[Acute Dyspnea at Sea Due to Misjudgement of Pre-existing Medical Conditions]. / Akute Luftnot auf See durch Fehleinschätzung von Vorerkrankungen.

A guest on a cruise ship must be disembarked during the voyage due to a probable malignant pleural effusion recurring after puncture and draining part of the fluid. As in this case, patients are often advised by their general practitioners or specialists to take part in an already planned cruise, although complications of existing underlying diseases cannot always be well treated in the on-board hospital. The diagnostic and therapeutic possibilities in the on-board hospital are clearly limited in many aspects compared to hospitals ashore and disembarkation is not desirable everywhere.

Adrenergic and metabolic effects of electrical weapons: review and meta-analysis of human data.

INTRODUCTION: Electronic control with the CEW (conducted electrical weapon) has gained widespread acceptance as the preferred force option due to its significant injury reduction. However, a CEW application does stress the human body. In the case of the CEW, the human body response is similar to the challenge of physical exercise combined with emotional stress over a very short time interval. There has been concern whether the tension of the skeletal-muscle system together with the emotional stress of being exposed to the effects of a CEW, can lead to severe metabolic dysfunction. METHODS: A systematic and careful search of the MedLine database was performed to find publications describing pathophysiological effects of CEWs. Additional publications were collected through a manual search of reference lists in retrieved articles. After preliminary exclusions, we carefully reviewed the remaining publications and found 24 papers reporting prospective human clinical research data on adrenergic, ventilation, or metabolic effects. Where there were multiple studies on the same endpoints, we performed meta-analyses. RESULTS: A CEW exposure provides a clinically insignificant increase in heart rate (7.5 BPM) and a drop in both systolic and diastolic blood pressure. Alpha-amylase goes down but cortisol levels increase-both epinephrine and norepinephrine levels are increased by levels similar to mild exercise. A CEW exposure increases ventilation but does not appear to interfere with gas exchange. Lactate is increased slightly while the pH is decreased slightly with changes equivalent to mild exercise. The lactate and pH changes appear quickly and do not appear to be affected by increasing the exposure duration from 5 to 30 s. CONCLUSIONS: Thorough review and meta-analyses show that electrical weapon exposures have mixed and mild adrenergic effects. Ventilation is increased and there are metabolic changes similar to mild exercise.

Body size in relation to incidence of subtypes of haematological malignancy in the prospective Million Women Study.

BACKGROUND: Greater adiposity and height have been associated with increased risk of haematological malignancies. Associations for disease subtypes are uncertain. METHODS: A cohort of 1.3 million middle-aged U.K. women was recruited in 1996-2001 and followed for 10 years on average. Potential risk factors were assessed by questionnaire. Death, emigration, and incident cancer were ascertained by linkage to national registers. Adjusted relative risks were estimated by Cox regression. RESULTS: During follow-up, 9162 participants were diagnosed with lymphatic or haematopoietic cancers. Each 10 kg m(-2) increase in body mass index was associated with relative risk of 1.20 (95% confidence interval: 1.13-1.28) for lymphoid and 1.37 (1.22-1.53) for myeloid malignancy (P=0.06 for heterogeneity); similarly, Hodgkin lymphoma 1.64 (1.21-2.21), diffuse large B-cell lymphoma 1.36 (1.17-1.58), plasma cell neoplasms 1.21 (1.06-1.39), acute myeloid leukaemia 1.47 (1.19-1.81), and myeloproliferative/myelodysplastic syndromes 1.32 (1.15-1.52). Each 10 cm increase in height was associated with relative risk of 1.21 (1.16-1.27) for lymphoid and 1.11 (1.02-1.21) for myeloid malignancy (P=0.07 for heterogeneity); similarly, mature T-cell malignancies 1.36 (1.03-1.79), diffuse large B-cell lymphoma 1.28 (1.14-1.43), follicular lymphoma 1.28 (1.13-1.44), plasma cell neoplasms 1.12 (1.01-1.24), chronic lymphocytic leukaemia/small lymphocytic lymphoma 1.23 (1.08-1.40), and acute myeloid leukaemia 1.22 (1.04-1.42). There was no significant heterogeneity between subtypes. CONCLUSION: In middle-aged women, greater body mass index and height were associated with modestly increased risks of many subtypes of haematological malignancy.

Evidence for under-diagnosis of childhood acute lymphoblastic leukaemia in poorer communities within Great Britain.

BACKGROUND: Recorded incidence of childhood acute lymphoblastic leukaemia tends to be lower in poorer communities. A 'preemptive infection hypothesis' proposes that some children with leukaemia die from infection without diagnosis of leukaemia. Various different blood abnormalities can occur in untreated leukaemia. METHODS: Logistic regression was used to compare pre-treatment blood counts among children aged 1-13 years at recruitment to national clinical trials for acute lymphoblastic leukaemia during 1980-2002 (N=5601), grouped by address at diagnosis within Great Britain into quintiles of the 1991 Carstairs deprivation index. Children combining severe neutropenia (risk of serious infection) with relatively normal haemoglobin and platelet counts (lack of pallor and bleeding) were postulated to be at risk of dying from infection without leukaemia being suspected. A deficit of these children among diagnosed patients from poorer communities was predicted. RESULTS: As predicted, there was a deficit of children at risk of non-diagnosis (two-sided P(trend)=0.004; N=2009), and an excess of children with pallor (P(trend)=0.045; N=5535) and bleeding (P(trend)=0.036; N=5541), among cases from poorer communities. CONCLUSION: Under-diagnosis in poorer communities may have contributed to socioeconomic variation in recorded childhood acute lymphoblastic leukaemia incidence within Great Britain, and elsewhere. Implications for clinical practice and epidemiological studies should be considered.

Alcohol drinking, tobacco smoking and subtypes of haematological malignancy in the UK Million Women Study.

BACKGROUND: Previous research suggests associations of lower alcohol intake and higher tobacco consumption with increased risks of haematological malignancy. The prospective Million Women Study provides sufficient power for reliable estimates of subtype-specific associations in women. METHODS: Approximately 1.3 million middle-aged women were recruited in the United Kingdom during 1996-2001 and followed for death, emigration and cancer registration until 2009 (mean 10.3 years per woman); potential risk factors were assessed by questionnaire. Adjusted relative risks were estimated by Cox regression. RESULTS: During follow-up, 9162 incident cases of haematological malignancy were recorded, including 7047 lymphoid and 2072 myeloid cancers. Among predominantly moderate alcohol drinkers, higher intake was associated with lower risk of lymphoid malignancies, in particular diffuse large B-cell lymphoma (relative risk 0.85 per 10 g alcohol per day (95% confidence interval 0.75-0.96)), follicular lymphoma (0.86 (0.76-0.98)) and plasma cell neoplasms (0.86 (0.77-0.96)). Among never- and current smokers, higher cigarette consumption was associated with increased risk of Hodgkin lymphoma (1.45 per 10 cigarettes per day (1.22-1.72)), mature T-cell malignancies (1.38 (1.10-1.73)) and myeloproliferative/myelodysplastic disease (1.42 (1.31-1.55)). CONCLUSION: These findings confirm and extend existing evidence for associations of subtypes of haematological malignancy with two common exposures in women.

Effects of changes in diagnosis and registration on time trends in recorded childhood cancer incidence in Great Britain.

BACKGROUND: Increases in recorded childhood cancer incidence are widely reported, but do not necessarily represent real increases in risk. Time trends might conceal underlying steps caused by changes in diagnosis and registration procedures. METHODS: Using records from the National Registry of Childhood Tumours 1966-2005 (N=54650), the age-sex-standardised rate for residents of Great Britain aged under 15 years was calculated by individual year of diagnosis for each cancer subtype, and the average annual percentage change (trend) was assessed. The timing of assumed step changes in rate was estimated by iterative Poisson regression, and compared graphically with the approximate timing of innovations previously identified from published sources. RESULTS: Estimated timing of underlying steps approximately coincided with the following relevant innovations: biochemical assays, mid-1980s (hepatic and germ-cell cancer); diagnostic imaging, mid-1980s to early 1990s (intracranial/intraspinal tumours, neuroblastoma, soft-tissue sarcoma); revised cancer registration scheme, 1971 (leukaemia, bone and soft-tissue sarcoma); mandatory registration, 1993 (intracranial/intraspinal tumours, retinoblastoma, melanoma/carcinoma); cancer registration improvements, 2001 (leukaemia, renal and hepatic cancer). CONCLUSION: While the possibility of some real change in risk cannot be excluded, for many cancer subtypes the estimated timing of underlying step changes in rate appeared to correspond with changes in diagnosis or registration procedures. Childhood cancer may have been considerably under-recorded in the past.

Population survival from childhood cancer in Britain during 1978-2005 by eras of entry to clinical trials.

BACKGROUND: Inclusion in clinical trials is generally viewed as best practice for most newly diagnosed childhood cancers, but the impact on population-based survival has rarely been examined. PATIENTS AND METHODS: The population-based data were analysed for 25 853 children (66% of all registered childhood cancers) diagnosed in Britain during 1978-2005 with acute lymphoblastic leukaemia (ALL), acute myeloid leukaemia (AML), Hodgkin lymphoma, non-Hodgkin lymphoma, medulloblastoma, neuroblastoma, Wilms tumour, hepatoblastoma, osteosarcoma, Ewing sarcoma, rhabdomyosarcoma and germ-cell tumours. The Kaplan-Meier survival curves were compared by log-rank tests. Time trends were analysed by Cox regression. Separate analyses were done for children with ALL, medulloblastoma and neuroblastoma according to clinically relevant age thresholds. RESULTS: Survival increased significantly during 1978-2005 for every diagnostic category; the annual reduction in risk of death ranged from 2.7% (rhabdomyosarcoma) to 12.0% (gonadal germ-cell tumours). Survival increased steadily between trial eras for ALL (age 1-14 years) and neuroblastoma (age 1-14 years), but changed little since the mid-1980s for medulloblastoma (age 0-2 years), osteosarcoma or Ewing sarcoma. CONCLUSIONS: Changes in survival between trial eras parallel those reported by the relevant clinical trials. The increasing level of participation in trials, facilitated by the organisation of specialist care, has underpinned the substantial improvements in survival seen at the population level.

Childhood leukaemia and socioeconomic status in England and Wales 1976-2005: evidence of higher incidence in relatively affluent communities persists over time.

BACKGROUND: Record-based studies have generally reported association of higher childhood leukaemia incidence with higher socioeconomic status (SES), but recent findings are less consistent. METHODS: We examined records from the National Registry of Childhood Tumours for evidence of this association in England and Wales during 1976-2005. All eligible leukaemia registrations (N=11940) were grouped by year of diagnosis in decades centred on census years 1981, 1991 and 2001 (N=3748, 3922, 4270, respectively). Using data from the census appropriate to the decade, SES for each case was measured by the child-population-weighted quintile of the Carstairs deprivation index of the census ward containing the address at diagnosis. RESULTS: In each decade, the age-standardised leukaemia rate in the poorest quintile was ∼90% of the rate in the most affluent. Using Poisson regression, the age-adjusted rate ratio per quintile decrease in SES was 0.96 (95% confidence interval 0.94-0.98; P<0.001 for trend) in 1976-1985, 0.97 (0.95-0.99; P=0.008) in 1986-1995 and 0.97 (0.95-0.99; P=0.009) in 1996-2005. Similar association was evident for lymphoid leukaemia, the major subgroup (N=9588 in total), but not for acute myeloid (N=1868) or other/unspecified leukaemia (N=484). CONCLUSION: Reported childhood leukaemia incidence in England and Wales continues to be higher in relatively affluent communities. Possible explanations include under-diagnosis of leukaemia in children from poorer communities, and/or association of higher SES with hypothesised risk factors, such as population mixing and delayed exposure to infection.

Childhood cancer registration in Britain: capture-recapture estimates of completeness of ascertainment.

BACKGROUND: Completeness of ascertainment is a very important aspect of cancer registration. There is no recent published estimate for childhood cancer in Britain. METHODS: We estimated completeness of ascertainment by the National Registry of Childhood Tumours for cancer diagnosed under age 15 years in residents of Britain during 2003-04. Stratified two-source capture-recapture was applied to notifications from general cancer registries (CRs) and specialist clinicians. Variation in notification patterns was assessed by logistic regression. Results were verified by cross-checking with Hospital Episode Statistics for leukaemia patients from England born in 1998 and diagnosed before 2005. RESULTS: CRs notified 92-96% of registrations, and specialist clinicians 93%. Notification patterns varied slightly according to registry region, age at diagnosis, diagnostic group, socioeconomic status, and whether the patient had died. Irrespective of stratification by these factors, the overall completeness estimate was 99-100% (assuming independence of sources). Estimated completeness was at least 99% within all subgroups, except for one region (Thames 98-99%) and two small diagnostic groups (germ-cell and gonadal cancer 98-99%, melanoma and non-skin cancer 97-98%). INTERPRETATION: The independence assumption cannot be fully justified, as both sources used records from treatment centres. With this caveat, ascertainment of recently diagnosed childhood cancer in Britain appears to be virtually complete.

Risk factors and incidence of thromboembolic events (TEEs) in older men and women with breast cancer.

BACKGROUND: The purpose of this study is to evaluate the risk factors and the prevalence of thromboembolic events (TEEs) in breast cancer patients. PATIENTS AND METHODS: This is a retrospective cohort study using the Surveillance, Epidemiology, and End Results-Medicare database. Breast cancer patients diagnosed from 1992 to 2005 ≥66 years old were identified. International Classification of Diseases, Ninth Revision, and Healthcare Common Procedure Coding System codes were used to identify TEEs within 1 year of the breast cancer diagnosis. Analyses were conducted using descriptive statistics and logistic regression. RESULTS: A total of 89 841 patients were included, of them 2658 (2.96%) developed a TEE. In the multivariable analysis, males had higher risk of a TEE than women [odd ratio (OR) = 1.57; confidence interval (CI) 1.10-2.25] and blacks had higher risk than whites (OR = 1.20; CI 1.04-1.40). Compared with stage I patients, patients with stage II, III and IV had 22%, 39% and 98% increase, respectively, in risk. Placement of central catheters (OR = 2.71; CI 2.43-3.02), chemotherapy treatment (OR = 1.66; CI 1.48-1.86) or treatment with erythropoiesis-stimulating agents (ESAs) (OR = 1.33; CI 1.33-1.52) increase the risk. Other significant predictors included comorbidities, age, receptor status, marital status and year of diagnosis. Similar estimates were seen for pulmonary embolism, deep vein thromboembolism and other TEEs. CONCLUSIONS: In total, 2.96% of patients in this cohort developed a TEE within 1 year from breast cancer diagnosis. Stage, gender, race, use of chemotherapy and ESAs, comorbidities, receptor status and catheter placement were associated with the development of TEEs.

Childhood cancer and magnetic fields from high-voltage power lines in England and Wales: a case-control study.

BACKGROUND: Epidemiological evidence suggests that chronic low-intensity extremely-low-frequency magnetic-field exposure is associated with increased risk of childhood leukaemia; it is not certain the association is causal. METHODS: We report a national case-control study relating childhood cancer risk to the average magnetic field from high-voltage overhead power lines at the child's home address at birth during the year of birth, estimated using National Grid records. From the National Registry of Childhood Tumours, we obtained records of 28,968 children born in England and Wales during 1962-1995 and diagnosed in Britain under age 15. We selected controls from birth registers, matching individually by sex, period of birth, and birth registration district. No participation by cases or controls was required. RESULTS: The estimated relative risk for each 0.2 µT increase in magnetic field was 1.14 (95% confidence interval 0.57 to 2.32) for leukaemia, 0.80 (0.43-1.51) for CNS/brain tumours, and 1.34 (0.84-2.15) for other cancers. CONCLUSION: Although not statistically significant, the estimate for childhood leukaemia resembles results of comparable studies. Assuming causality, the estimated attributable risk is below one case per year. Magnetic-field exposure during the year of birth is unlikely to be the whole cause of the association with distance from overhead power lines that we previously reported.

Exogenous interferences with Jaffe creatinine assays: addition of sodium dodecyl sulfate to reagent eliminates bilirubin and total protein interference with Jaffe methods.

BACKGROUND: The study evaluated the impact of interferences on the analytical specificity of three commercial and commonly used creatinine methods (two Jaffe and one enzymatic). METHODS: Manufacturer creatinine methods plus modified methods were tested with the following interferences: spiking serum with bilirubin, albumin, glucose, hemoglobin and lipid, and patient sera with maximum concentrations of bilirubin, 1,090 micromol/l and protein, 117.8 g/l. RESULTS: Hemoglobin, 7.5 g/l and lipaemic with triglyceride concentration of 6.27 mmol/l, did not interfere with all assays. Glucose >33.3 mmol/l increased creatinine recovery for Dimension method. Samples spiked with bilirubin imparted a negative bias for Dimension and Architect methods but imparted a positive bias for Vitros assay. However, using patient sera, negative bias with bilirubin was found for all methods, from which Architect method gave the highest effect (R(2)=0.861), followed by Vitros (R(2)=0.239) and Dimension (R(2)=0.163). Protein provided the positive bias for all creatinine measurements that increased with increasing concentration (R(2) ranging from 0.104 to 0.182, P<0.0001). Addition of sodium dodecyl sulfate (SDS) in alkaline-picrate reagent reduced the effect of bilirubin and protein for kinetic Jaffe method. Although adding potassium ferricyanide was well effective for eliminating negative interference of bilirubin, it was prone to interference from protein. CONCLUSIONS: Endogenous interferences continue to plague creatinine accuracy measurement in both Jaffe and enzymatic methods, and consequentially the estimated glomerular filtration rate. The addition of SDS to the alkaline-pirate reagent was shown to be effective in reducing bilirubin and protein interferences.

How to use linear regression and correlation in quantitative method comparison studies.

Linear regression methods try to determine the best linear relationship between data points while correlation coefficients assess the association (as opposed to agreement) between the two methods. Linear regression and correlation play an important part in the interpretation of quantitative method comparison studies. Their major strength is that they are widely known and as a result both are employed in the vast majority of method comparison studies. While previously performed by hand, the availability of statistical packages means that regression analysis is usually performed by software packages including MS Excel, with or without the software programe Analyze-it as well as by other software packages. Such techniques need to be employed in a way that compares the agreement between the two methods examined and more importantly, because we are dealing with individual patients, whether the degree of agreement is clinically acceptable. Despite their use for many years, there is a lot of ignorance about the validity as well as the pros and cons of linear regression and correlation techniques. This review article describes the types of linear regression and regression (parametric and non-parametric methods) and the necessary general and specific requirements. The selection of the type of regression depends on where one has been trained, the tradition of the laboratory and the availability of adequate software.

Childhood leukaemia near British nuclear installations: methodological issues and recent results.

In 2008, the German Childhood Cancer Registry published the results of the Kinderkrebs in der Umgebung von Kernkraftwerken (KiKK) study of childhood cancer and leukaemia around German nuclear power stations. The positive findings appeared to conflict with the results of a recent British analysis carried out by the Committee on Medical Aspects of Radiation in the Environment (COMARE), published in 2005. The present paper first describes the COMARE study, which was based on data from the National Registry of Children's Tumours (NRCT); in particular, the methodology used in this study is described. Although the results of the COMARE study were negative for childhood leukaemia, this apparent discrepancy could be accounted for by a number of differences in approach, especially those relating to the distances from the power stations and the ages of the children studied. The present study was designed to match the KiKK study as far as possible. The incidence observed (18 cases within 5 km against 14.58 expected, p = 0.21) was not significantly raised. The risk estimate for proximity in the regression fitted was actually negative, though the confidence intervals involved are so wide that the difference from that reported in the KiKK study is only marginally statistically significant (p = 0.063).

von Willebrand factor binding to platelet GpIb initiates signals for platelet activation.

The hypothesis that von Willebrand factor (vWF) binding to platelet membrane glycoprotein Ib (GpIb) initiates intracellular pathways of platelet activation was studied. We measured the biochemical responses of intact human platelets treated with ristocetin plus vWF multimers purified from human cryoprecipitate. vWF plus ristocetin causes the breakdown of phosphatidylinositol 4,5-bisphosphate, the production of phosphatidic acid (PA), the activation of protein kinase C (PKC), increase of ionized cytoplasmic calcium ([Ca2+]i), and the synthesis of thromboxane A2. PA production, PKC activation, and the rise of [Ca2+]i stimulated by the ristocetin-induced binding of vWF multimers to platelets are inhibited by an anti-GpIb monoclonal antibody, but are unaffected by anti-GpIIb-IIIa monoclonal antibodies. Indomethacin also inhibits these responses without impairing platelet aggregation induced by vWF plus ristocetin. These results indicate that vWF binding to platelets initiates specific intraplatelet signaling pathways. The mechanism by which this occurs involves an arachidonic acid metabolite-dependent activation of phospholipase C after vWF binding to platelet membrane GpIb. This signal then causes PKC activation and increases of [Ca2+]i, which promote platelet secretion and potentiate aggregation.

Protease-activated receptor-induced Akt activation--regulation and possible function.

BACKGROUND: Thrombin induces the activation of the platelet serine/threonine kinase Akt. Akt activation is dependent on its phosphorylation at Thr308 and Ser473. The mechanism by which thrombin induces Akt phosphorylation is controversial, as is the role of Akt in platelet function. OBJECTIVES: To investigate how protease-activated receptors (PARs) stimulate Akt and the role that Akt plays in human platelet function. METHODS: Platelets were stimulated through PAR1 or PAR4. Specific inhibitors were used to evaluate, by Western blotting, signaling pathways regulating Akt phosphorylation, and the role of activated Akt was evaluated by aggregometry and flow cytometry. RESULTS: Phospholipase C (PLC) controls Akt phosphorylation elicited by PARs. Stimulation of PAR1 or PAR4 resulted in rapid Akt phosphorylation, independently of secreted ADP and phosphatidylinositol-3-kinase (PI3K) activation. Akt phosphorylation approximately 60 s after PAR1 stimulation became entirely dependent on the purinergic receptor P2Y(12) and the activation of PI3K. In contrast, PAR4 partially sustained Akt phosphorylation independently of P2Y(12) and PI3K for up to 300 s. Pharmacologic inhibition of Akt reduced P-selectin expression and fibrinogen binding in platelets stimulated through PAR1, and delayed platelet aggregation in response to submaximal PAR1 or PAR4 stimulation, although aggregation at 300 s was unaffected. CONCLUSIONS: Platelet PAR stimulation causes rapid Akt phosphorylation downstream of PLC, whereas with continuous stimulation, ADP and PI3K are required for maintaining Akt phosphorylation. Activated Akt regulates platelet function by modulating secretion and alpha(IIb)beta(3) activation.

Extended pharmacologic thromboprophylaxis in oncologic liver surgery is safe and effective.

Essentials The risk for venous thromboembolism after liver surgery remains high in the modern era. We evaluated the safety/efficacy of extended anticoagulation in liver surgery. This protocol reports zero venous thromboembolism events in 124 liver surgery patients. Extended anticoagulation after oncologic liver surgery is safe and effective. SUMMARY: Background The incidence of venous thromboembolism (VTE) after liver surgery remains high. Objective To evaluate the safety and efficacy of extended pharmacologic thromboprophylaxis after liver surgery for the prevention of VTE. Patient/Methods From August 2013 to April 2015, 124 patients who underwent liver resection for malignancy were placed on an extended pharmacologic thromboprophylaxis protocol. Intraoperative VTE prophylaxis included thromboembolic deterrent hoses and sequential compression devices. Once hemostasis had been ensured following hepatectomy, daily anticoagulant VTE prophylaxis was initiated for the duration of hospitalization. After hospital discharge, the large majority of patients (114, 91.9%) continued to receive anticoagulant thromboprophylaxis (enoxaparin) to complete a total course of 14 days after minor/minimally invasive hepatectomy or 28 days after major hepatectomy or a history of VTE. Results The cohort included 39 (31.2%) major hepatectomies and 38 (31.5%) minor/minimally invasive approaches. The intraoperative, postoperative and overall transfusion rates were 5.6%, 8.1%, and 10.5%, respectively. Pharmacologic thromboprophylaxis was started on postoperative day (POD) 0 for 40 (32.3%) patients and on POD 1 for 84 (67.7%) patients. During 90 days of follow-up, no postoperative symptomatic deep vein thrombosis or pulmonary embolic events were diagnosed. Standard-protocol computed tomography scans of the chest, abdomen and pelvis that were obtained for 112 (90.3%) study patients showed no pulmonary emboli, or other thoracic, splanchnic or ileofemoral vein thromboses. Two (1.6%) patients had minor bleeding events that resolved after discontinuation of enoxaparin, requiring neither blood transfusion nor reoperation. The severe complication rate was 5.6%, with no 90-day mortalities. Conclusions These preliminary data suggest that extended pharmacologic thromboprophylaxis for liver surgery patients is safe and effective.

The carboxy-terminus of I kappaB alpha determines susceptibility to degradation by the catalytic core of the proteasome.

The Rel/NF-kappaB family of transcription factors controls the expression of a wide variety of genes that are implicated in immune and inflammatory responses and cellular proliferation. Disregulation of NF-kappaB is associated with cellular transformation and the maintenance of a high anti-apoptotic threshold in transformed cells. NF-kappaB activity is in turn regulated by its sequestration in the cytoplasm by the inhibitor I kappaB. I kappaB alpha, the most abundant and well-characterized member of the I kappaB multiprotein family, is rapidly degraded in response to multiple physiologic stimuli. In the present study we show that not only the amino-terminus, but also the carboxy-terminus of I kappaB alpha contain transferable signals that must be simultaneously present in an unrelated protein to render it susceptible to activation-induced, proteasome-mediated degradation. We show here that I kappaB alpha amino-terminal modifications occur independently of the carboxy-terminus. Moreover, we present evidence indicating a critical role for the carboxy-terminal region in facilitating proteolysis by the catalytic core of the proteasome. When incubated with 20S proteasome extracted from rat liver, I kappaB alpha was quickly degraded while a deletion mutant lacking the carboxy-terminus was resistant to proteolysis. Likewise, chimeric proteins of beta-galactosidase with the I kappaB alpha carboxy-terminus were degraded in vitro independently of the presence of the I kappaB alpha amino-terminus, whereas chimeric proteins lacking the I kappaB alpha carboxy-terminus were stable. Our results identify the carboxy-terminus of I kappaB alpha as a domain critical for degradation through interaction with an as yet unidentified component of the proteasome.

Control of platelet protein kinase C activation by cyclic AMP.

Experiments were performed to elucidate the role of adenosine 3': 5'-cyclic monophosphate (cAMP) in the control of platelet protein kinase C (PKC) activation. Platelet aggregation and secretion in response to 4 beta-phorbol 12-myristate 13-acetate (PMA) or 1-oleoyl-2-acetylglycerol (OAG) were inhibited by dibutyryl cAMP in a dose-dependent manner. Inhibition of these functional activities paralleled a decrease in the PMA-induced phosphorylation of the Mr 47,000 substrate (p47) of PKC by pre-incubation of platelets with dibutyryl cAMP. These changes were also observed when platelet cAMP was increased by prostacyclin (PGI2), forskolin, or theophylline. The ADP scavenger creatine phosphate/creatine phosphokinase (CP/CPK) and the cyclooxygenase inhibitor indomethacin also diminished the aggregation and p47 phosphorylation responses to PMA or OAG. Pre-incubation of platelets with dibutyryl cAMP significantly potentiated the inhibition of aggregation and p47 phosphorylation effected by CP/CPK and indomethacin. These results are consistent with the model that PMA- or OAG-induced activation of platelets is amplified by secreted ADP and that the response to secreted ADP is inhibited by cAMP. Furthermore, the findings that increased intracellular cAMP inhibits PMA- or OAG-induced p47 phosphorylation in excess of that due solely to CP/CPK, and that cAMP significantly potentiates the effects of ADP removal and inhibition of cyclooxygenase in blocking p47 phosphorylation suggest that cAMP also exerts non-ADP-mediated inhibitory effects on PKC in intact platelets.