ACC/AHA and ESC/EACTS Guidelines for the Management of Valvular Heart Diseases: JACC Guideline Comparison

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.

The feasibility of a self-management programme (My Life After Stroke; MLAS) for stroke survivors

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.

Effectiveness of Stepped-Care Intervention in Overweight and Obese Patients With Medial Tibiofemoral Osteoarthritis: A Randomized Controlled Trial

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/m² 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.

Association between radiographic anterior cruciate ligament tear and joint symptoms: Data from the osteoarthritis initiative

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/m² ) 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.

Stepped care approach for medial tibiofemoral osteoarthritis (STrEAMline): protocol for a randomised controlled trial

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/m², 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.

Psychosis as a sequelae of paraneoplastic syndrome in Small- Cell Lung Carcinoma: A psycho-neuroendocrine interface

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.

Comparison in knee osteoarthritis joint damage patterns among individuals with an intact, complete and partial anterior cruciate ligament rupture

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.

Does Age Influence the Risk of Incident Knee Osteoarthritis After a Traumatic Anterior Cruciate Ligament Injury?

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.

The epidemiology of osteoarthritis

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.

The epidemiology of osteoarthritis

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.

Evidence for an association between compound heterozygosity for germ line mutations in the hemochromatosis (HFE) gene and increased risk of colorectal cancer

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.

Bub1 and aurora B cooperate to maintain BubR1-mediated inhibition of APC/CCdc20

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/CCdc20 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.

Truncating APC mutations have dominant effects on proliferation, spindle checkpoint control, survival and chromosome stability

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.

Bub1 is required for kinetochore localization of BubR1, Cenp-E, Cenp-F and Mad2, and chromosome congression

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.

Involvement of mitochondria in acetaminophen-induced apoptosis and hepatic injury: roles of cytochrome c, Bax, Bid, and caspases

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.

Aurora B couples chromosome alignment with anaphase by targeting BubR1, Mad2, and Cenp-E to kinetochores

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.

The effect of exposure to a commercial 2,4-D formulation during gestation on the immune response in CD-1 mice

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.

Aneuploid colon cancer cells have a robust spindle checkpoint

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.

MAPK/ERK signaling in activated T cells inhibits CD95/Fas-mediated apoptosis downstream of DISC assembly

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.

Effector caspases are dispensable for the early nuclear morphological changes during chemical-induced 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 &gt;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.

Changes in body composition of children with chronic renal failure on growth hormone

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.

Functional characterization of Jurkat T cells rescued from CD95/Fas-induced apoptosis through the inhibition of caspases

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.

Inhibition of mitogen-activated kinase signaling sensitizes HeLa cells to Fas receptor-mediated apoptosis

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.

Effects of differential overexpression of Bcl-2 on apoptosis, proliferation, and telomerase activity in Jurkat T cells

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.

Liver poly(ADP-ribose)polymerase is resistant to cleavage by caspases

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.

Fas-mediated apoptosis in mouse hepatocytes involves the processing and activation of caspases

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.

Adrenergic mechanisms in infection. III. alpha-and beta-receptor blocking agents in treatment

Raised epinephrine concentrations concentrations developed in the blood of mice near death after an intraperitoneal challenge with 10(9) Staphylococcus aureus or Escherichia coli. Both epinephrine levels were elevated in the urine near death. These challenges were infections and not intoxications, as they could be successfully treated with antibiotics. Using the same model infections, we studied the effect of alpha-and beta-receptor blocking agents and other adrenergically active compounds. The compounds alone were not toxic in the doses used. alpha-Blockers, such as phenoxybenzamine, dibenamine, and ergotamine and beta-blockers, such as butoxamine, timolol, and practolol, were ineffective. Phentolamine alone or propranolol alone showed some evidence of an ability to prolong life in S. aureus infections. Together they lengthened life significantly in S. aureus-challenged mice. In E. coli infections this beneficial effect was not noted. Mice pretreated with reserpine (7 mg/kg) and challenged with S. aureus lived 55% longer than saline-treated controls. Less benefit was noted in E. coli infections. Serontonin treatment was helpful in S. aureus infections and deleterious in E. coli infections.

Ethylene Oxide for Sterilizing Diets

The filter paper strips used in V. L. Johnson and J. S. Dunlap "Electrophoretic separation of hemoglobins from the chicken" [Science 122, 1186 (1955)] should be listed as follows: S. and S. No. 2043 B.