Synergistic antileukemic interactions between 17-AAG and UCN-01 involve interruption of RAF/MEK- and AKT-related pathways

Interactions between the protein kinase C (PKC) and Chk1 inhibitor UCN-01 and the heat shock protein 90 (Hsp90) antagonist 17-AAG have been examined in human leukemia cells in relation to effects on signal transduction pathways and apoptosis. Simultaneous exposure (30 hours) of U937 monocytic leukemia cells to minimally toxic concentrations of 17-AAG (eg, 400 nM) and UCN-01 (eg, 75 nM) triggered a pronounced increase in mitochondrial injury (ie, loss of mitochondrial membrane potential [Deltapsim]; cytosolic release of cytochrome c), caspase activation, and apoptosis. Synergistic induction of apoptosis was also observed in other human leukemia cell types (eg, Jurkat, NB4). Coexposure of human leukemia cells to 17-AAG and the PKC inhibitor bisindolylmaleimide (GFX) did not result in enhanced lethality, arguing against the possibility that the PKC inhibitory actions of UCN-01 are responsible for synergistic interactions. The enhanced cytotoxicity of this combination was associated with diminished Akt activation and marked down-regulation of Raf-1, MEK1/2, and mitogen-activated protein kinase (MAPK). Coadministration of 17-AAG and UCN-01 did not modify expression of Hsp90, Hsp27, phospho-JNK, or phospho-p38 MAPK, but was associated with further p34cdc2 dephosphorylation and diminished expression of Bcl-2, Mcl-1, and XIAP. In addition, inducible expression of both a constitutively active MEK1/2 or myristolated Akt construct, which overcame inhibition of ERK and Akt activation, respectively, significantly attenuated 17-AAG/UCN-01-mediated lethality. Together, these findings indicate that the Hsp90 antagonist 17-AAG potentiates UCN-01 cytotoxicity in a variety of human leukemia cell types and suggest that interference with both the Akt and Raf-1/MEK/MAP kinase cytoprotective signaling pathways contribute to this phenomenon.     

Carnitine deficiency and L-carnitine supplementation in lysinuric protein intolerance

The aim of the study was to investigate the prevalence and mechanisms of development of carnitine deficiency in patients with lysinuric protein intolerance (LPI). In our cohort of 37 Finnish patients with LPI, 8 (8-52 years of age) have been diagnosed with hypocarnitinemia. Their free and total serum carnitine levels, acyl carnitine profiles, renal function, diet, and medication were compared with the data from 8 age- and sex-matched patients with LPI not treated with carnitine supplementation. In patients with LPI, hypocarnitinemia was strongly associated with female sex, renal insufficiency, and the use of ammonia-scavenging drugs. Of the 8 hypocarnitinemic patients, 3 complained of muscle weakness, and their symptoms disappeared during carnitine supplementation. Oral lysine supplementation did not correct hypocarnitinemia in our patients. The patients with LPI are at considerable risk for carnitine deficiency. Supplementation of hypocarnitinemic LPI patients with oral L-carnitine improved serum total carnitine values, but the ratio of free and total carnitine remained subnormal in all supplemented patients except one. Furthermore, decreased ratio of free and total serum carnitine was common even in LPI patients with normal total serum carnitine concentration.     

Assessment of sleepiness,fatigue, and depression among Gulf Cooperation Council commercial airline pilots

Purpose

No studies have assessed the prevalence of fatigue, depression, sleepiness, and the risk of obstructive sleep apnea (OSA) among commercial airlines pilots in the Gulf Cooperation Council (GCC).

Methods

This was a quantitative cross­sectional study conducted among pilots who were on active duty and had flown during the past 6 months for one of three commercial airline companies. We included participants with age between 20 and 65 years. Data were collected using a predesigned electronic questionnaire composed of questions related to demographic information in addition to the Fatigue Severity Scale (FSS), the Berlin Questionnaire, the Epworth Sleepiness Scale (ESS), and the Hospital Anxiety and Depression Scale (HADS).

Results

The study included 328 pilots with a mean age ± standard deviation of 41.4 ± 9.7 years. Overall, 224 (68.3%) pilots had an FSS score ≥ 36 indicating severe fatigue and 221 (67.4%) reported making mistakes in the cockpit because of fatigue. One hundred and twelve (34.1%) pilots had an ESS score ≥ 10 indicating excessive daytime sleepiness and 148 (45.1%) reported falling asleep at the controls at least once without previously agreeing with their colleagues. One hundred and thirteen (34.5%) pilots had an abnormal HADS depression score (≥ 8), and 96 (29.3%) pilots were at high risk for OSA requiring further assessment.

Conclusion

Fatigue, sleepiness, risk of OSA, and depression are prevalent among GCC commercial airline pilots. Regular assessment by aviation authorities is needed to detect and treat these medical problems.

     

Influence of gender on early and one-year clinical outcomes after saphenous vein graft stenting

Compared with men, women may have a worse prognosis after native coronary revascularization. However, the influence of gender on clinical outcomes after saphenous vein graft (SVG) stenting is unknown. The purpose of this study was to compare early and 1-year clinical outcomes between men and women after stent implantation in SVG. A total of 1,199 consecutive patients with 1,858 SVG lesions were studied. Procedural success, in-hospital events, and late clinical outcomes were compared between men (n = 951) and women (n = 248). Overall procedural success was similar between men and women (97% vs 96%, p = NS). However, in-hospital (3.2% vs 1.6%, p = 0.07) and 30-day cumulative (4.4% vs 1.9%, p = 0.02) mortality rates were higher in women than in men. In addition, women had a higher incidence of vascular complications (12% vs 7.3%, p = 0.006) and postprocedural acute renal failure (8.1% vs 4%, p = 0.02). At 1-year follow-up, mortality was 13% in women and 11% in men (p = NS) and target lesion revascularization was 18% versus 23%, respectively (p = NS). By multivariate regression analysis, independent correlates of in-hospital mortality were female gender (odds ratio [OR] 3.6, confidence interval [CI] 1.0 to 12.5, p = 0.05) and left ventricular ejection fraction (OR 0.9, CI 0.9 to 1.0, p = 0.01). Female gender was found to predict 30-day mortality (OR 2.5, CI 1.1 to 5.5, p = 0.02). The sole predictor of 1-year mortality was diabetes mellitus (OR 1.6, CI 1.1 to 2.3, p = 0.01). This study shows that women compared with men treated with stent implantation in SVG lesions have (1) a trend toward higher in-hospital mortality, (2) higher risk of 30-day mortality, (3) increased incidence of vascular complications and postprocedure acute renal failure, and (4) similar 1-year clinical outcome.     

Activation of p38 mitogen-activated protein kinase contributes to the early cardiodepressant action of tumor necrosis factor.

OBJECTIVES: The purpose of this study was to determine whether p38 mitogen-activated protein kinase (p38-MAPK) contributes to tumor necrosis factor-alpha (TNFalpha)-induced contractile depression. BACKGROUND: Tumor necrosis factor has both beneficial and detrimental consequences that may result from the activation of different downstream pathways. Tumor necrosis factor activates p38-MAPK, a stress-responsive kinase implicated in contractile depression and cardiac injury. METHODS: In isolated hearts from mice lacking the p38-MAPK activator, MAPK kinase 3 (MKK3), perfused at constant coronary pressure or flow, we measured the left ventricular developed pressure (LVDP) and the relationship between end-diastolic volume and LVDP in the presence and absence of 10 ng/ml TNFalpha. RESULTS: Within 15 min at constant pressure, TNFalpha significantly reduced LVDP and coronary flow in outbred and mkk3(+/+) mice. This early negative inotropic effect was associated with a marked phosphorylation of both p38-MAPK and its indirect substrate, HSP27. In hearts lacking MKK3, TNFalpha failed to activate p38-MAPK or to cause significant contractile dysfunction. The actions of TNFalpha were similarly attenuated in MAPK-activated protein kinase 2 (MK2)-deficient hearts, which have a marked reduction in myocardial p38-MAPK protein content, and by the p38-MAPK catalytic site inhibitor SB203580 (1 micromol/l). Under conditions of constant coronary flow, the p38-MAPK activation and contractile depression induced by TNFalpha, though attenuated, remained sensitive to the absence of MKK3 or the presence of SB203580. The role of p38-MAPK in TNFalpha-induced contractile depression was confirmed in isolated murine cardiac myocytes exposed to SB203580 or lacking MKK3. CONCLUSIONS: Tumor necrosis factor activates p38-MAPK in the intact heart and in isolated cardiac myocytes through MKK3. This activation likely contributes to the early cardiodepressant action of TNFalpha.     

Intensive chemotherapy with mitoxantrone administered as a single injection in patients with high-risk acute myeloid leukemia: results of the EMA 2000 trial

Following a dose-escalation study performed to assess the maximally tolerated dose of high-dose mitoxantrone in a single injection combined with chemotherapy, a phase II trial (EMA 2000 regimen) was performed in patients with refractory or relapsed acute myelogenous leukemia (AML) between October 2000 and December 2003. Sixty-two patients entered the study and received mitoxantrone 45 mg/m² on day 1 in combination with cytarabine and etoposide. Overall, 39 patients (63%) achieved complete remission (CR). Four patients died during remission induction, and 19 patients had resistant disease. Median time to granulocyte and platelet recovery was 34 and 39 days, respectively. The predominant non-hematologic toxicity was infection, with 53% severe infections. Thirty-three of the 39 remitters received subsequent treatment consisting of maintenance chemotherapy courses in 17 patients, allogeneic stem cell transplantation (SCT) in 7 patients, and autologous SCT in 9 patients. The median overall survival of the entire cohort was 8.1 months, with 18% at 2.5 years. EMA chemotherapy using a single injection of mitoxantrone is effective in the treatment of high-risk AML. CR proportion was significantly higher in patients with a first CR duration 6 months when compared with those from a control trial using standard-dose mitoxantrone (90 vs 70%, p=0.03).     

Prevalence of, and risk factors for, hepatitis C virus infection among recent initiates to injecting in London and Glasgow: cross sectional analysis

Our aim was to compare the prevalence of antibody to hepatitis C virus (anti-HCV) among recently initiated injecting drug users (IDUs) in London and Glasgow, and to identify risk factors which could explain differences in prevalence between the cities. Complementary studies of community recruited IDUs who had initiated injection drug use since 1996 were conducted during 2001-2002. Data on HCV risk behaviours were gathered using structured questionnaires with identical core questions and respondents were asked to provide an oral fluid specimen which was tested anonymously for anti-HCV but was linked to the questionnaire. Sensitivities of the anti-HCV assays for oral fluid were 92-96%. Prevalence of anti-HCV was 35% (122/354) in London and 57% (207/366) in Glasgow (P < 0.001). Multifactorially, factors significantly associated with raised odds of anti-HCV positivity were increasing length of injecting career, daily injection, polydrug use, having had a needlestick injury, and having served a prison sentence. In addition lower odds of anti-HCV positivity were associated with non-injection use of crack cocaine and recruitment from drug agencies. After adjustment for these factors, the increased odds of anti-HCV associated with being a Glasgow IDU were diminished but remained significant. HCV continues to be transmitted among the IDU population of both cities at high rates despite the availability of syringe exchange and methadone maintenance. Effectiveness of harm reduction interventions may be compromised by inadequate coverage and failure to reduce sufficiently the frequency of sharing different types of injecting equipment, as well as the high background prevalence of HCV, and its high infectivity. Comprehensive action is urgently required to reduce the incidence of HCV among injectors.     

Helicobacter pylori-Associated Upper Gastrointestinal Disease in Saudi Arabia: A Pathologic Evaluation of 298 Endoscopic Biopsies from 201 Consecutive Patients

In a prospective study, histopathological examination 298 upper gastrointestinal (UGI) biopsies, obtained from 201 consecutive patients, was made. Patients were referred with mild to severe dyspeptic symptoms. The aim of the study was to compare the rate of identification of Helicobacter pylori (H. pylori) in the histologically normal gastric mucosa with that in histologically confirmed gastritis or peptic ulcer disease. The gastroduodenal mucosa was histologically normal in 35 patients (17.4%); among those patients, H. pylori was identified in only three (9%). Chronic gastritis was histologically confirmed in 162 patients (80.6%). H. pylori was identified in 123 (76%) of those patients. The difference was statistically significant (p less than 0.00001). Furthermore, when cases with a histological diagnosis of superficial chronic active gastritis (SCAG) are considered separately, the identification rate of H. pylori increases to 88% (121 of 137). When this rate is compared with that of 8% (two of 25), found in superficial chronic quiescent gastritis (SCQG), the difference is highly significant (p less than 0.00001). Of 38 endoscopically diagnosed peptic ulcers, H. pylori was identified in the gastric mucosa of 34 (89%). The organisms were always seen in the antral gastric mucosa, but never in duodenal mucosa. Identification of H. pylori correlates significantly with the histologic activity of chronic gastritis, in both peptic ulcer disease and non-ulcer dyspepsia.     

Three-dimensional transesophageal echocardiographic demonstration of innominate artery dissection

We describe an adult patient with type I aortic dissection in whom it was feasible to demonstrate the extension of the dissection into the innominate artery using color Doppler three-dimensional transesophageal echocardiography.