Fas-mediated apoptosis. Likewise, the serine protease inhibitors, N-tosyl-L-phenyl chloromethyl ketone (TPCK) and 3,4-dichloroisocoumarin (DCI), prevented apoptosis, whereas N-tosyl-L-lysine chloromethyl ketone (TLCK), Ac-Leu-Leu-L-norleucinal, Ac-Leu-Leu-L-methional, and trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane were without effect. Examination of CED-3/caspase-3-related caspases revealed that pro-caspases-3 (CPP32) and -7 (Mch-3alpha) were rapidly processed after Fas antigen stimulation. Caspase-7 was further cleaved to form the catalytically active subunits. In contrast, the p17 subunit of caspase-3 was not detected, indicating slow formation or rapid degradation. The activation of CED-3-related caspases was further confirmed by an increase in the rate of Z-DEVD-7-amino-4-trifluoromethylcoumarin (Z-DEVD-AFC) hydrolysis that was sensitive to Ac-DEVD-CHO and was inhibited by pretreatment of the cells with TPCK but not by DCI. In contrast, no increase in the rates of hydrolysis of Z-YVAD-AFC, a substrate for caspase-1, was detected. Investigation of the in situ proteolytic cleavage of the CED-3 related caspases substrate, poly(ADP-ribose) polymerase, revealed that this protein was not degraded in hepatocytes undergoing Fas-mediated apoptosis. Taken together, our results show that processing of caspases, in particular, caspases-7 and -3, occurs during Fas-induced apoptosis of mouse hepatocytes and suggest a role of these proteases as well as serine protease(s) in the apoptotic response.